Severe Storms

MD 1868 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL COLORADO
Mesoscale Discussion 1868 NWS Storm Prediction Center Norman OK 0425 PM CDT Sun Aug 06 2023 Areas affected...Central Colorado Concerning...Severe potential...Watch unlikely Valid 062125Z - 062330Z Probability of Watch Issuance...20 percent SUMMARY...An isolated severe wind/hail threat may materialize across central Colorado if developing thunderstorms can become established. Confidence in this scenario is uncertain, and the threat is expected to remain sufficiently isolated to negate the need for a watch. However, trends will be monitored given the strong environmental shear. DISCUSSION...Early attempts at supercell development within an upslope flow regime are underway across the front range of central CO per recent KFTG imagery. Lift away from the terrain is rather meager, and a stout cap was sampled by recent ACAR soundings out of Denver, CO. While lift and thermodynamic conditions are not overly favorable for supercell sustenance away from the terrain, environmental wind shear is very favorable for organized convection. The same ACAR soundings sampled elongated, straight hodographs featuring deep-layer shear on the order of 50-60 knots. This wind profile favors storm splitting, which has already been observed with a few early (though transient) cells. Additionally, a mid-level baroclinic zone is noted in 700 mb analyses draped from central to southeast CO. This may be a preferential corridor for supercell propagation if shear-related pressure perturbations can compensate for the modest thermodynamic environment and allow storm maturation. If this occurs, supercells will be capable of very large hail and severe winds. Confidence in the manifestation of this threat, as well as the spatial coverage of storms, remains uncertain and currently precludes watch issuance, but trends will continue to be monitored. ..Moore/Edwards.. 08/06/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GLD...PUB...BOU... LAT...LON 38890511 39150542 39480555 39850548 40040533 40150499 40110474 39270317 39020290 38680265 38370263 38050270 37850299 37800335 38890511 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Sun Aug 06 2023 Valid 062000Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDDLE MISSISSIPPI/LOWER OHIO VALLEYS AND MID-SOUTH/SOUTHEAST...AND EAST-CENTRAL COLORADO... ...SUMMARY... A few tornadoes along with scattered damaging winds and large hail will be possible from late afternoon into tonight from the Mid-Mississippi to Lower Ohio Valleys. Scattered damaging winds will also be possible, mainly this afternoon into early evening across parts of the Mid-South and Southeast. ...Discussion... The only change this outlook update is to increase severe hail probabilities (categorical risk from Marginal Risk to Slight Risk) from the Palmer Divide east-southeastward into southeast CO for a supercell hail risk this evening into the late night hours. Recent time-lagged HRRR runs and HREF probabilities show storms developing over the Palmer Divide and moving east-southeast with a favorable buoyancy/shear profile for hail growth. The HREF but not HRRR also showed intense storms developing near the Raton Mesa but confidence in this scenario is a little lower (hence maintaining a Marginal Risk for the time being). ..Smith.. 08/06/2023 .PREV DISCUSSION... /ISSUED 1144 AM CDT Sun Aug 06 2023/ ...Middle Mississippi/Lower Ohio Valleys... Multiple eastward-moving/decaying MCVs are still evident across the region ahead of the primary synoptic cyclone across Iowa. Ahead of this cyclone, a moisture-rich warm sector will expand north-northeastward across downstate portions of Illinois/Indiana this afternoon into tonight in tandem with a warm front. An arc of initially semi-discrete thunderstorms are expected to develop within the somewhat narrow warm sector by mid/late-afternoon, initially across southeast Iowa/far eastern Missouri and west-central/southwest Illinois. Seasonally strong winds through a deep-layer will support supercellular development, with low-level shear/SRH expected to be maximized particularly across southern Illinois 1) in vicinity of the warm front and 2) toward/after sunset as winds within the lowest 1-3 km AGL increase. A few tornadoes are possible regionally, including supercell-related potential for large hail mainly within the first couple of hours of deep convective development. Into late evening, upscale growth into one or two organized clusters is plausible, with the potential for an MCS to evolve along the northern extent of the surface-based instability plume. An elongated swath or two of damaging winds with embedded severe gusts, along with a couple brief tornadoes may be sustained into the early overnight into the Lower Ohio Valley. ...Mid-South/Southeast States... The boundary layer across the region continues to steadily warm/destabilize. A decaying MCS/MCV across Arkansas at midday appears to already being influencing subsequent thunderstorm development downstream across northern Mississippi, while additional storms continue near the southern Appalachians. 