Aggregator

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

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1138 AM CST Mon Jan 23 2023 Valid 241200Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE MIDDLE AND UPPER TEXAS COAST...AND FROM SOUTHERN LOUISIANA EASTWARD INTO THE FLORIDA PANHANDLE... ...SUMMARY... Severe thunderstorms are expected from the middle to upper Texas Coast Tuesday afternoon, spreading into parts of southeastern Louisiana and across coastal Mississippi, Alabama and the western Florida Panhandle by Wednesday morning. Damaging winds and several tornadoes are anticipated, with a conditional threat of a strong tornado. ...Synopsis... A deep upper low will move eastward from northern TX during the day into the middle MS Valley by 12Z Wed. Leading this trough will be a 80-100 midlevel jet streak, with extreme 70+ kt 850 mb wind fields translating east across the Gulf Coast states. At the surface, low pressure will develop across southeast TX during the day, pivoting northeast across LA and AR overnight. Meanwhile, a warm front will extend east from the low, with mid 60s F dewpoints south of the Houston area. This front will lift north of I-10 in LA after 00Z, with mid to upper 60s F dewpoints eventually overspreading southeast LA, and the coastal counties of MS, AL, and the western FL Panhandle. A cold front will surge east across the northern Gulf coast states immediately behind the warm front, resulting in a limited warm sector. ...Middle and upper TX Coast - Daytime... Rain and elevated storms will rapidly expand across central TX during the day, with intensification occurring over south-central into southeast TX as the warm sector develops northward. Storms are forecast to become severe after 18Z along the cold front, and warm front intersection where a surface low will develop. Here, dewpoints are expected to be sufficient for surface-based storm inflow, with MLCAPE to around 1000 J/kg. Shear profiles will be extreme, with effective SRH over 500 m2/s2 and near 800 m2/s2 along the warm front south of the Houston area. Supercells will be likely along the developing line of storms near the cold front, and a favored area for strong tornadoes will be as this lift intersects the warm front. Heating is unlikely given the early moisture return and saturated boundary layer, but the extreme shear warrants an outlook for isolated strong tornadoes. ...Southern LA...MS...AL...FL Panhandle - Evening and Overnight... A squall line is forecast to move across the Sabine River around 00Z, progressing across LA and into MS through 06Z. The degree of severe risk will be closely tied to boundary-layer destabilization, and southern parts of the line across southern LA may weaken with time. Damaging winds appear most likely with much of the line, but southern parts of the line will have better access to more unstable air, with conditional tornado risk. SBCAPE will eventually exceed 500 J/kg, with extreme SRH of 400-800 m2/s2 coincident with positive SBCAPE. Additional supercells with tornado threat may develop after 09Z near the warm front/ahead of the cold front from southern AL into the FL Panhandle, with damaging winds and a few tornadoes possible with MLCAPE > 500 J/kg moving onshore. ..Jewell.. 01/23/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1054 AM CST Mon Jan 23 2023 Valid 231700Z - 241200Z Minor adjustments were made to the eastern edge of the Elevated area with this morning update. Guidance has come in with more conservative relative humidity reductions with eastward extent in western Texas. This is likely due to southeasterly flow bringing an increase in low clouds and moisture, which is being observed in visible satellite this morning. HREF conditional probabilities place the highest chances (60-70 percent) of Elevated fire weather conditions across far western Texas within Mission Valley. This area will remain mostly sunny with strong downslope flow out of northern Mexico, which will aid relative humidity reductions around 15-20 percent by the afternoon. Localized areas of Critical fire weather conditions will be possible. Given the localized nature and potential for increasing mid-level cloud cover across the region by late afternoon, a Critical area was not included. ..Thornton.. 01/23/2023 .PREV DISCUSSION... /ISSUED 0202 AM CST Mon Jan 23 2023/ ...Synopsis... Elevated fire weather conditions remain probable across far west Texas this afternoon as winds increase in response to a strengthening cyclone over northern Mexico. Early-morning water-vapor imagery and upper-air analyses show a strong upper jet over the Pacific Northwest associated with a shortwave trough. This feature is expected to amplify as it digs into the Southwest over the next 24 hours. This will deepen a broad surface low evident in surface observations over southern AZ/NM as of 07 UTC. In response, winds are expected to increase to 20-25 mph from the TX Gulf Coast to far west TX. An antecedent dry air mass over south-central/ southwest TX, coupled with downslope flow out of northern Mexico, will favor 15-20% RH with winds near 20 mph across far west TX. Elevated conditions may develop further east into south-central TX by late afternoon, but increasing cloud cover and weak moisture return introduce uncertainty into the magnitude of daytime heating. Regardless, regional ERCs between the 70-80th percentile should support at least a low-end, wind-driven fire weather concern. ...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 1014 AM CST Mon Jan 23 2023 Valid 231630Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. today and through the overnight hours. ...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. ..Squitieri.. 01/23/2023 Read more

No watches are valid as of Sun Jan 22 20:01:01 UTC 2023.

