Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Fri Mar 22 2024 Valid 221630Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...South FL and the Keys... Few changes have been made to the ongoing forecast. Multiple MCSs continue to be noted over the Gulf of Mexico today, tracking slowly eastward. The first system is affecting far south FL, with widespread precipitation and a few embedded thunderstorms. Dense cloud cover is limiting destabilization, suggesting that near-term severe threat is rather low. Nevertheless, an isolated cell cable of gusty winds or a brief spin-up is possible through mid-afternoon. A second MCS is seen on IR imagery over the central Gulf and will approach south FL and the Keys after dark. It is unclear whether destabilization will occur in the wake of the first system, but CAM guidance suggests a somewhat greater potential for organized convection and perhaps a few supercells in the 03-06z period. Forecast soundings indicate relatively strong low-level and deep layer shear during this time, promoting a risk of damaging winds or perhaps a tornado or two. This risk is conditional on the evolution of the first MCS and whether the air mass can recover. ...FL Panhandle... Another cluster of thunderstorms is occurring late this morning over southern AL and southeast LA. This activity will track eastward across the FL Panhandle through the day. Considerable cloud cover and limited low-level moisture (dewpoints in the upper 50s and lower 60s) will limit instability. However, most CAM solutions indicate a few stronger updrafts may develop later this afternoon. Relatively cool temperatures aloft and moderately steep mid-level lapse rates would suggest some risk of hail or gusty winds in any robust cells that can form. ..Hart/Thornton.. 03/22/2024 Read more

MD 0281 CONCERNING HEAVY SNOW FOR NORTHEAST IA TO THE IL/WI BORDER
Mesoscale Discussion 0281 NWS Storm Prediction Center Norman OK 0611 AM CDT Fri Mar 22 2024 Areas affected...Northeast IA to the IL/WI border Concerning...Heavy snow Valid 221111Z - 221515Z SUMMARY...A narrow band of heavy snow developing in north-central Iowa should shift east across parts of northeast Iowa towards the Illinois-Wisconsin border through late morning. Rates of 1-2"/hr should be expected, but may remain of relatively short-duration at any one location. DISCUSSION...The north side of a high-reflectivity convective plume across central IA appears to have finally cooled enough to maintain all snow to the surface, per recent surface observations and DOT cameras. 03Z SREF probabilities and 00Z HREF snowbands guidance have been highly insistent that a relatively narrow (around 25 miles wide) heavy snow band should translate east, likely centered on the US-20 corridor per observational trends. This suggests heavy snow will be of relatively short duration at any one location, but snowfall rates should easily reach 1-2"/hr given the focused 700-mb frontogenesis beneath the dendritic growth zone and the deep, nearly isothermal layer just below freezing to the surface. ..Grams.. 03/22/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...MKX...DVN...ARX...DMX... LAT...LON 42479377 42669334 42839235 42899085 42918998 42868936 42748915 42528915 42298930 42188951 42159017 42019145 42059249 42099316 42239373 42479377 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0742 AM CDT Fri Mar 22 2024 Valid 221300Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE FLORIDA KEYS INTO A SMALL PART OF SOUTHERN MAINLAND FLORIDA... ...SUMMARY... Severe thunderstorm gusts, isolated large hail and a tornado or two are possible today and tonight over parts of the Florida Keys into a small part of southern mainland Florida. ...Synopsis... In mid/upper levels, a slow-moving/cutoff low west of coastal northern CA and OR will approach the coast slowly through the period, but remain offshore until day 2. Downstream, a progressive, split-flow pattern is evident over the central/eastern CONUS, with a broad yet distinct northern-stream jet across parts of the Upper Midwest, Great Lakes, and Northeast. To the south, a prominent, southern-stream shortwave trough was apparent in moisture-channel imagery over eastern OK and east TX, with intermittently closed 500-mb low between MLC-PRX. This perturbation should become a purely open-wave trough today and broaden somewhat, with the trough near a MEM-LFT axis and offshore from southwestern LA by 00Z. The 12Z/tomorrow trough position should reach to near an axis from CHA-MGM-PNS to the central Gulf. At the surface, 11Z analysis showed a broad area of low pressure from north-central/northeast TX to south-central LA, including a frontal-wave low near ARA. A cold front extended from that low southwestward across the TX shelf waters to south of BRO, and should sweep eastward-southeastward to the central/southwestern Gulf by 00Z, when the low reaches southern AL. A