Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0132 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...Synopsis... ...Central/Northern Plains... A shortwave trough moving across the Canadian Provinces will bring enhanced westerly flow across the northern Rockies. Warm and dry downslope flow east of the Bighorn Mountains will be likely across eastern Wyoming into portions of far southeastern South Dakota. A period of elevated fire weather conditions will be likely, with relative humidity reductions to 10-15% amid sustained westerly winds 15-20 mph. Fuels within this region are sufficiently dry to support wildfire spread, with little observed rainfall in the last 30 days. ...Southwest... An enhanced belt of mid-level flow within a deepening mid-level low will spread across the Southwest. Boundary-layer mixing into this strong deep-layer flow will favor dry/breezy conditions across portions of western NM and eastern AZ during this afternoon. Locally elevated fire-weather conditions will be possible. Fuels across the southwest are generally unsupportive of large-fire spread at this time. Elsewhere, a minimal overlap of breezy surface winds and low RH should limit fire-weather concerns. ..Thornton.. 09/20/2024 ...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 0132 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...Synopsis... ...Central/Northern Plains... A shortwave trough moving across the Canadian Provinces will bring enhanced westerly flow across the northern Rockies. Warm and dry downslope flow east of the Bighorn Mountains will be likely across eastern Wyoming into portions of far southeastern South Dakota. A period of elevated fire weather conditions will be likely, with relative humidity reductions to 10-15% amid sustained westerly winds 15-20 mph. Fuels within this region are sufficiently dry to support wildfire spread, with little observed rainfall in the last 30 days. ...Southwest... An enhanced belt of mid-level flow within a deepening mid-level low will spread across the Southwest. Boundary-layer mixing into this strong deep-layer flow will favor dry/breezy conditions across portions of western NM and eastern AZ during this afternoon. Locally elevated fire-weather conditions will be possible. Fuels across the southwest are generally unsupportive of large-fire spread at this time. Elsewhere, a minimal overlap of breezy surface winds and low RH should limit fire-weather concerns. ..Thornton.. 09/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 AM CDT Fri Sep 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO MISSOURI... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday from northwest Texas to central Missouri. ...Southern Plains to Missouri... An upper trough over the central/southern Rockies Sunday morning will track east over the central/southern Plains. Around 40-50 kt southwesterly flow will overspread northwest TX into KS/OK and MO ahead of this feature. At the surface, A cold front will develop southeast across the Mid-MS Valley to southern Plains. Convection may be ongoing across portions of the central/southern Plains to the Mid-MS Valley Sunday morning, resulting in some uncertainty in airmass destabilization through peak heating. Nevertheless, a seasonally moist airmass and favorable vertical shear will support organized thunderstorm clusters during the afternoon/evening ahead of the advancing cold front. Some risk for damaging gusts will accompany this activity from northwest TX into central MO. ..Leitman.. 09/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 AM CDT Fri Sep 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO MISSOURI... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday from northwest Texas to central Missouri. ...Southern Plains to Missouri... An upper trough over the central/southern Rockies Sunday morning will track east over the central/southern Plains. Around 40-50 kt southwesterly flow will overspread northwest TX into KS/OK and MO ahead of this feature. At the surface, A cold front will develop southeast across the Mid-MS Valley to southern Plains. Convection may be ongoing across portions of the central/southern Plains to the Mid-MS Valley Sunday morning, resulting in some uncertainty in airmass destabilization through peak heating. Nevertheless, a seasonally moist airmass and favorable vertical shear will support organized thunderstorm clusters during the afternoon/evening ahead of the advancing cold front. Some risk for damaging gusts will accompany this activity from northwest TX into central MO. ..Leitman.. 09/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 AM CDT Fri Sep 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO MISSOURI... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday from northwest Texas to central Missouri. ...Southern Plains to Missouri... An upper trough over the central/southern Rockies Sunday morning will track east over the central/southern Plains. Around 40-50 kt southwesterly flow will overspread northwest TX into KS/OK and MO ahead of this feature. At the surface, A cold front will develop southeast across the Mid-MS Valley to southern Plains. Convection may be ongoing across portions of the central/southern Plains to the Mid-MS Valley Sunday morning, resulting in some uncertainty in airmass destabilization through peak heating. Nevertheless, a seasonally moist airmass and favorable vertical shear will support organized thunderstorm clusters during the afternoon/evening ahead of the advancing cold front. Some risk for damaging gusts will accompany this activity from northwest TX into central MO. ..Leitman.. 09/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 AM CDT Fri Sep 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO MISSOURI... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday from northwest Texas to central Missouri. ...Southern Plains to Missouri... An upper trough over the central/southern Rockies Sunday morning will track east over the central/southern Plains. Around 40-50 kt southwesterly flow will overspread northwest TX into KS/OK and MO ahead of this feature. At the surface, A cold front will develop southeast across the Mid-MS Valley to southern Plains. Convection may be ongoing across portions of the central/southern Plains to the Mid-MS Valley Sunday morning, resulting in some uncertainty in airmass destabilization through peak heating. Nevertheless, a seasonally moist airmass and favorable vertical shear will support organized thunderstorm clusters during the afternoon/evening ahead of the advancing cold front. Some risk for damaging gusts will accompany this activity from northwest TX into central MO. ..Leitman.. 09/20/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0125 AM CDT Fri Sep 20 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS INTO MISSOURI... ...SUMMARY... Isolated severe thunderstorms are possible on Sunday from northwest Texas to central Missouri. ...Southern Plains to Missouri... An upper trough over the central/southern Rockies Sunday morning will track east over the central/southern Plains. Around 40-50 kt southwesterly flow will overspread northwest TX into KS/OK and MO ahead of this feature. At the surface, A cold front will develop southeast across the Mid-MS Valley to southern Plains. Convection may be ongoing across portions of the central/southern Plains to the Mid-MS Valley Sunday morning, resulting in some uncertainty in airmass destabilization through peak heating. Nevertheless, a seasonally moist airmass and favorable vertical shear will support organized thunderstorm clusters during the afternoon/evening ahead of the advancing cold front. Some risk for damaging gusts will accompany this activity from northwest TX into central MO. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1223 AM CDT Fri Sep 20 2024 Valid 211200Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EASTERN NEW MEXICO AND WESTERN TEXAS... ...SUMMARY... Isolated severe thunderstorms are possible on Saturday afternoon to early evening in New Mexico and the southern High Plains, the mid Missouri Valley to upper Mississippi Valley, and central Appalachians region. ...Southern High Plains vicinity... A southern stream upper low and attendant trough will progress east across the Four Corners and southern Rockies on Saturday. An area of enhanced southwesterly flow aloft associated with the ejecting trough will become oriented over eastern NM into the OK/TX Panhandles by 00z/Sun. While strong heating will result in some boundary layer mixing, south/southeasterly low-level flow will result in persistent theta-e advection, and dewpoints from the upper 50s to low 60s F are expected. Steepening midlevel lapse rates will contribute to modest destabilization, with 1000-1500 J/kg MLCAPE forecast across parts of eastern NM into the TX Panhandle/South Plains vicinity. Vertically veering wind profiles amid strengthening midlevel flow will support isolated supercell thunderstorms. Large hail and sporadic strong/severe gusts are possible. Given increasing consistency in forecast guidance, a Slight risk (level 2 of 5) has been included for parts of the eastern NM Plains into west Texas. Additional strong storms are possible to the north and west across northeast NM into south-central CO beneath the core of mid/upper low. Instability will be weaker across this area, but isolated strong gusts and marginal hail will still be possible with the strongest storms. ...Western PA into northern/central VA... A low-amplitude mid/upper shortwave trough is forecast to move across the Northeast on Saturday. Northwesterly deep-layer flow will overspread the Upper OH Valley toward the Mid-Atlantic coast. A corridor of low to mid 60s F dewpoints and pockets of stronger heating will support weak destabilization. Modest vertical shear (around 20-25 kt effective shear) will aid in at least transient organized updrafts. Elongated/straight hodographs and cool temperatures aloft suggest marginally severe hail will be possible with the stronger cells. Locally strong gusts also will be possible where stronger heating and steepening of low-level lapse rates occurs. ...Central Plains