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SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Mon Apr 15 2024 Valid 161200Z - 171200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHEAST IOWA...NORTHERN MISSOURI...AND WEST-CENTRAL ILLINOIS... ...SUMMARY... Scattered severe thunderstorms are likely from Tuesday morning into the evening across a portion of the central states from the Corn Belt to the Ozark Plateau. The most concentrated area of significant severe hail and tornado potential is forecast over southern Iowa into northern Missouri and west-central Illinois. A more isolated severe threat is anticipated across portions of the Mid-Atlantic states. ...Synopsis... A robust upper-level low is evident in mid-morning water-vapor imagery over the Four Corners region. At the surface, pressure falls are ongoing as a lee cyclone begins to consolidate across the High Plains. Over the next 24-48 hours, this surface low is forecast to migrate east towards the MS River Valley, likely reaching northern IA by late afternoon/early evening as it begins to occlude. Thunderstorms will be focused within a preceding warm advection plume, along a leading outflow boundary associated with early-morning convection, and along a trailing cold front. The most intense convection is expected in the vicinity of the surface low along the northern fringe of the warm sector where strong synoptic ascent will overspread a buoyant air mass with favorable low-level wind shear; however, several mesoscale details that will likely determine the overall magnitude of the severe event will be dependent on the intensity/coverage of early-morning convection, which introduces uncertainty into the forecast. ...Corn Belt/Lower MO and Mid-MS Valleys... Latest guidance continues to show reasonably good agreement in the potential for ongoing showers and thunderstorms across eastern NE/KS at 12 UTC Tuesday morning. This activity should intensify through the morning across northern MO/central IA amid diurnal heating of a moist, and weakly capped warm sector. While somewhat modest mid-level lapse rates (6-7 C/km) will limit MLCAPE to around 1000 J/kg, strong veering flow in the lowest 2 km and 60-70 knot flow aloft may support early supercell development with an attendant tornado/wind threat. Low-level helicity will likely be maximized along the surface warm/occluding front across portions of western IL into IA, and recent CAMs continue to show a strong UH signal across this region. However, this potential will likely be modulated by two factors. The first is the degree of cloud cover/stratiform precipitation on the northern fringe of the warm sector - especially across MO/IA/IL, which may limit the degree of low-level destabilization. The second is storm coverage, which remains very uncertain given high spread in recent CAMs' depiction of convective evolution over the next 24 hours. Greater thunderstorm coverage than currently anticipated at 12 UTC may complicate convective mode later in the day, and the strong synoptic ascent in the vicinity of the surface low, coupled with weak capping, may favor higher convective coverage. If this occurs, northerly storm motions along the primary boundary may favor storm interactions/consolidation into one or more clusters/lines that may favor a severe wind risk over tornado/hail. Regardless, the overall synoptic regime and forecast environment support maintaining the current risk probabilities. The strong effective bulk shear values (60-70 knots) and effective SRH near 250 m2/s2 suggest that significant hail and/or significant tornadoes are possible if a predominantly discrete mode can be realized. Some solutions hint at re-development late afternoon along the cold front across northern MO/southern IA, but confidence in this scenario is low given the high dependence on rapid destabilization after preceding convection. ...OH Valley into the Mid-Atlantic... Isolated to scattered thunderstorms are expected to develop by late morning within a warm advection regime over the OH River Valley. While buoyancy will be somewhat meager (500-1000 J/kg MLCAPE), elongated deep-layer hodographs may support storm longevity as they meander southeast into the Appalachians/Mid-Atlantic region. Surface temperatures warming into the low to mid 80s will steepen low-level lapse rates to near 8 C/km, which may support a few damaging gusts with the stronger cells. ..Moore.. 04/15/2024 Read more

No watches are valid as of Mon Apr 15 17:31:02 UTC 2024.

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Apr 15 2024 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms are likely across parts of the Great Plains, beginning mainly this evening and continuing overnight. Several tornadoes, large to very large hail, and damaging wind gusts all appear possible. Strong tornadoes may occur this evening across parts of Kansas and Nebraska. Scattered severe gusts are probable this afternoon into the evening across portions of Virginia. ...Synopsis... Water-vapor imagery this morning shows a large, closed upper cyclone over UT with this feature ejecting over the southern/central Plains tonight. A strong mid/upper-level jet will overspread much of the southern/central Plains while a cyclone deepens over the High Plains today. Southerly low-level flow will facilitate moisture return northward concurrent with a warm front advancing northward across the central Great Plains. A dryline is forecast to mix eastward across