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SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1024 AM CST Fri Dec 27 2024 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING FROM SOUTHEAST LA/MS INTO SOUTHWEST AL AND THE WESTERN FL PANHANDLE... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Central Gulf Coast Region... A compact negative-tilted shortwave trough that has provided occasionally strong thunderstorms to parts of southern MS/southeast LA is tracking away from the Gulf Coast region. Low-level winds are slowly veering/decreasing with time, suggesting the threat of supercell structures and associated severe threat is marginal through mid-afternoon. Another strong upper trough that is now over north TX will graze the same area late this afternoon, possibly resulting in a re-invigoration of convection across southeast MS and southwest AL. The air mass has been slow to recover, with mid 60s dewpoints restricted to areas just a few rows of counties inland. Widespread clouds will also limit destabilization. Locally gusty winds or a brief tornado will remain possible with this renewed early evening activity, but the overall threat appears marginal. ..Hart/Leitman.. 12/27/2024 Read more

MD 2290 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL GULF COAST
Mesoscale Discussion 2290 NWS Storm Prediction Center Norman OK 0708 AM CST Fri Dec 27 2024 Areas affected...central Gulf Coast Concerning...Severe potential...Watch unlikely Valid 271308Z - 271415Z Probability of Watch Issuance...5 percent SUMMARY...A low-probability, brief tornado risk may persist through the rest of mid-morning across southeast Mississippi. DISCUSSION...A confluent band of mainly discrete convection has persisted over the past couple hours, generally perpendicular to a northwest/southeast-oriented warm front that is roughly approaching a PIB to MOB line. Transient supercell structures have been noted, and these may persist through about 15Z. The 12Z LIX RAOB sampled a bit of near-surface stability, but otherwise contained a conditionally favorable buoyancy/shear space for a supercell tornado. As noted in the 13Z SWODY1, the background synoptic environment is unlikely to support substantially greater organization. In conjunction, with further waning of large-scale ascent, overall tornado potential in this area should be brief and temporally diminish by late morning. ..Grams/Edwards.. 12/27/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MOB...JAN...LIX... LAT...LON 31398902 31288834 30968788 30828772 30268808 30238845 30278896 30228946 30288971 30538972 31188918 31398902 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0643 AM CST Fri Dec 27 2024 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST STATES... ...SUMMARY... A few strong to locally severe thunderstorms could occur today across parts of the central Gulf Coast States. ...Synopsis... In mid/upper levels, a broad area of cyclonic flow will persist around mean troughing, from the Great Basin and Rockies across the Great Plains to the Mississippi Valley. The leading shortwave trough -- in a series of them to influence convective potential through early next week -- is apparent in moisture-channel imagery over the MO Bootheel southward over portions of the Mid-South region. This feature will weaken considerably as it ejects northeastward to OH by 00Z, in response to an upstream trough initially over the southern/central Plains to Black Hills and western Dakotas. That higher-amplitude perturbation will reach the eastern Dakotas, lower Missouri Valley and Ozarks by 00Z, then eject northeastward to the Upper Great Lakes by the end of the period. A third shortwave trough -- currently moving inland from the Pacific Northwest Coast -- should dig southeastward rapidly across the Great Basin, reaching the southern High Plains and Permian Basin regions by 12Z tomorrow. At the surface, 11Z analysis showed a low over the western Ozarks between SGF-HRO, with occluded front arching across the Mid-South to west-central MS, warm front over south-central MS to near MOB then southeastward across the FL Keys. A slow-moving cold to quasistationary front was drawn from west-central MS across the southwestern LA coastline and TX shelf waters to a weak low over Padre Island. The low should move north-northeastward to northern WI by 12Z tomorrow, with frontolysis occurring to its south near the Mississippi Valley. Cyclogenesis will occur overnight over northwest TX in advance of the third mid/upper-level shortwave trough. ...Portions of central Gulf Coast region... Multiple rounds of convection are expected through this evening, with the best-organized cells offering locally strong-severe gusts and a marginal tornado risk. This includes a couple bands of ongoing convection -- along a dominant western convergence zone just ahead of the cold front, from eastern to southwestern MS and coastal south-central LA, and another near I-59 in southern MS. The 12Z LIX sounding sampled the coastal airmass between these well, with MLCAPE around 1400 J kg, effective SRH around 270 J/kg, modest winds between 250-500 mb, and effective-shear magnitude near 30 kt. With the leading trough ejecting away from the area and weakening fast, and the next remaining stronger but passing abeam of the outlook area to the north, net height changes through most of the period should be near neutral, with some rises possible