Severe Storms

MD 0612 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL PORTION OF THE FL PENINSULA
Mesoscale Discussion 0612 NWS Storm Prediction Center Norman OK 0255 PM CDT Tue Apr 25 2023 Areas affected...central portion of the FL Peninsula Concerning...Severe potential...Watch unlikely Valid 251955Z - 252200Z Probability of Watch Issuance...5 percent SUMMARY...Isolated large hail and localized damaging gusts are possible through 7pm EDT. DISCUSSION...Visible satellite and radar imagery show developing storms along the west coast sea breeze from near Ocala southward through the I-4 corridor east of Tampa Bay. KTBW and KMLB VAD data show 50-kt westerly flow at 7-8 km which is aiding in both storm venting/organization. RAP forecast soundings show around 1500 J/kg MLCAPE with relatively steep low-level lapse rates in areas not behind the cooler sea-breeze front. A few marginal supercell structures are possible with the more intense storms and large hail will be the primary risk (hail diameter 1.0 to 1.75 inches). The overall risk will be isolated in coverage and the temporal window of opportunity will likely be relegated between now (350pm EDT) and 700pm EDT. A localized damaging gust cannot be ruled out, especially with a collapsing core. ..Smith/Gleason.. 04/25/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MLB...TBW...JAX... LAT...LON 27158182 27298210 28068230 28758218 29168218 29268190 29088163 28428130 27738035 27388043 27158182 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1255 PM CDT Tue Apr 25 2023 Valid 261200Z - 271200Z The previous forecast (see below) remains on track, and no changes were needed with this update. ..Weinman.. 04/25/2023 .PREV DISCUSSION... /ISSUED 0149 AM CDT Tue Apr 25 2023/ ...Synopsis... The upper-level trough will shift into the southern Plains on Wednesday and leave much less favorable fire weather conditions in its wake. Some dry northerly flow will likely develop in the High Plains as high pressure builds south and a cold front surges southward. There will be a brief period during the afternoon where some dry and breezy northwest flow may exist across southeast New Mexico and vicinity. This will occur where heating and deep mixing can develop ahead of the cold front and some stronger mid-level flow may come toward the surface. Elsewhere, fire weather concerns will be minimal with moist fuels and/or light winds for most regions. ...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 1255 PM CDT Tue Apr 25 2023 Valid 261200Z - 271200Z The previous forecast (see below) remains on track, and no changes were needed with this update. ..Weinman.. 04/25/2023 .PREV DISCUSSION... /ISSUED 0149 AM CDT Tue Apr 25 2023/ ...Synopsis... The upper-level trough will shift into the southern Plains on Wednesday and leave much less favorable fire weather conditions in its wake. Some dry northerly flow will likely develop in the High Plains as high pressure builds south and a cold front surges southward. There will be a brief period during the afternoon where some dry and breezy northwest flow may exist across southeast New Mexico and vicinity. This will occur where heating and deep mixing can develop ahead of the cold front and some stronger mid-level flow may come toward the surface. Elsewhere, fire weather concerns will be minimal with moist fuels and/or light winds for most regions. ...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 1220 PM CDT Tue Apr 25 2023 Valid 261200Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF NORTH TEXAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA... ...SUMMARY... Severe storms producing damaging winds and very large hail are expected over much of northern Texas Wednesday afternoon and evening. Isolated to scattered severe storms producing hail may also occur from the Florida Peninsula into central Georgia. ...Synopsis... A southern-stream shortwave trough, and accompanying mid-level speed max, is expected to move from the southern High Plains into the southern Plains on Wednesday. This system will initially be positively titled, but should trend towards a more neutral tilt with time. Low-level moisture advection is anticipated across TX throughout the day today (Tuesday), with this moist air mass expected to remain in place as the shortwave pushes through on Wednesday. Surface low associated with the shortwave will likely begin the period over northwest TX, before then moving eastward along the warm front across north TX just ahead of the shortwave as it moves through. Dryline extending southward from this low will make some eastward progress across TX Big County and southwest TX, before likely stalling during the evening. A cold front will then sweep southward/southeastward across west TX and through much of north and central TX tomorrow evening and overnight. Severe thunderstorms are possible along the dryline across north TX, with additional strong to severe storms also possible along the cold front as it