the southern/central High Plains through peak afternoon heating, before retreating westward this evening across parts of the TX/OK Panhandles and western KS. ...Northern/Central Plains (Kansas/Nebraska/South Dakota)... No appreciable change in thinking from the previous forecast in the overall severe scenario for later today/tonight. Capping will likely inhibit storm initiation over the northern/central Plains through at least late afternoon. However, strong southerly low-level flow will advect increasingly rich moisture northward with upper 50s to low 60s surface dewpoints by early this evening across the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE is forecast concurrent with strengthening mid/upper-level flow. Once convective initiation occurs (early evening), rapid supercell development is expected as a LLJ intensifies. Large to very large hail (around 2-3 inches in diameter) will be a threat with any supercells that can form along/near the warm front, or southward along the length of the dryline into western KS. Enlarged hodographs during the evening will occur through midnight while some additional increase in low-level moisture acts to counter increasing CINH due to cooling surface temperatures. If a few discrete supercells can maintain a feed of effective near-surface inflow parcels, the tornado risk will likely become focused with those storms. Given the strength of shear/buoyancy combination, strong tornadoes appear possible this evening/tonight across portions of KS/NE. As additional storms develop, an evolving cluster growing upscale will potentially yield severe gusts, most likely from north-central KS into central NE overnight. ...Southern Plains (Oklahoma/Texas)... A lower coverage of storms is expected to develop farther south along the dryline over parts of the southern Great Plains late this afternoon into tonight. Ample mid to high-level clouds will tend to limit daytime heating to some extent along the length of the dryline. However, model guidance shows sufficient agreement in depicting storm development across parts of northwest TX by late this afternoon. Supercells appear likely with this activity given strong (50-60 kt) deep-layer shear and large buoyancy. Isolated large to very large hail will probably be the main threat with this convection as it moves towards north-central TX. But, occasional severe/damaging winds and perhaps a couple of tornadoes may also occur through the early evening. Most guidance indicates any supercells which develop will weaken with eastward extent as they encounter increasing MLCIN, and become increasingly displaced from the better large-scale ascent with the upper trough/low ejecting over the central Plains. A highly conditional severe threat remains apparent across OK late this afternoon and evening, with a favorable parameter space to support supercells capable of producing all severe hazards. But, much of OK may have a relative minimum in convective activity until late tonight as a Pacific cold front overtakes the dryline. ...Lower OH Valley into the Mid-Atlantic states... Morning surface mesoanalysis places a residual frontal zone draped over central IN/OH with a low-level moisture reservoir (low 60s deg F surface dewpoints) extending from the confluence of the MS/OH rivers northeastward into the lower Wabash Valley. Atop this moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will overspread the OH Valley eastward into VA today. The richer low-level moisture will likely remain west of the Appalachians across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast. Widely scattered thunderstorms are forecast to develop by mid afternoon within the moist axis along/south of a stalled front over the OH Valley. Effective shear 25-35 kt will support a mix of supercells and organized line segments capable of hail and wind. Farther east, steep lapse rates from the surface to 500 mb are depicted in forecast soundings by early to mid afternoon (8 deg C/km). Although PW will be lower across the Mid-Atlantic region, a more deeply mixed boundary layer is forecast with strong westerly mid-level flow (40 kt). Initial cellular storms will likely develop over the higher terrain with subsequent development across northern VA. A band of storms posing a risk for severe gusts (60-70 mph) and resultant wind damage is forecast. Given the lapse rate profile coupled with ample mid- to high-level flow and a linear mode, have increased wind probabilities and an upgrade to level 3 categorical outlook this update. The overall severe threat should gradually diminish through late evening with the loss of diurnal heating. ..Smith/Bentley.. 04/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Apr 15 2024 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms are likely across parts of the Great Plains, beginning mainly this evening and continuing overnight. Several tornadoes, large to very large hail, and damaging wind gusts all appear possible. Strong tornadoes may occur this evening across parts of Kansas and Nebraska. Scattered severe gusts are probable this afternoon into the evening across portions of Virginia. ...Synopsis... Water-vapor imagery this morning shows a large, closed upper cyclone over UT with this feature ejecting over the southern/central Plains tonight. A strong mid/upper-level jet will overspread much of the southern/central Plains while a cyclone deepens over the High Plains today. Southerly low-level flow will facilitate