Severe Storms

MD 1681 CONCERNING SEVERE THUNDERSTORM WATCH 540... FOR PORTIONS OF EXTREME EASTERN TEXAS...CENTRAL AND SOUTHERN LOUISIANA INTO SOUTHERN MISSISSIPPI
Mesoscale Discussion 1681 NWS Storm Prediction Center Norman OK 0456 PM CDT Sat Jul 22 2023 Areas affected...portions of extreme eastern Texas...central and southern Louisiana into southern Mississippi Concerning...Severe Thunderstorm Watch 540... Valid 222156Z - 222330Z The severe weather threat for Severe Thunderstorm Watch 540 continues. SUMMARY...The severe threat continues across Severe Thunderstorm Watch 540. Damaging gusts remain the primary threat, though an instance or two of large hail cannot be ruled out. DISCUSSION...Multicellular clusters have organized roughly into two west-east oriented bands of storms over the past couple of hours, with a history of a couple of strong, damaging gusts. MRMS mosaic radar imagery suggest that the cores of the stronger storms are quite deep, with 30 dBZ echoes extending to 60 kft in spots, with 50 dBZ echoes reaching over 35 kft. Though deep-layer shear remains modest, 21Z mesoanalysis depicts over 4000 J/kg MLCAPE residing ahead of these deep cores (driven mainly by rich low-level moisture beneath 6-7 C/km mid-level lapse rates per latest RAP forecast soundings). Furthermore, the RAP forecast soundings show PWATS well over 2 inches given the rich moisture. As such, water-loading within these deep storm cores may promote additional damaging gusts (some potentially exceeding severe limits), and even an instance or two of large hail cannot be completely ruled out. The severe threat should persist through the remainder of the diurnal heating cycle, or when storms overturn all of the boundary layer over land, which ever comes first. ..Squitieri.. 07/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MOB...JAN...LIX...LCH...SHV... LAT...LON 31699438 31959182 31989098 31518986 30778923 30308926 29468969 29219049 29329176 29559259 29879362 31699438 Read more

WW 0541 Status Updates
STATUS REPORT ON WW 541 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..07/22/23 ATTN...WFO...TOP...GLD...DDC...ICT...GID...LBF... STATUS REPORT FOR WS 541 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC027-029-039-041-051-053-061-065-089-105-123-127-137-141-143- 147-153-157-161-163-167-169-179-183-195-201-222240- KS . KANSAS COUNTIES INCLUDED ARE CLAY CLOUD DECATUR DICKINSON ELLIS ELLSWORTH GEARY GRAHAM JEWELL LINCOLN MITCHELL MORRIS NORTON OSBORNE OTTAWA PHILLIPS RAWLINS REPUBLIC RILEY ROOKS RUSSELL SALINE SHERIDAN SMITH TREGO WASHINGTON NEC001-019-029-035-041-047-057-059-061-063-065-073-079-081-083- 085-087-099-101-111-129-135-137-145-169-181-222240- NE . NEBRASKA COUNTIES INCLUDED ARE ADAMS BUFFALO CHASE CLAY CUSTER DAWSON DUNDY FILLMORE FRANKLIN Read more

WW 541 SEVERE TSTM KS NE 222030Z - 230400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 541 NWS Storm Prediction Center Norman OK 330 PM CDT Sat Jul 22 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Kansas Southern Nebraska * Effective this Saturday afternoon and evening from 330 PM until 1100 PM CDT. * Primary threats include... Scattered large hail likely with isolated very large hail events to 2.5 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Widely scattered supercell storms are forming over southern Nebraska. These storms will track southward through the afternoon and early evening, posing a risk of very large hail and damaging winds. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 30 miles north northwest of Imperial NE to 50 miles east southeast of Concordia KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). 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. && OTHER WATCH INFORMATION...CONTINUE...WW 539...WW 540... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 33025. ...Hart Read more

WW 539 SEVERE TSTM AL FL GA MS CW 221645Z - 230000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 539 NWS Storm Prediction Center Norman OK 1145 AM CDT Sat Jul 22 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Alabama Northern Florida including the Panhandle Southern Georgia Southern Mississippi Coastal Waters * Effective this Saturday morning and evening from 1145 AM until 700 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are developing along a boundary sagging southward across the Gulf Coast region. A few of these storms will pose a risk of damaging downburst winds through the afternoon. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 5 miles northwest of Gulfport MS to 25 miles northeast of Jacksonville FL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). 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 29025. ...Hart Read more

