Severe Storms

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0706 AM CST Mon Mar 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN UPPER GREAT LAKES REGION SOUTHWESTWARD TO TEXAS...AND INTO THE LOWER MISSISSIPPI VALLEY AREA... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and even a tornado may also occur. ...Synopsis... A broad area of cyclonic flow aloft will remain in place over the western two-thirds of the country, and is expected to gradually expand eastward with time. As the upper troughing expands, a surface baroclinic zone extending from the Texas Panhandle to the Upper Great Lakes will gradually shift southeastward as a cold front, particularly during the second half of the period. Along and ahead of this boundary, convection -- and isolated severe weather -- is expected to evolve. ...Southern Upper Great Lakes vicinity southwestward to Texas... While weak capping should prevail across the southern Plains today, mixing in the vicinity of a weak dryline over central Texas could allow an isolated storm or two to develop, and possibly persist into the evening. Given steep lapse rates aloft and deep mixed layer, hail and/or wind exceeding severe levels could occur, in this highly conditional scenario. More likely development of showers and thunderstorms is expected along the surface baroclinic zone that extends northward into the Upper Great Lakes region, perhaps beginning late this afternoon across northern portions of the risk area and then expanding southward along the cold front with time. With moderately strong flow aloft atop the frontal zone across northern portions of the risk area, a couple of stronger/rotating storms may evolve. Though hail is expected to be the main risk given steep mid-level lapse rates, a locally strong gust or two, or brief tornado, would also be possible if a sustained, rotating storm can develop. As storms develop south-southwestward into the evening and overnight, into a region of weaker shear but steep lapse rates, potential for hail with a few of the strongest storms is expected. At this time, any focused areas for greater severe potential remain difficult to discern, and thus will maintain the broad MRGL risk area this forecast. ...Lower Mississippi Valley vicinity... Weak QG ascent is forecast to spread into Louisiana and adjacent Mississippi this afternoon and into this evening, as somewhat ill-defined/weak cyclonic disturbances in the southern-stream flow move across northern Mexico and Texas this morning, and begin affecting the Lower Mississippi Valley area. A gradual increase in convection through the afternoon is expected, as weak destabilization of the moist boundary layer occurs. Some increase in mid-level west-southwesterly flow with time will occur across this area, as the upper disturbance(s) approach, providing ample shear for a few stronger storms to potentially evolve. Hail would likely remain the primary severe risk with one or two of the strongest storms, though a stronger wind gust or even a brief tornado cannot be ruled out given weakly veering flow with height, and the moist boundary layer supporting surface-based updrafts. ..Goss/Broyles.. 03/04/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0706 AM CST Mon Mar 04 2024 Valid 041300Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE SOUTHERN UPPER GREAT LAKES REGION SOUTHWESTWARD TO TEXAS...AND INTO THE LOWER MISSISSIPPI VALLEY AREA... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and even a tornado may also occur. ...Synopsis... A broad area of cyclonic flow aloft will remain in place over the western two-thirds of the country, and is expected to gradually expand eastward with time. As the upper troughing expands, a surface baroclinic zone extending from the Texas Panhandle to the Upper Great Lakes will gradually shift southeastward as a cold front, particularly during the second half of the period. Along and ahead of this boundary, convection -- and isolated severe weather -- is expected to evolve. ...Southern Upper Great Lakes vicinity southwestward to Texas... While weak capping should prevail across the southern Plains today, mixing in the vicinity of a weak dryline over central Texas could allow an isolated storm or two to develop, and possibly persist into the evening. Given steep lapse rates aloft and deep mixed layer, hail and/or wind exceeding severe levels could occur, in this highly conditional scenario. More likely development of showers and thunderstorms is expected along the surface baroclinic zone that extends northward into the Upper Great Lakes region, perhaps beginning late this afternoon across northern portions of the risk area and then expanding southward along the cold front with time. With moderately strong flow aloft atop the frontal zone across northern portions of the risk area, a couple of stronger/rotating storms may evolve. Though hail is expected to be the main risk given steep mid-level lapse rates, a locally strong gust or two, or brief tornado, would also be possible if a sustained, rotating storm can develop. As storms develop south-southwestward into the evening and overnight, into a region of weaker shear but steep lapse rates, potential for hail with a few of the strongest storms is expected. At this time, any focused areas for greater severe potential remain difficult to discern, and thus will maintain the broad MRGL risk area this forecast. ...Lower Mississippi Valley vicinity... Weak QG ascent is forecast to spread into Louisiana and adjacent Mississippi this afternoon and into this evening, as somewhat ill-defined/weak cyclonic disturbances in the southern-stream flow move across northern Mexico and Texas this morning, and begin affecting the Lower Mississippi Valley area. A gradual increase in convection through the afternoon is expected, as weak destabilization of the moist boundary layer occurs. Some increase in mid-level west-southwesterly flow with time will occur across this area, as the upper disturbance(s) approach, providing ample shear for a few stronger storms to potentially evolve. Hail would likely remain the primary severe risk with one or two of the strongest storms, though a stronger wind gust or even a brief tornado cannot be ruled out given weakly veering flow with height, and the moist boundary layer supporting surface-based updrafts. ..Goss/Broyles.. 