moisture return northward concurrent with a warm front advancing northward across the central Great Plains. A dryline is forecast to mix eastward across the southern/central High Plains through peak afternoon heating, before retreating westward this evening across parts of the TX/OK Panhandles and western KS. ...Northern/Central Plains (Kansas/Nebraska/South Dakota)... No appreciable change in thinking from the previous forecast in the overall severe scenario for later today/tonight. Capping will likely inhibit storm initiation over the northern/central Plains through at least late afternoon. However, strong southerly low-level flow will advect increasingly rich moisture northward with upper 50s to low 60s surface dewpoints by early this evening across the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE is forecast concurrent with strengthening mid/upper-level flow. Once convective initiation occurs (early evening), rapid supercell development is expected as a LLJ intensifies. Large to very large hail (around 2-3 inches in diameter) will be a threat with any supercells that can form along/near the warm front, or southward along the length of the dryline into western KS. Enlarged hodographs during the evening will occur through midnight while some additional increase in low-level moisture acts to counter increasing CINH due to cooling surface temperatures. If a few discrete supercells can maintain a feed of effective near-surface inflow parcels, the tornado risk will likely become focused with those storms. Given the strength of shear/buoyancy combination, strong tornadoes appear possible this evening/tonight across portions of KS/NE. As additional storms develop, an evolving cluster growing upscale will potentially yield severe gusts, most likely from north-central KS into central NE overnight. ...Southern Plains (Oklahoma/Texas)... A lower coverage of storms is expected to develop farther south along the dryline over parts of the southern Great Plains late this afternoon into tonight. Ample mid to high-level clouds will tend to limit daytime heating to some extent along the length of the dryline. However, model guidance shows sufficient agreement in depicting storm development across parts of northwest TX by late this afternoon. Supercells appear likely with this activity given strong (50-60 kt) deep-layer shear and large buoyancy. Isolated large to very large hail will probably be the main threat with this convection as it moves towards north-central TX. But, occasional severe/damaging winds and perhaps a couple of tornadoes may also occur through the early evening. Most guidance indicates any supercells which develop will weaken with eastward extent as they encounter increasing MLCIN, and become increasingly displaced from the better large-scale ascent with the upper trough/low ejecting over the central Plains. A highly conditional severe threat remains apparent across OK late this afternoon and evening, with a favorable parameter space to support supercells capable of producing all severe hazards. But, much of OK may have a relative minimum in convective activity until late tonight as a Pacific cold front overtakes the dryline. ...Lower OH Valley into the Mid-Atlantic states... Morning surface mesoanalysis places a residual frontal zone draped over central IN/OH with a low-level moisture reservoir (low 60s deg F surface dewpoints) extending from the confluence of the MS/OH rivers northeastward into the lower Wabash Valley. Atop this moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will overspread the OH Valley eastward into VA today. The richer low-level moisture will likely remain west of the Appalachians across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast. Widely scattered thunderstorms are forecast to develop by mid afternoon within the moist axis along/south of a stalled front over the OH Valley. Effective shear 25-35 kt will support a mix of supercells and organized line segments capable of hail and wind. Farther east, steep lapse rates from the surface to 500 mb are depicted in forecast soundings by early to mid afternoon (8 deg C/km). Although PW will be lower across the Mid-Atlantic region, a more deeply mixed boundary layer is forecast with strong westerly mid-level flow (40 kt). Initial cellular storms will likely develop over the higher terrain with subsequent development across northern VA. A band of storms posing a risk for severe gusts (60-70 mph) and resultant wind damage is forecast. Given the lapse rate profile coupled with ample mid- to high-level flow and a linear mode, have increased wind probabilities and an upgrade to level 3 categorical outlook this update. The overall severe threat should gradually diminish through late evening with the loss of diurnal heating. ..Smith/Bentley.. 