warm front -- initially extending from the low eastward over coastal LA then southeastward over the eastern Gulf, should move northeastward toward the north- central/northeastern Gulf Coast and south FL/Keys today, but with some diffusion/realignments of its baroclinicity by convective processes. By the end of the period, the low should reach the Piedmont of the Carolinas, with cold front over GA and the eastern Gulf. Multiple rounds of convection will cross the east-central/ northeastern Gulf through the period on either side of the warm front. Convection should be most consistently intense over the Gulf, but potentially brushing coastal/near-coastal parts of the areas discussed below. ...South FL/Keys... At least isolated severe gusts and/or hail are possible across portions of south FL and the Keys, with the available instability and severe threat increasing southward. Multiple rounds of convection over the eastern Gulf should lay down boundaries acting as both foci and poleward delimiters for organized severe potential of upshear convection. Based on lightning, satellite and radar imagery, the first of these complexes extends from just offshore from APF west-southwestward to near 24N88W, with a patchy precip shield extending eastward and northeastward over much of the peninsula. That precip/cloud cover should blunt most of the diabatic heating-related overland destabilization today, though theta-e advection (especially over the Keys and vicinity) should yield surface-based buoyancy gradually over the next several hours. Most convection-allowing guidance has shrunk/weakened the leading complex considerably while approaching south FL and the Keys this morning, but also, has failed to grasp its southwestward extent so far. As such, mesoscale uncertainty persists as to the ultimate location and layout of the associated outflow boundary. Still, the general idea of greater unconditional severe potential with southward extent remains valid -- be it from the remains of the ongoing activity or, more likely, a later MCS now over the central/ north-central Gulf and expected to turn southeastward along the boundary and toward the outlook area, arriving tonight. Along and south of the boundary, where the near-surface layer is least modified by prior activity, upper 60s to low 70s F surface dewpoints should offset modest midlevel lapse rates aloft enough to yield 1000-1500 J/kg MLCAPE by this evening. Forecast soundings suggest favorable veering of winds with height into strong mid/upper-level flow, with 50-60-kt effective-shear magnitudes. Damaging winds and a tornado or two will be the main concerns. ...Southeastern LA to FL coastal bend... An ongoing, predominantly elevated area of thunderstorms -- from portions of southeastern LA southwestward across the LA shelf waters -- should proceed eastward near the north-central/northeastern Gulf Coast today. Additional development is possible to its east, also over shelf waters and/or the Gulf Coast. Isolated, marginally severe gusts or hail may occur. Activity should continue to move eastward in step with partial destabilization/recovery in the form of low-level warm advection and moisture transport, around and atop outflow from a complex of thunderstorms now over the east-central open Gulf. Enough theta-e recovery in low levels has occurred to support continued organization of the main MCS near the LA coastline, but at strong/ subsevere levels. This general trend should continue as activity shifts eastward across coastal MS/AL/FL Panhandle and offshore, amidst 60-70-kt effective-shear magnitudes and strong midlevel winds supporting fast convective translation. As such, momentum transfer from midlevels (via rear-inflow-jet processes or directly in individual/embedded downdrafts) may produce gusts capable of penetrating to the surface near severe levels. Favorable deep shear and lapse rates aloft also will persist eastward for hail production aloft, some of which may reach the surface near severe limits as well. ..Edwards/Grams.. 03/22/2024 Read more

MD 0280 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR COASTAL SOUTHEAST LA
Mesoscale Discussion 0280 NWS Storm Prediction Center Norman OK 0509 AM CDT Fri Mar 22 2024 Areas affected...Coastal southeast LA Concerning...Severe potential...Watch unlikely Valid 221009Z - 221215Z Probability of Watch Issuance...5 percent SUMMARY...An organized but elevated QLCS should continue eastward across the rest of southeast LA through mid-morning. The tail end of the line segment along the immediate coast will have the best chance to produce strong gusts from 45-60 mph and marginally severe hail of 0.75-1.25". DISCUSSION...A longer-lived MCS with a history of embedded bowing structures has largely evolved into more of a north/south-oriented short-line segment across south-central LA and the adjacent nearshore waters. A pronounced rear-inflow jet is evident in the time-series of LCH VWP data, and this line segment should remain organized as it progresses east across southeast LA. Peak measured wind gusts have ranged from 45-50 mph, as the elevated character of the line segment has mitigated severe gusts at the surface. With the line paralleling the MUCAPE gradient, convection closer to the immediate coast will have the best chance to become marginally severe. The offshore surface warm front should continue to drift north, but it does not appear it will advance inland fast enough relative to the line's forward speed, outside of possibly Plaquemines Parish. ..Grams/Edwards.. 