pushes through. ...Southern Plains... As discussed in the synopsis, a surface low is forecast to begin the period over the TX Big Country, before gradually moving eastward along the warm front. This warm front is expected to be quite sharp, but guidance still varies on its location tomorrow afternoon. Given that widespread showers and thunderstorms are expected across OK from overnight Tuesday into Wednesday morning, a more southerly warm front location is currently preferred, likely in the vicinity of the Red River. As such, the greatest severe potential will likely exist from northwest TX into north TX Wednesday afternoon and evening. Here, seasonably cool mid-level temperatures atop mid 60s dewpoints will result in moderate to strong buoyancy. General expectation is for thunderstorm initiation to occur along the dryline during the early afternoon as mesoscale ascent attendant to the dryline is augmented by increasing large-scale ascent. This general expectation may be complicated by residual outflow that may be in place over north/central TX in the wake of early morning storms. However, uncertainty regarding the location and depth of any outflow limits predictability at this forecast range. Initial development will likely be supercellular, supported by increasing mid-level flow and strong deep-layer shear. Steep lapse rates will favor large to very large (i.e. greater than 2 inches in diameter) with these initial supercells. Low-level flow is expected to be relatively modest, limiting low-level shear and potentially keeping the tornado threat low. However, given the potential for interaction with residual outflow and/or the warm front, some higher threat may materialize in more confined corridors. Given previously mentioned uncertainties regarding outflow and warm front positions, will defer any increase in tornado probabilities to later outlooks. Upscale growth is anticipated after a few hours after initiation, with the resulting MCS tracking eastward/southeastward across east TX and northern LA. Marginal wind probabilities were extended into far west-central MS to account for the potential that the convective line will be in that vicinity early Thursday morning. ...GA/FL... Seasonably cold mid-level temperatures are expected across GA and FL on Wednesday, with 500-mb temperatures ranging from -14 deg C across south FL to -16 deg C over southern GA. Modest mid-level flow and forcing for ascent is also anticipated as a weak shortwave trough moves over the peninsula. This large-scale ascent in tandem with forcing along sea breeze boundaries is expected to result in scattered thunderstorm coverage. Hail and/or damaging gusts are possible with any more robust/longer-lived storms. ..Mosier.. 04/25/2023 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Tue Apr 25 2023 Valid 261200Z - 271200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER MUCH OF NORTH TEXAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE FLORIDA PENINSULA... ...SUMMARY... Severe storms producing damaging winds and very large hail are expected over much of northern Texas Wednesday afternoon and evening. Isolated to scattered severe storms producing hail may also occur from the Florida Peninsula into central Georgia. ...Synopsis... A southern-stream shortwave trough, and accompanying mid-level speed max, is expected to move from the southern High Plains into the southern Plains on Wednesday. This system will initially be positively titled, but should trend towards a more neutral tilt with time. Low-level moisture advection is anticipated across TX throughout the day today (Tuesday), with this moist air mass expected to remain in place as the shortwave pushes through on Wednesday. Surface low associated with the shortwave will likely begin the period over northwest TX, before then moving eastward along the warm front across north TX just ahead of the shortwave as it moves through. Dryline extending southward from this low will make some eastward progress across TX Big County and southwest TX, before likely stalling during the evening. A cold front will then sweep southward/southeastward across west TX and through much of north and central TX tomorrow evening and overnight. Severe thunderstorms are possible along the dryline across north TX, with additional strong to severe storms also possible along the cold front as it pushes through. ...Southern Plains... As discussed in the synopsis, a surface low is forecast to begin the period over the TX Big Country, before gradually moving eastward along the warm front. This warm front is expected to be quite sharp, but guidance still varies on its location tomorrow afternoon. Given that widespread showers and thunderstorms are expected across OK from overnight Tuesday into Wednesday morning, a more southerly warm front location is currently preferred, likely in the vicinity of the Red River. As such, the greatest severe potential will likely exist from northwest TX into north TX Wednesday