Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0201 PM CST Wed Jan 25 2023 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... No changes are needed to the D2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/25/2023 .PREV DISCUSSION... /ISSUED 0102 AM CST Wed Jan 25 2023/ ...Synopsis... No elevated fire-weather conditions are expected today as mild RH and winds dominate the CONUS. As a broad upper-level cyclone propagates eastward toward the East Coast, a zonally oriented trough is expected to form in its wake stretching from the Great Lakes west-southwestward through the Four Corners region. An upstream area of enhanced mid-/upper-level flow will translate toward the trough axis; backing flow in time will yield broad northeasterly flow over southern CA. As a result, sustained winds around 15-20 kts and RH minima around 15-20% are possible Friday evening along the coast in the lee of the southern CA terrain, as well as in the Colorado Desert. However, fuel and soil moisture remain high after excessive rainfall in recent weeks. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Wed Jan 25 20:03:02 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0140 PM CST Wed Jan 25 2023 Valid 252000Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR COASTAL PORTIONS OF THE CAROLINAS... ...SUMMARY... A couple of damaging thunderstorm wind gusts and a tornado or two will remain possible, mainly along the Carolina Coastline this evening. A damaging gust is also possible across northern Florida through the rest of the afternoon. ...20Z Update... The Slight risk was removed from portions of southern Georgia into northern Florida. Buoyancy has either diminished or remained scant across this region (with no more than 100-300 J/kg MLCAPE) amid decreasing deep-layer ascent. Veering surface winds will also decrease convergence along the convective line and reduce hodograph size/shape, further limiting the severe threat. However, the Slight Risk has been maintained along the Carolina Coastline, where the northward advection of mid 60s F surface dewpoints remains possible late this afternoon into early evening. Some of the latest HRRR guidance suggests low-topped supercells may initiate just off of the coast. However, any westward development of storms may support a low-end threat for a couple of damaging gusts and perhaps a tornado given the presence of a strong low-level jet and associated large, curved hodographs. ..Squitieri/Leitman.. 01/25/2023 .PREV DISCUSSION... /ISSUED 1025 AM CST Wed Jan 25 2023/ ...Synopsis... A surface low across the OH Valley will continue to translate northeast toward the Northeast as the mid-level longwave trough deepens across the eastern U.S. today. A surface cold front and associated line of deep-moist convection continues to progress across the Southeast and should reach the Atlantic Seaboard by evening. Adequate buoyancy and deep-layer shear ahead of the convective line should promote strong thunderstorm potential, with some severe threat evident. ...South Carolina into northern Florida Today... A squall line continues to progress eastward across western SC into northern FL, with a history of occasional damaging gusts and more recently, a brief tornado south of TLH. Latest guidance consensus continues to show modest moisture overspread by mediocre tropospheric lapse rates, contributing to thin SB/MLCAPE profiles (with no more than a couple hundred J/kg expected). In addition, the departure of the surface low suggests that deep-layer and low-level shear should gradually weaken with time. While a couple of damaging gusts and perhaps another tornado or two remain possible, the severe threat should gradually temper by late afternoon. ...Portions of eastern North Carolina late this afternoon... Later this afternoon, the axis of the low-level jet should become focused across the eastern Carolinas, leading to the advection of relatively rich low-level moisture and an increase in both deep-layer ascent and deep/low-level shear. The coupling of strong southwesterly low-level flow and westerly mid-level flow will contribute to sizeable, curved hodographs. Nonetheless, latest point-forecast sounding analysis suggest that buoyancy will still be scant at best toward the shoreline. If stronger storms manage to develop onshore, a couple of damaging gusts and perhaps a tornado are possible. Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1036 AM CST Wed Jan 25 2023 Valid 251700Z - 261200Z ...NO CRITICAL AREAS... No updates are needed to the current Day 1 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/25/2023 .PREV DISCUSSION... /ISSUED 1229 AM CST Wed Jan 25 2023/ ...Synopsis... Elevated fire weather conditions are not expected today. Moderate RH and mild winds will overspread the bulk of the CONUS in the wake of a powerful synoptic cyclone. Recent rainfall from this system and others in the past several days continue to yield low ERCs and fire potential. Locally drier 10-1000-hr fuels persist in the Big Bend region, but winds are expected to remain below elevated levels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1032 AM CST Wed Jan 25 2023 Valid 261200Z - 271200Z ...NO THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for thunderstorms appears negligible across the U.S. Thursday through Thursday night. ...Synopsis... A surface low is forecast over New England Thursday morning. A cold front attendant to the low will mostly be offshore the Atlantic coast, with the southern extent of the boundary arcing southwest across southern FL. The cold front will develop southeast across the southern FL Peninsula and the Keys through the day. While a moist and weakly unstable airmass will be in place ahead of the front, warm temperatures aloft and weak forcing for ascent will largely limit thunderstorm potential. A few lightning flashes are possible offshore the southeast FL/Keys coast, but thunderstorms inland are not expected. High surface pressure and/or a dearth of boundary-layer moisture/instability will preclude thunderstorm activity elsewhere across the U.S. on Thursday. ..Leitman.. 01/25/2023 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1025 AM CST Wed Jan 25 2023 Valid 251630Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF NORTHERN FLORIDA TOWARD THE CAROLINA COASTLINE... ...SUMMARY... Damaging thunderstorm wind gusts and a tornado or two will remain possible from the Florida coastal bend area to the eastern Carolinas and west-central/northern Florida through the afternoon. ...Synopsis... A surface low across the OH Valley will continue to translate northeast toward the Northeast as the mid-level longwave trough deepens across the eastern U.S. today. A surface cold front and associated line of deep-moist convection continues to progress across the Southeast and should reach the Atlantic Seaboard by evening. Adequate buoyancy and deep-layer shear ahead of the convective line should promote strong thunderstorm potential, with some severe threat evident. ...South Carolina into northern Florida Today... A squall line continues to progress eastward across western SC into northern FL, with a history of occasional damaging gusts and more recently, a brief tornado south of TLH. Latest guidance consensus continues to show modest moisture overspread by mediocre tropospheric lapse rates, contributing to thin SB/MLCAPE profiles (with no more than a couple hundred J/kg expected). In addition, the departure of the surface low suggests that deep-layer and low-level shear should gradually weaken with time. While a couple of damaging gusts and perhaps another tornado or two remain possible, the severe threat should gradually temper by late afternoon. ...Portions of eastern North Carolina late this afternoon... Later this afternoon, the axis of the low-level jet should become focused across the eastern Carolinas, leading to the advection of relatively rich low-level moisture and an increase in both deep-layer ascent and deep/low-level shear. The coupling of strong southwesterly low-level flow and westerly mid-level flow will contribute to sizeable, curved hodographs. Nonetheless, latest point-forecast sounding analysis suggest that buoyancy will still be scant at best toward the shoreline. If stronger storms manage to develop onshore, a couple of damaging gusts and perhaps a tornado are possible. ..Squitieri.. 01/25/2023 Read more

MD 0105 CONCERNING HEAVY SNOW FOR PORTIONS OF CENTRAL AND NORTHEAST INDIANA INTO SOUTHEASTERN LOWER MICHIGAN
Mesoscale Discussion 0105 NWS Storm Prediction Center Norman OK 0914 AM CST Wed Jan 25 2023 Areas affected...portions of central and northeast Indiana into southeastern Lower Michigan Concerning...Heavy snow Valid 251514Z - 252045Z SUMMARY...Moderate to heavy snow should continue northeast across central and northern IN, extreme northwest OH, and far southeast Lower Michigan into the mid-afternoon hours. A few instances of 1+ inch/hr snowfall rates are possible in the heavier bands. DISCUSSION...A surface low is centered around the IN/KY border and is poised to continue drifting northeast toward Lake Ontario through the day while also intensifying. Strong surface-700 mb warm-air/moisture advection will continue to feed relatively rich moisture to the dendritic growth zone (-12 to -17C layer). Upglide of this moisture while wrapping around the surface low should continue to foster at least moderate to occasional bouts of heavy snow through 20Z northwest of the mid-level dry slot. The heaviest snow (including brief instances of 1+ inch/hr snowfall rates) will be most likely where 700 mb frontogenesis and associated lift will be strongest. Latest mesoanalysis suggests that this corridor is situated across central into northern IN/extreme northwest OH and far southeast lower MI. ..Squitieri.. 