Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1032 AM CDT Fri Apr 12 2024 Valid 121700Z - 131200Z No changes to the ongoing forecast. ..Wendt.. 04/12/2024 .PREV DISCUSSION... /ISSUED 0200 AM CDT Fri Apr 12 2024/ ...Synopsis... In the wake of the upper-level cyclone departing to the east, transient ridging aloft will give way to increasingly strong southwest flow over the southern Rockies. An embedded perturbation passing overhead will aid in deepening a lee trough over parts of the southern High Plains Friday. Downslope surface winds are forecast to increase through afternoon over part of eastern NM and southeastern CO. Dry southerly return flow is also possible across parts of the TX Rio Grande Valley. The gusty winds and low humidity will likely support elevated to locally critical fire-weather conditions. ...Northeast New Mexico and southern Colorado... As flow aloft begins to strengthen ahead of the approaching shortwave trough, a deepening lee trough will bolster westerly surface flow over northeastern NM and southern CO. Dry downslope trajectories and daytime heating should support widespread minimum RH values of 10-15%. Overlapping with sustained surface winds of 15-25 mph, and dry fuels devoid of recent rainfall, several hours of elevated to locally critical fire-weather conditions are likely over parts of NM and southern CO. ...Texas Rio Grande Valley... To the east of the deepening lee trough, southerly winds are forest to increase through much of the day with the approach of the upper-level shortwave trough. With limited surface moisture in place behind the previous frontal passage, dry return flow is expected over parts of South TX and the central Rio Grande Valley. Periodic surface wind gusts of 15-20 mph and diurnal RH minimums of 15-20% may support a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1032 AM CDT Fri Apr 12 2024 Valid 121700Z - 131200Z No changes to the ongoing forecast. ..Wendt.. 04/12/2024 .PREV DISCUSSION... /ISSUED 0200 AM CDT Fri Apr 12 2024/ ...Synopsis... In the wake of the upper-level cyclone departing to the east, transient ridging aloft will give way to increasingly strong southwest flow over the southern Rockies. An embedded perturbation passing overhead will aid in deepening a lee trough over parts of the southern High Plains Friday. Downslope surface winds are forecast to increase through afternoon over part of eastern NM and southeastern CO. Dry southerly return flow is also possible across parts of the TX Rio Grande Valley. The gusty winds and low humidity will likely support elevated to locally critical fire-weather conditions. ...Northeast New Mexico and southern Colorado... As flow aloft begins to strengthen ahead of the approaching shortwave trough, a deepening lee trough will bolster westerly surface flow over northeastern NM and southern CO. Dry downslope trajectories and daytime heating should support widespread minimum RH values of 10-15%. Overlapping with sustained surface winds of 15-25 mph, and dry fuels devoid of recent rainfall, several hours of elevated to locally critical fire-weather conditions are likely over parts of NM and southern CO. ...Texas Rio Grande Valley... To the east of the deepening lee trough, southerly winds are forest to increase through much of the day with the approach of the upper-level shortwave trough. With limited surface moisture in place behind the previous frontal passage, dry return flow is expected over parts of South TX and the central Rio Grande Valley. Periodic surface wind gusts of 15-20 mph and diurnal RH minimums of 15-20% may support a few hours of elevated fire-weather conditions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0748 AM CDT Fri Apr 12 2024 Valid 121300Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NEVADA...EASTERN OREGON...IDAHO...AND FAR WESTERN MONTANA... ...SUMMARY... Isolated severe wind gusts and hail may occur with thunderstorms over northern Nevada, eastern Oregon, Idaho, and far western Montana late this afternoon and early evening. ...Northern Nevada into Eastern Oregon, Idaho, and Far Western Montana... An upper low over the eastern Pacific will dig southward towards the northern/central CA Coast through tonight, with a belt of moderately enhanced flow extending over parts of the Northwest. Low-level moisture across the northern Great Basin into the northern Rockies is expected to remain quite meager, with PW values generally around 0.7 inch or less. Even so, daytime heating should encourage a very well-mixed boundary layer to develop by later this afternoon as a surface low consolidates over northern NV. Isolated to scattered thunderstorms should develop this afternoon from parts of northern NV and eastern OR into ID and eventually western MT. With up to 500 J/kg of MLCAPE present amid sufficient deep-layer for some updraft organization, some of this activity could become strong to severe. Isolated severe wind gusts may occur with any convective downdrafts, as low/mid-level lapse rates will likely be quite steep. Occasional hail also appears possible with the more robust cores. Convection should weaken this evening with eastward extent into ID/western MT with the loss of daytime heating. ...Ohio Valley into the Mid-Atlantic and Northeast... Low-topped thunderstorms should develop along a cold front this morning into the afternoon across parts of the Northeast. Poor lapse rates, weak buoyancy, and generally meridional flow at low/mid levels across eastern NY into parts of southern New England will likely hinder an organized severe threat from developing. A separate area of convection may develop this afternoon across parts of the OH Valley into the central Appalachians and perhaps Carolinas. This activity will be tied to cold mid-level temperatures associated with a shortwave trough embedded within a broad upper trough/low over the eastern CONUS. With generally west-northwesterly flow behind a front, instability should remain very weak. Still, enhanced low-level winds may reach the surface with a well-mixed boundary layer, and occasional strong/gusty winds could occur this afternoon. ..Gleason/Grams.. 