afternoon and evening. Here, seasonably cool mid-level temperatures atop mid 60s dewpoints will result in moderate to strong buoyancy. General expectation is for thunderstorm initiation to occur along the dryline during the early afternoon as mesoscale ascent attendant to the dryline is augmented by increasing large-scale ascent. This general expectation may be complicated by residual outflow that may be in place over north/central TX in the wake of early morning storms. However, uncertainty regarding the location and depth of any outflow limits predictability at this forecast range. Initial development will likely be supercellular, supported by increasing mid-level flow and strong deep-layer shear. Steep lapse rates will favor large to very large (i.e. greater than 2 inches in diameter) with these initial supercells. Low-level flow is expected to be relatively modest, limiting low-level shear and potentially keeping the tornado threat low. However, given the potential for interaction with residual outflow and/or the warm front, some higher threat may materialize in more confined corridors. Given previously mentioned uncertainties regarding outflow and warm front positions, will defer any increase in tornado probabilities to later outlooks. Upscale growth is anticipated after a few hours after initiation, with the resulting MCS tracking eastward/southeastward across east TX and northern LA. Marginal wind probabilities were extended into far west-central MS to account for the potential that the convective line will be in that vicinity early Thursday morning. ...GA/FL... Seasonably cold mid-level temperatures are expected across GA and FL on Wednesday, with 500-mb temperatures ranging from -14 deg C across south FL to -16 deg C over southern GA. Modest mid-level flow and forcing for ascent is also anticipated as a weak shortwave trough moves over the peninsula. This large-scale ascent in tandem with forcing along sea breeze boundaries is expected to result in scattered thunderstorm coverage. Hail and/or damaging gusts are possible with any more robust/longer-lived storms. ..Mosier.. 04/25/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1145 AM CDT Tue Apr 25 2023 Valid 251700Z - 261200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHEASTERN AZ...SOUTHERN NM...AND FAR WEST TX... The forecast remains on track, and no changes were needed with this update. For details on today's fire-weather threat, see the previous discussion below. ..Weinman.. 04/25/2023 .PREV DISCUSSION... /ISSUED 0147 AM CDT Tue Apr 25 2023/ ...Synopsis... A mid-level trough will move southeast from the Great Basin to the central Rockies today. This will bring moderate mid-level flow over a region which will be deeply mixed this afternoon. In addition, a lee cyclone will develop in the southern High Plains which will tighten the pressure gradient. These factors will combine for strong winds across much of the Southwest and southern High Plains. The driest region with the warmest temperatures will be across southern New Mexico and Far West Texas which is where the Critical delineation is. In addition, some thunderstorms are possible ahead of the approaching mid-level trough. These storms should be dry with PWAT values around 0.3 to 0.4. Fuels at higher terrain remain snow covered or moist/green. However, some critically dry fuels exist at lower elevation. Therefore, some lightning starts are possible in the lower elevations within the IsoDryT area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1145 AM CDT Tue Apr 25 2023 Valid 251700Z - 261200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHEASTERN AZ...SOUTHERN NM...AND FAR WEST TX... The forecast remains on track, and no changes were needed with this update. For details on today's fire-weather threat, see the previous discussion below. ..Weinman.. 04/25/2023 .PREV DISCUSSION... /ISSUED 0147 AM CDT Tue Apr 25 2023/ ...Synopsis... A mid-level trough will move southeast from the Great Basin to the central Rockies today. This will bring moderate mid-level flow over a region which will be deeply mixed this afternoon. In addition, a lee cyclone will develop in the southern High Plains which will tighten the pressure gradient. These factors will combine for strong winds across much of the Southwest and southern High Plains. The driest region with the warmest temperatures will be across southern New Mexico and Far West Texas which is where the Critical delineation is. In addition, some thunderstorms are possible ahead of the approaching mid-level trough. These storms should be dry with PWAT values around 0.3 to 0.4. Fuels at higher terrain remain snow covered or moist/green. However, some critically dry fuels exist at lower elevation. Therefore, some lightning starts are possible in the lower elevations within the IsoDryT area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0165 Status Updates