01/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CLE...DTX...IWX...GRR...IND...LOT... LAT...LON 42948289 42748288 42438292 42208303 41888332 41808351 41588405 41258485 40768542 40318627 40098682 40098734 40368739 40748710 41508607 42368454 42888314 42948289 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0151 PM CST Tue Jan 24 2023 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE UPPER TEXAS COAST...AND EXTENDING EAST ALONG THE NORTHERN GULF COAST... ...SUMMARY... Damaging winds and a few tornadoes remain possible today across the upper Texas Coast, and extending eastward tonight across coastal areas of Louisiana, Mississippi, Alabama, and the western Florida Panhandle. ...Upper TX Coast eastward along the northern Gulf Coast... A focused area of tornado potential currently exists near the Houston area near the warm front and surface low. Extreme pressure falls have been noted over the area ahead of a line of storms with 2hr falls around 8 mb. Shear remains quite strong with effective SRH over 500 m2/s2. In addition, surface/boundary-layer winds are intense which will enhance storm relative inflow. As such, a tornado and damaging wind risk may increase over the next few hours. A strong tornado is possible conditional on storm mode and access to the warm side of the warm front. Later this evening and overnight, the warm front will move onshore across LA mainly after 00Z, and into southern AL/FL Panhandle after 06Z. Shear will remain strong and favorable for supercells with tornado risk. ..Jewell.. 01/24/2023 .PREV DISCUSSION... /ISSUED 0954 AM CST Tue Jan 24 2023/ ...Synopsis... Surface low intensification should continue along the western Gulf Coast today as a strengthening mid-level trough overspreads the lower MS Valley. Though a relatively stable low-level airmass remains in place inland, a moist and (surface-based) buoyant airmass resides immediately offshore of the southern TX coastline. This airmass should be drawn roughly 50-150 nm onshore into TX ahead of the surface low through the afternoon, and later tonight along the central Gulf Coast. An intense low-level jet will also overspread the Gulf Coast shoreline ahead of the surface low, with impressive vertical shear profiles and marginal (but potentially adequate) buoyancy promoting severe thunderstorm development through the period. ...Texas Shoreline this Afternoon... Elevated convection is ongoing across southeast Texas within an elevated warm-air advection regime ahead of the surface low. With time, continued low-level moisture advection and (limited) diurnal heating will encourage gradual surface-based destabilization immediately ahead of the surface low for the TX counties along the shore. As such, elevated thunderstorms in these counties may gradually become surface-based. The 50-70 kt low-level jet, overspread by 80-100 kts of west-southwesterly 500 mb flow will contribute to very large, highly curved hodographs. Guidance suggests that near 70 F/upper 60s F surface temperatures/dewpoints and resultant 500 J/kg thin SBCAPE is all that is needed to draw at least 300-500 m2/s2 of SRH into the effective inflow-bearing layer. Storms that root into the boundary layer may acquire strong rotation. Given the very impressive low-level shear, any tornado that can form (whether brief or sustained) could be strong. An instance or two of large hail is also possible given the presence of near 7 C/km mid-level lapse rates (per 15Z mesoanalysis). ...Lower Mississippi Valley Tonight... As the surface low approaches the lower MS Valley this evening into tonight, a line of semi-discrete but strong thunderstorms should move across southern LA into southern MS and AL, immediately preceded by a marginal but potentially surface-based airmass. Though questions remain how far inland the most buoyant air parcels will advect, at least some potential exists for mid to upper 60s F dewpoints to overspread coastal counties. Should this occur, enough surface-based instability will be present (i.e. around 500 J/kg SBCAPE) to support a severe gust/tornado threat given impressive vertical shear profiles (similar to TX during the day). Given the presence of very strong low-level shear, at least a couple of strong tornadoes are possible. Read more

WW 0027 Status Updates
STATUS REPORT ON WW 27 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 S CRP TO 15 NE VCT TO 35 S UTS. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 0095 ..WEINMAN..01/24/23 ATTN...WFO...LCH...CRP...HGX... STATUS REPORT FOR WT 27 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC003-011-019-023-053-242040- LA . LOUISIANA PARISHES INCLUDED ARE ALLEN BEAUREGARD CALCASIEU CAMERON JEFFERSON DAVIS TXC007-039-057-071-157-167-199-201-239-241-245-291-321-351-361- 391-409-469-481-242040- TX . TEXAS COUNTIES INCLUDED ARE ARANSAS BRAZORIA CALHOUN CHAMBERS FORT BEND GALVESTON HARDIN HARRIS JACKSON JASPER JEFFERSON LIBERTY MATAGORDA NEWTON ORANGE REFUGIO SAN PATRICIO VICTORIA WHARTON Read more

