Severe Storms

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 PM CST Thu Nov 30 2023 Valid 010100Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA... ...SUMMARY... A few severe storms/tornadoes remain possible tonight from southeast Texas into southern Louisiana. Isolated hail is also possible across southern Oklahoma into northeast Texas. ...01z Update... Early-evening water-vapor imagery depicts a well-defined short-wave trough over the southern High Plains, ejecting northeast in line with earlier model guidance. Seasonally cold 500mb temperatures (less than -20C) are spreading across western OK/northwestern TX which is contributing to elevated buoyancy for parcels lifted above the boundary layer. 00z sounding from OUN exhibited steep 3-6km lapse rates and MUCAPE around 400 J/kg. Marginally severe hail appears possible with convection immediately ahead of the ejecting vort/short wave. Farther southeast along the upper TX Coast, deep-layer flow is beginning to veer which has shunted the primary zone of confluence for deep convection just east of the Houston metro region. Latest radar data suggests the most robust updrafts are noted along the southwestern flank of a southwest-northeast line that extends from the lower Sabine River Valley toward Galveston Bay. This is likely due to higher dew points/buoyancy along the western fringe of the strongest low-level warm advection. Current thinking is warm advection will continue to be the primary instigator in thunderstorm activity along the upper TX/southwestern LA Coast tonight as the main zone of strong midlevel height falls will spread well north of this region. Greatest potential for a tornado or two will occur with near-surface-based storms in proximity to greater SRH, which is now east of Houston. Even so, the tornado threat should remain isolated. ..Darrow.. 12/01/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 PM CST Thu Nov 30 2023 Valid 010100Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA... ...SUMMARY... A few severe storms/tornadoes remain possible tonight from southeast Texas into southern Louisiana. Isolated hail is also possible across southern Oklahoma into northeast Texas. ...01z Update... Early-evening water-vapor imagery depicts a well-defined short-wave trough over the southern High Plains, ejecting northeast in line with earlier model guidance. Seasonally cold 500mb temperatures (less than -20C) are spreading across western OK/northwestern TX which is contributing to elevated buoyancy for parcels lifted above the boundary layer. 00z sounding from OUN exhibited steep 3-6km lapse rates and MUCAPE around 400 J/kg. Marginally severe hail appears possible with convection immediately ahead of the ejecting vort/short wave. Farther southeast along the upper TX Coast, deep-layer flow is beginning to veer which has shunted the primary zone of confluence for deep convection just east of the Houston metro region. Latest radar data suggests the most robust updrafts are noted along the southwestern flank of a southwest-northeast line that extends from the lower Sabine River Valley toward Galveston Bay. This is likely due to higher dew points/buoyancy along the western fringe of the strongest low-level warm advection. Current thinking is warm advection will continue to be the primary instigator in thunderstorm activity along the upper TX/southwestern LA Coast tonight as the main zone of strong midlevel height falls will spread well north of this region. Greatest potential for a tornado or two will occur with near-surface-based storms in proximity to greater SRH, which is now east of Houston. Even so, the tornado threat should remain isolated. ..Darrow.. 12/01/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 PM CST Thu Nov 30 2023 Valid 010100Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA... ...SUMMARY... A few severe storms/tornadoes remain possible tonight from southeast Texas into southern Louisiana. Isolated hail is also possible across southern Oklahoma into northeast Texas. ...01z Update... Early-evening water-vapor imagery depicts a well-defined short-wave trough over the southern High Plains, ejecting northeast in line with earlier model guidance. Seasonally cold 500mb temperatures (less than -20C) are spreading across western OK/northwestern TX which is contributing to elevated buoyancy for parcels lifted above the boundary layer. 