03/04/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0400 AM CST Mon Mar 04 2024 Valid 071200Z - 121200Z ...DISCUSSION... A multi-day severe event appears increasingly probable for the latter portion of this week into the early weekend. For Day 4/Thursday, a 15% severe area has been introduced across parts of TX into the lower MS Valley for mainly a large hail threat Thursday night into early Friday morning. A southern-stream upper trough is forecast to eject across the Southwest/northern Mexico into the southern Plains in this time frame. Steep mid-level lapse rates should overspread the gradually destabilizing warm sector, with the ECMWF and its ensemble in particular suggesting that ample MUCAPE will be available Thursday night across parts of north-central into east TX. Any thunderstorms that can initiate in the strengthening low-level warm advection regime across this region should pose a threat for large hail given ample cloud-bearing shear to support elevated supercells. Some of this activity could become near-surface-based towards 12Z Friday morning across the lower MS Valley as surface dewpoints quickly increase into the mid/upper 60s. The severe threat will likely continue into Day 5/Friday, where a 15% severe area has been introduced from east TX into the lower MS Valley and parts of the central Gulf Coast states. There is still some uncertainty in guidance regarding the ejection of the upper trough and placement of related surface features. Regardless, there is enough agreement that rich low-level moisture will advance inland across these areas to support a threat for surface-based convection ahead of whatever activity develops across north-central TX late Thursday night into early Friday morning. Forecast soundings from both the GFS and ECMWF show strong effective bulk shear that will support the potential for supercells producing large hail, damaging winds, and tornadoes. Convection may also grow upscale into bowing line segments while continuing to pose a threat for severe/damaging winds and a few tornadoes. The main uncertainty remains how far inland/north the warm sector will be able to advance, particularly across MS/AL. For now, have opted to remain conservative with the northward extent of the 15% severe area by highlighting where at least mid 60s surface dewpoints appear probable. Some severe risk may persist into Day 6/Saturday across parts of the Southeast towards the Carolinas. However, model guidance shows substantial spread in the evolution of the upper trough at this extended time frame. Convection may also have a tendency to outpace the developing warm sector with time. While parts of FL/GA/SC/NC will be monitored for possible inclusion in a 15% severe area in later outlooks, predictability for early this weekend remains too low at this time. Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Mon Mar 04 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula. ...Synopsis... An upper trough is forecast to advance quickly northeastward across FL, GA, and the Carolinas into the western Atlantic on Wednesday. A related, weak surface low should develop over inland portions of GA to the southeastern VA vicinity by Wednesday afternoon. While isolated thunderstorms appear possible across these areas along/east of a front, greater instability should generally remain offshore over the warmer Gulf Stream waters. A separate area of thunderstorm activity may also occur primarily Wednesday night across parts of the southern/central Plains as low-level moisture gradually advances northward over these regions ahead of a developing upper cyclone over the eastern Pacific and adjacent portions of the Southwest and northern Mexico. MUCAPE is currently expected to remain too limited to support a meaningful hail threat with any elevated thunderstorms that can develop with strengthening low-level warm advection through the end of the period. ...Florida Peninsula... Cool temperatures at mid levels (500 mb around -10 to -12C) should aid in moderate instability developing across parts of the central and southern FL Peninsula through Wednesday afternoon. Ascent associated with the upper trough, and a related mid/upper-level jet, will help foster scattered thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the day. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels should support an isolated hail threat with any of the stronger cores that can develop. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates steepen with daytime heating. Even though the overall severe threat may tend to remain fairly isolated, there is enough of a favorable signal in most guidance for convection to include a Marginal Risk for parts of the central/southern FL Peninsula. ..Gleason.. 