WW 0540 Status Updates
STATUS REPORT ON WW 540 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BENTLEY..07/22/23 ATTN...WFO...LCH...LIX...JAN... STATUS REPORT FOR WS 540 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS LAC001-003-005-007-009-011-019-033-037-039-045-047-053-055-063- 077-079-091-093-095-097-099-103-105-115-117-121-125-222240- LA . LOUISIANA PARISHES INCLUDED ARE ACADIA ALLEN ASCENSION ASSUMPTION AVOYELLES BEAUREGARD CALCASIEU EAST BATON ROUGE EAST FELICIANA EVANGELINE IBERIA IBERVILLE JEFFERSON DAVIS LAFAYETTE LIVINGSTON POINTE COUPEE RAPIDES ST. HELENA ST. JAMES ST. JOHN THE BAPTISTST. LANDRY ST. MARTIN ST. TAMMANY TANGIPAHOA VERNON WASHINGTON WEST BATON ROUGE WEST FELICIANA MSC005-035-045-073-091-109-113-147-157-222240- MS . MISSISSIPPI COUNTIES INCLUDED ARE AMITE FORREST HANCOCK LAMAR MARION PEARL RIVER PIKE WALTHALL WILKINSON Read more

WW 540 SEVERE TSTM LA MS TX CW 221915Z - 230200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 540 NWS Storm Prediction Center Norman OK 215 PM CDT Sat Jul 22 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Louisiana Southern Mississippi East Texas Coastal Waters * Effective this Saturday afternoon and evening from 215 PM until 900 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms continue to develop along a boundary sagging into southern Louisiana/Mississippi. The strong cells along this line will pose a risk of locally damaging wind gusts. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 45 miles west southwest of Fort Polk LA to 40 miles east northeast of Slidell LA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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. && OTHER WATCH INFORMATION...CONTINUE...WW 539... 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 29025. ...Hart Read more

MD 1680 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN NEW MEXICO AND THE WESTERN TEXAS PANHANDLE INTO SOUTHWEST TEXAS
Mesoscale Discussion 1680 NWS Storm Prediction Center Norman OK 0354 PM CDT Sat Jul 22 2023 Areas affected...Eastern New Mexico and the western Texas Panhandle into Southwest Texas Concerning...Severe potential...Watch unlikely Valid 222054Z - 222300Z Probability of Watch Issuance...20 percent SUMMARY...Scattered storms capable of large hail and strong winds possible late afternoon/early evening. DISCUSSION...Scattered thunderstorm development is expected across eastern New Mexico through the afternoon and early evening, with some uncertainty as to how far into Texas storms will track. Cumulus has increased across northeastern New Mexico with attempts at cell development over the last hour. Additionally, areas of convection ongoing across the high terrain may move into the lower elevations through the afternoon as well. MLCAPE is observed around 1000-2000 J/kg. Shear is largely confined to far northeastern New Mexico into the Texas Panhandle. Given uncertainty in coverage and if storms will track into the best shear/instability overlap, a watch is unlikely at this time. Isolated instances of large hail and gusty winds will be possible. ..Thornton/Hart.. 07/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LUB...AMA...MAF...PUB...ABQ... LAT...LON 35200526 35830477 36380435 36850379 37050334 37030272 36700255 36340240 35930238 35510236 35190240 34730240 34110247 33860261 33690278 33570299 33410347 33310398 33680481 34290533 35200526 Read more