04/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Apr 15 2024 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms are likely across parts of the Great Plains, beginning mainly this evening and continuing overnight. Several tornadoes, large to very large hail, and damaging wind gusts all appear possible. Strong tornadoes may occur this evening across parts of Kansas and Nebraska. Scattered severe gusts are probable this afternoon into the evening across portions of Virginia. ...Synopsis... Water-vapor imagery this morning shows a large, closed upper cyclone over UT with this feature ejecting over the southern/central Plains tonight. A strong mid/upper-level jet will overspread much of the southern/central Plains while a cyclone deepens over the High Plains today. Southerly low-level flow will facilitate moisture return northward concurrent with a warm front advancing northward across the central Great Plains. A dryline is forecast to mix eastward across the southern/central High Plains through peak afternoon heating, before retreating westward this evening across parts of the TX/OK Panhandles and western KS. ...Northern/Central Plains (Kansas/Nebraska/South Dakota)... No appreciable change in thinking from the previous forecast in the overall severe scenario for later today/tonight. Capping will likely inhibit storm initiation over the northern/central Plains through at least late afternoon. However, strong southerly low-level flow will advect increasingly rich moisture northward with upper 50s to low 60s surface dewpoints by early this evening across the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE is forecast concurrent with strengthening mid/upper-level flow. Once convective initiation occurs (early evening), rapid supercell development is expected as a LLJ intensifies. Large to very large hail (around 2-3 inches in diameter) will be a threat with any supercells that can form along/near the warm front, or southward along the length of the dryline into western KS. Enlarged hodographs during the evening will occur through midnight while some additional increase in low-level moisture acts to counter increasing CINH due to cooling surface temperatures. If a few discrete supercells can maintain a feed of effective near-surface inflow parcels, the tornado risk will likely become focused with those storms. Given the strength of shear/buoyancy combination, strong tornadoes appear possible this evening/tonight across portions of KS/NE. As additional storms develop, an evolving cluster growing upscale will potentially yield severe gusts, most likely from north-central KS into central NE overnight. ...Southern Plains (Oklahoma/Texas)... A lower coverage of storms is expected to develop farther south along the dryline over parts of the southern Great Plains late this afternoon into tonight. Ample mid to high-level clouds will tend to limit daytime heating to some extent along the length of the dryline. However, model guidance shows sufficient agreement in depicting storm development across parts of northwest TX by late this afternoon. Supercells appear likely with this activity given strong (50-60 kt) deep-layer shear and large buoyancy. Isolated large to very large hail will probably be the main threat with this convection as it moves towards north-central TX. But, occasional severe/damaging winds and perhaps a couple of tornadoes may also occur through the early evening. Most guidance indicates any supercells which develop will weaken with eastward extent as they encounter increasing MLCIN, and become increasingly displaced from the better large-scale ascent with the upper trough/low ejecting over the central Plains. A highly conditional severe threat remains apparent across OK late this afternoon and evening, with a favorable parameter space to support supercells capable of producing all severe hazards. But, much of OK may have a relative minimum in convective activity until late tonight as a Pacific cold front overtakes the dryline. ...Lower OH Valley into the Mid-Atlantic states... Morning surface mesoanalysis places a residual frontal zone draped over central IN/OH with a low-level moisture reservoir (low 60s deg F surface dewpoints) extending from the confluence of the MS/OH rivers northeastward into the lower Wabash Valley. Atop this moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will overspread the OH Valley eastward into VA today. The richer low-level moisture will likely remain west of the Appalachians across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast. Widely scattered thunderstorms are forecast to develop by mid afternoon within the moist axis along/south of a stalled front over the OH Valley. Effective shear 25-35 kt will support a mix of supercells and organized line segments capable of hail and wind. Farther east, steep lapse rates from the surface to 500 mb are depicted in forecast soundings by early to mid afternoon (8 deg C/km). Although PW will be lower across the Mid-Atlantic region, a more deeply mixed boundary layer is forecast with strong westerly mid-level flow (40 kt). Initial cellular storms will likely develop over the higher terrain with subsequent development across northern VA. A band of storms posing a risk for severe gusts (60-70 mph) and resultant wind damage is forecast. Given the lapse rate profile coupled with ample mid- to high-level flow and a linear mode, have increased wind probabilities and an upgrade to level 3 categorical outlook this update. The overall severe threat should gradually diminish through late evening with the loss of diurnal heating. ..Smith/Bentley.. 