03/04/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Mon Mar 04 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula. ...Synopsis... An upper trough is forecast to advance quickly northeastward across FL, GA, and the Carolinas into the western Atlantic on Wednesday. A related, weak surface low should develop over inland portions of GA to the southeastern VA vicinity by Wednesday afternoon. While isolated thunderstorms appear possible across these areas along/east of a front, greater instability should generally remain offshore over the warmer Gulf Stream waters. A separate area of thunderstorm activity may also occur primarily Wednesday night across parts of the southern/central Plains as low-level moisture gradually advances northward over these regions ahead of a developing upper cyclone over the eastern Pacific and adjacent portions of the Southwest and northern Mexico. MUCAPE is currently expected to remain too limited to support a meaningful hail threat with any elevated thunderstorms that can develop with strengthening low-level warm advection through the end of the period. ...Florida Peninsula... Cool temperatures at mid levels (500 mb around -10 to -12C) should aid in moderate instability developing across parts of the central and southern FL Peninsula through Wednesday afternoon. Ascent associated with the upper trough, and a related mid/upper-level jet, will help foster scattered thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the day. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels should support an isolated hail threat with any of the stronger cores that can develop. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates steepen with daytime heating. Even though the overall severe threat may tend to remain fairly isolated, there is enough of a favorable signal in most guidance for convection to include a Marginal Risk for parts of the central/southern FL Peninsula. ..Gleason.. 03/04/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Mon Mar 04 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula. ...Synopsis... An upper trough is forecast to advance quickly northeastward across FL, GA, and the Carolinas into the western Atlantic on Wednesday. A related, weak surface low should develop over inland portions of GA to the southeastern VA vicinity by Wednesday afternoon. While isolated thunderstorms appear possible across these areas along/east of a front, greater instability should generally remain offshore over the warmer Gulf Stream waters. A separate area of thunderstorm activity may also occur primarily Wednesday night across parts of the southern/central Plains as low-level moisture gradually advances northward over these regions ahead of a developing upper cyclone over the eastern Pacific and adjacent portions of the Southwest and northern Mexico. MUCAPE is currently expected to remain too limited to support a meaningful hail threat with any elevated thunderstorms that can develop with strengthening low-level warm advection through the end of the period. ...Florida Peninsula... Cool temperatures at mid levels (500 mb around -10 to -12C) should aid in moderate instability developing across parts of the central and southern FL Peninsula through Wednesday afternoon. Ascent associated with the upper trough, and a related mid/upper-level jet, will help foster scattered thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the day. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels should support an isolated hail threat with any of the stronger cores that can develop. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates steepen with daytime heating. Even though the overall severe threat may tend to remain fairly isolated, there is enough of a favorable signal in most guidance for convection to include a Marginal Risk for parts of the central/southern FL Peninsula. ..Gleason.. 03/04/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Mon Mar 04 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula. ...Synopsis... An upper trough is forecast to advance quickly northeastward across FL, GA, and the Carolinas into the western Atlantic on Wednesday. A related, weak surface low should develop over inland portions of GA to the southeastern VA vicinity by Wednesday afternoon. While isolated thunderstorms appear possible across these areas along/east of a front, greater instability should generally remain offshore over the warmer Gulf Stream waters. A separate area of thunderstorm activity may also occur primarily Wednesday night across parts of the southern/central Plains as low-level moisture gradually advances northward over these regions ahead of a developing upper cyclone over the eastern Pacific and adjacent portions of the Southwest and northern Mexico. MUCAPE is currently expected to remain too limited to support a meaningful hail threat with any elevated thunderstorms that can develop with strengthening low-level warm advection through the end of the period. ...Florida Peninsula... Cool temperatures at mid levels (500 mb around -10 to -12C) should aid in moderate instability developing across parts of the central and southern FL Peninsula through Wednesday afternoon. Ascent associated with the upper trough, and a related mid/upper-level jet, will help foster scattered thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the day. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels should support an isolated hail threat with any of the stronger cores that can develop. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates steepen with daytime heating. Even though the overall severe threat may tend to remain fairly isolated, there is enough of a favorable signal in most guidance for convection to include a Marginal Risk for parts of the central/southern FL Peninsula. ..Gleason.. 03/04/2024 Read more