00z sounding from OUN exhibited steep 3-6km lapse rates and MUCAPE around 400 J/kg. Marginally severe hail appears possible with convection immediately ahead of the ejecting vort/short wave. Farther southeast along the upper TX Coast, deep-layer flow is beginning to veer which has shunted the primary zone of confluence for deep convection just east of the Houston metro region. Latest radar data suggests the most robust updrafts are noted along the southwestern flank of a southwest-northeast line that extends from the lower Sabine River Valley toward Galveston Bay. This is likely due to higher dew points/buoyancy along the western fringe of the strongest low-level warm advection. Current thinking is warm advection will continue to be the primary instigator in thunderstorm activity along the upper TX/southwestern LA Coast tonight as the main zone of strong midlevel height falls will spread well north of this region. Greatest potential for a tornado or two will occur with near-surface-based storms in proximity to greater SRH, which is now east of Houston. Even so, the tornado threat should remain isolated. ..Darrow.. 12/01/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0648 PM CST Thu Nov 30 2023 Valid 010100Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS INTO SOUTHERN LOUISIANA... ...SUMMARY... A few severe storms/tornadoes remain possible tonight from southeast Texas into southern Louisiana. Isolated hail is also possible across southern Oklahoma into northeast Texas. ...01z Update... Early-evening water-vapor imagery depicts a well-defined short-wave trough over the southern High Plains, ejecting northeast in line with earlier model guidance. Seasonally cold 500mb temperatures (less than -20C) are spreading across western OK/northwestern TX which is contributing to elevated buoyancy for parcels lifted above the boundary layer. 00z sounding from OUN exhibited steep 3-6km lapse rates and MUCAPE around 400 J/kg. Marginally severe hail appears possible with convection immediately ahead of the ejecting vort/short wave. Farther southeast along the upper TX Coast, deep-layer flow is beginning to veer which has shunted the primary zone of confluence for deep convection just east of the Houston metro region. Latest radar data suggests the most robust updrafts are noted along the southwestern flank of a southwest-northeast line that extends from the lower Sabine River Valley toward Galveston Bay. This is likely due to higher dew points/buoyancy along the western fringe of the strongest low-level warm advection. Current thinking is warm advection will continue to be the primary instigator in thunderstorm activity along the upper TX/southwestern LA Coast tonight as the main zone of strong midlevel height falls will spread well north of this region. Greatest potential for a tornado or two will occur with near-surface-based storms in proximity to greater SRH, which is now east of Houston. Even so, the tornado threat should remain isolated. ..Darrow.. 12/01/2023 Read more

MD 2293 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWESTERN OKLAHOMA INTO NORTH-CENTRAL TEXAS
Mesoscale Discussion 2293 NWS Storm Prediction Center Norman OK 0525 PM CST Thu Nov 30 2023 Areas affected...southwestern Oklahoma into north-central Texas Concerning...Severe potential...Watch unlikely Valid 302325Z - 010100Z Probability of Watch Issuance...5 percent SUMMARY...A marginal risk of severe hail will be possible over the next couple of hours. DISCUSSION...Recent radar trends have shown strengthening cores within the cells near the Red River along the Texas/Oklahoma border. Mid-level cooling associated with the upper-level trough has given way to a small corridor of MLCAPE around 500 J/kg along the OK/TX border. Forecast soundings from the RAP along with objective analysis show steep mid-level lapse rates around 7-7.5 c/km and deep layer shear around 35-40 kts. This will support potential for a few instances of severe hail (up to 1-1.25 in). Recent reports of hail up to 3/4 inch have been noted near Childress. Due to short time window within the better instability and due to nocturnal cooling, it is unlikely that the hail threat will be long lived. As such, a watch is not anticipated. ..Thornton/Smith.. 11/30/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...LUB...AMA... LAT...LON 34000016 34350024 34710018 34860011 34930010 35069999 35209954 35139900 34969849 34749825 34369801 34189793 33929795 33519813 33419917 33569977 34000016 Read more

No watches are valid as of Thu Nov 30 23:27:02 UTC 2023.

