Severe Storms

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Thu Mar 13 2025 Valid 132000Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF ALABAMA...WESTERN FLORIDA...AND SOUTHERN GEORGIA... ...SUMMARY... Isolated strong to severe thunderstorms capable of producing hail and locally damaging gusts are possible from parts of Alabama, into southwest Georgia, and the Florida Panhandle this afternoon and early evening. ...20z Update... Minimal changes were made to the MRGL risk area over parts of the Southeast, mainly to trim the western extent. Mid-level subsidence behind the weakening vort max over parts of MS/TN will tend to limit thunderstorm potential to the west through the remainder of the afternoon. To the east, increasing low-level moisture and steep lapse rates will support isolated thunderstorms with a risk for hail and sporadic damaging gusts. Elsewhere, strong mid-level height falls are expected over the western US as a powerful upper trough approaches. A few elevated thunderstorms are possible within warm air advection over the Upper Midwest ahead of shallow returning surface moisture. To the west, cool mid-level temperatures overspreading meager low-level moisture will also support isolated thunderstorm chances over a broad area from the Desert Southwest to the Rockies. Somewhat stronger, low-topped convection is possible along the cold front from southern AZ into far western NM this evening and tonight. Given the strength of the wind fields aloft, a few severe gusts will be possible. Though, the very limited buoyancy should limit the severe threat. See the previous discussion for more info. ..Lyons.. 03/13/2025 .PREV DISCUSSION... /ISSUED 1122 AM CDT Thu Mar 13 2025/ ...Southeast... A mid-level vorticity maximum over the Mid-South late this morning will become less well defined as it moves slowly eastward across the TN Valley and Southeast through the period. Stronger mid-level flow is expected to remain over southern/coastal portions of the Southeast today. But, cold mid-level temperatures (around -18 to -21 C at 500 mb per 12Z regional soundings) in conjunction with filtered daytime heating and modest low-level moistening will support weak destabilization from parts of AL into southwest GA, and the FL Panhandle. Current expectations are for isolated to scattered thunderstorms to develop across these areas through the afternoon, as modest ascent with the weakening mid-level trough moves through. Most guidance suggests that greater convective coverage may occur over parts of southeast AL into southwest GA and perhaps the FL Panhandle, in closer proximity to greater low-level moisture and the mid-level jet. With modest to sufficient deep-layer shear, clusters to marginal supercell structures could pose an isolated threat for both severe hail and damaging winds this afternoon through early evening. See Mesoscale Discussion 167 for additional details on convective development and evolution through 20Z. ...Southern Arizona... A cold front will move eastward across southern AZ today, as an upper trough progresses over the Southwest. Showers and thunderstorms are expected to spread across this region in tandem with the front. Winds aloft will be quite strong, as an 80-100 kt mid/upper-level jet max digs southward along/near the international border. Some higher momentum flow may mix to the surface, and a gust could approach severe limits within low-topped convection. However, the weak thermodynamic profile would suggest the severe threat will remain low. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Thu Mar 13 2025 Valid 151200Z - 161200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN EASTERN LA...MS...AND AL... ...SUMMARY... A severe weather outbreak is expected on Saturday across the central Gulf Coast States and Deep South into the Tennessee Valley. Numerous significant tornadoes are possible on Saturday afternoon and evening, centered on eastern Louisiana, Mississippi, and Alabama. Widespread damaging wind swaths and scattered large hail are likely. ...Central Gulf Coast/Deep South/TN Valley... Primary change is to expand level 4-MDT north in AL and all categories west in the tight gradient of severe potential from the Sabine to Lower MS Valleys. A particularly volatile scenario for destructive severe remains evident during the afternoon to evening on Saturday centered on the level 4-MDT risk region. In the wake of the vigorous shortwave trough and very deep surface cyclone crossing the North-Central States on D2, a broad upper trough will linger across the southern Great Plains. An intense mid-level jetlet, in excess of 100 kts at 500-mb, should eject through the basal portion of this trough in south TX on Saturday afternoon. This will induce secondary cyclogenesis along the slow-moving baroclinic zone from the Ark-La-Tex to the central Great Lakes. Another day of air mass modification ahead of this wave will yield a pronounced plume of rich northwest Gulf moisture that should be pristine across southeast LA into central MS through late morning. As mid-level height falls overspread the diurnally warming air mass, increasing convective development is expected along the deepening baroclinic zone, as well as residual outflows to its northeast in the TN Valley from prior late D2 convection. Steep mid-level lapse rates atop the richly moist boundary layer should yield at least moderate MLCAPE across the Lower MS Valley. Vertically veering wind profiles with strong anvil-level divergence amid the favorable instability should support robust updrafts and intense supercells. Low-level shear will strengthen during the afternoon and evening, setting the stage for a severe-weather outbreak including significant tornadoes, damaging gusts, and large hail. A pronounced dropoff in severe may be realized with northward extent across the TN Valley as an emerging band and/or highly organized line outpaces the rich Gulf air. Despite weaker instability with eastern extent into GA/SC, the intense wind fields may sustain damaging wind and embedded tornado potential well into the overnight. ...OH Valley to Lower Great Lakes... Forecast confidence is low with regard to severe potential north of the TN Valley. Weakening late D2 convection should be in a decaying process at 12Z Saturday. Much of the region will then be in between waves until late afternoon. Guidance differs on the degree of diurnal destabilization ahead of the deepening surface cyclone that should track north-northeast from the Ark-La-Tex. It is plausible that widespread Mid/Deep South to TN Valley convection during the day Saturday will temper the northward extent of instability by Saturday evening/night within a predominately meridional deep-layer wind profile. As such, the overall severe risk appears conditional, but given the fast flow regime, potential for damaging winds and perhaps a few tornadoes may be realized. ..Grams.. 03/13/2025 Read more

