Severe Storms

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1137 PM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL CAROLINAS... ...SUMMARY... Severe thunderstorms are possible today across coastal Carolinas. Damaging winds and some tornado threat are the primary hazards. ...Coastal Carolinas... Late-evening satellite imagery depicts a well-defined midlevel short-wave trough ejecting northeast toward the northern Florida Peninsula. This feature is forecast to advance across the Carolinas later today. In response, a very strong LLJ has developed which will nose into southern SC by 17/12z. 850mb flow is forecast to increase in excess of 80kt by 18/00z across eastern NC into extreme southeast VA. Latest model guidance suggests the associated surface low will track from off the northeast FL Coast to near CRE by early evening, then lift north along the middle Atlantic Coast into NJ during the overnight hours. This evolution suggests modified boundary-layer air mass will advance inland across coastal Carolinas permitting adequate surface-based buoyancy to develop immediately ahead of the surface low. Forecast soundings exhibit modest instability near the coast with MLCAPE approaching 1000 J/kg where dew points can rise into the upper 60s. While lapse rates will remain poor, very strong deep-layer shear/SRH favor supercells. Damaging winds are certainly possible with more organized convection given that 50-70kt winds should be within 1km AGL. Isolated tornado threat can also be expected with any supercells that emerge within this environment. ..Darrow/Squitieri.. 12/17/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1137 PM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL CAROLINAS... ...SUMMARY... Severe thunderstorms are possible today across coastal Carolinas. Damaging winds and some tornado threat are the primary hazards. ...Coastal Carolinas... Late-evening satellite imagery depicts a well-defined midlevel short-wave trough ejecting northeast toward the northern Florida Peninsula. This feature is forecast to advance across the Carolinas later today. In response, a very strong LLJ has developed which will nose into southern SC by 17/12z. 850mb flow is forecast to increase in excess of 80kt by 18/00z across eastern NC into extreme southeast VA. Latest model guidance suggests the associated surface low will track from off the northeast FL Coast to near CRE by early evening, then lift north along the middle Atlantic Coast into NJ during the overnight hours. This evolution suggests modified boundary-layer air mass will advance inland across coastal Carolinas permitting adequate surface-based buoyancy to develop immediately ahead of the surface low. Forecast soundings exhibit modest instability near the coast with MLCAPE approaching 1000 J/kg where dew points can rise into the upper 60s. While lapse rates will remain poor, very strong deep-layer shear/SRH favor supercells. Damaging winds are certainly possible with more organized convection given that 50-70kt winds should be within 1km AGL. Isolated tornado threat can also be expected with any supercells that emerge within this environment. ..Darrow/Squitieri.. 12/17/2023 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1137 PM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS COASTAL CAROLINAS... ...SUMMARY... Severe thunderstorms are possible today across coastal Carolinas. Damaging winds and some tornado threat are the primary hazards. ...Coastal Carolinas... Late-evening satellite imagery depicts a well-defined midlevel short-wave trough ejecting northeast toward the northern Florida Peninsula. This feature is forecast to advance across the Carolinas later today. In response, a very strong LLJ has developed which will nose into southern SC by 17/12z. 850mb flow is forecast to increase in excess of 80kt by 18/00z across eastern NC into extreme southeast VA. Latest model guidance suggests the associated surface low will track from off the northeast FL Coast to near CRE by early evening, then lift north along the middle Atlantic Coast into NJ during the overnight hours. This evolution suggests modified boundary-layer air mass will advance inland across coastal Carolinas permitting adequate surface-based buoyancy to develop immediately ahead of the surface low. Forecast soundings exhibit modest instability near the coast with MLCAPE approaching 1000 J/kg where dew points can rise into the upper 60s. While lapse rates will remain poor, very strong deep-layer shear/SRH favor supercells. Damaging winds are certainly possible with more organized convection given that 50-70kt winds should be within 1km AGL. Isolated tornado threat can also be expected with any supercells that emerge within this environment. ..Darrow/Squitieri.. 12/17/2023 Read more

MD 2332 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WEST-CENTRAL FLORIDA
Mesoscale Discussion 2332 NWS Storm Prediction Center Norman OK 1115 PM CST Sat Dec 16 2023 Areas affected...West-Central Florida Concerning...Severe potential...Watch possible Valid 170515Z - 170615Z Probability of Watch Issuance...40 percent SUMMARY...A few low-topped supercells will affect the offshore waters and coastal areas of the Tampa Bay region. The strongest cells are expected to remain offshore, but conditions are being monitored. DISCUSSION...Latest radar/satellite imagery shows a couple of low-topped rotating storms approx. 20-30 miles offshore to the southwest of Tampa. These storms are just east of a well-defined MCV/vorticity max, and roughly along a surface warm front that extends from Tampa Bay eastward across the central FL Peninsula. VAD profiles show very large low-level vertical shear, with 1km AGL winds exceeding 50 knots, and 0-3km SRH values over 500 m2/s2. Forecast soundings show very weak CAPE, but dewpoints near 70f suggest the potential for surface-based updrafts. If one of these cells can be sustained as it moves ashore, there is a chance of a damaging wind gust or brief tornado. The threat area and overall risk remains rather marginal at this time, but is being closely monitored for a possible tornado watch if trends increase. ..Hart/Smith.. 12/17/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...TBW... LAT...LON 28278385 28228267 27698204 26868233 26968306 27478363 28278385 Read more