MD 2292 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF EAST-CENTRAL/SOUTHEAST TX INTO EXTREME SOUTHWEST LA
Mesoscale Discussion 2292 NWS Storm Prediction Center Norman OK 0352 PM CST Thu Nov 30 2023 Areas affected...Parts of east-central/southeast TX into extreme southwest LA Concerning...Severe potential...Watch unlikely Valid 302152Z - 302315Z Probability of Watch Issuance...20 percent SUMMARY...Some threat for a tornado and locally damaging gusts may still evolve late this afternoon. DISCUSSION...Convection persists this afternoon near the upper TX coast, while storms have also recently developed near the western edge of deeper moisture across parts of east-central TX. Thus far, convection has struggled to become organized, despite the presence of rich low-level moisture and favorable wind profiles. This is likely due to widespread cloudiness across the region, with weak low-level lapse rates where convection is ongoing. While MLCINH is not prohibitive for surface-based storms (largely due to the rich low-level moisture), the short-term potential for organized storms remains uncertain, with a continued tendency for convection to remain slightly elevated as it moves through a poor lapse rate environment where clouds remain entrenched. However, with favorable deep-layer shear and 0-1 km SRH of 200-300 m2/s2 (greater closer to the coast) across the region, a transient supercell and/or a stronger line segment cannot be ruled out through the remainder of the afternoon, with an attendant threat of a tornado and/or locally damaging gusts. With the threat expected to remain rather isolated through the afternoon, short-term watch issuance is unlikely. Some uptick remains possible sometime this evening, especially into far southeast TX/southwest LA, and trends will continue to be monitored for an increase in storm organization/intensity, given the favorable wind profiles and low-level moisture in place. ..Dean.. 11/30/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LCH...SHV...HGX...FWD...EWX... LAT...LON 30489664 32059641 32109583 31679523 30979508 30279356 29919326 29739332 29579367 29409414 29149461 28929499 28649542 28529567 28529582 28579589 28939594 29239603 29479636 29879670 30389666 30489664 Read more

No Mesoscale Discussions are in effect as of Thu Nov 30 21:30:02 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0248 PM CST Thu Nov 30 2023 Valid 021200Z - 081200Z Multiple mid-level troughs will traverse the CONUS east of the Rockies through mid next week, before an upper ridge overspreads the central U.S. During the weekend through early next week, surface lee troughing/cyclone development will encourage dry downslope flow across the southern High Plains each day, with near critical surface winds/RH possible on Day 3/Saturday. However, appreciable rainfall is ongoing across the southern High Plains, casting doubt on the receptiveness of fuels to support significant wildfire spread potential. Critical highlights have been withheld this outlook. Still, an instance or two of more locally Elevated conditions cannot be ruled out over the southern High Plains this weekend into early next week where RH less than 20 percent, strong wind gusts, and drier fuel beds can all overlap. ..Squitieri.. 11/30/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 2291 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTHEAST TEXAS INTO FAR SOUTHEASTERN OKLAHOMA
Mesoscale Discussion 2291 NWS Storm Prediction Center Norman OK 1244 PM CST Thu Nov 30 2023 Areas affected...Northeast Texas into far southwestern Oklahoma Concerning...Severe potential...Watch unlikely Valid 301844Z - 302045Z Probability of Watch Issuance...5 percent SUMMARY...The potential for isolated severe hail, and perhaps damaging wind gusts, should increase through the mid-afternoon hours across northeast Texas and portions of far southwestern Oklahoma. Watch issuance is not expected. DISCUSSION...Over the past hour, the coverage and intensity of convection has increased across central to northeast TX as lift within a warm advection regime and ahead of an approaching upper wave increases. While much of this convection is well displaced from a narrow plume of surface-based buoyancy stretching from the TX Gulf coast into central TX, MUCAPE across northeast TX has steadily increased to around 1000 J/kg amid warming/moistening within the 925-850 mb layer. Observed storm motions and a lack of apparent low-level mesocyclones further suggest that this convection is rooted above the surface, but elongated hodographs above 2 km (featuring effective bulk shear values near 40 knots), should support storm organization with an attendant risk of isolated large hail. Cooling cloud top temperatures and an uptick in lightning counts over the past 15-30 minutes suggest convection is beginning to realize this environment, so an increasing hail threat seems probable (though clustered storm modes may inhibit the overall threat). Recent hi-res guidance, including HRRR-based SCRAMM solutions and WOFS ensemble output, appears to have picked up on this trend and shows increasing potential for isolated hail across northeast TX over the next several hours. While the signal for severe winds is comparatively weaker, a few damaging gusts will be possible. Regardless, the overall severe threat should remain too limited to warrant watch issuance. ..Moore/Thompson.. 