STATUS REPORT ON WW 165 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..04/24/23 ATTN...WFO...MLB...MFL...TBW... STATUS REPORT FOR WS 165 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS FLC009-011-027-043-049-051-055-061-085-093-095-097-099-105-111- 117-242240- FL . FLORIDA COUNTIES INCLUDED ARE BREVARD BROWARD DESOTO GLADES HARDEE HENDRY HIGHLANDS INDIAN RIVER MARTIN OKEECHOBEE ORANGE OSCEOLA PALM BEACH POLK ST. LUCIE SEMINOLE AMZ552-555-610-650-242240- CW . ADJACENT COASTAL WATERS INCLUDED ARE VOLUSIA-BREVARD COUNTY LINE TO SEBASTIAN INLET 0-20 NM SEBASTIAN INLET TO JUPITER INLET 0-20 NM LAKE OKEECHOBEE Read more

WW 165 SEVERE TSTM FL CW 241835Z - 250000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 165 NWS Storm Prediction Center Norman OK 235 PM EDT Mon Apr 24 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central and South Florida Coastal Waters * Effective this Monday afternoon and evening from 235 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are expected to rapidly intensify this afternoon across the watch area as an upper trough approaches. The strongest storms will pose a risk of hail and damaging wind gusts. The severe thunderstorm watch area is approximately along and 55 statute miles east and west of a line from 35 miles west northwest of Melbourne FL to 45 miles south of West Palm Beach FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for 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. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...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 28025. ...Hart Read more

MD 0610 CONCERNING SEVERE THUNDERSTORM WATCH 165... FOR CENTRAL/SOUTH FL
Mesoscale Discussion 0610 NWS Storm Prediction Center Norman OK 0338 PM CDT Mon Apr 24 2023 Areas affected...Central/South FL Concerning...Severe Thunderstorm Watch 165... Valid 242038Z - 242245Z The severe weather threat for Severe Thunderstorm Watch 165 continues. SUMMARY...Threat for thunderstorms capable of hail and/or damaging gusts continues across central and southern FL. DISCUSSION...Regional radar imagery shows numerous ongoing thunderstorms across central and south FL, with a predominantly multicellular storm mode. A few supercells, both left and right moving, have be observed as well. Somewhat chaotic storm motion has been noted, as these storms have tended to discretely propagate along their outflow. There have already been numerous storm interactions as well. Temperatures have already dropped into mid 70s across central FL, where mesoanalysis now suggests some convective inhibition is in place. Even with this inhibition, large-scale forcing for ascent will persist across the region, augmenting any mesoscale ascent along outflow boundaries and/or that results from surface convergence. As such, thunderstorms are expected to continue for the next few hours, with an attendant risk for hail and/or damaging gusts. Storm coverage will likely begin to decrease over west-central/southwest FL first as the ascent moves through, with gradual clearing then occurring west to east across the peninsula. ..Mosier.. 04/24/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW... LAT...LON 28518235 28898207 29008135 28648059 27357975 26197956 25658019 25908115 27228197 28518235 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Mon Apr 24 2023 Valid 251200Z - 261200Z ...CRITICAL FIRE WEATHER AREA FOR FAR SOUTHEASTERN AZ...SOUTHERN NM...AND FAR WEST TX... The primary changes with this update were a northward expansion of the Elevated highlights and the introduction of an Isolated Dry Thunderstorm area in central NM. As large-scale ascent increases ahead of a southeastward-advancing midlevel low, sufficient midlevel moisture atop a deeply mixed boundary layer will support isolated to widely scattered dry thunderstorm development over the higher terrain in central NM during the afternoon. Quick southeastward storm motions will allow this activity to overspread the lower elevations (where fuels are modestly supportive of lightning ignitions), and around 0.5 inch PW should aid in limiting rainfall accumulation. For additional details on the Day 2/Tuesday fire-weather threat, see the previous discussion below. ..Weinman.. 04/24/2023 .PREV DISCUSSION... /ISSUED 1236 AM CDT Mon Apr 24 2023/ ...Synopsis... A closed mid-level low will shift southeast from the Great Basin into the central Rockies on Tuesday. Meanwhile, a surface low will develop across eastern New Mexico. West of this surface low, a deeply mixed boundary layer is expected, which will bring some stronger mid-level flow toward the surface. Therefore, this deep mixing, combined with the strengthening pressure gradient, will lead to windy conditions across much of the Southwest. Higher moisture values and potentially some light rain (mountain snow) are possible across northern New Mexico. This should dampen fuel receptiveness and keep relative humidity somewhat higher. Therefore, the greatest fire weather threat will be across southern New Mexico and Far West Texas where winds of 20-25 mph and relative humidity of 10 to 15 percent are expected. ...