04/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Apr 15 2024 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms are likely across parts of the Great Plains, beginning mainly this evening and continuing overnight. Several tornadoes, large to very large hail, and damaging wind gusts all appear possible. Strong tornadoes may occur this evening across parts of Kansas and Nebraska. Scattered severe gusts are probable this afternoon into the evening across portions of Virginia. ...Synopsis... Water-vapor imagery this morning shows a large, closed upper cyclone over UT with this feature ejecting over the southern/central Plains tonight. A strong mid/upper-level jet will overspread much of the southern/central Plains while a cyclone deepens over the High Plains today. Southerly low-level flow will facilitate moisture return northward concurrent with a warm front advancing northward across the central Great Plains. A dryline is forecast to mix eastward across the southern/central High Plains through peak afternoon heating, before retreating westward this evening across parts of the TX/OK Panhandles and western KS. ...Northern/Central Plains (Kansas/Nebraska/South Dakota)... No appreciable change in thinking from the previous forecast in the overall severe scenario for later today/tonight. Capping will likely inhibit storm initiation over the northern/central Plains through at least late afternoon. However, strong southerly low-level flow will advect increasingly rich moisture northward with upper 50s to low 60s surface dewpoints by early this evening across the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE is forecast concurrent with strengthening mid/upper-level flow. Once convective initiation occurs (early evening), rapid supercell development is expected as a LLJ intensifies. Large to very large hail (around 2-3 inches in diameter) will be a threat with any supercells that can form along/near the warm front, or southward along the length of the dryline into western KS. Enlarged hodographs during the evening will occur through midnight while some additional increase in low-level moisture acts to counter increasing CINH due to cooling surface temperatures. If a few discrete supercells can maintain a feed of effective near-surface inflow parcels, the tornado risk will likely become focused with those storms. Given the strength of shear/buoyancy combination, strong tornadoes appear possible this evening/tonight across portions of KS/NE. As additional storms develop, an evolving cluster growing upscale will potentially yield severe gusts, most likely from north-central KS into central NE overnight. ...Southern Plains (Oklahoma/Texas)... A lower coverage of storms is expected to develop farther south along the dryline over parts of the southern Great Plains late this afternoon into tonight. Ample mid to high-level clouds will tend to limit daytime heating to some extent along the length of the dryline. However, model guidance shows sufficient agreement in depicting storm development across parts of northwest TX by late this afternoon. Supercells appear likely with this activity given strong (50-60 kt) deep-layer shear and large buoyancy. Isolated large to very large hail will probably be the main threat with this convection as it moves towards north-central TX. But, occasional severe/damaging winds and perhaps a couple of tornadoes may also occur through the early evening. Most guidance indicates any supercells which develop will weaken with eastward extent as they encounter increasing MLCIN, and become increasingly displaced from the better large-scale ascent with the upper trough/low ejecting over the central Plains. A highly conditional severe threat remains apparent across OK late this afternoon and evening, with a favorable parameter space to support supercells capable of producing all severe hazards. But, much of OK may have a relative minimum in convective activity until late tonight as a Pacific cold front overtakes the dryline. ...Lower OH Valley into the Mid-Atlantic states... Morning surface mesoanalysis places a residual frontal zone draped over central IN/OH with a low-level moisture reservoir (low 60s deg F surface dewpoints) extending from the confluence of the MS/OH rivers northeastward into the lower Wabash Valley. Atop this moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will overspread the OH Valley eastward into VA today. The richer low-level moisture will likely remain west of the Appalachians across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast. Widely scattered thunderstorms are forecast to develop by mid afternoon within the moist axis along/south of a stalled front over the OH Valley. Effective shear 25-35 kt will support a mix of supercells and organized line segments capable of hail and wind. Farther east, steep lapse rates from the surface to 500 mb are depicted in forecast soundings by early to mid afternoon (8 deg C/km). Although PW will be lower across the Mid-Atlantic region, a more deeply mixed boundary layer is forecast with strong westerly mid-level flow (40 kt). Initial cellular storms will likely develop over the higher terrain with subsequent development across northern VA. A band of storms posing a risk for severe gusts (60-70 mph) and resultant wind damage is forecast. Given the lapse rate profile coupled with ample mid- to high-level flow and a linear mode, have increased wind probabilities and an upgrade to level 3 categorical outlook this update. The overall severe threat should gradually diminish through late evening with the loss of diurnal heating. ..Smith/Bentley.. 