25-35 kt 700-mb westerlies across the Tennessee Valley should be adequate to support semi-organized multicell clusters amid an extensive plume of large buoyancy across the Deep South. Scattered damaging wind swaths from water-loaded downbursts will be possible through early evening. Later tonight, strengthening low-level warm theta-e advection focused along residual outflow/effective baroclinic zone over the Mid-South could influence additional strong thunderstorm development. This activity could pose an isolated threat for severe hail initially before potentially clustering into a localized damaging wind threat overnight. ...Central/southern Rockies and Front Range... The presence of 50s F surface dew points will support potential for isolated but regenerative thunderstorms to develop along the Front Range during the late afternoon and evening. A rather confined corridor for weak buoyancy with MLCAPE of only 500-1000 J/kg should be maximized near the Front Range. Deep-layer wind profiles will be quite favorable for supercells and large hail potential given near-perfectly straight-line hodographs. Downstream of a minor shortwave trough over the interior Northwest, isolated to scattered afternoon thunderstorms are anticipated around the UT/WY/CO border area within a weak buoyancy plume. Adequate deep-layer shear will exist for a threat of marginally severe hail and wind centered on the late afternoon. ...Central/southern Appalachians to Lake Erie... Multiple MCVs are expected to aid scattered intensifying thunderstorm development downstream of these features this afternoon. Pockets of modestly stronger low to mid-level flow attendant to these MCVs may support sporadic localized damaging winds, and perhaps even some funnel/brief tornado potential in vicinity of Lake Erie near a weak surface low/warm front. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0239 PM CDT Sun Aug 06 2023 Valid 071200Z - 081200Z The Elevated risk across southwestern Texas was expanded into central Texas/Texas Hill Country. Winds will be marginal (sustained at 10-15 mph) but recent fire activity in this region has been increasing with extremely critical fuels and very hot/unstable conditions. This, in combination with afternoon relative humidity reductions to 15-20 percent, support inclusion of the region into an Elevated risk. Otherwise, the Southwest Elevated remains on track with no further updates needed. See previous discussion for more information. ..Thornton.. 08/06/2023 .PREV DISCUSSION... /ISSUED 0137 AM CDT Sun Aug 06 2023/ ...Synopsis... Fire weather concerns will once again be focused across the greater Four Corners region on Monday with more regional potential across parts of southwest Texas. ...Four Corners... Moderate mid-level flow is expected to persist across the greater Four Corners region on Monday. The deepening of a modest lee trough along the High Plains will increase the probability of 15-20 mph winds, and deep boundary-layer mixing will foster gusts up to 30-35 mph. RH values in the low teens will be common, and may fall as low as the single digits. Consequently, critical wind/RH conditions are possible, but confidence in the coverage/duration of such conditions is uncertain given a lack of more prominent upper-level or surface features. Additionally, some question remains regarding the southern extent of the threat due to the potential for isolated showers/thunderstorms across AZ and western NM. Regardless, widespread elevated conditions appear likely. ...Southwest Texas... The regional pressure gradient is expected to strengthen slightly through the day across southwest TX as a modest lee surface trough develops across the southern High Plains under zonal flow aloft. This will boost the potential for sustained 15 mph winds across the region. While not overly strong, they should be sufficient to support a regional fire weather concern given antecedent critically dry fuels, forecast temperatures exceeding 100 F, and RH values falling into the low 20s. The weak nature of the surface trough and associated mass response casts uncertainty onto the coverage/duration of this threat, but ensemble guidance hints at sufficient potential to warrant Elevated highlights. ...Nevada... The zonal flow regime over the Great Basin/Four Corners will likely result in dry downslope flow off the northern Sierra Nevada Monday afternoon. This could result in areas of elevated fire weather conditions across western NV, and possibly as far east as central NV. Confidence in the coverage and overlap of elevated conditions with receptive fuels is uncertain away from the immediate lee of the terrain, but trends will be monitored for 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 