SPC 0830Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0228 AM CST Mon Mar 04 2024 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Isolated strong to severe thunderstorms may occur Wednesday across parts of the Florida Peninsula. ...Synopsis... An upper trough is forecast to advance quickly northeastward across FL, GA, and the Carolinas into the western Atlantic on Wednesday. A related, weak surface low should develop over inland portions of GA to the southeastern VA vicinity by Wednesday afternoon. While isolated thunderstorms appear possible across these areas along/east of a front, greater instability should generally remain offshore over the warmer Gulf Stream waters. A separate area of thunderstorm activity may also occur primarily Wednesday night across parts of the southern/central Plains as low-level moisture gradually advances northward over these regions ahead of a developing upper cyclone over the eastern Pacific and adjacent portions of the Southwest and northern Mexico. MUCAPE is currently expected to remain too limited to support a meaningful hail threat with any elevated thunderstorms that can develop with strengthening low-level warm advection through the end of the period. ...Florida Peninsula... Cool temperatures at mid levels (500 mb around -10 to -12C) should aid in moderate instability developing across parts of the central and southern FL Peninsula through Wednesday afternoon. Ascent associated with the upper trough, and a related mid/upper-level jet, will help foster scattered thunderstorms moving eastward from the eastern Gulf across the FL Peninsula through the day. Even though deep-layer shear may only strengthen to around 25-35 kt, somewhat elongated/straight hodographs at mid/upper levels should support an isolated hail threat with any of the stronger cores that can develop. Occasional damaging winds also appear possible with convective downdrafts as low-level lapse rates steepen with daytime heating. Even though the overall severe threat may tend to remain fairly isolated, there is enough of a favorable signal in most guidance for convection to include a Marginal Risk for parts of the central/southern FL Peninsula. ..Gleason.. 03/04/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Mon Mar 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST TEXAS/OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms appear possible Tuesday across parts of east Texas/Oklahoma into the lower Mississippi Valley. Occasional large hail and damaging winds should be the main threats. ...East Texas/Oklahoma into the Lower Mississippi Valley... A mid-level, southern-stream shortwave trough will be located over the lower MS Valley at the start of the period Tuesday morning. This feature should continue moving east-northeastward across the central Gulf Coast states and Southeast through early Wednesday morning. Multiple clusters of thunderstorms will probably be ongoing Tuesday morning across parts of east TX into the lower MS Valley in association with modest lift attendant to the shortwave trough. Although boundary-layer instability may be somewhat muted Tuesday morning with lingering MLCIN, the presence of modestly steepened mid-level lapse rates and diurnal heating of a moist low-level airmass should contribute to weak to moderate instability developing by Tuesday afternoon east of a surface dryline across east TX, and south of a cold front extending from central/eastern OK into the Ozarks and mid MS Valley. Isolated hail and damaging winds may occur with the ongoing activity Tuesday morning, as enhanced mid-level winds with the shortwave trough contribute to sufficient deep-layer shear to support some updraft organization. Various high-resolution model guidance suggests potential for this morning activity to consolidate into one or more clusters as it spreads east-southeastward over the lower MS Valley. If this occurs, then perhaps a greater damaging wind threat may exist assuming sufficient destabilization is realized. Once these thunderstorms move offshore, the isolated severe threat should generally lessen across the lower MS Valley, except for in the vicinity of the cold front and dryline. Additional convective development along both of these boundaries Tuesday afternoon appears possible, even though large-scale ascent will be nebulous at best behind the departing shortwave trough. Still, with moderate MLCAPE forecast to develop by both the NAM and RAP, any robust convection that can develop could produce isolated large hail and damaging winds, even as deep-layer shear remains modest. The Marginal Risk for hail/wind has been expanded northward a bit into eastern OK, AR, and towards the Mid-South vicinity to account for this possible afternoon/early evening development. ..Gleason.. 03/04/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Mon Mar 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST TEXAS/OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms appear possible Tuesday across parts of east Texas/Oklahoma into the lower Mississippi Valley. Occasional large hail and damaging winds should be the main threats. ...East Texas/Oklahoma into the Lower Mississippi Valley... A mid-level, southern-stream shortwave trough will be located over the lower MS Valley at the start of the period Tuesday morning. This feature should continue moving east-northeastward across the central Gulf Coast states and Southeast through early Wednesday morning. Multiple clusters of thunderstorms will probably be ongoing Tuesday morning across parts of east TX into the lower MS Valley in association with modest lift attendant to the shortwave trough. Although boundary-layer instability may be somewhat muted Tuesday morning with lingering MLCIN, the presence of modestly steepened mid-level lapse rates and diurnal heating of a moist low-level airmass should contribute to weak to moderate instability developing by Tuesday afternoon east of a surface dryline across east TX, and south of a cold front extending from central/eastern OK into the Ozarks and mid MS Valley. Isolated hail and damaging winds may occur with the ongoing activity Tuesday morning, as enhanced mid-level winds with the shortwave trough contribute to sufficient deep-layer shear to support some updraft organization. Various high-resolution model guidance