MD 0087 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF FAR NORTHERN FLORIDA INTO SOUTHERN GEORGIA
Mesoscale Discussion 0087 NWS Storm Prediction Center Norman OK 0157 PM CST Sun Jan 22 2023 Areas affected...portions of far northern Florida into southern Georgia Concerning...Severe potential...Watch unlikely Valid 221957Z - 222200Z Probability of Watch Issuance...20 percent SUMMARY...An uptick in thunderstorm intensity may occur over the next few hours, with isolated strong to potentially severe thunderstorms possible. A damaging gust or tornado should be the main threats with the strongest storms. A WW issuance is unlikely given the expected sparse nature of the severe threat. DISCUSSION...MRMS mosaic and regional radar imagery and NLDN lightning data all suggest that thunderstorms may be intensifying ahead of a weak surface low and associated cold front along the FL/AL/GA border area. Ahead of the surface low, adequate low-level warm-air advection and diurnal heating have modified the boundary layer at least as far north as the FL/GA border, with 70 F temperatures and upper 60s F dewpoints becoming common. 19Z mesoanalysis and 18Z RAP forecast soundings characterize the warm-sector with 500-1000 J/kg of thin MLCAPE amid mainly straight hodographs (as also supported by regional VADs). As such, linear segments and semi-discrete cells may organize and intensify enough to support an isolated severe threat through mid-afternoon. A couple of damaging gusts are possible. However, a tornado or two may occur, especially along the warm front, where locally backed surface winds may contribute to enough streamwise vorticity/low-level hodograph curvature to support low-level updraft rotation. Still, the overall severe threat is expected to remain isolated and a WW issuance appears unlikely at this time. ..Squitieri/Hart.. 01/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...JAX...FFC...TAE... LAT...LON 30968480 31658410 31888356 32078297 32088235 31788154 31468122 30588153 30298213 30188335 30248426 30358478 30588505 30968480 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 PM CST Sun Jan 22 2023 Valid 231200Z - 241200Z No changes are needed to the D2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0119 AM CST Sun Jan 22 2023/ ...Synopsis... Elevated fire weather concerns appear probable across portions of the Rio Grande Valley of far west TX. Early-morning water-vapor imagery shows a progressive shortwave trough over the Pacific Northwest, which is forecast to amplify as it moves into southern Arizona over the next 48 hours. This will result in strengthening mid-level flow over the far southern Rockies and the development of a strong lee cyclone over northern Mexico. In response, southeasterly surface winds across southern and southwest TX are forecast to increase to 15-25 mph with minimal moisture return. Partly cloudy to mostly clear skies should favor adequate diurnal warming for RH values to fall into the teens and low 20s. Coupled with regional ERC values near the 75th percentile, elevated fire weather conditions appear probable, and brief, localized critical conditions are possible across far west TX. ...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 0150 PM CST Sun Jan 22 2023 Valid 231200Z - 241200Z No changes are needed to the D2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0119 AM CST Sun Jan 22 2023/ ...Synopsis... Elevated fire weather concerns appear probable across portions of the Rio Grande Valley of far west TX. Early-morning water-vapor imagery shows a progressive shortwave trough over the Pacific Northwest, which is forecast to amplify as it moves into southern Arizona over the next 48 hours. This will result in strengthening mid-level flow over the far southern Rockies and the development of a strong lee cyclone over northern Mexico. In response, southeasterly surface winds across southern and southwest TX are forecast to increase to 15-25 mph with minimal moisture return. Partly cloudy to mostly clear skies should favor adequate diurnal warming for RH values to fall into the teens and low 20s. Coupled with regional ERC values near the 75th percentile, elevated fire weather conditions appear probable, and brief, localized critical conditions are possible across far west TX. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0143 PM CST Sun Jan 22 2023 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN FL...SOUTHERN GA AND SOUTHEAST SC... ...SUMMARY... A few marginally severe thunderstorms are possible through this evening over a corridor from northern Florida into southern Georgia and southern South Carolina. An isolated tornado or damaging gust is possible. ...20z Update... Only minor adjustments have been made to the outlook with the 20z update. Thunderstorm activity/intensity may increase over the next few hours as convection moves toward northern FL/southeast GA. Stronger heating has resulted in somewhat better destabilization and steepening of low-level lapse rates across this area. Stronger convection will continue to pose a threat for locally damaging gusts, while moderate speed shear contributes to somewhat enlarged low-level hodographs, supporting rotation and possibly a tornado. The severe threat is expected to diminish this evening. ..Leitman.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0959 AM CST Sun Jan 22 2023/ ...Synopsis... A 1010 mb surface low over the FL Panhandle with continue to drift to the northeast as a mid-level longwave trough continues to approach the Gulf Coast states from the west. Modest northeastward advection of low-level moisture will promote marginal buoyancy across the southeast into the Carolinas, that in tandem with deep-layer ascent will support at least scattered thunderstorms throughout the day. Isolated severe thunderstorms are possible. ...Northern Florida into southern South Carolina.. Heavier showers with isolated embedded thunderstorms are ongoing within a confluence band across portions of the FL Panhandle into southern GA and southern SC. This confluence band will drift slowly eastward through the afternoon in tandem with the surface low. As warm-air/moisture advection continues along and ahead of the confluence band, and as a cold front approaches from the west, both increasing buoyancy and deep-layer ascent may support a brief uptick in convective intensity later today. From northern FL into southern GA and far southern SC, surface temperatures rising into the upper 60s F (with at least mid 60s F surface dewpoints), overspread by 5.5-6 C/km mid-level lapse rates will result in 500-1000 J/kg of thin MLCAPE. Though vertical wind profiles should be largely unidirectional, strong speed shear will contribute to widespread 50+ kts of effective bulk shear, with regional VADs and point-forecast soundings also indicating modest low-level hodograph curvature (and 200-300 m2/s2 effective SRH). As such, any storms that manage to organize and intensify later this afternoon could acquire some low-level rotation, with an isolated tornado or damaging gust possible before the confluence band moves offshore. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0143 PM CST Sun Jan 22 2023 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN FL...SOUTHERN GA AND SOUTHEAST SC... ...SUMMARY... A few marginally severe thunderstorms are possible through this evening over a corridor from northern Florida into southern Georgia and southern South Carolina. An isolated tornado or damaging gust is possible. ...20z Update... Only minor adjustments have been made to the outlook with the 20z update. Thunderstorm activity/intensity may increase over the next few hours as convection moves toward northern FL/southeast GA. Stronger heating has resulted in somewhat better destabilization and steepening of low-level lapse rates across this area. Stronger convection will continue to pose a threat for locally damaging gusts, while moderate speed shear contributes to somewhat enlarged low-level hodographs, supporting rotation and possibly a tornado. The severe threat is expected to diminish this evening. ..Leitman.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0959 AM CST Sun Jan 22 2023/ ...Synopsis... A 1010 mb surface low over the FL Panhandle with continue to drift to the northeast as a mid-level longwave trough continues to approach the Gulf Coast states from the west. Modest northeastward advection of low-level moisture will promote marginal buoyancy across the southeast into the Carolinas, that in tandem with deep-layer ascent will support at least scattered thunderstorms throughout the day. Isolated severe thunderstorms are possible. ...Northern Florida into southern South Carolina.. Heavier showers with isolated embedded thunderstorms are ongoing within a confluence band across portions of the FL Panhandle into southern GA and southern SC. This confluence band will drift slowly