04/15/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Apr 15 2024 Valid 151630Z - 161200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GREAT PLAINS AND CENTRAL AND EASTERN VIRGINIA... ...SUMMARY... Scattered severe thunderstorms are likely across parts of the Great Plains, beginning mainly this evening and continuing overnight. Several tornadoes, large to very large hail, and damaging wind gusts all appear possible. Strong tornadoes may occur this evening across parts of Kansas and Nebraska. Scattered severe gusts are probable this afternoon into the evening across portions of Virginia. ...Synopsis... Water-vapor imagery this morning shows a large, closed upper cyclone over UT with this feature ejecting over the southern/central Plains tonight. A strong mid/upper-level jet will overspread much of the southern/central Plains while a cyclone deepens over the High Plains today. Southerly low-level flow will facilitate moisture return northward concurrent with a warm front advancing northward across the central Great Plains. A dryline is forecast to mix eastward across the southern/central High Plains through peak afternoon heating, before retreating westward this evening across parts of the TX/OK Panhandles and western KS. ...Northern/Central Plains (Kansas/Nebraska/South Dakota)... No appreciable change in thinking from the previous forecast in the overall severe scenario for later today/tonight. Capping will likely inhibit storm initiation over the northern/central Plains through at least late afternoon. However, strong southerly low-level flow will advect increasingly rich moisture northward with upper 50s to low 60s surface dewpoints by early this evening across the warm sector. Prior to storm initiation, 2000-3000 J/kg MLCAPE is forecast concurrent with strengthening mid/upper-level flow. Once convective initiation occurs (early evening), rapid supercell development is expected as a LLJ intensifies. Large to very large hail (around 2-3 inches in diameter) will be a threat with any supercells that can form along/near the warm front, or southward along the length of the dryline into western KS. Enlarged hodographs during the evening will occur through midnight while some additional increase in low-level moisture acts to counter increasing CINH due to cooling surface temperatures. If a few discrete supercells can maintain a feed of effective near-surface inflow parcels, the tornado risk will likely become focused with those storms. Given the strength of shear/buoyancy combination, strong tornadoes appear possible this evening/tonight across portions of KS/NE. As additional storms develop, an evolving cluster growing upscale will potentially yield severe gusts, most likely from north-central KS into central NE overnight. ...Southern Plains (Oklahoma/Texas)... A lower coverage of storms is expected to develop farther south along the dryline over parts of the southern Great Plains late this afternoon into tonight. Ample mid to high-level clouds will tend to limit daytime heating to some extent along the length of the dryline. However, model guidance shows sufficient agreement in depicting storm development across parts of northwest TX by late this afternoon. Supercells appear likely with this activity given strong (50-60 kt) deep-layer shear and large buoyancy. Isolated large to very large hail will probably be the main threat with this convection as it moves towards north-central TX. But, occasional severe/damaging winds and perhaps a couple of tornadoes may also occur through the early evening. Most guidance indicates any supercells which develop will weaken with eastward extent as they encounter increasing MLCIN, and become increasingly displaced from the better large-scale ascent with the upper trough/low ejecting over the central Plains. A highly conditional severe threat remains apparent across OK late this afternoon and evening, with a favorable parameter space to support supercells capable of producing all severe hazards. But, much of OK may have a relative minimum in convective activity until late tonight as a Pacific cold front overtakes the dryline. ...Lower OH Valley into the Mid-Atlantic states... Morning surface mesoanalysis places a residual frontal zone draped over central IN/OH with a low-level moisture reservoir (low 60s deg F surface dewpoints) extending from the confluence of the MS/OH rivers northeastward into the lower Wabash Valley. Atop this moisture, a plume of steep 700-500 mb lapse rates (8.0 to 8.3 deg C/km) sampled at the Lincoln, IL and Wilmington, OH raob sites, will overspread the OH Valley eastward into VA today. The richer low-level moisture will likely remain west of the Appalachians across the lower OH Valley where 1500-2500 J/kg MLCAPE is forecast. Widely scattered thunderstorms are forecast to develop by mid afternoon within the moist axis along/south of a stalled front over the OH Valley. Effective shear 25-35 kt will support a mix of supercells and organized line segments capable of hail and wind. Farther east, steep lapse rates from the surface to 500 mb are depicted in forecast soundings by early to mid afternoon (8 deg C/km). Although PW will be lower across the Mid-Atlantic region, a more deeply mixed boundary layer is forecast with strong westerly mid-level flow (40 kt). Initial cellular storms will likely develop over the higher terrain with subsequent development across northern VA. A band of storms posing a risk for severe gusts (60-70 mph) and resultant wind damage is forecast. Given the lapse rate profile coupled with ample mid- to high-level flow and a linear mode, have increased wind probabilities and an upgrade to level 3 categorical outlook this update. The overall severe threat should gradually diminish through late evening with the loss of diurnal heating. ..Smith/Bentley.. 04/15/2024 Read more