suggests potential for this morning activity to consolidate into one or more clusters as it spreads east-southeastward over the lower MS Valley. If this occurs, then perhaps a greater damaging wind threat may exist assuming sufficient destabilization is realized. Once these thunderstorms move offshore, the isolated severe threat should generally lessen across the lower MS Valley, except for in the vicinity of the cold front and dryline. Additional convective development along both of these boundaries Tuesday afternoon appears possible, even though large-scale ascent will be nebulous at best behind the departing shortwave trough. Still, with moderate MLCAPE forecast to develop by both the NAM and RAP, any robust convection that can develop could produce isolated large hail and damaging winds, even as deep-layer shear remains modest. The Marginal Risk for hail/wind has been expanded northward a bit into eastern OK, AR, and towards the Mid-South vicinity to account for this possible afternoon/early evening development. ..Gleason.. 03/04/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Mon Mar 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST TEXAS/OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms appear possible Tuesday across parts of east Texas/Oklahoma into the lower Mississippi Valley. Occasional large hail and damaging winds should be the main threats. ...East Texas/Oklahoma into the Lower Mississippi Valley... A mid-level, southern-stream shortwave trough will be located over the lower MS Valley at the start of the period Tuesday morning. This feature should continue moving east-northeastward across the central Gulf Coast states and Southeast through early Wednesday morning. Multiple clusters of thunderstorms will probably be ongoing Tuesday morning across parts of east TX into the lower MS Valley in association with modest lift attendant to the shortwave trough. Although boundary-layer instability may be somewhat muted Tuesday morning with lingering MLCIN, the presence of modestly steepened mid-level lapse rates and diurnal heating of a moist low-level airmass should contribute to weak to moderate instability developing by Tuesday afternoon east of a surface dryline across east TX, and south of a cold front extending from central/eastern OK into the Ozarks and mid MS Valley. Isolated hail and damaging winds may occur with the ongoing activity Tuesday morning, as enhanced mid-level winds with the shortwave trough contribute to sufficient deep-layer shear to support some updraft organization. Various high-resolution model guidance suggests potential for this morning activity to consolidate into one or more clusters as it spreads east-southeastward over the lower MS Valley. If this occurs, then perhaps a greater damaging wind threat may exist assuming sufficient destabilization is realized. Once these thunderstorms move offshore, the isolated severe threat should generally lessen across the lower MS Valley, except for in the vicinity of the cold front and dryline. Additional convective development along both of these boundaries Tuesday afternoon appears possible, even though large-scale ascent will be nebulous at best behind the departing shortwave trough. Still, with moderate MLCAPE forecast to develop by both the NAM and RAP, any robust convection that can develop could produce isolated large hail and damaging winds, even as deep-layer shear remains modest. The Marginal Risk for hail/wind has been expanded northward a bit into eastern OK, AR, and towards the Mid-South vicinity to account for this possible afternoon/early evening development. ..Gleason.. 03/04/2024 Read more

SPC 0700Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1250 AM CST Mon Mar 04 2024 Valid 051200Z - 061200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF EAST TEXAS/OKLAHOMA INTO THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Isolated strong to severe thunderstorms appear possible Tuesday across parts of east Texas/Oklahoma into the lower Mississippi Valley. Occasional large hail and damaging winds should be the main threats. ...East Texas/Oklahoma into the Lower Mississippi Valley... A mid-level, southern-stream shortwave trough will be located over the lower MS Valley at the start of the period Tuesday morning. This feature should continue moving east-northeastward across the central Gulf Coast states and Southeast through early Wednesday morning. Multiple clusters of thunderstorms will probably be ongoing Tuesday morning across parts of east TX into the lower MS Valley in association with modest lift attendant to the shortwave trough. Although boundary-layer instability may be somewhat muted Tuesday morning with lingering MLCIN, the presence of modestly steepened mid-level lapse rates and diurnal heating of a moist low-level airmass should contribute to weak to moderate instability developing by Tuesday afternoon east of a surface dryline across east TX, and south of a cold front extending from central/eastern OK into the Ozarks and mid MS Valley. Isolated hail and damaging winds may occur with the ongoing activity Tuesday morning, as enhanced mid-level winds with the shortwave trough contribute to sufficient deep-layer shear to support some updraft organization. Various high-resolution model guidance suggests potential for this morning activity to consolidate into one or more clusters as it spreads east-southeastward over the lower MS Valley. If this occurs, then perhaps a greater damaging wind threat may exist assuming sufficient destabilization is realized. Once these thunderstorms move offshore, the isolated severe threat should generally lessen across the lower MS Valley, except for in the vicinity of the cold front and dryline. Additional convective development along both of these boundaries Tuesday afternoon appears possible, even though large-scale ascent will be nebulous at best behind the departing shortwave trough. Still, with moderate MLCAPE forecast to develop by both the NAM and RAP, any robust convection that can develop could produce isolated large hail and damaging winds, even as deep-layer shear remains modest. The Marginal Risk for hail/wind has been expanded northward a bit into eastern OK, AR, and towards the Mid-South vicinity to account for this possible afternoon/early evening development. ..Gleason.. 