eastward through the afternoon in tandem with the surface low. As warm-air/moisture advection continues along and ahead of the confluence band, and as a cold front approaches from the west, both increasing buoyancy and deep-layer ascent may support a brief uptick in convective intensity later today. From northern FL into southern GA and far southern SC, surface temperatures rising into the upper 60s F (with at least mid 60s F surface dewpoints), overspread by 5.5-6 C/km mid-level lapse rates will result in 500-1000 J/kg of thin MLCAPE. Though vertical wind profiles should be largely unidirectional, strong speed shear will contribute to widespread 50+ kts of effective bulk shear, with regional VADs and point-forecast soundings also indicating modest low-level hodograph curvature (and 200-300 m2/s2 effective SRH). As such, any storms that manage to organize and intensify later this afternoon could acquire some low-level rotation, with an isolated tornado or damaging gust possible before the confluence band moves offshore. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0143 PM CST Sun Jan 22 2023 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN FL...SOUTHERN GA AND SOUTHEAST SC... ...SUMMARY... A few marginally severe thunderstorms are possible through this evening over a corridor from northern Florida into southern Georgia and southern South Carolina. An isolated tornado or damaging gust is possible. ...20z Update... Only minor adjustments have been made to the outlook with the 20z update. Thunderstorm activity/intensity may increase over the next few hours as convection moves toward northern FL/southeast GA. Stronger heating has resulted in somewhat better destabilization and steepening of low-level lapse rates across this area. Stronger convection will continue to pose a threat for locally damaging gusts, while moderate speed shear contributes to somewhat enlarged low-level hodographs, supporting rotation and possibly a tornado. The severe threat is expected to diminish this evening. ..Leitman.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0959 AM CST Sun Jan 22 2023/ ...Synopsis... A 1010 mb surface low over the FL Panhandle with continue to drift to the northeast as a mid-level longwave trough continues to approach the Gulf Coast states from the west. Modest northeastward advection of low-level moisture will promote marginal buoyancy across the southeast into the Carolinas, that in tandem with deep-layer ascent will support at least scattered thunderstorms throughout the day. Isolated severe thunderstorms are possible. ...Northern Florida into southern South Carolina.. Heavier showers with isolated embedded thunderstorms are ongoing within a confluence band across portions of the FL Panhandle into southern GA and southern SC. This confluence band will drift slowly eastward through the afternoon in tandem with the surface low. As warm-air/moisture advection continues along and ahead of the confluence band, and as a cold front approaches from the west, both increasing buoyancy and deep-layer ascent may support a brief uptick in convective intensity later today. From northern FL into southern GA and far southern SC, surface temperatures rising into the upper 60s F (with at least mid 60s F surface dewpoints), overspread by 5.5-6 C/km mid-level lapse rates will result in 500-1000 J/kg of thin MLCAPE. Though vertical wind profiles should be largely unidirectional, strong speed shear will contribute to widespread 50+ kts of effective bulk shear, with regional VADs and point-forecast soundings also indicating modest low-level hodograph curvature (and 200-300 m2/s2 effective SRH). As such, any storms that manage to organize and intensify later this afternoon could acquire some low-level rotation, with an isolated tornado or damaging gust possible before the confluence band moves offshore. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0143 PM CST Sun Jan 22 2023 Valid 222000Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS NORTHERN FL...SOUTHERN GA AND SOUTHEAST SC... ...SUMMARY... A few marginally severe thunderstorms are possible through this evening over a corridor from northern Florida into southern Georgia and southern South Carolina. An isolated tornado or damaging gust is possible. ...20z Update... Only minor adjustments have been made to the outlook with the 20z update. Thunderstorm activity/intensity may increase over the next few hours as convection moves toward northern FL/southeast GA. Stronger heating has resulted in somewhat better destabilization and steepening of low-level lapse rates across this area. Stronger convection will continue to pose a threat for locally damaging gusts, while moderate speed shear contributes to somewhat enlarged low-level hodographs, supporting rotation and possibly a tornado. The severe threat is expected to diminish this evening. ..Leitman.