03/22/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LIX...LCH... LAT...LON 29929171 29969092 30078997 30298929 30378875 30248844 29798849 29078880 28908918 28838954 28869006 28889124 29159181 29929171 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Mar 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... A highly amplified upper trough, with multiple embedded shortwaves, appears likely to continue progressing eastward across the western/central CONUS early next week. One such shortwave trough should move quickly northeastward across the Upper Midwest while becoming increasingly displaced from the surface warm sector. Another, southern-stream shortwave trough is forecast to advance across northern Mexico and the southern Plains into the lower MS Valley and Southeast from Day 4/Monday into Day 5/Tuesday. A consensus of the latest deterministic and ensemble guidance shows a somewhat slower ejection of the southern-stream shortwave trough, and related placement of a surface cold front. Accordingly, greater low-level moisture may not advance as far northward across the lower MS Valley as previously expected. The 15% severe delineation for Monday has been adjusted accordingly, and highlights the area where confidence is greatest that weak, but sufficient, instability will overlap with strong low-level and deep-layer shear. A risk of supercells/bowing line segments and tornadoes should exist Monday through Monday night from parts of east TX into LA/MS and vicinity, along and south of a warm front and secondary surface low development. The embedded shortwave trough should move north-northeastward across the lower MS Valley into the TN/OH Valleys on Tuesday. Greater low-level moisture (60s surface dewpoints) will likely remain confined to portions of the central Gulf Coast states, namely southeastern LA into southern/central MS/AL and the FL Panhandle. These areas will perhaps have the best potential for a continuation of the Monday severe threat into Tuesday. But, there are concerns that the convection will outpace the low-level moisture return. Will defer the possible inclusion of a 15% severe area for Tuesday across this region to a later outlook, pending greater confidence that convection will be able to maintain its intensity and remain surface-based. For Day 6/Wednesday and beyond, potential for a continuation of the severe threat across parts of the southeastern states becomes even more uncertain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Mar 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... A highly amplified upper trough, with multiple embedded shortwaves, appears likely to continue progressing eastward across the western/central CONUS early next week. One such shortwave trough should move quickly northeastward across the Upper Midwest while becoming increasingly displaced from the surface warm sector. Another, southern-stream shortwave trough is forecast to advance across northern Mexico and the southern Plains into the lower MS Valley and Southeast from Day 4/Monday into Day 5/Tuesday. A consensus of the latest deterministic and ensemble guidance shows a somewhat slower ejection of the southern-stream shortwave trough, and related placement of a surface cold front. Accordingly, greater low-level moisture may not advance as far northward across the lower MS Valley as previously expected. The 15% severe delineation for Monday has been adjusted accordingly, and highlights the area where confidence is greatest that weak, but sufficient, instability will overlap with strong low-level and deep-layer shear. A risk of supercells/bowing line segments and tornadoes should exist Monday through Monday night from parts of east TX into LA/MS and vicinity, along and south of a warm front and secondary surface low development. The embedded shortwave trough should move north-northeastward across the lower MS Valley into the TN/OH Valleys on Tuesday. Greater low-level moisture (60s surface dewpoints) will likely remain confined to portions of the central Gulf Coast states, namely southeastern LA into southern/central MS/AL and the FL Panhandle. These areas will perhaps have the best potential for a continuation of the Monday severe threat into Tuesday. But, there are concerns that the