03/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CST Sun Mar 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE LOWER/MID MS VALLEY AND MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and a tornado or two may also occur. ...Synopsis... A large-scale mid/upper-level trough will cover much of the central/western CONUS through the day. Within the broader trough, multiple belts of stronger flow will impinge upon portions of the southern Plains, lower/mid MS Valley, and Midwest. A strong northern-stream shortwave trough will move quickly northeastward away from the upper Great Lakes during the morning, with multiple lower-amplitude vorticity maxima following in its wake. Meanwhile, a southern-stream mid/upper-level shortwave trough will move from northern Mexico into Texas by afternoon, and towards the lower MS Valley by late evening. A surface cyclone is forecast to move along a frontal boundary from the south-central Plains northeastward toward the mid MS Valley by evening. ...Parts of IL/MO into eastern IA and southern WI... A surface boundary is forecast to move northward as a warm front into parts of eastern IA, northern IL, and perhaps southern WI during the day, before stalling and then moving southeastward as a cold front during the evening. Across the warm sector, modest low-level moisture (dewpoints generally in the mid/upper 50s F) beneath relatively cold temperatures aloft will support MLCAPE increasing into the 1000-1500 J/kg range this afternoon. Some weakening of mid/upper-level flow is expected through the day in the wake of the departing shortwave, but will remain sufficient to support effective shear of 35-45 kt, which is conditionally favorable for organized convection. While a strong elevated storm or two will be possible across WI during the morning, the primary concern is for storm development in the vicinity of the surface front by late afternoon or early evening. Guidance varies regarding the timing of initiation and placement of the surface features, but in general, scattered thunderstorm development is expected from northeast MO/eastern IA into northern IL and southern WI. An initial supercell or two will be possible, though there may be a tendency toward more of a complex or linear mode with time as the front begins to push southeastward. Hail appears to be the most likely hazard at this time, though there will also be some potential for isolated strong/damaging gusts. Some tornado potential could also evolve if a surface-based supercell or two can be sustained. Uncertainties regarding placement/timing of the surface front and longevity of any supercell potential preclude higher probabilities across the region at this time. ...Parts of TX/eastern OK into the Ozarks and lower MS Valley... Relatively rich low-level moisture (with dewpoints increasing through the 60s F) will stream northward through the day across parts of TX, eastern OK, AR, and LA. Thunderstorm development will be possible by late morning into the afternoon along the northern periphery of the deeper returning moisture across parts of LA and perhaps into adjacent portions of southwest MS and southeast TX. Steep midlevel lapse rates atop the deepening moisture will support preconvective MLCAPE of 1500-2000 J/kg, with sufficient deep-layer shear for organized convection. A few strong multicells and perhaps a supercell or two will be possible, with an attendant threat of hail and locally damaging gusts. Farther west into TX, the diurnal severe threat is more conditional, with large-scale ascent expected to remain rather weak and relatively limited convergence along the dryline. However, a very isolated supercell or two cannot be ruled out during the late afternoon and evening, which would pose a large-hail threat. Overnight, most guidance suggests renewed storm development near the ArkLaTex region, likely in response to the southern-stream shortwave trough approaching the region. Storms within this late-night regime would likely be slightly elevated, but moderate buoyancy and favorable deep-layer shear may support an isolated hail and/or damaging-gust threat into early Tuesday morning. ..Dean/Weinman.. 03/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CST Sun Mar 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE LOWER/MID MS VALLEY AND MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and a tornado or two may also occur. ...Synopsis... A large-scale mid/upper-level trough will cover much of the central/western CONUS through the day. Within the broader trough, multiple belts of stronger flow will impinge upon portions of the southern Plains, lower/mid MS Valley, and Midwest. A strong northern-stream shortwave trough will move quickly northeastward away from the upper Great Lakes during the morning, with multiple lower-amplitude vorticity maxima following in its wake. Meanwhile, a southern-stream mid/upper-level shortwave trough will move from northern Mexico into Texas by afternoon, and towards the lower MS Valley by late evening. A surface cyclone is forecast to move along a frontal boundary from the south-central Plains northeastward toward the mid MS Valley by evening. ...Parts of IL/MO into eastern IA and southern WI... A surface boundary is forecast to move northward as a warm front into parts of eastern IA, northern