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0959 AM CST Sun Jan 22 2023/ ...Synopsis... A 1010 mb surface low over the FL Panhandle with continue to drift to the northeast as a mid-level longwave trough continues to approach the Gulf Coast states from the west. Modest northeastward advection of low-level moisture will promote marginal buoyancy across the southeast into the Carolinas, that in tandem with deep-layer ascent will support at least scattered thunderstorms throughout the day. Isolated severe thunderstorms are possible. ...Northern Florida into southern South Carolina.. Heavier showers with isolated embedded thunderstorms are ongoing within a confluence band across portions of the FL Panhandle into southern GA and southern SC. This confluence band will drift slowly eastward through the afternoon in tandem with the surface low. As warm-air/moisture advection continues along and ahead of the confluence band, and as a cold front approaches from the west, both increasing buoyancy and deep-layer ascent may support a brief uptick in convective intensity later today. From northern FL into southern GA and far southern SC, surface temperatures rising into the upper 60s F (with at least mid 60s F surface dewpoints), overspread by 5.5-6 C/km mid-level lapse rates will result in 500-1000 J/kg of thin MLCAPE. Though vertical wind profiles should be largely unidirectional, strong speed shear will contribute to widespread 50+ kts of effective bulk shear, with regional VADs and point-forecast soundings also indicating modest low-level hodograph curvature (and 200-300 m2/s2 effective SRH). As such, any storms that manage to organize and intensify later this afternoon could acquire some low-level rotation, with an isolated tornado or damaging gust possible before the confluence band moves offshore. Read more

MD 0086 CONCERNING HEAVY SNOW FOR NORTHEAST OHIO INTO FAR NORTHWEST PENNSYLVANIA AND EXTREME SOUTHWEST NEW YORK
Mesoscale Discussion 0086 NWS Storm Prediction Center Norman OK 1203 PM CST Sun Jan 22 2023 Areas affected...northeast Ohio into far northwest Pennsylvania and extreme southwest New York Concerning...Heavy snow Valid 221803Z - 222000Z SUMMARY...A couple hours of heavy snow may accompany the primary band of precipitation exiting the OH Valley. A couple instances of 1+ inch/hour snowfall rates are possible. DISCUSSION...A snow band with a history of producing brief bouts of heavier snowfall rates continues to move northeast across OH in tandem with deeper moisture and the approach of a mid-level trough. Warm-air/moisture advection continues across the eastern OH Valley toward the Appalachians, with tropospheric profiles remaining below freezing from central/northeast OH into far northwest PA and extreme southwest NY. Here, continued moistening of the dendritic growth zone and 700 mb frontogenesis will promote enough lift for moderate to occasional heavy snow, as already indicated by ASOS stations at the Erie and Akron-Fulton International Airports. As such, 1+ inch/hr rates are still possible into early afternoon. ..Squitieri.. 01/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BUF...CTP...PBZ...CLE... LAT...LON 41148207 41588147 42018041 42477936 42467897 42127873 41647931 41238001 40918087 40768148 40768180 40848206 41148207 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1049 AM CST Sun Jan 22 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Monday through Monday night. ...Synopsis... A progressive upper-level pattern is expected on Monday as a series of troughs develop eastward across the CONUS. The first trough, located over the Midwest and Southeast will shift east/northeast, moving offshore the Atlantic coast Monday night. A cold front associated with this system will mainly be offshore the Atlantic coast Monday morning, with the southern extent of the boundary arcing across central FL. A few lightning flashes will be possible across the central/southern FL Peninsula as the front shifts south through the afternoon. However, weak instability/poor lapse rates and modest large-scale ascent will preclude severe potential. The second trough/upper low, located over the Southwest and northwest Mexico, will pivot east toward the southern Rockies/northern Mexico. Increasing midlevel moisture on strong southwesterly flow ahead of the trough, and cooling midlevel temperatures resulting in a plume of steepening midlevel lapse rates, will support isolated elevated thunderstorms across parts of southeast AZ/southwest NM into the southern High Plains and west-central TX Monday evening into early Tuesday. Severe storms are not expected with this activity. ..Leitman.. 