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 0245 PM CDT Mon Apr 24 2023 Valid 242000Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL/SOUTH FLORIDA... ...SUMMARY... A few severe thunderstorms should occur this afternoon and early evening over parts of central/south Florida, with large hail and damaging winds possible. ...20Z Update... Only minor changes have been made to the Slight Risk across parts of central/south FL based on ongoing convective trends and short-term guidance. A threat for large hail and damaging winds will continue through the afternoon and early evening with robust convection that has developed across this area. See recently issued Severe Thunderstorm Watch 165 for more details. ..Gleason.. 04/24/2023 .PREV DISCUSSION... /ISSUED 1100 AM CDT Mon Apr 24 2023/ ...Central/South FL... Morning water vapor loop shows a progressive mid-level shortwave trough moving across the eastern Gulf of Mexico toward the FL Peninsula. Large scale forcing for ascent will overspread FL in the next few hours as diurnal heating maximizes. This should lead to numerous showers and thunderstorms. Forecast soundings show relatively cool temperatures aloft (-12C at 500mb), along with rich low-level moisture and robust daytime heating. Low-level winds are relatively weak, but mid/upper level winds are sufficiently strong to support a combination of multicell and occasional supercell structures capable of large hail and damaging winds. One forecast concern is that rapid storm development during the mid-afternoon may quickly exhaust the available instability, leading to a rather short window of opportunity for severe storms. ...AZ/NM... Clear skies are present this morning over much of AZ/NM, where steep low-level lapse rates and marginal CAPE values are expected to develop later today. Most model guidance agrees that scattered fast-moving showers and thunderstorms will form from northeast AZ into central/northern NM, where relatively strong westerly deep-layer flow is present. This environment appears favorable for a few dry microbursts, however very limited coverage and low confidence precludes a 5% severe wind outlook. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Mon Apr 24 2023 Valid 251200Z - 261200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF TEXAS... ...SUMMARY... Severe thunderstorms will be possible Tuesday over parts of Texas, with a risk of large to very large hail, damaging gusts, and perhaps a couple of tornadoes. ...Southern Plains... An upper trough/low will advance from the Great Basin/Four Corners region to the southern High Plains on Tuesday. A low-amplitude, southern-stream shortwave trough is forecast to move eastward across much of TX through the day, eventually reaching the lower MS Valley Tuesday night. Modest lee cyclogenesis across eastern NM should encourage the northward return of low-level moisture across west/central TX along/south of a surface warm front and east of a dryline. Convective development and evolution across most of the warm sector during the day still appears rather uncertain/conditional owing to a residual cap and limited daytime heating from widespread cloudiness. A better chance for the development of high-based thunderstorms is apparent across the southern High Plains as the upper trough advances south-southeastward. This activity will spread into a modestly unstable airmass, with surface dewpoints mainly in the 40s to perhaps low 50s. But, sufficiently strong deep-layer shear should support modestly organized updrafts, with an isolated threat for both hail and strong/gusty winds. With steep mid-level lapse rates and weak MUCAPE forecast, some threat for severe hail may also exist to the north of the front across parts of western into southern/central OK with elevated thunderstorms. Slightly better low-level moisture, characterized by mid/upper 50s to mid 60s surface dewpoints, are forecast from western north TX into central/north TX by Tuesday afternoon along/south of the warm front. Any thunderstorms that can form across this region would probably become severe and pose a threat for large to very large hail and damaging winds, as greater instability and strong deep-layer shear foster organized updrafts and the potential for supercells. However, uncertainty remains rather high regarding the number of severe thunderstorms that may form owing to nebulous/modest large-scale ascent. The risk for a couple of tornadoes may also increase with this activity late Tuesday afternoon/evening as a southerly low-level jet modestly strengthens. Have expanded the Slight Risk a bit to the northwest to include more of western north TX and vicinity. But, opted to not include the TX/OK Panhandles due to continued concerns about sufficient instability to support more than an isolated/marginal severe threat. ...Florida... Generally zonal flow at mid/upper levels will be present over much of FL on Tuesday. Even though low-level winds will remain weak, strengthening mid/upper-level westerlies may support some updraft organization with any thunderstorms that can develop Tuesday afternoon over parts of the central/southern FL Peninsula along sea breeze boundaries. Strong daytime heating, combined with upper 60s surface dewpoints and cool temperatures aloft, will likely lead to MLCAPE approaching 1000-1500 J/kg across the southeastern FL Peninsula. Even though large-scale ascent will remain minimal, at least isolated thunderstorms should form, with straight hodographs favoring marginally severe hail. Occasional damaging winds may also occur. ..Gleason.. 