1243 PM CDT Sun Aug 06 2023 Valid 071200Z - 081200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR THE MID-ATLANTIC STATES INTO THE SOUTHERN APPALACHIANS AND CAROLINAS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE CENTRAL HIGH PLAINS... ...SUMMARY... Severe thunderstorms are possible Monday across portions of the southern Appalachians, mid-Atlantic and northeast U.S. Scattered swaths of damaging gusts are expected with this activity. Additional widely scattered thunderstorms are possible across the central High Plains, posing a risk for large hail and severe gusts. ...Synopsis... A potent mid/upper shortwave trough will move from IL to the central Appalachians during the period. A seasonally anomalous belt of strong west/southwesterly flow will move through the base of the trough and overspread the central/southern Appalachians into the Mid-Atlantic states. In the low levels, low pressure will develop east from northern IL to Lake Erie through evening. A cold front attendant to the surface low will sweep east/southeast across the Midwest during the day and reach the Appalachians and northern MS/AL late overnight. ...OH Valley to Mid-Atlantic to the southern Appalachians and Carolinas... Scattered showers and isolated storms are forecast to be ongoing over the OH Valley Monday morning with more widely spaced convection trailing west-southwest into the Mid South/Ozarks. Considerable cloud cover with northward extent over a large moist/warm sector will limit destabilization into portions of PA and north. Farther south, heating of a very moist boundary layer will yield a moderate to very unstable airmass (1500 to 3000+ J/kg MLCAPE) from PA southward into the southern Appalachians. Multiple bands and clusters will likely begin to develop towards midday over the upper OH Valley and central Appalachians. Less certain is convective timing over the TN Valley where a large spread of model solutions is currently depicted. Nonetheless, scattered thunderstorms will likely develop by early to mid afternoon and become quite extensive from northern AL/GA into PA/VA/WV/MD. A mix of semi-discrete cells and clusters are possible initially and a risk for all severe hazards is expected given favorable shear profiles for storm organization/low-level rotation. Upscale growth is expected as storms move into the northern VA/MD and Chesapeake Bay vicinity during the late afternoon/early evening where the wind risk will seemingly be maximized. Much of the activity will eventually move east of the Mid-Atlantic coast during the evening and areas farther south through the Carolina Piedmont and into the coastal plain. ...Central into the southern High Plains... Moderate mid/upper northwesterly flow will continue to stream across the central High Plains vicinity on Monday. Moderately cool 500 mb temps around -10 C will support steep midlevel lapse rates. Modest boundary layer moisture is forecast along a surface trough, with dewpoints generally in the 50s, supporting moderate instability. Strong vertical shear (effective shear greater than 45 kt) will foster organized updrafts, while elongated/straight hodographs suggest large hail will be possible and perhaps a narrow window for very large hail with initial supercells. A deeply-mixed boundary-layer with dewpoint depressions around 20 F also may foster strong gust potential. The latest models show some of this activity continuing into west-central KS after dark. Farther south, models are suggesting thunderstorms will develop on the southern fringe of stronger westerlies near the eastern NM/TX South Plains vicinity. Deep, well-mixed boundary-layer profiles will potentially support isolated severe gusts during the early evening. ...Northeast TX toward the Lower MS Valley... A surface boundary is forecast to extend west to east across the region. Differential heating along the boundary, and a very moist/unstable airmass will support isolated thunderstorm development. Vertical shear will be rather weak, but isolated strong gusts may accompany thunderstorms during the afternoon. Isolated coverage/longevity of this activity preclude higher risk probabilities. ..Smith.. 08/06/2023 Read more

MD 1849 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN KS