in the near term (indicating the ongoing activity is unlikely to get substantially better organized than at present). However, a progressive lobe of midlevel vorticity -- extending southeastward from the second trough -- will foster large-scale DCVA/lift late this afternoon into evening over portions of MS and northern/western AL before the lobe ejects away and dissipates. This will be well-timed with peak afternoon warming, to steepen low-middle-level lapse rates and weaken MLCINH, contributing to potential regeneration/strengthening of the western convective/ convergence band. That process, with 60s F warm-sector surface dewpoints between the cold and warm fronts, should contribute to 1000-2500 J/kg MLCAPE. Deep shear and low-level hodographs should favor at least isolated supercells, with 35-45-kt effective-shear magnitudes and 200-300 J/kg effective SRH (maximized near the warm front). However, by mid/late afternoon, deep ascent and shear will have peaked over most of the area. With increasing displacement between the stronger flow/forcing aloft related to the second trough, and the favorable boundary-layer airmass, already marginal severe potential should diminish overnight. ..Edwards/Grams.. 12/27/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Dec 27 2024 Valid 301200Z - 041200Z ...DISCUSSION... Overall severe-weather potential should remain relatively low next week, largely attributable to a frontal intrusion into the Gulf of Mexico on Day 3/Sunday. Air mass modification/modest-caliber elevated moisture return may occur Monday/Day 4 from the western Gulf of Mexico into southeast Texas and Lower Mississippi Valley, as a shortwave trough amplifies over the southern Plains and Ozarks. A few strong storms cannot be entirely ruled out late Monday, but such potential should remain low overall. Additional low-level moistening will occur across parts of the Gulf Coast and Southeast on Tuesday/Day 5 ahead of the amplifying mid-level trough and associated cold front, but again, overall severe potential should remain low given the moisture and instability limitations. Convective potential should be very low, perhaps virtually nil, between Wednesday-Friday Days 6-8 as cold/stable continental trajectories prevail east of the Rockies. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Dec 27 2024 Valid 301200Z - 041200Z ...DISCUSSION... Overall severe-weather potential should remain relatively low next week, largely attributable to a frontal intrusion into the Gulf of Mexico on Day 3/Sunday. Air mass modification/modest-caliber elevated moisture return may occur Monday/Day 4 from the western Gulf of Mexico into southeast Texas and Lower Mississippi Valley, as a shortwave trough amplifies over the southern Plains and Ozarks. A few strong storms cannot be entirely ruled out late Monday, but such potential should remain low overall. Additional low-level moistening will occur across parts of the Gulf Coast and Southeast on Tuesday/Day 5 ahead of the amplifying mid-level trough and associated cold front, but again, overall severe potential should remain low given the moisture and instability limitations. Convective potential should be very low, perhaps virtually nil, between Wednesday-Friday Days 6-8 as cold/stable continental trajectories prevail east of the Rockies. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Dec 27 2024 Valid 301200Z - 041200Z ...DISCUSSION... Overall severe-weather potential should remain relatively low next week, largely attributable to a frontal intrusion into the Gulf of Mexico on Day 3/Sunday. Air mass modification/modest-caliber elevated moisture return may occur Monday/Day 4 from the western Gulf of Mexico into southeast Texas and Lower Mississippi Valley, as a shortwave trough amplifies over the southern Plains and Ozarks. A few strong storms cannot be entirely ruled out late Monday, but such potential should remain low overall. Additional low-level moistening will occur across parts of the Gulf Coast and Southeast on Tuesday/Day 5 ahead of the amplifying mid-level trough and associated cold front, but again, overall severe potential should remain low given the moisture and instability limitations. Convective potential should be very low, perhaps virtually nil, between Wednesday-Friday Days 6-8 as cold/stable continental trajectories prevail east of the Rockies. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CST Fri Dec 27 2024 Valid 301200Z - 041200Z ...DISCUSSION... Overall severe-weather potential should remain relatively low next week, largely attributable to a frontal intrusion into the Gulf of Mexico on Day 3/Sunday. Air mass modification/modest-caliber elevated moisture return may occur Monday/Day 4 from the western Gulf of Mexico into southeast Texas and Lower Mississippi Valley, as a shortwave trough amplifies over the southern Plains and Ozarks. A few strong storms cannot be entirely ruled out late Monday, but such potential should remain low overall. Additional low-level moistening will occur across parts of the Gulf Coast and Southeast on Tuesday/Day 5 ahead of the amplifying mid-level trough and associated cold front, but again, overall severe potential should remain low given the moisture and instability limitations. Convective potential should be very low, perhaps virtually nil, between Wednesday-Friday Days 6-8 as cold/stable continental trajectories prevail east of the Rockies. Read more