04/12/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CDT Fri Apr 12 2024 Valid 151200Z - 201200Z ...DISCUSSION... ...Significant severe weather possible late afternoon Monday through Tuesday evening across the central states... Latest ensemble and deterministic guidance continues an overall slower trend with the evolution of an amplifying shortwave trough expected to be over parts of the Southwest early Monday. As it crosses the southern Rockies into the central Great Plains by midday Tuesday, the tropospheric flow field will amplify Monday night through Tuesday morning. Substantial lee cyclogenesis will occur over the central High Plains by Monday afternoon, and this cyclone should track into the Mid-MO Valley vicinity by Tuesday afternoon before occluding over the Upper MS Valley late Tuesday. This overall slower trend results in expansion of severe probabilities west-southwestward on D5. Low-level moisture modification from the northwest Gulf, while sufficient for severe storms, does not appear to be overly rich. As such, the more westward initiation of convection during the late afternoon to early evening Monday may be within a more deeply mixed environment across parts of the dryline. Still, there is consensus that a plume of low to mid 60s surface dew points should be advected ahead of the dryline across much of western OK into western north TX. More widespread convective development will occur during the evening to overnight time frame, especially as the Pacific cold front overtakes the dryline and surges east from parts of KS southward. With this coinciding with the period of tropospheric flow amplification, it is plausible an extensive convective band is maintained east-northeast into early Tuesday. Whether this outpaces the relatively confined warm-moist sector and weakens, or is maintained through the end of D4 is unclear. This will have profound implications on the degree of daytime destabilization downstream over parts of the Corn Belt to the south-central states. With slower timing, and if convection can adequately weaken, a conditionally more favorable tornado threat may occur on Tuesday over the Mid-MS Valley vicinity. Otherwise, should convection continue east-northeast, greater buoyancy may largely be confined south across the Ark-La-Tex into the Mid-South. As such, will defer to later outlooks for a potential 30 percent area on D5-Tuesday. Severe probabilities appear too low in D6-8 to warrant consideration of highlights as predictability wanes. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Fri Apr 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PA TO EAST IN... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday, mainly from late afternoon into the evening, across Pennsylvania to eastern Indiana. ...PA to eastern IN... A mid-level jetlet attendant to a low-amplitude shortwave impulse should progress across the northern Great Lakes and Ontario into New England by Sunday evening. To its south-southwest, a pronounced elevated mixed layer across the Midwest and southern Great Lakes will shift southeastward into the Mid-Atlantic and Southeast States. This elevated mixed layer will likely cap surface-based convection until peak heating along a southeast-sagging cold front. 00Z NAM soundings appear relatively reasonable with this evolution as modified low-level moisture return emanating from the southern Great Plains struggles to reduce MLCIN until cooling aloft spreads in from the west-northwest. MLCAPE should eventually reach 500-1000 J/kg over IN/OH, with progressively weaker values over PA. Hodographs across the region should be dominated by low-level curvature enlargement, with little speed or directional shear component above that within the buoyancy layer. Seemingly, a west/east-oriented cluster along the front should develop by late afternoon to early evening and move south with the undercutting front, while embedded cells attempt to parallel the deep-layer west-northwesterly flow regime. This setup appears to favor low probabilities across each of the hazards into Sunday evening. The western extent of the threat into IN will likely be modulated by progressively greater MLCIN that may not be eliminated prior to frontal passage. ..Grams.. 04/12/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Fri Apr 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PA TO EAST IN... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday, mainly from late afternoon into the evening, across Pennsylvania to eastern Indiana. ...PA to eastern IN... A mid-level jetlet attendant to a low-amplitude shortwave impulse should progress across the northern Great Lakes and Ontario into New England by Sunday evening. To its south-southwest, a pronounced elevated mixed layer across the Midwest and southern Great Lakes will shift southeastward into the Mid-Atlantic and Southeast States. This elevated mixed layer will likely cap surface-based convection until peak heating along a southeast-sagging cold front. 