11/30/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SHV...TSA...HGX...FWD...OUN... LAT...LON 31409742 31779765 32809746 33529748 33949761 34369566 34179495 33879449 33059425 32399443 31749489 31529539 31409742 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Nov 30 2023 Valid 302000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA... ...SUMMARY... A few severe storms/tornadoes are possible through tonight from southeast Texas into southern Louisiana. Farther north, isolated hail and strong wind gusts will also be possible across parts of East/North Texas and southern Oklahoma. ...20z Update... The only changes with the 20z update were to trim the western edges of the outlook area based on latest observation trends and location of current convection. Widespread cloud cover and scattered convection has limited heating, and combined with poor low-level lapse rates, low-level inhibition is limited surface-based storm development. Some stronger storms may still develop this evening near the Sabine River as the surface cold front tracks southeast. However, overall severe potential will likely remain somewhat subdued due to poor thermodynamics despite favorable vertical shear. ..Leitman.. 11/30/2023 .PREV DISCUSSION... /ISSUED 1025 AM CST Thu Nov 30 2023/ ...Northwest Gulf coast and southern Plains through tonight... Thunderstorms are forming this morning over southeast TX from Matagorda Bay northeastward through the Houston area to Toledo Bend reservoir. The convection appears to be driven by low-level warm advection, as well as a subtle/lead speed max ejecting aloft, in advance of the primary shortwave trough over NM. Observed and forecast hodographs (with substantial length and curvature) across southeast TX look favorable for right-moving supercells with some tornado potential. However, with widespread cloud cover and warm advection being the primary mode of storm initiation, the updrafts may be rooted slightly above the ground. Thus, the convection may not take full advantage of the shear profiles, compared to a more favorable scenario where fully surface-based storms formed in a warmer environment upstream and moved into the environment expected across southeast TX/upper TX coast this afternoon/evening. Regardless, there will be some potential for supercells and a few tornadoes given the strong low-level shear in a moistening/gradually destabilizing environment, with the aforementioned caveats related to poor low-level lapse rates. This threat will slowly increase across southeast TX/upper TX coast through the afternoon and continue through tonight while spreading eastward into southwest/south central LA. Farther northwest, elevated thunderstorm development is expected from central/north TX into southern OK, in the zone of ascent preceding the primary shortwave trough that will begin to move east-northeastward this afternoon from NM toward OK and north TX. The strongest of these storms will pose some threat for marginally severe hail based on some steepening of midlevel lapse rates and relatively long hodographs aloft. A narrow zone of buoyancy rooted near the surface may develop later this afternoon from western north TX into extreme southwest OK, near the primary surface cyclone. However, the main forcing for ascent will be east/northeast of this zone by late afternoon, and forecast hodographs reflect low-midlevel wave passage with a pronounced veer-back signature relatively close to the ground (as low as 1 km AGL). Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Nov 30 2023 Valid 302000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA... ...SUMMARY... A few severe storms/tornadoes are possible through tonight from southeast Texas into southern Louisiana. Farther north, isolated hail and strong wind gusts will also be possible across parts of East/North Texas and southern Oklahoma. ...20z Update... The only changes with the 20z update were to trim the western edges of the outlook area based on latest observation trends and location of current convection. Widespread cloud cover and scattered convection has limited heating, and combined with poor low-level lapse rates, low-level inhibition is limited surface-based storm development. Some stronger storms may still develop this evening near the Sabine River as the surface cold front tracks southeast. However, overall severe potential will likely remain somewhat subdued due to poor thermodynamics despite favorable vertical shear. ..Leitman.. 