MD 1679 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR WESTERN WISCONSIN AND MINNESOTA
Mesoscale Discussion 1679 NWS Storm Prediction Center Norman OK 0336 PM CDT Sat Jul 22 2023 Areas affected...western Wisconsin and Minnesota Concerning...Severe potential...Watch unlikely Valid 222036Z - 222230Z Probability of Watch Issuance...20 percent SUMMARY...Scattered storms capable of large hail may continue through the afternoon. DISCUSSION...Ongoing thunderstorm activity across Minnesota and Wisconsin have produced scattered reports of 0.50"-1.25" hail, along with one report of 2.5 inch hail near Marcell, MN. Convection is further aided by a mid-level impulse digging southward across Minnesota at this time. RAP sounding analysis indicates largely straight hodographs with steep low-level lapse rates and unstable conditions through the profile. MLCAPE around 1500 J/kg overlaps deep layer shear around 30-35 kts. Discrete convection has been able to produce larger hail within this environment. Forcing for ascent remains somewhat weak, though moisture convergence is evident from surface objective analysis and surface observations. Uncertainty if discrete storm mode will continue and duration/coverage of the large hail threat. Instances of sub-severe hail and hail up to 1-1.5 will be possible. Trends will continue to be monitored but a watch is unlikely to be issued at this time. ..Thornton/Hart.. 07/22/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...ARX...MPX...FGF...FSD... LAT...LON 44379096 44239102 43899172 43809258 43729337 43719403 43779495 43829552 43829606 44099621 44419633 45019605 46239555 46859556 47359558 48109504 48059356 47749298 47109277 46479275 46169227 46009175 45689092 45299056 44379096 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Sat Jul 22 2023 Valid 222000Z - 231200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS AND SOUTHEAST... ...SUMMARY... Strong to severe thunderstorms capable of large hail and damaging winds remain possible into this evening across parts of the central Plains. Storms capable of isolated damaging gusts may persist into this evening across parts of the Southeast, and develop by early evening over parts of Arizona. ...20Z Update... The Slight Risk has been trimmed slightly across parts of AL/GA, in the immediate wake of storms sagging southward toward the Gulf Coast. The Marginal Risk has been expanded across parts of northern MN, southwest MN into southeast SD, and north-central NE, where developing cumulus and storm initiation has been recently observed within a somewhat favorable (but weakly forced) environment, with hail and localized damaging gusts the primary threats. A small part of the Marginal Risk has been trimmed across far northeast MN/northwest WI, where substantial redevelopment appears likely in the wake of earlier convection. Otherwise, no major changes have been made. Storms capable of locally damaging winds will remain possible through the afternoon across parts of the Southeast, and may develop by early this evening across parts of Arizona. Storms capable of hail and localized severe gusts may increase in coverage late this afternoon and evening across parts of the central Plains, with a more isolated threat into the upper Midwest. See the previous discussion below for more information. See MCD 1677 for more information regarding the threat across parts of the central Plains. ..Dean.. 07/22/2023 .PREV DISCUSSION... /ISSUED 1118 AM CDT Sat Jul 22 2023/ ...KS Vicinity... Morning visible satellite imagery shows clear skies over most of KS, where strong heating will combine with dewpoints in the mid 60s to yield afternoon MLCAPE around 1500 J/kg. Large scale forcing is subtle in this region, with weak mid-level height rises and diffuse surface boundaries expected to influence storm potential. Nevertheless, most 12z CAM solutions continue to show potential for widely scattered thunderstorms by late afternoon. Deep northwest flow aloft will provide sufficient vertical shear for rotating updrafts capable of large hail and damaging wind gusts. ...Gulf Coast Region... A weak surface boundary extends from southern MS eastward into southern GA today. The air mass along and south of the boundary is very moist and unstable. Scattered thunderstorms are expected to affect this region through the afternoon. The southern fringe of stronger mid-level westerlies lies along the boundary, and will likely result in at least isolated instances of damaging wind gusts. Please refer to MCD #1675 for further details. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0243 PM CDT Sat Jul 22 2023 Valid 231200Z - 241200Z ...Southern California... Updated Hi-res model guidance has trended stronger with the aforementioned shortwave rotating around the west side of the upper-level ridge. Area model soundings show dry low-levels, with deep inverted V structures, and sufficient CAPE for thunderstorms across portions of the southern California mountains and deserts. The stronger shortwave, and presence of increasing monsoon moisture lend higher confidence in dry thunderstorm coverage being slightly higher than previously forecast. Storms are most likely across portions of the High deserts and eastern most Transverse Ranges. More localized storms are possible farther west across the Ventura and Peninsular Ranges, but uncertainty increases toward the coast. With the greater confidence in isolated storm coverage, dry fuels and lightning, an IsoDryT area has been added for portions of southern CA. ...Northern Great Basin into southern/western ID... In addition to gusty winds and lower humidity, isolated thunderstorms are possible across portions of northeastern NV, into far eastern OR and southern ID D2/Sun evening into early D3/Mon. With a deep and dry mixed layer present on area forecast soundings, little wetting rain potential is expected with any storms able to develop. The highest confidence in storm coverage is across portions of eastern ID where less receptive fuels are present. However, very isolated dry storms are possible, with some potential for lightning ignitions within receptive fuels, across portions of far southeast OR and southwestern ID. ..Lyons.. 07/22/2023 .PREV DISCUSSION... /ISSUED 0104 AM CDT Sat Jul 22 2023/ ...Synopsis... The upper-level ridge will start to shift east on Sunday which will allow some stronger mid-level flow to overspread the Northwest and the northern Great Basin. Downslope flow in the lee of the Sierra and deep mixing across northern Nevada/southern Oregon will allow winds to increase to 15 to 20 mph during the afternoon amid single-digit relative humidity. Some enhancement of the flow is possible across southern Nevada on Sunday as a weak mid-level shortwave trough moves northward around the western edge of the anticyclone. This shortwave trough is currently across central New Mexico and may undergo some convective enhancement during the D1/Saturday period. Due to the influence of Day 1 convection on the strength of this trough, will not add an Elevated area at this time. Some elevated conditions are possible in the Snake River Plain on Sunday as stronger mid-level flow overspreads the region and low pressure develops in the northern Great Basin. However, fuels in the area remain only marginally dry. Therefore, an Elevated delineation is not warranted at this time. ...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 1228 PM CDT Sat Jul 22 2023 Valid 231200Z - 241200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF ARIZONA...AND ALSO ACROSS PARTS OF GEORGIA AND THE CAROLINAS... ...SUMMARY... Thunderstorms with isolated damaging wind will be possible across parts of Georgia and the Carolinas on Sunday. Thunderstorms with isolated severe thunderstorm gusts are also possible mainly Sunday evening over portions of Arizona. ...Synopsis... An upper ridge centered over the Four Corners region is forecast to build into a larger portion of the central/southern Plains on Sunday, as an upper trough over the eastern CONUS gradually weakens and shifts eastward. At the surface, a weakening cold front will likely be draped somewhere from south-central TX northeastward into southern parts of LA/MS/AL, central/southern GA, and the eastern Carolinas. A weak surface low may develop over the northern High Plains and move southeastward along a surface trough. ...Parts of Georgia and the Carolinas... Moderate buoyancy is expected to develop along/ahead of the cold front across parts of the Southeast. The most favorable overlap of instability, stronger flow aloft, and storm coverage is expected from parts of Georgia into the Carolinas, immediately in advance of the main upper trough. Scattered to numerous thunderstorms may develop during the afternoon, with deep-layer shear sufficient for a few modestly organized cells/clusters capable of localized damaging gusts and small to perhaps marginally severe hail. Isolated strong storms may also develop farther west near the southern Appalachians, within a drier but modestly unstable regime. Coverage of the severe threat appears too low for probabilities at this time, but some threat for isolated damaging gusts could evolve in this area as well. ...Arizona... Very strong heating and increasing PW will support isolated to scattered thunderstorm development during the late afternoon near the Mogollon Rim, and potentially into the lower deserts across AZ. Isolated microbursts will be possible with the initial development. 15-20 kt of easterly midlevel flow along the southern periphery of the ridge may support a few outflow-driven, westward-moving clusters capable of at least localized severe gusts into Sunday evening. Some threat could reach as far as the lower CO River Valley before weakening. ...Central/northern Plains into the Midwest... A broad portion of the central/northern Plains and Midwest will reside in a regime characterized by northwesterly mid/upper-level flow, modest low-level moisture, relatively steep low/midlevel lapse rates, and generally weak large-scale ascent. Very isolated storm development will be possible within this regime, with sufficient instability and deep-layer to support a conditional supercell risk. Severe probabilities may eventually be needed for some part of this area, if confidence increases in the location and coverage of potential development. ..Dean.. 07/22/2023 Read more