00Z NAM soundings appear relatively reasonable with this evolution as modified low-level moisture return emanating from the southern Great Plains struggles to reduce MLCIN until cooling aloft spreads in from the west-northwest. MLCAPE should eventually reach 500-1000 J/kg over IN/OH, with progressively weaker values over PA. Hodographs across the region should be dominated by low-level curvature enlargement, with little speed or directional shear component above that within the buoyancy layer. Seemingly, a west/east-oriented cluster along the front should develop by late afternoon to early evening and move south with the undercutting front, while embedded cells attempt to parallel the deep-layer west-northwesterly flow regime. This setup appears to favor low probabilities across each of the hazards into Sunday evening. The western extent of the threat into IN will likely be modulated by progressively greater MLCIN that may not be eliminated prior to frontal passage. ..Grams.. 04/12/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Fri Apr 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PA TO EAST IN... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday, mainly from late afternoon into the evening, across Pennsylvania to eastern Indiana. ...PA to eastern IN... A mid-level jetlet attendant to a low-amplitude shortwave impulse should progress across the northern Great Lakes and Ontario into New England by Sunday evening. To its south-southwest, a pronounced elevated mixed layer across the Midwest and southern Great Lakes will shift southeastward into the Mid-Atlantic and Southeast States. This elevated mixed layer will likely cap surface-based convection until peak heating along a southeast-sagging cold front. 00Z NAM soundings appear relatively reasonable with this evolution as modified low-level moisture return emanating from the southern Great Plains struggles to reduce MLCIN until cooling aloft spreads in from the west-northwest. MLCAPE should eventually reach 500-1000 J/kg over IN/OH, with progressively weaker values over PA. Hodographs across the region should be dominated by low-level curvature enlargement, with little speed or directional shear component above that within the buoyancy layer. Seemingly, a west/east-oriented cluster along the front should develop by late afternoon to early evening and move south with the undercutting front, while embedded cells attempt to parallel the deep-layer west-northwesterly flow regime. This setup appears to favor low probabilities across each of the hazards into Sunday evening. The western extent of the threat into IN will likely be modulated by progressively greater MLCIN that may not be eliminated prior to frontal passage. ..Grams.. 04/12/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Fri Apr 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PA TO EAST IN... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday, mainly from late afternoon into the evening, across Pennsylvania to eastern Indiana. ...PA to eastern IN... A mid-level jetlet attendant to a low-amplitude shortwave impulse should progress across the northern Great Lakes and Ontario into New England by Sunday evening. To its south-southwest, a pronounced elevated mixed layer across the Midwest and southern Great Lakes will shift southeastward into the Mid-Atlantic and Southeast States. This elevated mixed layer will likely cap surface-based convection until peak heating along a southeast-sagging cold front. 00Z NAM soundings appear relatively reasonable with this evolution as modified low-level moisture return emanating from the southern Great Plains struggles to reduce MLCIN until cooling aloft spreads in from the west-northwest. MLCAPE should eventually reach 500-1000 J/kg over IN/OH, with progressively weaker values over PA. Hodographs across the region should be dominated by low-level curvature enlargement, with little speed or directional shear component above that within the buoyancy layer. Seemingly, a west/east-oriented cluster along the front should develop by late afternoon to early evening and move south with the undercutting front, while embedded cells attempt to parallel the deep-layer west-northwesterly flow regime. This setup appears to favor low probabilities across each of the hazards into Sunday evening. The western extent of the threat into IN will likely be modulated by progressively greater MLCIN that may not be eliminated prior to frontal passage. ..Grams.. 04/12/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CDT Fri Apr 12 2024 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PA TO EAST IN... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday, mainly from late afternoon into the evening, across Pennsylvania to eastern Indiana. ...PA to eastern IN... A mid-level jetlet attendant to a low-amplitude shortwave impulse should progress across the northern Great Lakes and Ontario into New England by Sunday evening. To its south-southwest, a pronounced elevated mixed layer across the Midwest and southern Great Lakes will shift southeastward into the Mid-Atlantic and Southeast States. This elevated mixed layer will likely cap surface-based convection until peak heating along a southeast-sagging cold front. 00Z NAM soundings appear relatively reasonable with this evolution as modified low-level moisture return emanating from the southern Great Plains struggles to reduce MLCIN until cooling aloft spreads in from the west-northwest. MLCAPE should eventually reach 500-1000 J/kg over IN/OH, with progressively weaker values over PA. Hodographs across the region should be dominated by low-level curvature enlargement, with little speed or directional shear component above that within the buoyancy layer. Seemingly, a west/east-oriented cluster along the front should develop by late afternoon to early evening and move south with the undercutting front, while embedded cells attempt to parallel the deep-layer west-northwesterly flow regime. This setup appears to favor low probabilities across each of the hazards into Sunday evening. The western extent of the threat into IN will likely be modulated by progressively greater MLCIN that may not be eliminated prior to frontal passage. ..Grams.. 04/12/2024 Read more