MD 2331 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF THE SOUTHERN AND CENTRAL FLORIDA PENINSULA AND KEYS
Mesoscale Discussion 2331 NWS Storm Prediction Center Norman OK 0759 PM CST Sat Dec 16 2023 Areas affected...portions of the southern and central Florida Peninsula and Keys Concerning...Severe potential...Watch possible Valid 170159Z - 170430Z Probability of Watch Issuance...60 percent SUMMARY...Strong to potentially severe thunderstorms may move ashore from the Gulf of Mexico over the next several hours. Isolated tornadoes and damaging gusts are the main threats. The need for a Tornado Watch issuance depends on how much instability can precede the approaching line of thunderstorms. DISCUSSION...A surface low continues to deepen across the eastern Gulf of Mexico and approach the FL Peninsula as an upper-level trough continues to amplify over the MS Valley. A confluence band preceding the aforementioned surface low is comprised of convection that has percolated in intensity over the last few hours, and is poised to move ashore sometime before Midnight EST. Widespread rain and convection have been overspreading the Peninsula for much of the day, with 00Z soundings over TBW and MFL depicting low/mid-level lapse rates barely exceeding 5 C/km. Despite low 70s F dewpoints, buoyancy has been meager so far, though gradual increases in instability are possible across southern FL tonight. Shear profiles are impressive ahead of the rapidly deepening surface low, with the same aforementioned observed soundings showing very large, curved hodographs in the 0-3 km layer. As such, it is not out of the question for a few damaging gusts or tornadoes to occur if a persistent updraft can develop and ingest any available surface-based, unstable parcels. As such, conditions are being monitored for the need of a Tornado Watch issuance. ..Squitieri/Smith.. 12/17/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...KEY...TBW...JAX... LAT...LON 24618209 24878158 25198122 25618137 26378205 27288262 28458282 29388200 29538127 29238091 28188054 26878006 25978004 25268010 24788047 24528111 24488169 24618209 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0637 PM CST Sat Dec 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA AND KEYS... ...SUMMARY... The threat for a few damaging gusts and tornadoes will increase tonight into Sunday morning across the Florida Peninsula and Keys. ...01z Update... Eastern Gulf Basin short-wave trough is ejecting northeast toward the FL Peninsula this evening. Surface low associated with this short wave will approach the FL Gulf Coast after 06z, then advance off the Atlantic Coast near Jacksonville by sunrise. 00z soundings over the southeastern US have yet to destabilize materially, but weak buoyancy is noted at MFL where SBCAPE is on the order of 500 J/kg. However, strong shear is in place and a marked increase in the LLJ is expected later this evening with 850mb flow likely to exceed 60-80kt by the end of the period. Latest lightning data suggests the strongest/deepest convection is immediately ahead of the short wave/surface low, at least 100mi west of the Peninsula. With time, buoyancy should increase such that deeper updrafts/lightning will develop with convection over land. Severe probabilities remain unchanged from 20z, and damaging gusts and tornadoes remain possible, especially after midnight. ..Darrow.. 12/17/2023 Read more

No watches are valid as of Sat Dec 16 22:34:01 UTC 2023.

No Mesoscale Discussions are in effect as of Sat Dec 16 22:34:01 UTC 2023.