Mesoscale Discussion 1849 NWS Storm Prediction Center Norman OK 0522 PM CDT Sat Aug 05 2023 Areas affected...Western KS Concerning...Severe potential...Watch possible Valid 052222Z - 052345Z Probability of Watch Issuance...60 percent SUMMARY...Strong/severe thunderstorms will spread/develop east across CO into western KS this evening. Hail/wind are the primary threats. DISCUSSION...Central High Plains short-wave trough currently extends across the NE Panhandle into eastern CO. Thunderstorms have been gradually increasing ahead of this feature within a corridor of seasonally strong buoyancy, especially from Yuma to Pueblo County Colorado. Latest satellite imagery suggests an agitated cu field within the boundary layer across northwestern KS with several deepening towers over Gove/Trego County region. 35-50kt 500mb flow across CO into KS favors eastward propagation over the next few hours. Given the air mass currently observed over the central High Plains, new severe thunderstorm watch appears warranted. ..Darrow/Mosier.. 08/05/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD... LAT...LON 37370200 39780175 39499969 37210049 37370200 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0459 PM CDT Sat Aug 05 2023 Valid 071200Z - 131200Z ...Southwest... Dry westerly flow across the northern Arizona and north/central New Mexico will continue to augment drying fuels on D3 - Monday and D4 - Tuesday. Moisture will attempt to move into far southern/south-central New Mexico Monday into Tuesday, which will limit the southward extent of lower relative humidity. The mid-level high will begin to build back in across the Four Corners Region from Tuesday onward, with decreasing wind and increasing temperatures. Pockets of Elevated fire weather concerns will be possible with afternoon relative humidity around 15-20 percent but breezes will be localized and remain below Critical criteria. A return of more appreciable monsoon moisture further north into northern Arizona/western New Mexico looks favorable by late in the period as the high builds with weak troughing off the west coast enhancing southerly moisture transport off the Gulf of California. ...Central Texas... Extremely hot and dry conditions continue to render extremely dry fuels across central/southwestern Texas. Elevated conditions are possible most each day of the extended period, with the limiting factor being widespread sustained winds at or above 15 mph. Even in the absence of winds, fuels and extremely hot and unstable conditions continue to foster increased fire behavior. A surface front sagging southward Sunday into early Monday will cool highs and bring increase in cloud cover and shower/thunderstorm potential across northern Texas near the Red River Valley. Mainly light rainfall is forecast within this region, which may not change the status of fuels considerably heading into increasing winds on Tuesday/Wednesday as a surface low develops across the Southern Plains. Afternoon relative humidity reductions to 15-20 percent and sustained winds 15-20 mph will be possible on Tuesday and Wednesday. 40 percent probabilities were introduced on these days with better confidence in the stronger winds overlapping continued hot/dry conditions. ..Thornton.. 08/05/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1848 CONCERNING TORNADO WATCH 589... FOR NORTHWESTERN IOWA INTO ADJACENT AREAS OF SOUTH DAKOTA AND NEBRASKA
Mesoscale Discussion 1848 NWS Storm Prediction Center Norman OK 0502 PM CDT Sat Aug 05 2023 Areas affected...Northwestern Iowa into adjacent areas of South Dakota and Nebraska Concerning...Tornado Watch 589... Valid 052202Z - 060000Z The severe weather threat for Tornado Watch 589 continues. SUMMARY...The threat for a tornado or two continues across northwestern Iowa into adjacent areas of southeast South Dakota and northwest Nebraska. DISCUSSION...Thunderstorm activity over the mid-Missouri River Valley continues to be focused along a surface warm front noted in recent surface analysis. By most metrics, this convective intensity has been muted with modest reflectivity values, transient lightning pulses, and somewhat warm cloud top temperatures. However, cells continue to take on supercellular characteristics early on in their life cycle, and weak low to mid-level rotation is noted in KFSD velocity data. KFSD VWP observations well north of the warm front show 0-1 km SRH values near 200 m2/s2 where surface winds are easterly. This is likely an overestimate for the what cells are experiencing along the warm front (where winds are out of the southeast). But taken in context of the velocity trends suggests that SRH is likely sufficient to maintain a tornado threat for more robust cells that can become established prior to moving into a more stable air mass north/northeast of the warm front. ..Moore.. 08/05/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...FSD...OAX... LAT...LON 41489551 41949588 42389633 42729702 43049721 43339697 43289606 42879521 42589469 42119433 41599426 41289444 41189467 41159502 41239529 41489551 Read more

WW 0592 Status Updates
STATUS REPORT ON WW 592 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/05/23 ATTN...WFO...ILX...IND... STATUS REPORT FOR WT 592 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC023-033-079-101-159-052340- IL . ILLINOIS COUNTIES INCLUDED ARE CLARK CRAWFORD JASPER LAWRENCE RICHLAND INC005-011-013-015-021-023-027-031-035-045-055-057-059-063-065- 067-071-079-081-083-093-095-097-101-105-107-109-119-121-133-139- 145-153-157-159-165-167-171-052340- IN . INDIANA COUNTIES INCLUDED ARE BARTHOLOMEW BOONE BROWN CARROLL CLAY CLINTON DAVIESS DECATUR DELAWARE FOUNTAIN GREENE HAMILTON HANCOCK HENDRICKS HENRY HOWARD JACKSON JENNINGS JOHNSON KNOX LAWRENCE MADISON MARION MARTIN MONROE MONTGOMERY MORGAN OWEN PARKE PUTNAM Read more