IL, and perhaps southern WI during the day, before stalling and then moving southeastward as a cold front during the evening. Across the warm sector, modest low-level moisture (dewpoints generally in the mid/upper 50s F) beneath relatively cold temperatures aloft will support MLCAPE increasing into the 1000-1500 J/kg range this afternoon. Some weakening of mid/upper-level flow is expected through the day in the wake of the departing shortwave, but will remain sufficient to support effective shear of 35-45 kt, which is conditionally favorable for organized convection. While a strong elevated storm or two will be possible across WI during the morning, the primary concern is for storm development in the vicinity of the surface front by late afternoon or early evening. Guidance varies regarding the timing of initiation and placement of the surface features, but in general, scattered thunderstorm development is expected from northeast MO/eastern IA into northern IL and southern WI. An initial supercell or two will be possible, though there may be a tendency toward more of a complex or linear mode with time as the front begins to push southeastward. Hail appears to be the most likely hazard at this time, though there will also be some potential for isolated strong/damaging gusts. Some tornado potential could also evolve if a surface-based supercell or two can be sustained. Uncertainties regarding placement/timing of the surface front and longevity of any supercell potential preclude higher probabilities across the region at this time. ...Parts of TX/eastern OK into the Ozarks and lower MS Valley... Relatively rich low-level moisture (with dewpoints increasing through the 60s F) will stream northward through the day across parts of TX, eastern OK, AR, and LA. Thunderstorm development will be possible by late morning into the afternoon along the northern periphery of the deeper returning moisture across parts of LA and perhaps into adjacent portions of southwest MS and southeast TX. Steep midlevel lapse rates atop the deepening moisture will support preconvective MLCAPE of 1500-2000 J/kg, with sufficient deep-layer shear for organized convection. A few strong multicells and perhaps a supercell or two will be possible, with an attendant threat of hail and locally damaging gusts. Farther west into TX, the diurnal severe threat is more conditional, with large-scale ascent expected to remain rather weak and relatively limited convergence along the dryline. However, a very isolated supercell or two cannot be ruled out during the late afternoon and evening, which would pose a large-hail threat. Overnight, most guidance suggests renewed storm development near the ArkLaTex region, likely in response to the southern-stream shortwave trough approaching the region. Storms within this late-night regime would likely be slightly elevated, but moderate buoyancy and favorable deep-layer shear may support an isolated hail and/or damaging-gust threat into early Tuesday morning. ..Dean/Weinman.. 03/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CST Sun Mar 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE LOWER/MID MS VALLEY AND MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and a tornado or two may also occur. ...Synopsis... A large-scale mid/upper-level trough will cover much of the central/western CONUS through the day. Within the broader trough, multiple belts of stronger flow will impinge upon portions of the southern Plains, lower/mid MS Valley, and Midwest. A strong northern-stream shortwave trough will move quickly northeastward away from the upper Great Lakes during the morning, with multiple lower-amplitude vorticity maxima following in its wake. Meanwhile, a southern-stream mid/upper-level shortwave trough will move from northern Mexico into Texas by afternoon, and towards the lower MS Valley by late evening. A surface cyclone is forecast to move along a frontal boundary from the south-central Plains northeastward toward the mid MS Valley by evening. ...Parts of IL/MO into eastern IA and southern WI... A surface boundary is forecast to move northward as a warm front into parts of eastern IA, northern IL, and perhaps southern WI during the day, before stalling and then moving southeastward as a cold front during the evening. Across the warm sector, modest low-level moisture (dewpoints generally in the mid/upper 50s F) beneath relatively cold temperatures aloft will support MLCAPE increasing into the 1000-1500 J/kg range this afternoon. Some weakening of mid/upper-level flow is expected through the day in the wake of the departing shortwave, but will remain sufficient to support effective shear of 35-45 kt, which is conditionally favorable for organized convection. While a strong elevated storm or two will be possible across WI during the morning, the primary concern is for storm development in the vicinity of the surface front by late afternoon or early evening. Guidance varies regarding the timing of initiation and placement of the surface features, but in general, scattered thunderstorm development is expected from northeast MO/eastern IA into northern IL and southern WI. An initial supercell or two will be possible, though there may be a tendency toward more of a complex or linear mode with time as the front begins to push southeastward. Hail appears to be the most likely hazard at this time, though there will also be some potential for isolated strong/damaging gusts. Some tornado potential could also evolve if a surface-based supercell or two can be sustained. Uncertainties regarding placement/timing of the surface front and longevity of any supercell potential preclude higher probabilities across the region at this time. ...Parts of TX/eastern OK into the Ozarks and lower MS Valley... Relatively rich low-level moisture (with