MD 0167 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PART OF CENTRAL AND SOUTHERN ALABAMA INTO SOUTHWESTERN GEORGIA
Mesoscale Discussion 0167 NWS Storm Prediction Center Norman OK 1117 AM CDT Thu Mar 13 2025 Areas affected...part of central and southern Alabama into southwestern Georgia Concerning...Severe potential...Watch unlikely Valid 131617Z - 131845Z Probability of Watch Issuance...20 percent SUMMARY...Scattered thunderstorm development is increasing likely across parts of south central Alabama into southwestern Georgia through mid to late afternoon. This may include a few intensifying storms with potential to produce marginally severe hail and, gradually, a small organizing cluster or two accompanied by strong surface gusts later this afternoon. DISCUSSION...Beneath cool mid-level troughing in the 700-500 mb layer, a gradual boundary-layer moistening, and warming due to insolation and advection, are contributing to ongoing destabilization across the region. This is occurring as forecast soundings suggest that weak to modest large-scale ascent erodes a relatively warm capping layer between 850-700 mb. It appears this is supporting the deepening convective development evident in latest satellite and radar imagery, which guidance generally indicates will lead to increasing scattered thunderstorm development though 18-20Z. Beneath 35-50 kt west-northwesterly flow around 500 mb, deep-layer shear appears sufficient to support gradually intensifying and organizing convection, in the presence of mixed-layer CAPE on the order of 500-750+ J/kg. This may include one or two storms exhibiting mid-level updraft rotation, with the potential to produce marginally severe hail, and perhaps a small evolving cluster or two eventually accompanied by a few strong surface gusts later this afternoon, while propagating east-southeastward. ..Kerr/Gleason.. 03/13/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FFC...TAE...BMX...MOB... LAT...LON 33108706 33018650 33038575 32868493 32058407 31238452 30818531 31308598 31628714 32548769 33108706 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Thu Mar 13 2025 Valid 141200Z - 151200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS IN SOUTHEAST IA...EASTERN MO...IL...FAR WESTERN KY/NORTHWEST TN/NORTHEAST AR... ...SUMMARY... A regional outbreak of severe storms is likely over the Lower/Mid-Missouri/Mississippi Valleys and Lower Ohio Valley late Friday afternoon into Saturday morning. Tornadoes, several of which could be strong, widespread damaging winds with gusts from 70 to 90 mph, and scattered large hail up to baseball size will be possible. ...Synopsis... Primary change this outlook cycle has been to mainly expand MRGL/SLGT/ENH damaging wind probabilities west to north in the Lower/Mid-MO Valley. No change to the level 4/MDT risk with greater uncertainty over the southern extent of widespread damaging wind potential into the Mid-South, but where strong tornado potential persists. ...Lower/Mid-MO, Mid-MS, and Lower OH Valleys... A powerful shortwave trough will amplify from the southern High Plains into the Upper MS Valley. This will induce further deepening of an intense surface cyclone across the central Great Plains to the Mid-MO Valley. Initial surface-based thunderstorm development is expected by early to mid-afternoon along the northwest periphery of a modified moisture plume emanating north from the South-Central States. Well-mixed, inverted-v thermodynamic profiles will support downward momentum transport in the left-exit region of an intense 700-mb jet curling across the Ozarks to the Mid-MS Valley. This should yield a rapidly progressing QLCS from the Lower to Mid-MO Valley across much of the Mid-MS Valley into Friday evening, with semi-discrete supercells trailing to the southeast portion of the convective plume. Given the fast low to mid-level flow regime, embedded gusts from 60-80 kts should be common along with a QLCS/embedded supercell tornado threat. The latter will be greater with southeast extent where a ribbon of somewhat richer low-level moisture should reach the Mid-MS Valley. Convection should tend to weaken overnight more quickly on the north end of the outlook area as it outpaces the confined surface-based instability plume. But some overnight damaging wind/tornado potential should persist across the Lower OH Valley. ...Mid-South to Lower MS and TN Valleys... South of the QLCS regime, forecast confidence in sustaining deep convection lowers with southern extent. Persistent southerly low-level flow will bring mid to upper 60s F dewpoints northward across the region by Friday evening/night. Forecast soundings indicate rather favorable thermodynamic and kinematic profiles, conditionally supporting intense and long-track supercells. Neutral to weak mid-level height falls are expected, with the strong low-level jet tending to shift north/east of the Lower MS Valley overnight. This suggests forcing mechanisms will be modest, which is likely behind guidance spread with the depiction of deep convection during the evening and overnight. A few broken to semi-discrete supercells appear most probable in the Mid-South, posing a risk for strong tornadoes, significant damaging wind gusts, and very large hail. These threats appear more conditional farther south/east in the Lower MS and TN Valleys. ..Grams.. 03/13/2025 Read more