WW 27 TORNADO LA TX CW 241650Z - 250000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 27 NWS Storm Prediction Center Norman OK 1050 AM CST Tue Jan 24 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Southwest Louisiana Middle/Upper Texas Coast Coastal Waters * Effective this Tuesday morning and evening from 1050 AM until 600 PM CST. * Primary threats include... A few tornadoes likely with a couple intense tornadoes possible Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorm coverage is expected to increase across the middle and upper TX coast this afternoon. Environmental conditions, in particular strong low-level vertical shear, is expected to support strong to severe thunderstorms, including a few supercells. These supercells could be capable of all severe threats, including tornadoes. The tornado watch area is approximately along and 45 statute miles north and south of a line from 45 miles southwest of Victoria TX to 25 miles east northeast of Lake Charles LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 23040. ...Mosier Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0115 PM CST Tue Jan 24 2023 Valid 251200Z - 261200Z ...NO CRITICAL AREAS... No changes are needed to the current D2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/24/2023 .PREV DISCUSSION... /ISSUED 0111 AM CST Tue Jan 24 2023/ ...Synopsis... No elevated fire weather conditions are expected across the country during the period. Cooler temperatures and higher RH will be abundant behind a surging cold front. Near-elevated RH may overspread portions of the Rio Grande Valley where 75-90+ ERCs reside, but winds are expected to be very weak. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 0095 CONCERNING TORNADO WATCH 27... FOR MIDDLE/UPPER TX COAST
Mesoscale Discussion 0095 NWS Storm Prediction Center Norman OK 1250 PM CST Tue Jan 24 2023 Areas affected...Middle/Upper TX Coast Concerning...Tornado Watch 27... Valid 241850Z - 242045Z The severe weather threat for Tornado Watch 27 continues. SUMMARY...Environment across the middle and upper TX coast remains favorable of supercells capable of tornadoes. In particular, a corridor of relatively higher tornado threat may exist from Wharton County into Fort Bend County for the next hour or two. DISCUSSION...Recent surface analysis places a surface low about 50 miles north of VCT entering Colorado County TX. A warm front extends eastward from this low into Galveston Bay. Conditions south of this front are characterized by temperatures in the low 70s and dewpoints in the upper 60s. Based on recent forecast soundings and mesoanalysis, these conditions appear to support surface-based buoyancy. Very strong wind fields remain in place, with surface wind gusts to 30 kt and the HGX VAD showing 70 kt at 1 km. STP is around 3 for much of the warm sector. As a result, the warm sector environment appears very supportive of supercells capable of tornadoes. Of particular interest currently is the storm entering western Wharton county, largely because of its location within the open warm sector and very favorable conditions downstream. As a result, the corridor from Wharton County into Fort Bend County may have a relatively higher threat for tornadoes over the next hour or two. ..Mosier.. 01/24/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...HGX...EWX... LAT...LON 29189670 29549638 29759560 29599513 29129526 28909563 28779619 28919658 29189670 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1128 AM CST Tue Jan 24 2023 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM PARTS OF NORTHERN FLORIDA INTO THE EASTERN CAROLINAS... ...SUMMARY... A risk for damaging winds will exist across parts of the Southeast on Wednesday. Isolated tornadoes will be possible over the eastern Carolinas by late afternoon, and from the Florida Panhandle into far southwest Georgia early in the day. ...Synopsis... A large-scale upper trough will exist over much of the central and eastern CONUS on Wednesday, with a strong leading wave moving from the OH Valley into the Northeast by Thursday morning. Low pressure will move from KY into OH during the day, with a cold front pushing east toward the Appalachians. Meanwhile, a warm front will lift rapidly north across GA and the Carolinas, with 60s F dewpoints. Warm advection will be aided by a strong 50-70 kt low-level jet overspreading the warm sector. ...FL Panhandle into southern GA... Storms are likely to be ongoing along the cold front near the AL/GA border and into the Gulf of Mexico. MLCAPE of a few hundred J/kg will exist early Wednesday, with SRH of 300-400 m2/s2 common. This will support a tornado risk, as well as damaging winds with the line. As the main upper system lifts away, the primary tornado risk is expected to maximize in the 12Z to 18Z time frame, with less SBCAPE farther east into northern FL. Still, a few severe gusts may occur during the afternoon as the frontal convection shifts east and boundary-layer wind speeds remain strong. Midlevel lapse rates will become poor, limiting storm severity. ...Carolinas... A plume of mid 60s F dewpoints will stream northward off the Atlantic and into the eastern Carolinas during the afternoon as a line of convection approaches from the west. These storms are expected to increase in intensity as they encounter the higher dewpoints, resulting in severe wind and tornado potential, perhaps in QLCS fashion. Effective SRH of 300-400 m2/s2 is expected over eastern NC. Forecast soundings suggest dewpoints at or above 65 will clearly support surface-based inflow. ..Jewell.. 01/24/2023 Read more