to Mid-MO/Upper MS Valley... The forecast for this region remains quite uncertain for Saturday. Most guidance depicts some degree of convection ongoing across parts of IA/MO Saturday morning. The evolution of this activity will impact how the airmass destabilizes/recovers late in the afternoon across the region. Nevertheless, large-scale ascent will increase over the Upper Midwest as a northern stream upper trough traverses the Canadian Prairies and the international border vicinity. Southerly low-level flow will maintain 60s dewpoints ahead of a cold front tracking southeast across MN and the Mid-MO/Upper MS Valley from late afternoon into the evening. Isolated strong to severe thunderstorms producing hail and gusty winds will be possible, but the overall risk remains uncertain. ..Leitman.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1226 AM CDT Fri Sep 20 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM SOUTHWEST LOWER MICHIGAN INTO PARTS OF INDIANA...ILLINOIS...AND SOUTHEAST MISSOURI...AND OVER PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible during the late afternoon over parts of Illinois, Indiana, and southwest Lower Michigan. Isolated strong to severe storms are also possible across parts of the south-central Plains. ...Synopsis... A leading shortwave trough will weaken as it moves across the upper Great Lakes today, while a secondary and stronger system moves into MT and the northern Plains late. An upper high will hold over the southern Plains, which will aid a strengthening midlevel height gradient over the central and northern Plains as the wave approaches from the northwest. Meanwhile, a deep upper low will affect southern CA and move into AZ through Saturday morning. At the surface, a trough will develop over the northern High Plains late in the day, with high pressure over the eastern states. A weak/residual boundary will extend roughly from Lake MI into central IL, MO, and toward I-70 in KS, with a moist air mass to the south. Mid to upper 60s F dewpoints will return north late this evening and overnight as southerly winds around 850 mb increase to over 40 kt. Otherwise, a cold front associated with the MT disturbance will push across the Dakotas and into central NE overnight and through 12Z Saturday. ...Western Lower MI into IN and IL... Daytime heating of a moist low-level air mass will yield a moderately unstable and uncapped air mass near the weak surface boundary. Scattered thunderstorms are anticipated from western Lower MI southwestward into southern MO as a result. However, forecast soundings indicate poor midlevel lapse rates along with substantial midlevel dry air, which may diminish severity somewhat. That said, locally strong gusts will be possible, and perhaps small to marginal hail. ...Central Plains... Strong heating and southwest surface winds will lead to a plume of steep low-level lapse rates from the TX Panhandle toward the KS/OK border this afternoon. Meanwhile, higher dewpoints will remain near a stalled front over KS, which will support high-based storms initially over northeast NM across the Panhandles and into southwest KS. Given the very deep mixed layers, a few strong to severe gusts may occur. With time, outflow may yield downstream development with more robust cores and perhaps marginal hail across south-central KS. During the late evening, the returning boundary and associated theta-e advection may support a rash of storms from near the NE/KS border, with veering 850 mb winds over time redirecting said advection and lift eastward across the KC Metro. Strong wind gusts appear to be the main risk with such activity. ..Jewell/Thornton.. 09/20/2024 Read more

MD 2089 CONCERNING SEVERE THUNDERSTORM WATCH 677... FOR SOUTHEASTERN MINNESOTA...WESTERN WISCONSIN
Mesoscale Discussion 2089 NWS Storm Prediction Center Norman OK 0741 PM CDT Thu Sep 19 2024 Areas affected...forsoutheastern Minesotta...western Wisconsin Concerning...Severe Thunderstorm Watch 677... Valid 200041Z - 200245Z The severe weather threat for Severe Thunderstorm Watch 677 continues. SUMMARY...Severe threat continues within WW677. DISCUSSION...Storms continue along a northward lifting warm front and cold front moving across portions of eastern MN into western WI. Recent storm reports from storms along the warm front have produced instances of hail up to 1.25 in. Recent 00z RAOB from MPX shows a warm layer aloft with MLCAPE around 1900 J/kg and deep layer shear around 30 kts. Hodographs are primarily linear with generally uniformly westerly winds aloft. This will continue to support mixed mode of multi-cell clusters and occasional supercells capable of large hail. The highest threat for large hail will remain along and north of the warm front in the near term. Further severe development will continue along and ahead of the cold front as well, with potential for hail and instances of strong to severe wind. ..Thornton.. 09/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX... LAT...LON 44119332 45409268 45469098 45219069 44589080 43999153 43759191 43609313 43609316 44119332 Read more