WW 0535 Status Updates
STATUS REPORT ON WW 535 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BUNTING..07/21/23 ATTN...WFO...MEG... STATUS REPORT FOR WS 535 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC031-035-037-077-093-107-111-123-211940- AR . ARKANSAS COUNTIES INCLUDED ARE CRAIGHEAD CRITTENDEN CROSS LEE MISSISSIPPI PHILLIPS POINSETT ST. FRANCIS MSC003-009-013-017-027-033-057-071-081-093-095-107-115-117-119- 135-137-139-141-143-145-161-211940- MS . MISSISSIPPI COUNTIES INCLUDED ARE ALCORN BENTON CALHOUN CHICKASAW COAHOMA DESOTO ITAWAMBA LAFAYETTE LEE MARSHALL MONROE PANOLA PONTOTOC PRENTISS QUITMAN TALLAHATCHIE TATE TIPPAH TISHOMINGO TUNICA UNION YALOBUSHA Read more

No Mesoscale Discussions are in effect as of Fri Jul 21 18:31:03 UTC 2023.

WW 0534 Status Updates
STATUS REPORT ON WW 534 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..BUNTING..07/21/23 ATTN...WFO...OKX...BOX...ALY...GYX... STATUS REPORT FOR WS 534 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-003-005-007-009-011-013-015-211940- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD LITCHFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MAC003-011-013-015-027-211940- MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE FRANKLIN HAMPDEN HAMPSHIRE WORCESTER NHC005-011-013-019-211940- NH . NEW HAMPSHIRE COUNTIES INCLUDED ARE CHESHIRE HILLSBOROUGH MERRIMACK SULLIVAN Read more

WW 534 SEVERE TSTM CT MA NH NY VT 211700Z - 220000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 534 NWS Storm Prediction Center Norman OK 100 PM EDT Fri Jul 21 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Western and Central Massachusetts Southern New Hampshire Eastern New York Southern Vermont * Effective this Friday afternoon and evening from 100 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Widely scattered thunderstorms are expected through the afternoon across the region, with a few intense cells possible. Damaging wind gusts are the primary threat. The severe thunderstorm watch area is approximately along and 50 statute miles east and west of a line from 35 miles north northwest of Keene NH to 45 miles west southwest of Groton CT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 25025. ...Hart Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Fri Jul 21 2023 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS INTO THE UPPER MIDWEST...SOUTHEAST...AND ARIZONA... ...SUMMARY... Widely scattered strong to severe thunderstorms appear possible on Saturday across parts of the central Plains into the Upper Midwest, Southeast, and Arizona. ...Synopsis... An upper ridge will remain centered over much of the western CONUS Saturday, while broad upper troughing encompasses the central and eastern states. Modestly enhanced west-northwesterly mid-level flow should be present between these two features. Greater low-level moisture should remain confined to parts of the Southeast along and south of a convectively reinforced front. But, sufficient moisture across the central Plains and Upper Midwest should be in place to support at least isolated robust convection. ...Central Plains/Upper Midwest... Around 30-40 kt of northwesterly mid-level flow will remain over much of the central Plains into the Upper Midwest on Saturday. While low-level moisture may remain fairly shallow/limited by late July standards, steepened low/mid-level lapse rates and daytime heating should promote the development of weak to moderate instability by late Saturday afternoon. Large-scale ascent appears nebulous, but isolated to scattered convection may still develop along and southeast of a weak surface trough. With 25-40 kt of deep-layer shear forecast, a widely spaced mix of multicells and supercells may develop and spread southeastward through Saturday evening while posing an isolated threat for large hail and severe wind gusts. Based on latest guidance, have expanded the Marginal Risk to encompass more of the central Plains and Upper Midwest. ...Southeast... Scattered showers and thunderstorms may be ongoing Saturday morning across parts of MS/AL into GA and perhaps SC. The convectively reinforced outflow/front and a separate sea breeze will likely be foci for renewed convective development by Saturday afternoon. A belt of modest westerly mid-level winds at the base of the large-scale upper trough will exist across much of the Southeast. Plentiful low-level moisture, with surface dewpoints generally in the 70s, and ample diurnal heating will likely foster moderate to strong instability by early Saturday afternoon. Scattered to numerous thunderstorms should develop in this environment along and south of the front. Strong to locally damaging winds may occur with the more robust convection given the very moist profiles, and some clustering may occur. Isolated hail also appears possible with the strongest cores. At this point, not enough confidence exists to include greater severe wind probabilities. But, have expanded the Marginal Risk to include more of the Gulf Coast into north FL. ...Arizona... An upper-level anticyclone will remain centered near the Four Corners region Saturday. It appears that modest (15-20 kt) east-northeasterly mid-level winds will be present across parts of southern AZ and vicinity. As thunderstorms develop over the higher terrain, there may be enough low/mid-level flow to push this convection westward into the lower terrain of southern/central AZ. Very steep low/mid-level lapse rates with a well-mixed boundary layer and ample DCAPE should support some threat for severe winds if this occurs. With a better signal of this potential in recent high-resolution guidance, have added a Marginal Risk for severe/damaging winds. ..Gleason.. 07/21/2023 Read more