WW 592 TORNADO IL IN 052145Z - 060500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 592 NWS Storm Prediction Center Norman OK 545 PM EDT Sat Aug 5 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Far East-Central Illinois Central and Southern Indiana * Effective this Saturday afternoon and Sunday morning from 545 PM until 100 AM EDT. * Primary threats include... A couple tornadoes possible Isolated damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms are expected to develop ahead of a surface low moving eastward across the Ohio Valley. Low-level shear appears strong enough to support a few thunderstorms capable of damaging gusts and/or tornadoes as these storms move eastward this afternoon and evening. The tornado watch area is approximately along and 55 statute miles east and west of a line from 35 miles west northwest of Muncie IN to 50 miles southwest of Bloomington IN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 588...WW 589...WW 590...WW 591... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24030. ...Mosier Read more

WW 0591 Status Updates
STATUS REPORT ON WW 591 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/05/23 ATTN...WFO...AMA...LUB... STATUS REPORT FOR WS 591 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OKC007-139-052340- OK . OKLAHOMA COUNTIES INCLUDED ARE BEAVER TEXAS TXC011-045-065-069-117-153-179-189-195-211-233-279-295-341-357- 359-369-375-381-393-421-437-483-052340- TX . TEXAS COUNTIES INCLUDED ARE ARMSTRONG BRISCOE CARSON CASTRO DEAF SMITH FLOYD GRAY HALE HANSFORD HEMPHILL HUTCHINSON LAMB LIPSCOMB MOORE OCHILTREE OLDHAM PARMER POTTER RANDALL ROBERTS SHERMAN SWISHER WHEELER THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more

WW 591 SEVERE TSTM OK TX 052100Z - 060500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 591 NWS Storm Prediction Center Norman OK 400 PM CDT Sat Aug 5 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Oklahoma Panhandle Texas Panhandle * Effective this Saturday afternoon from 400 PM until Midnight CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 80 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...Isolated severe thunderstorms are possible mainly this afternoon with a large hail and severe gust risk. Additional storms are forecast to develop this evening with a more significant severe wind threat accompanying the stronger storms through the late evening. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles east northeast of Guymon OK to 20 miles southwest of Plainview TX. 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 588...WW 589...WW 590... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Smith Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 SE BVX TO 35 SW DYR TO 10 S DYR TO 25 NNE DYR. ..LYONS..08/05/23 ATTN...WFO...MEG... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ARC035-077-107-123-052340- AR . ARKANSAS COUNTIES INCLUDED ARE CRITTENDEN LEE PHILLIPS ST. FRANCIS MSC009-027-033-093-107-119-137-143-052340- MS . MISSISSIPPI COUNTIES INCLUDED ARE BENTON COAHOMA DESOTO MARSHALL PANOLA QUITMAN TATE TUNICA TNC017-023-033-047-053-069-075-077-097-109-113-157-167-052340- TN . TENNESSEE COUNTIES INCLUDED ARE CARROLL CHESTER CROCKETT Read more

WW 590 SEVERE TSTM AR MS TN 052030Z - 060200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 590 NWS Storm Prediction Center Norman OK 330 PM CDT Sat Aug 5 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Arkansas Northern Mississippi Western Tennessee * Effective this Saturday afternoon and evening from 330 PM until 900 PM CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A broken band of thunderstorms will continue to develop and intensify through the afternoon into the early evening. Wind damage is possible with the stronger cells as the storms move east. Marginally severe hail may accompany the stronger cores. The severe thunderstorm watch area is approximately along and 45 statute miles north and south of a line from 25 miles east southeast of Jackson TN to 65 miles west southwest of Memphis TN. 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 588...WW 589... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 29020. ...Smith Read more

WW 0589 Status Updates
STATUS REPORT ON WW 589 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/05/23 ATTN...WFO...FSD...DMX...OAX... STATUS REPORT FOR WT 589 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC035-047-085-093-119-133-141-143-149-165-167-193-052240- IA . IOWA COUNTIES INCLUDED ARE CHEROKEE CRAWFORD HARRISON IDA LYON MONONA O'BRIEN OSCEOLA PLYMOUTH SHELBY SIOUX WOODBURY MNC105-117-133-052240- MN . MINNESOTA COUNTIES INCLUDED ARE NOBLES PIPESTONE ROCK NEC003-021-027-037-039-043-051-053-107-119-139-141-167-173-177- 179-052240- NE . NEBRASKA COUNTIES INCLUDED ARE ANTELOPE BURT CEDAR Read more