MD 0094 CONCERNING HEAVY SNOW FOR PORTIONS OF CENTRAL AND EASTERN OKLAHOMA INTO NORTHWEST ARKANSAS
Mesoscale Discussion 0094 NWS Storm Prediction Center Norman OK 1108 AM CST Tue Jan 24 2023 Areas affected...portions of central and eastern Oklahoma into northwest Arkansas Concerning...Heavy snow Valid 241708Z - 242315Z SUMMARY...Periods of moderate to heavy snow should develop across portions of central Oklahoma into northwestern Arkansas through the afternoon. A couple of 1+ inch/hour snowfall rates are possible, resulting in periods of reduced visibility. DISCUSSION...Broad and deep moisture advection continues across the southern Plains as a strengthening mid-level trough and resultant height falls overspreads the region through the day. Currently, mostly rain is falling from central OK and points south and east. However, up to moderate snowfall rates have been reported across portions of the OKC metropolitan area into western Oklahoma over the past few hours. Furthermore, 16Z mesoanalysis shows 925 mb temperatures dropping to at/below freezing across central OK in tandem with recently reported snow. While surface temperatures are at/above freezing across central OK, the Oklahoma Mesonet shows a 4-6 F temperature drop around and just south of the OKC metropolitan area over the last 3 hours. With temperatures below freezing at/above 850 mb, the cooling surface-925 mb temperatures suggest that the rain-to-snow transition should continue across central OK and progress eastward to central AR by mid afternoon. Rich moisture advection and deep-layer ascent within the dendritic growth zone (-12 to -17C layer) may support at least brief bouts of 1+ inch/hr snowfall rates. Latest high-resolution guidance consensus indicates the best chance for 1+ inch/hr snowfall rates will be around and just to the south and east of the OKC metropolitan area in the 18-22Z (Noon-4 PM CST) time frame, with the threat spreading into northwest AR during the 22-00Z (4-6 PM CST) period. ..Squitieri.. 01/24/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...TSA...OUN... LAT...LON 35259373 34559481 34059719 33919843 34069901 34299917 34609890 35369777 35759715 36299523 36319417 36169303 35589309 35259373 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1046 AM CST Tue Jan 24 2023 Valid 241700Z - 251200Z ...CRITICAL FIRE WEATHER AREA FOR LOWER RIO GRANDE PLAINS... Mainly light precipitation fell across the current Elevated/Critical areas this morning. Mid-level cloud cover is still apparent across this region on visible satellite. Skies are expected to begin clearing around 18z, which should be better for surface heating and deepening of the mixed layer to allow relative humidity reductions. Given the current trends, the forecast remains on track, with only minor adjustments to bring the Elevated further south into the Rio Grande Valley to account for recent trends and morning rainfall observations. ..Thornton.. 01/24/2023 .PREV DISCUSSION... /ISSUED 1248 AM CST Tue Jan 24 2023/ ...Synopsis... Critical fire-weather conditions are expected across portions of south TX today. A potent upper-level cut-off low will move through the region, inducing moderate surface winds and low RH behind a cold front. Sustained winds around 15-25 kts collocated with RH generally around 15-25% are expected across the area. A more localized pocket of drier air is predicted to advect eastward through the lower Rio Grande Plains and might contribute to locally critical conditions; this might be most impactful during the 21-03z timeframe before the arrival of cooler temperatures (and higher RH) behind the primary cold front. Fuels across the region support locally critical conditions with ERCs of generally 75-90+, especially farther north. However, the overall threat may be tempered somewhat by ongoing precipitation. This is expected to continue for the next few hours and could yield around 0.2-0.3" by the start of the period. At this point, subsequent drying of 1-10-hr fuels is expected to be sufficient to yield critical fire-weather conditions later in the day. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0954 AM CST Tue Jan 24 2023 Valid 241630Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF COASTAL TEXAS INTO COASTAL AREAS OF THE LOWER MISSISSIPPI VALLEY... ...SUMMARY... Severe thunderstorm winds, strong tornadoes and large hail are likely today near the middle/upper Texas Coast, with a damaging gust/tornado threat continuing eastward tonight across coastal areas of Louisiana, Mississippi, Alabama, and the western Florida Panhandle. ...Synopsis... Surface low intensification should continue along the western Gulf Coast today as a strengthening mid-level trough overspreads the lower MS Valley. Though a relatively stable low-level airmass remains in place inland, a moist and (surface-based) buoyant airmass resides immediately offshore of the southern TX coastline. This airmass should be drawn roughly 50-150 nm onshore into TX ahead of the surface low through the afternoon, and later tonight along the central Gulf Coast. An intense low-level jet will also overspread the Gulf Coast shoreline ahead of the surface low, with impressive vertical shear profiles and marginal (but potentially adequate) buoyancy promoting severe thunderstorm development through the period. ...Texas Shoreline this Afternoon... Elevated convection is ongoing across southeast Texas within an elevated warm-air advection regime ahead of the surface low. With time, continued low-level moisture advection and (limited) diurnal heating will encourage gradual surface-based destabilization immediately ahead of the surface low for the TX counties along the shore. As such, elevated thunderstorms in these counties may gradually become surface-based. The 50-70 kt low-level jet, overspread by 80-100 kts of west-southwesterly 500 mb flow will contribute to very large, highly curved hodographs. Guidance suggests that near 70 F/upper 60s F surface temperatures/dewpoints and resultant 500 J/kg thin SBCAPE is all that is needed to draw at least 300-500 m2/s2 of SRH into the effective inflow-bearing layer. Storms that root into the boundary layer may acquire strong rotation. Given the very impressive low-level shear, any tornado that can form (whether brief or sustained) could be strong. An instance or two of large hail is also possible given the presence of near 7 C/km mid-level lapse rates (per 15Z mesoanalysis). ...Lower Mississippi Valley Tonight... As the surface low approaches the lower MS Valley this evening into tonight, a line of semi-discrete but strong thunderstorms should move across southern LA into southern MS and AL, immediately preceded by a marginal but potentially surface-based airmass. Though questions remain how far inland the most buoyant air parcels will advect, at least some potential exists for mid to upper 60s F dewpoints to overspread coastal counties. Should this occur, enough surface-based instability will be present (i.e. around 500 J/kg SBCAPE) to support a severe gust/tornado threat given impressive vertical shear profiles (similar to TX during the day). Given the presence of very strong low-level shear, at least a couple of strong tornadoes are possible. ..Squitieri/Mosier.. 01/24/2023 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0140 PM CST Mon Jan 23 2023 Valid 232000Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. today and through the overnight hours. ...Southwest States into TX... Minimal thunderstorm activity is expected for much of the day, except for isolated flashes over parts of eastern AZ and NM beneath cold temperatures aloft and with the addition of heating. The more substantial thunderstorm chances will occur after about 09Z tonight into west/west-central TX. Here, an increasing low-level jet will bring in higher theta-e air, resulting in lift and scattered storms. Severe weather is not expected due to only weak elevated instability. ..Jewell.. 01/23/2023 .PREV DISCUSSION... /ISSUED 1014 AM CST Mon Jan 23 2023/ ...Synopsis... A mid-level trough will traverse the Southwest as a second upper trough ejects into the Atlantic today. Surface high pressure and associated cooler, stable low-level air will overspread most of the CONUS, limiting the potential for thunderstorm development. The one exception will be portions of the Southwest into western and central TX, where colder temperatures aloft will promote marginal buoyancy amid deep-layer ascent accompanying the first aforementioned mid-level trough. Isolated thunderstorms may form across eastern AZ and western NM mainly during the late afternoon/early evening, with at least scattered thunderstorms developing across eastern NM into central TX tonight to 12Z Tuesday morning. A lightning flash or two may still occur across portions of the southern FL Peninsula this afternoon with convection along the cold front. However, decreasing low-level convergence and upper-level support suggest that thunderstorm development should be sparse at best, warranting the discontinuation of 10 percent thunder probabilities. Read more

No watches are valid as of Mon Jan 23 19:44:01 UTC 2023.