01/22/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1049 AM CST Sun Jan 22 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Monday through Monday night. ...Synopsis... A progressive upper-level pattern is expected on Monday as a series of troughs develop eastward across the CONUS. The first trough, located over the Midwest and Southeast will shift east/northeast, moving offshore the Atlantic coast Monday night. A cold front associated with this system will mainly be offshore the Atlantic coast Monday morning, with the southern extent of the boundary arcing across central FL. A few lightning flashes will be possible across the central/southern FL Peninsula as the front shifts south through the afternoon. However, weak instability/poor lapse rates and modest large-scale ascent will preclude severe potential. The second trough/upper low, located over the Southwest and northwest Mexico, will pivot east toward the southern Rockies/northern Mexico. Increasing midlevel moisture on strong southwesterly flow ahead of the trough, and cooling midlevel temperatures resulting in a plume of steepening midlevel lapse rates, will support isolated elevated thunderstorms across parts of southeast AZ/southwest NM into the southern High Plains and west-central TX Monday evening into early Tuesday. Severe storms are not expected with this activity. ..Leitman.. 01/22/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1049 AM CST Sun Jan 22 2023 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across the U.S. Monday through Monday night. ...Synopsis... A progressive upper-level pattern is expected on Monday as a series of troughs develop eastward across the CONUS. The first trough, located over the Midwest and Southeast will shift east/northeast, moving offshore the Atlantic coast Monday night. A cold front associated with this system will mainly be offshore the Atlantic coast Monday morning, with the southern extent of the boundary arcing across central FL. A few lightning flashes will be possible across the central/southern FL Peninsula as the front shifts south through the afternoon. However, weak instability/poor lapse rates and modest large-scale ascent will preclude severe potential. The second trough/upper low, located over the Southwest and northwest Mexico, will pivot east toward the southern Rockies/northern Mexico. Increasing midlevel moisture on strong southwesterly flow ahead of the trough, and cooling midlevel temperatures resulting in a plume of steepening midlevel lapse rates, will support isolated elevated thunderstorms across parts of southeast AZ/southwest NM into the southern High Plains and west-central TX Monday evening into early Tuesday. Severe storms are not expected with this activity. ..Leitman.. 01/22/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1049 AM CST Sun Jan 22 2023 Valid 221700Z - 231200Z ...NO CRITICAL AREAS... No updates are needed to the current D1 Fire Weather Outlook. See previous discussion below. ..Thornton.. 01/22/2023 .PREV DISCUSSION... /ISSUED 0115 AM CST Sun Jan 22 2023/ ...Synopsis... Fire weather potential will remain low for today across the country. Latest surface observations and satellite imagery show a weak cold front moving off the TX coast into the northern Gulf. Surface pressure rises are noted across central TX behind this front, and further building of an extensive surface high is expected across the Plains over the next 24 hours as upper ridging shifts east. This will result in meager pressure-gradient winds across central to southern TX where fuels are currently the driest. Ensemble guidance supports this assessment with low probabilities for winds exceeding 20 mph across the region, and, consequently, low fire weather potential. ...Please see www.spc.noaa.gov/fire for graphic product... Read more