04/24/2023 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Mon Apr 24 2023 Valid 241700Z - 251200Z The forecast remains on track, and no changes were needed with this update. For details, see the previous discussion below. ..Weinman.. 04/24/2023 .PREV DISCUSSION... /ISSUED 1234 AM CDT Mon Apr 24 2023/ ...Synopsis... A weak mid-level shortwave trough, observed on upper-level water-vapor imagery this morning across the Great Basin, will move east and cross the central Rockies during the day today. This will initiate lee troughing across much of the southern and central High Plains. However, the tightening pressure gradient will be most pronounced across the TX/OK Panhandles and into western Kansas where low-level moisture will be sufficiently high to limit any fire weather concerns. However, deep mixing is expected across Arizona and New Mexico. Mid-level flow around 35 to 40 knots is expected across the Southwest, some of which may be transported to the surface through mixing processes. Therefore, elevated fire weather conditions are expected from far southeast Arizona into southwestern and western New Mexico. In addition, a few dry thunderstorms are possible across northern Arizona and New Mexico. However, these thunderstorms are expected mainly over higher terrain where fuels are not critically dry. Therefore, have elected not to add a IsoDryT area. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sun Apr 23 21:25:02 UTC 2023.

No Mesoscale Discussions are in effect as of Sun Apr 23 21:25:02 UTC 2023.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0240 PM CDT Sun Apr 23 2023 Valid 232000Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms has diminished across the lower Rio Grande Valley, and now appears negligible across the U.S. late this afternoon through tonight. ...20Z Update... The more intense leading line and gust front of the south-southeastward propagating, organized mesoscale convective system have progressed offshore of lower Texas coastal areas, and south of the lower Rio Grande Valley. However, the trailing stratiform precipitation and associated lightning may continue to impact coastal areas another hour or two. Elsewhere, some adjustments to the categorical risk of thunderstorms (greater than 10 percent probability) have been made to account for ongoing trends concerning destabilization and the progression of the synoptic features. ..Kerr.. 04/23/2023 .PREV DISCUSSION... /ISSUED 1103 AM CDT Sun Apr 23 2023/ ...Deep South TX... A long-lived linear MCS continues to progress southeastward across south TX this morning, with several reports of strong to severe wind gusts along the leading edge. Ample low level moisture and CAPE will allow these storms to persist through the day and eventually move off the south TX coast by mid/late afternoon - ending the threat. Refer to MCD #607 for further details. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 PM CDT Sun Apr 23 2023 Valid 241200Z - 251200Z The forecast remains on track, and no changes were needed with this update. For details, see the previous discussion below. ..Weinman.. 04/23/2023 .PREV DISCUSSION... /ISSUED 0122 AM CDT Sun Apr 23 2023/ ...Synopsis... On Monday, lee troughing is expected, while high pressure continues to dominate central and eastern portions of the southern Plains. Therefore, a tightening pressure gradient is expected to develop across Arizona/New Mexico. In addition, deep mixing is expected in this region with moderate 30-35 knots of mid-level flow. These factors will combine to result in some breezy conditions across the Southwest on Monday. Northern New Mexico will be cooler with greater moisture, and some thunderstorms will be possible. These storms will be on the drier side, however, the regions most susceptible to lightning are in higher terrain where fuels remain moist/snow covered. Therefore, no dry thunderstorm area is expected at this time. However, a warmer and drier airmass is expected across southeast Arizona and southern New Mexico and as a result, an Elevated fire weather area has been added to address the greater fire weather concerns. ...