dewpoints increasing through the 60s F) will stream northward through the day across parts of TX, eastern OK, AR, and LA. Thunderstorm development will be possible by late morning into the afternoon along the northern periphery of the deeper returning moisture across parts of LA and perhaps into adjacent portions of southwest MS and southeast TX. Steep midlevel lapse rates atop the deepening moisture will support preconvective MLCAPE of 1500-2000 J/kg, with sufficient deep-layer shear for organized convection. A few strong multicells and perhaps a supercell or two will be possible, with an attendant threat of hail and locally damaging gusts. Farther west into TX, the diurnal severe threat is more conditional, with large-scale ascent expected to remain rather weak and relatively limited convergence along the dryline. However, a very isolated supercell or two cannot be ruled out during the late afternoon and evening, which would pose a large-hail threat. Overnight, most guidance suggests renewed storm development near the ArkLaTex region, likely in response to the southern-stream shortwave trough approaching the region. Storms within this late-night regime would likely be slightly elevated, but moderate buoyancy and favorable deep-layer shear may support an isolated hail and/or damaging-gust threat into early Tuesday morning. ..Dean/Weinman.. 03/04/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1155 PM CST Sun Mar 03 2024 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE SOUTHERN PLAINS INTO THE LOWER/MID MS VALLEY AND MIDWEST... ...SUMMARY... Isolated strong to severe thunderstorms will be possible this afternoon into tonight from parts of central Texas into the lower Mississippi Valley, as well as from the Ozarks into the Midwest. Large hail is expected to be the main threat, but strong/gusty winds and a tornado or two may also occur. ...Synopsis... A large-scale mid/upper-level trough will cover much of the central/western CONUS through the day. Within the broader trough, multiple belts of stronger flow will impinge upon portions of the southern Plains, lower/mid MS Valley, and Midwest. A strong northern-stream shortwave trough will move quickly northeastward away from the upper Great Lakes during the morning, with multiple lower-amplitude vorticity maxima following in its wake. Meanwhile, a southern-stream mid/upper-level shortwave trough will move from northern Mexico into Texas by afternoon, and towards the lower MS Valley by late evening. A surface cyclone is forecast to move along a frontal boundary from the south-central Plains northeastward toward the mid MS Valley by evening. ...Parts of IL/MO into eastern IA and southern WI... A surface boundary is forecast to move northward as a warm front into parts of eastern IA, northern IL, and perhaps southern WI during the day, before stalling and then moving southeastward as a cold front during the evening. Across the warm sector, modest low-level moisture (dewpoints generally in the mid/upper 50s F) beneath relatively cold temperatures aloft will support MLCAPE increasing into the 1000-1500 J/kg range this afternoon. Some weakening of mid/upper-level flow is expected through the day in the wake of the departing shortwave, but will remain sufficient to support effective shear of 35-45 kt, which is conditionally favorable for organized convection. While a strong elevated storm or two will be possible across WI during the morning, the primary concern is for storm development in the vicinity of the surface front by late afternoon or early evening. Guidance varies regarding the timing of initiation and placement of the surface features, but in general, scattered thunderstorm development is expected from northeast MO/eastern IA into northern IL and southern WI. An initial supercell or two will be possible, though there may be a tendency toward more of a complex or linear mode with time as the front begins to push southeastward. Hail appears to be the most likely hazard at this time, though there will also be some potential for isolated strong/damaging gusts. Some tornado potential could also evolve if a surface-based supercell or two can be sustained. Uncertainties regarding placement/timing of the surface front and longevity of any supercell potential preclude higher probabilities across the region at this time. ...Parts of TX/eastern OK into the Ozarks and lower MS Valley... Relatively rich low-level moisture (with dewpoints increasing through the 60s F) will stream northward through the day across parts of TX, eastern OK, AR, and LA. Thunderstorm development will be possible by late morning into the afternoon along the northern periphery of the deeper returning moisture across parts of LA and perhaps into adjacent portions of southwest MS and southeast TX. Steep midlevel lapse rates atop the deepening moisture will support preconvective MLCAPE of 1500-2000 J/kg, with sufficient deep-layer shear for organized convection. A few strong multicells and perhaps a supercell or two will be possible, with an attendant threat of hail and locally damaging gusts. Farther west into TX, the diurnal severe threat is more conditional, with large-scale ascent expected to remain rather weak and relatively limited convergence along the dryline. However, a very isolated supercell or two cannot be ruled out during the late afternoon and evening, which would pose a large-hail threat. Overnight, most guidance suggests renewed storm development near the ArkLaTex region, likely in response to the southern-stream shortwave trough approaching the region. Storms within this late-night regime would likely be slightly elevated, but moderate buoyancy and favorable deep-layer shear may support an isolated hail and/or damaging-gust threat into early Tuesday morning. ..Dean/Weinman.. 03/04/2024 Read more