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CST Sat Dec 16 2023 Valid 181200Z - 241200Z The mid-level flow pattern across the CONUS will remain amplified at the start of the extended forecast period. A broad and deep trough with a strong coastal low will continue to intensify over the East Coast before shifting eastward by midweek. At the same time, a Pacific trough will move inland with broad southwesterly flow extending over parts of CA, WA and OR. Flow aloft will weaken as transient ridging builds over the central US through the end of the work week. Simultaneously, the Pacific trough will transition to a cutoff low over the West Coast with widespread precipitation likely into the early weekend. Across the center of the country, weaker flow aloft beneath transient ridging and surface high pressure should keep temperatures mild, but winds quite weak. Stronger flow aloft will likely return late next weekend into early next week as several upper-level troughs are expected to transit the central US. With the active flow pattern expected to continue toward the end of the extended forecast period, widespread precipitation, mild temperatures and weak winds should dampen fire-weather concerns over much of the CONUS. ..Lyons.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CST Sat Dec 16 2023 Valid 181200Z - 241200Z The mid-level flow pattern across the CONUS will remain amplified at the start of the extended forecast period. A broad and deep trough with a strong coastal low will continue to intensify over the East Coast before shifting eastward by midweek. At the same time, a Pacific trough will move inland with broad southwesterly flow extending over parts of CA, WA and OR. Flow aloft will weaken as transient ridging builds over the central US through the end of the work week. Simultaneously, the Pacific trough will transition to a cutoff low over the West Coast with widespread precipitation likely into the early weekend. Across the center of the country, weaker flow aloft beneath transient ridging and surface high pressure should keep temperatures mild, but winds quite weak. Stronger flow aloft will likely return late next weekend into early next week as several upper-level troughs are expected to transit the central US. With the active flow pattern expected to continue toward the end of the extended forecast period, widespread precipitation, mild temperatures and weak winds should dampen fire-weather concerns over much of the CONUS. ..Lyons.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CST Sat Dec 16 2023 Valid 181200Z - 241200Z The mid-level flow pattern across the CONUS will remain amplified at the start of the extended forecast period. A broad and deep trough with a strong coastal low will continue to intensify over the East Coast before shifting eastward by midweek. At the same time, a Pacific trough will move inland with broad southwesterly flow extending over parts of CA, WA and OR. Flow aloft will weaken as transient ridging builds over the central US through the end of the work week. Simultaneously, the Pacific trough will transition to a cutoff low over the West Coast with widespread precipitation likely into the early weekend. Across the center of the country, weaker flow aloft beneath transient ridging and surface high pressure should keep temperatures mild, but winds quite weak. Stronger flow aloft will likely return late next weekend into early next week as several upper-level troughs are expected to transit the central US. With the active flow pattern expected to continue toward the end of the extended forecast period, widespread precipitation, mild temperatures and weak winds should dampen fire-weather concerns over much of the CONUS. ..Lyons.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CST Sat Dec 16 2023 Valid 181200Z - 241200Z The mid-level flow pattern across the CONUS will remain amplified at the start of the extended forecast period. A broad and deep trough with a strong coastal low will continue to intensify over the East Coast before shifting eastward by midweek. At the same time, a Pacific trough will move inland with broad southwesterly flow extending over parts of CA, WA and OR. Flow aloft will weaken as transient ridging builds over the central US through the end of the work week. Simultaneously, the Pacific trough will transition to a cutoff low over the West Coast with widespread precipitation likely into the early weekend. Across the center of the country, weaker flow aloft beneath transient ridging and surface high pressure should keep temperatures mild, but winds quite weak. Stronger flow aloft will likely return late next weekend into early next week as several upper-level troughs are expected to transit the central US. With the active flow pattern expected to continue toward the end of the extended forecast period, widespread precipitation, mild temperatures and weak winds should dampen fire-weather concerns over much of the CONUS. ..Lyons.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0351 PM CST Sat Dec 16 2023 Valid 181200Z - 241200Z The mid-level flow pattern across the CONUS will remain amplified at the start of the extended forecast period. A broad and deep trough with a strong coastal low will continue to intensify over the East Coast before shifting eastward by midweek. At the same time, a Pacific trough will move inland with broad southwesterly flow extending over parts of CA, WA and OR. Flow aloft will weaken as transient ridging builds over the central US through the end of the work week. Simultaneously, the Pacific trough will transition to a cutoff low over the West Coast with widespread precipitation likely into the early weekend. Across the center of the country, weaker flow aloft beneath transient ridging and surface high pressure should keep temperatures mild, but winds quite weak. Stronger flow aloft will likely return late next weekend into early next week as several upper-level troughs are expected to transit the central US. With the active flow pattern expected to continue toward the end of the extended forecast period, widespread precipitation, mild temperatures and weak winds should dampen fire-weather concerns over much of the CONUS. ..Lyons.. 12/16/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 PM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...NO CRITICAL AREAS... Widespread precipitation and cool temperatures are again expected to limit fire-weather concerns over much of the CONUS. See the previous discussion. ..Lyons.. 12/16/2023 .PREV DISCUSSION... /ISSUED 1228 AM CST Sat Dec 16 2023/ ...Synopsis... A series of mid-level troughs will traverse the eastern CONUS as a mid-level trough approaches the West Coast tomorrow/Sunday. Cool conditions will overspread much of the U.S. east of the Rockies, with appreciable precipitation accumulations possible over California with the approaching West Coast mid-level trough. As such, significant, widespread wildfire-growth potential appears negligible across the CONUS. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 PM CST Sat Dec 16 2023 Valid 171200Z - 181200Z ...NO CRITICAL AREAS... Widespread precipitation and cool temperatures are again expected to limit fire-weather concerns over much of the CONUS. See the previous discussion. ..Lyons.. 12/16/2023 .PREV DISCUSSION... /ISSUED 1228 AM CST Sat Dec 16 2023/ ...Synopsis... A series of mid-level troughs will traverse the eastern CONUS as a mid-level trough approaches the West Coast tomorrow/Sunday. Cool conditions will overspread much of the U.S. east of the Rockies, with appreciable precipitation accumulations possible over California with the approaching West Coast mid-level trough. As such, significant, widespread wildfire-growth potential appears negligible across the CONUS. ...Please see www.spc.noaa.gov/fire for graphic product... Read more