MD 0090 CONCERNING WINTER MIXED PRECIPITATION FOR PORTIONS OF MASSACHUSETTS INTO NEW HAMPSHIRE AND SOUTHERN MAINE
Mesoscale Discussion 0090 NWS Storm Prediction Center Norman OK 1247 PM CST Mon Jan 23 2023 Areas affected...portions of Massachusetts into New Hampshire and southern Maine Concerning...Winter mixed precipitation Valid 231847Z - 232145Z SUMMARY...Wintry mixed precipitation across portions of Massachusetts into southern New Hampshire should transition to mostly snow over the next few hours. Meanwhile, moderate to briefly heavy snow may persist across portions of southern Maine, with an instance or two of 1+ inch/hr snowfall rates still possible into mid-afternoon. DISCUSSION...A 992 mb surface low is located roughly 200 nm offshore of the coast of ME, and continues to progress eastward along with the associated wrap-around moisture which has supported several hours of wintry precipitation across northern New England. A wintry mix has been observed over portions of southern NH into MA for the last few hours. However, the departure of the surface low supports surface-700 mb cold-air advection across New England, as suggested by the 18Z mesoanalysis. As such, a transition to mainly moderate snow is expected across southern NH into MA through the afternoon. Farther north, a saturated dendritic growth zone remains in place across southern parts of ME. While decreasing deep-layer ascent with the departing surface low suggests that the snow event in this area may have passed peak intensity, at least a few more hours of moderate to occasionally snow remains possible, and an instance or two of 1+ inch/hr snowfall rates cannot be ruled out through at least 22Z. ..Squitieri.. 01/23/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAR...GYX...BOX... LAT...LON 42187095 41997183 42177267 43237178 44277086 44716964 44566874 44266898 43956969 43327059 42547105 42187095 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1245 PM CST Mon Jan 23 2023 Valid 241200Z - 251200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE RIO GRAND VALLEY AND RIO GRAND PLAINS IN TEXAS... A Critical delineation was added across the Rio Grand Valley and Rio Grand Plains in Texas on Tuesday afternoon. Within this region, mainly light precipitation (a few hundredths) is forecast. Clearing skies and deep mixing, in combination with downslope warming and drying by the afternoon, will allow for strong winds (sustained at 20-30 mph) and relative humidity reductions to 15-20 percent. Given the status of fuels currently mentioned below, notable drought conditions, and forecast for strong winds, it is likely that the 1-hr fuels will be able to cure and support fire spread by the afternoon. As such, a Critical delineation was supported within the region of highest conditional probability of Critical conditions using ensemble guidance. The Elevated risk area was reduced due to the potential for more beneficial rainfall, as mentioned in the previous discussion below. ..Thornton.. 01/23/2023 .PREV DISCUSSION... /ISSUED 0207 AM CST Mon Jan 23 2023/ ...Synopsis... Elevated fire weather concerns appear probable along the Rio Grande Tuesday afternoon. The surface low currently along the southern AZ/NM border is expected to intensify and propagate east along the Gulf Coast through the day Tuesday. Coincidentally, a Pacific cold front/dryline is forecast to rapidly progress east across southern TX through the day. West/northwesterly winds at 15 to 25 mph are expected in the wake of this front. Recent ensemble guidance hints that locations along the Rio Grande and into far southern TX will see the highest potential for sustained 20+ mph winds through the late morning and early afternoon. Cool air filtering in behind the front and lingering cloud cover will likely modulate diurnal RH reductions for much of southern TX, but trajectories emanating from the higher terrain of far west TX and northern Mexico will support some degree of downslope warming/drying along the Rio Grande. With ERC values approaching the 90th percentile for parts of the region, elevated fire weather conditions appear probable. However, the fire weather concern will be conditional on this region's not receiving wetting precipitation by early Tuesday morning ahead of the frontal passage. Trends in forecast and observed precipitation will be monitored and the forecast adjusted accordingly. Furthermore, a wind-driven fire concern is possible along the TX Gulf Coast where ERC values are locally highest and 15-20 mph winds are expected. However, the combination of limited RH reductions and wetting QPF preclude additional highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more