WW 535 SEVERE TSTM AR MS TN 211725Z - 212300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 535 NWS Storm Prediction Center Norman OK 1225 PM CDT Fri Jul 21 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Arkansas Northern Mississippi Southwest Tennessee * Effective this Friday afternoon and evening from 1225 PM until 600 PM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated very large hail events to 2 inches in diameter possible SUMMARY...A line of thunderstorms over northeast Arkansas will track eastward this afternoon across the watch area. Locally damaging wind gusts and hail are possible. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 60 miles west of Memphis TN to 55 miles northeast of Tupelo MS. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 534... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Hart Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1134 AM CDT Fri Jul 21 2023 Valid 211700Z - 221200Z ...17z Update... Across parts of the Northwest, morning surface obs showed a few areas of gusty winds through the Cascade Gaps and western Columbia Basin. Fair to moderate overnight humidity recoveries will quickly erode this morning, with afternoon RH values below 25% likely. Gusty west winds through the gaps are expected through the afternoon hours with brief, locally elevated, fire-weather conditions possible. The Elevated area over the Columbia Gorge was modified slightly for the latest guidance. Please see the prior discussion for more information. ..Lyons.. 07/21/2023 .PREV DISCUSSION... /ISSUED 1251 AM CDT Fri Jul 21 2023/ ...Synopsis... An upper-level ridge will remain across the West today, roughly centered within the Great Basin into the northern Rockies. In the Northwest, an upper-level trough will approach the area through the period. The strongest winds will reach western portions of the region around Saturday morning. At the surface, the pressure pattern for most areas west of the Divide will be diffuse. A thermal pressure trough will develop in the Columbia Basin. Fire weather concerns will generally be low across most areas with dry fuels given weak surface winds. Hot and dry conditions are likely within much of the Great Basin and Southwest. Where winds are locally stronger, localized elevated conditions may occur. ...Columbia Gorge... A few hours of marginally elevated fire weather conditions are possible during the afternoon. Confidence in RH reaching 15-20% is reasonably high, though some guidance shows only 20-25%. Winds will be the limiting factor. Only around 15 mph winds are expected with perhaps brief periods near 20 mph within the terrain itself. The potential for stronger winds will be limited as the surface trough will be modest and stronger mid-level flow will not arrive until after the diurnal RH minimum. ...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 1116 AM CDT Fri Jul 21 2023 Valid 211630Z - 221200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID-SOUTH/TENNESSEE VALLEY/SOUTHEAST...NORTHEAST STATES...AND SOUTHERN HIGH PLAINS... ...SUMMARY... Severe thunderstorms capable of wind damage and some hail are expected across the Mid-South and Tennessee Valley to the Southeast States, while additional severe storms will be possible across the Northeast and High Plains. ...AR into the Southeast States... A large MCS that tracked across southern OK last night is now over northern/central AR. This system and its attendant MCV will move into western TN this afternoon, where sufficient heating and a very moist air mass will support the potential for re-intensification. If this scenario occurs, locally damaging wind gusts would be the main concern. To the southeast of the MCS, a weak surface boundary extends across southeast AR into portions of MS/AL/GA. A very unstable air mass will become established this afternoon along this axis, where scattered thunderstorm development is expected. MLCAPE values around 3000 J/kg will combine with winds in the 5-7km layer around 30 knots to pose some risk of damaging wind gusts in the stronger cells. The risk of wind damage will increase later this afternoon if sufficient thunderstorm coverage can result in more organized outflows. ...New England... An upper trough is moving across the northeast states today, with an associated cold front currently extending across parts of eastern NY/PA. Clouds have been clearing ahead of the front across western New England, where temperatures will rapidly warm into the 80s. Ample low-level moisture is present from southern VT/NH southward, where upper 60s/lower 70s dewpoints will yield afternoon MLCAPE values of 1500-2000 J/kg. Forecast soundings show sufficient deep layer shear for a few organized/rotating storms capable of strong/damaging wind gusts and perhaps hail for a few hours this afternoon. ...Northeast NM... Weak easterly low-level upslope flow is present today over northeast NM, helping to transport 60s dewpoints westward toward the higher terrain. Thunderstorms are expected to form in the mountains near Raton and drift southeastward through the afternoon. Steep low-level lapse rates and 30-40 knots of effective shear will promote the development of a few supercells capable of large hail and damaging wind gusts. ..Hart/Thornton.. 07/21/2023 Read more

WW 0533 Status Updates
STATUS REPORT ON WW 533 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 ESE FSM TO 35 ESE FYV TO 15 ENE UMN. WW 533 WILL BE ALLOWED TO EXPIRE AT 211500Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1663 ..DEAN..07/21/23 ATTN...WFO...TSA... STATUS REPORT FOR WS 533 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC015-087-211500- AR . ARKANSAS COUNTIES INCLUDED ARE CARROLL MADISON THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more