11/30/2023 .PREV DISCUSSION... /ISSUED 1025 AM CST Thu Nov 30 2023/ ...Northwest Gulf coast and southern Plains through tonight... Thunderstorms are forming this morning over southeast TX from Matagorda Bay northeastward through the Houston area to Toledo Bend reservoir. The convection appears to be driven by low-level warm advection, as well as a subtle/lead speed max ejecting aloft, in advance of the primary shortwave trough over NM. Observed and forecast hodographs (with substantial length and curvature) across southeast TX look favorable for right-moving supercells with some tornado potential. However, with widespread cloud cover and warm advection being the primary mode of storm initiation, the updrafts may be rooted slightly above the ground. Thus, the convection may not take full advantage of the shear profiles, compared to a more favorable scenario where fully surface-based storms formed in a warmer environment upstream and moved into the environment expected across southeast TX/upper TX coast this afternoon/evening. Regardless, there will be some potential for supercells and a few tornadoes given the strong low-level shear in a moistening/gradually destabilizing environment, with the aforementioned caveats related to poor low-level lapse rates. This threat will slowly increase across southeast TX/upper TX coast through the afternoon and continue through tonight while spreading eastward into southwest/south central LA. Farther northwest, elevated thunderstorm development is expected from central/north TX into southern OK, in the zone of ascent preceding the primary shortwave trough that will begin to move east-northeastward this afternoon from NM toward OK and north TX. The strongest of these storms will pose some threat for marginally severe hail based on some steepening of midlevel lapse rates and relatively long hodographs aloft. A narrow zone of buoyancy rooted near the surface may develop later this afternoon from western north TX into extreme southwest OK, near the primary surface cyclone. However, the main forcing for ascent will be east/northeast of this zone by late afternoon, and forecast hodographs reflect low-midlevel wave passage with a pronounced veer-back signature relatively close to the ground (as low as 1 km AGL). Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0154 PM CST Thu Nov 30 2023 Valid 302000Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST TEXAS AND SOUTHWEST LOUISIANA... ...SUMMARY... A few severe storms/tornadoes are possible through tonight from southeast Texas into southern Louisiana. Farther north, isolated hail and strong wind gusts will also be possible across parts of East/North Texas and southern Oklahoma. ...20z Update... The only changes with the 20z update were to trim the western edges of the outlook area based on latest observation trends and location of current convection. Widespread cloud cover and scattered convection has limited heating, and combined with poor low-level lapse rates, low-level inhibition is limited surface-based storm development. Some stronger storms may still develop this evening near the Sabine River as the surface cold front tracks southeast. However, overall severe potential will likely remain somewhat subdued due to poor thermodynamics despite favorable vertical shear. ..Leitman.. 11/30/2023 .PREV DISCUSSION... /ISSUED 1025 AM CST Thu Nov 30 2023/ ...Northwest Gulf coast and southern Plains through tonight... Thunderstorms are forming this morning over southeast TX from Matagorda Bay northeastward through the Houston area to Toledo Bend reservoir. The convection appears to be driven by low-level warm advection, as well as a subtle/lead speed max ejecting aloft, in advance of the primary shortwave trough over NM. Observed and forecast hodographs (with substantial length and curvature) across southeast TX look favorable for right-moving supercells with some tornado potential. However, with widespread cloud cover and warm advection being the primary mode of storm initiation, the updrafts may be rooted slightly above the ground. Thus, the convection may not take full advantage of the shear profiles, compared to a more favorable scenario where fully surface-based storms formed in a warmer environment upstream and moved into the environment expected across southeast TX/upper TX coast this afternoon/evening. Regardless, there will be some potential for supercells and a few tornadoes given the strong low-level shear in a moistening/gradually destabilizing environment, with the aforementioned caveats related to poor low-level lapse rates. This threat will slowly increase across southeast TX/upper TX coast through the afternoon and continue through tonight while spreading eastward into southwest/south central LA. Farther northwest, elevated thunderstorm development is expected from central/north TX into southern OK, in the zone of ascent preceding the primary shortwave trough that will begin to move east-northeastward this afternoon from NM toward OK and north TX. The strongest of these storms will pose some threat for marginally severe hail based on some steepening of midlevel lapse rates and relatively long hodographs aloft. A narrow zone of buoyancy rooted near the surface may develop later this afternoon from western north TX into extreme southwest OK, near the primary surface cyclone. However, the main forcing for ascent will be east/northeast of this zone by late afternoon, and forecast hodographs reflect low-midlevel wave passage with a pronounced veer-back signature relatively close to the ground (as low as 1 km AGL). Read more