WW 589 TORNADO IA MN NE SD 052000Z - 060300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 589 NWS Storm Prediction Center Norman OK 300 PM CDT Sat Aug 5 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Western Iowa Southwest Minnesota Northeast Nebraska Southeast South Dakota * Effective this Saturday afternoon and evening from 300 PM until 1000 PM CDT. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 70 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Widely scattered severe thunderstorms will develop through the remainder of the afternoon into the evening over the watch area. A few of the stronger storms will be capable of a tornado risk, in addition to a large hail and severe wind hazard. The tornado watch area is approximately along and 60 statute miles east and west of a line from 50 miles north northwest of Sioux Falls SD to 20 miles south southwest of Tekamah NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. && OTHER WATCH INFORMATION...CONTINUE...WW 588... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 26030. ...Smith Read more

WW 0588 Status Updates
STATUS REPORT ON WW 588 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/05/23 ATTN...WFO...BOU...PUB...GLD...ABQ...AMA... STATUS REPORT FOR WS 588 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC001-005-009-011-017-025-031-035-039-041-055-061-063-071-073- 087-089-099-101-119-121-125-052240- CO . COLORADO COUNTIES INCLUDED ARE ADAMS ARAPAHOE BACA BENT CHEYENNE CROWLEY DENVER DOUGLAS ELBERT EL PASO HUERFANO KIOWA KIT CARSON LAS ANIMAS LINCOLN MORGAN OTERO PROWERS PUEBLO TELLER WASHINGTON YUMA NMC059-052240- NM . NEW MEXICO COUNTIES INCLUDED ARE UNION OKC025-052240- Read more

WW 588 SEVERE TSTM CO NM OK TX 051930Z - 060400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 588 NWS Storm Prediction Center Norman OK 130 PM MDT Sat Aug 5 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Eastern Colorado Northeast New Mexico Oklahoma Panhandle Texas Panhandle * Effective this Saturday afternoon and evening from 130 PM until 1000 PM MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 4 inches in diameter likely Scattered damaging winds and isolated significant gusts to 75 mph possible A tornado or two possible SUMMARY...Scattered thunderstorms are forecast to intensify this afternoon into the evening and spread generally from west to east across the watch area. Large to giant hail is possible with the more intense supercells, along with severe gusts with the stronger thunderstorms. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 15 miles northwest of Akron CO to 35 miles west southwest of Dalhart TX. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 4 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Smith Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 0315 PM CDT Sat Aug 05 2023 Valid 061200Z - 071200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE MID-MISSISSIPPI INTO PARTS OF THE OHIO AND TENNESSEE VALLEYS... CORRECTED FOR GENERAL THUNDER LINE ...SUMMARY... Widely scattered to scattered severe thunderstorms are expected Sunday over portions of the Midwest and Ohio and Tennessee Valley regions. ...Synopsis... A shortwave trough now over the Dakotas will continue into the Midwest and parts of the Mid-Mississippi/Lower Ohio Valleys on Sunday. Multiple convectively augmented shortwave troughs/MCVs are expected to exist within the Great Lakes region as well as the Lower Ohio Valley. At the surface, low pressure systems are forecast within the Lower Great Lakes and the Mid-Missouri Valley. A cold front is expected to be moving through the southern Plains. A warm front will be present within the Ohio Valley into perhaps parts of the Mid-Atlantic. ...Mississippi/Ohio/Tennessee Valleys... Confidence is highest in convection occurring with a shortwave trough/MCV that moves out of Nebraska/Iowa on Saturday night. Convection may be ongoing into parts of eastern Iowa/western Illinois early in the period. There is some uncertainty on the degree of destabilization as there will likely be some impact in the wake of two MCVs moving out of the area early in the period. The greatest amount of surface heating is still expected from parts of central/southern Illinois and southern Indiana southward into Tennessee. Storm coverage will be maximized near the MCV, but other development may occur farther south along the cold front as well. Strong/damaging wind gusts are the primary threat expected, but some large hail could occur as well. There could be a more concentrated area of wind damage potential in southern Illinois/Indiana, but confidence is too low for an increase in wind probabilities. ...Southeast... An MCV from convection in the southern Plains will move into the Mid-South/Southeast during the afternoon. Strong surface heating of a moist airmass and forcing