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 1221 PM CDT Sun Apr 23 2023 Valid 241200Z - 251200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS MONDAY ACROSS PARTS OF THE FLORIDA PENINSULA... ...SUMMARY... Strong thunderstorms may impact interior and Atlantic coastal areas of the Florida Peninsula Monday, and pose at least some risk for severe weather. ...Synopsis... Within a persistent split flow across the mid-latitude eastern Pacific into Atlantic, one blocking high, centered near Newfoundland and Labrador, appears likely to remain prominent through this period and beyond. This high will be flanked to its southeast by a low over the mid-latitude Atlantic, and to its southwest by a low which is forecast to begin redeveloping southeast of the Upper Midwest through the lower Great Lakes region. Upstream, within one increasingly amplified branch of westerlies, models suggest that mid-level ridging will build across southern portions of the eastern mid-latitude Pacific, toward U.S. Pacific coastal areas, while a downstream short wave perturbation digs into the Great Basin with a developing embedded mid-level low. In advance of the latter feature, a moistening southerly return flow likely will commence across the lower Rio Grande Valley into the southern Great Plains. However, relatively cool surface-based air, associated surface high pressure encompassing most areas east of the high plains, likely will be maintained, while inhibition increases aloft, associated with the northward and eastward advection of elevated mixed-layer air. Across the Gulf Coast/Gulf of Mexico vicinity, models indicate considerable strengthening of westerly mid/upper flow through the period. As this occurs, it appears that a perturbation emerging from the lower Rio Grande Valley today will overspread the Florida Peninsula during the day Monday. ...Florida... To the south of a reinforcing, but stalling and weakening surface front, models indicate that low-level moisture will be maintained or begin to increase across much of the southern and central peninsula during the day Monday. It appears that this will include mid/upper 60s surface dew points on easterly near-surface flow, particularly across central and southern Atlantic coastal into interior areas, beneath relatively cool mid-level temperatures. With insolation, this may contribute to moderate mixed-layer CAPE on the order of 1000-2000+ J/kg, prior to the approach of the mid-level short wave trough Monday afternoon. Aided by the strengthening large-scale forcing for ascent, it appears that this destabilization may yield increasingly widespread thunderstorm development across interior into Atlantic coastal areas through late afternoon. Beneath the moderate to strong mid/upper flow, deep-layer shear may become conducive for some of this convection to organize, with supercell structures also possible, which may pose a risk for severe wind and hail before convection weakens by Monday evening. ..Kerr.. 04/23/2023 Read more

MD 0598 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR NORTH FLORIDA TO THE GEORGIA AND SOUTH CAROLINA COAST
Mesoscale Discussion 0598 NWS Storm Prediction Center Norman OK 0354 PM CDT Sat Apr 22 2023 Areas affected...North Florida to the Georgia and South Carolina Coast Concerning...Severe potential...Watch unlikely Valid 222054Z - 222300Z Probability of Watch Issuance...20 percent SUMMARY...Isolated to scattered thunderstorms are gradually developing along an approaching cold front and regional sea-breeze boundaries. A few strong to severe storms are possible and may pose a sporadic hail/damaging wind threat. Watch issuance is not anticipated. DISCUSSION...Over the past 1-2 hours, a few isolated cells have developed along, and moved off of, a migratory cold front approaching north FL and the GA/SC coast. The lift associated with the front is well-timed with peak diurnal heating with MLCAPE values up to 1500 J/kg noted in recent RAP mesoanalysis and latest hi-res forecast soundings. While hodographs are somewhat poorly structured per recent VWP observations, there appears to be sufficient deep-layer shear for storm organization. Effective shear vectors largely oriented along the frontal boundary along the GA/SC coast will favor a tendency for storm interactions/upscale growth, which may limit the overall propensity for long-lived severe convection. However, shear vectors off the boundary across north FL may support more long-lived convection that should pose a more robust, albeit isolated, large hail and damaging wind threat. Additional convection developing along sea-breeze boundaries across north FL will likely see similar intensification. Relatively modest ascent along the cold front will likely favor more isolated convection, limiting the overall coverage of the threat. ..Moore/Goss.. 04/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...MLB...TBW...JAX...TAE... LAT...LON 29818361 30608249 31058206 31968149 32428114 32678083 32628057 32388030 32148049 31778088 31108117 30548116 29988114 29548096 29138074 28838061 28418045 28118050 27988091 28128139 28738254 29138319 29498355 29668363 29818361 Read more