convection will outpace the low-level moisture return. Will defer the possible inclusion of a 15% severe area for Tuesday across this region to a later outlook, pending greater confidence that convection will be able to maintain its intensity and remain surface-based. For Day 6/Wednesday and beyond, potential for a continuation of the severe threat across parts of the southeastern states becomes even more uncertain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Mar 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... A highly amplified upper trough, with multiple embedded shortwaves, appears likely to continue progressing eastward across the western/central CONUS early next week. One such shortwave trough should move quickly northeastward across the Upper Midwest while becoming increasingly displaced from the surface warm sector. Another, southern-stream shortwave trough is forecast to advance across northern Mexico and the southern Plains into the lower MS Valley and Southeast from Day 4/Monday into Day 5/Tuesday. A consensus of the latest deterministic and ensemble guidance shows a somewhat slower ejection of the southern-stream shortwave trough, and related placement of a surface cold front. Accordingly, greater low-level moisture may not advance as far northward across the lower MS Valley as previously expected. The 15% severe delineation for Monday has been adjusted accordingly, and highlights the area where confidence is greatest that weak, but sufficient, instability will overlap with strong low-level and deep-layer shear. A risk of supercells/bowing line segments and tornadoes should exist Monday through Monday night from parts of east TX into LA/MS and vicinity, along and south of a warm front and secondary surface low development. The embedded shortwave trough should move north-northeastward across the lower MS Valley into the TN/OH Valleys on Tuesday. Greater low-level moisture (60s surface dewpoints) will likely remain confined to portions of the central Gulf Coast states, namely southeastern LA into southern/central MS/AL and the FL Panhandle. These areas will perhaps have the best potential for a continuation of the Monday severe threat into Tuesday. But, there are concerns that the convection will outpace the low-level moisture return. Will defer the possible inclusion of a 15% severe area for Tuesday across this region to a later outlook, pending greater confidence that convection will be able to maintain its intensity and remain surface-based. For Day 6/Wednesday and beyond, potential for a continuation of the severe threat across parts of the southeastern states becomes even more uncertain. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Fri Mar 22 2024 Valid 251200Z - 301200Z ...DISCUSSION... A highly amplified upper trough, with multiple embedded shortwaves, appears likely to continue progressing eastward across the western/central CONUS early next week. One such shortwave trough should move quickly northeastward across the Upper Midwest while becoming increasingly displaced from the surface warm sector. Another, southern-stream shortwave trough is forecast to advance across northern Mexico and the southern Plains into the lower MS Valley and Southeast from Day 4/Monday into Day 5/Tuesday. A consensus of the latest deterministic and ensemble guidance shows a somewhat slower ejection of the southern-stream shortwave trough, and related placement of a surface cold front. Accordingly, greater low-level moisture may not advance as far northward across the lower MS Valley as previously expected. The 15% severe delineation for Monday has been adjusted accordingly, and highlights the area where confidence is greatest that weak, but sufficient, instability will overlap with strong low-level and deep-layer shear. A risk of supercells/bowing line segments and tornadoes should exist Monday through Monday night from parts of east TX into LA/MS and vicinity, along and south of a warm front and secondary surface low development. The embedded shortwave trough should move north-northeastward across the lower MS Valley into the TN/OH Valleys on Tuesday. Greater low-level moisture (60s surface dewpoints) will likely remain confined to portions of the central Gulf Coast states, namely southeastern LA into southern/central MS/AL and the FL Panhandle. These areas will perhaps have the best potential for a continuation of the Monday severe threat into Tuesday. But, there are concerns that the convection will outpace the low-level moisture return. Will defer the possible inclusion of a 15% severe area for Tuesday across this region to a later outlook, pending greater confidence that convection will be able to maintain its intensity and remain surface-based. For Day 6/Wednesday and beyond, potential for a continuation of the severe threat across parts of the southeastern states becomes even more uncertain. Read more