from the MCV could promote development of a cluster of storms. The location of this activity is a bit uncertain, but wind damage risk is probable where development occurs given the steep low/mid-level lapse rates. ...Mid-Atlantic... An MCV is forecast to move out of eastern Kentucky/Tennessee. Given cloud cover expected with this feature, downstream destabilization is far from certain especially given the poor mid-level lapse rates expected. Isolated wind damage may occur with a few stronger storms. Should an area of greater surface heating/storm intensity become apparent, wind probabilities could be increased. ...Eastern Colorado... Moderate mid-level winds will persist across the Divide in the wake of the mid-level trough. Modestly moist post-frontal upslope flow may be enough to initiate a few strong storms. Wind profiles would favor some potential for at least small hail. Currently, thermodynamic profiles do not appear conducive to a greater threat of large hail. Hail probabilities will be withheld for now. ..Wendt.. 08/05/2023 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Sat Aug 05 2023 Valid 052000Z - 061200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN COLORADO INTO SOUTHERN KANSAS AND NORTHERN/CENTRAL OKLAHOMA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EASTERN ILLINOIS INTO CENTRAL AND SOUTHERN PARTS OF INDIANA... ...SUMMARY... The most concentrated area of severe thunderstorms with potential for destructive wind and hail is expected across parts of the south-central Great Plains the remainder of this afternoon through tonight. Potential for a few tornadoes will exist separately over the Mid-Missouri and Wabash Valleys during the late this afternoon to early evening. ...20Z Update... Weak warm advection activity from far southern Kansas into northern Oklahoma has tempered destabilization especially for southeast Kansas into southwest Missouri. Given these observational trends along with model solutions that have generally handled this activity better, wind probabilities have been reduced for these areas. Even with some stabilization remaining into northeast Oklahoma, the low-level jet still may support an organized MCS moving into central/northeast Oklahoma tonight. Probabilities remain unchanged in northeast Oklahoma and have been increased into parts of central Oklahoma. Given the potential for clustering in parts of Arkansas into western Tennessee and northern Mississippi, wind probabilities have been adjusted accordingly. Ongoing activity will move into strongly buoyant airmass where temperatures have risen into the upper 90s to low 100s F. See mesoscale discussion #1846 for more short-term details across these areas. ..Wendt.. 08/05/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Sat Aug 05 2023/ ...Synopsis... Water-vapor imagery this morning shows a rather complex upper-air pattern with several important features that will influence the severe threat this afternoon into tonight. An MCV located over the southeast KS/northeast OK vicinity will continue to move east across the Ozarks during the day. Another MCV over IL will gradually shift east into IN by this evening. A mid-level low will move little over SD during the period, while a belt of stronger mid- to upper-level flow associated with an upper jet noses into the central High Plains. In the low levels, extensive outflow is evident over much of the northern half of OK into KS in wake of earlier morning thunderstorm activity near the OK/KS border. Easterly low-level flow will aid in maintaining moist conditions into eastern CO southward to the Raton Mesa. A narrow moist plume will protrude northward from eastern NE/western IA into southeast SD ahead of a gradually eastward-moving cool front. Low-level confluence will aid in focusing thunderstorm development over the lower Wabash Valley beginning early this afternoon through early evening. ...Eastern CO/northeast NM into the TX Panhandle and KS/OK... Not much change from previous forecast thinking. Convective outflow late this morning arcs westward across central OK through the central TX Panhandle. Near and north of the outflow, late morning thunderstorms over OK may continue to linger into the mid afternoon across the northern half of OK and pose an isolated risk for severe gusts. The initial thunderstorm development and more appreciable severe risk will probably focus near the Raton Mesa and Palmer Divide towards mid-afternoon. Moist upslope flow beneath the left exit region of an upper jet overspreading the central High Plains will facilitate a favorable setup for supercells. Potential will exist for regenerative supercells spreading east-southeast off the higher terrain. A few of these may become long-lived and capable of producing baseball to softball-sized hail centered on the southeast CO vicinity given highly elongated mid to upper hodographs and large buoyancy amid very steep mid-level lapse rates. A strengthening low-level jet over west TX during the evening will favor increasing convective development with multiple severe thunderstorm clusters spreading across western and southern KS, the Panhandles, and western to northern OK. Severe wind gusts will become more prolific as this occurs, which should include potential for sporadic gusts from 70-85 mph. ...Ozarks/Mid South... Ongoing thunderstorm cluster late this morning will continue to move east into a destabilizing and very unstable airmass across northern AR. Strong heating via mostly clear skies will result in temperatures warming into the 90s with mid to upper 70s dewpoints. Forecast soundings show a moderate mid-level flow enhancement via the approaching disturbance and MLCAPE 3000-4500 J/kg. Although uncertainty is high regarding details, it is possible some rejuvenation to the thunderstorm activity occurs on the periphery of the deeper cores going forward into the early-mid afternoon. If this occurs, widely scattered strong to severe gusts are possible into the early evening. ...Mid-MO Valley vicinity... A mid-level low over central SD will drift east with stronger destabilization confined downstream of it from southeast SD to eastern NE and far western IA. Early afternoon convective development will initially be most pronounced across southeast SD and likely arc southward into at least northeast NE before spreading into northwest IA later. Weaknesses in the mid-level wind profile may yield a linear cluster type mode, but some enlargement to the low-level hodograph, especially in the SD/NE/IA border area, should foster low-level updraft rotation capable of producing a couple tornadoes. Otherwise, slow-moving linear clusters will yield a threat for isolated severe hail and wind persisting through the evening. ...IL/IN vicinity... An MCV over central IL will drift east into IN through tonight. Continued destabilization despite appreciable cloud cover will become increasingly conducive for scattered storms to develop by early to mid afternoon. Forecast soundings show a spatially confined corridor of favorable low-level SRH overlapping the northeast extent of the surface-based instability plume in southern parts of IL/IN. A few supercells will probably evolve as storms mature through the late afternoon/early evening and move east into south-central IN. Any vigorous updraft/supercell will be capable of at least an isolated, short-term risk for a tornado given the wind profile/moist low levels. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0205 PM CDT Sat Aug 05 2023 Valid 061200Z - 071200Z Only minor adjustments were made to the D2 Elevated across the Southwest. Otherwise, the outlook remains on track with no further updates needed. See previous discussion below for more information. ..Thornton.. 08/05/2023 .PREV DISCUSSION... /ISSUED 0145 AM CDT Sat Aug 05 2023/ ...Synopsis... Elevated fire weather concerns are anticipated again for Sunday afternoon across parts of central TX - largely driven by very dry fuels and hot temperatures - as well as the Southwest/Four Corners region. ...Southern Plains... Critically dry fuels and anomalously hot temperatures (reaching or exceeding 100-105 F) will result in another day of elevated fire weather concerns for parts of central TX. A modest influx of Gulf moisture will limit RH reductions to the mid 20s for most locations, and ensemble guidance shows only limited potential for sustained winds of 15+ mph. These factors will modulate the overall fire concern, but recent reports of active fire behavior within this hot/dry regime and the potential for wind gusts between 15-20 mph warrant maintaining fire weather highlights. ...Southwest/Four Corners... A belt of 20-30 knot mid-level flow is expected to become established across northern AZ/NM by Sunday afternoon as an upper trough shifts east into the Plains. While low-level gradient winds are expected to be modest, deep diurnal mixing will not only drive RH reductions into the teens, but will also allow for efficient downward momentum transfer, resulting in frequent gusts up to 20-30 mph. Elevated to locally critical conditions appear likely north/northeast of the Mogollon Rim into northwest NM and adjacent parts of southern UT/CO. Fuels across this region continue to dry and should be receptive to fire spread by Sunday afternoon. ...Northern Great Basin... Latest ensemble guidance shows a weak convective signal across parts of southern ID, northern NV, and northern UT Sunday afternoon as a weak upper low migrates east. Forecast soundings from across these regions show adequate buoyancy for thunderstorms with deep, well-mixed boundary layers and PWAT values on the order of 0.6 to 0.8 inches. These thermodynamic conditions are favorable for isolated dry thunderstorms, but only marginally dry fuels should mitigate the overall fire concern. ...Please see www.spc.noaa.gov/fire for graphic product... Read more