Severe Storms

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

WW 0585 Status Updates
STATUS FOR WATCH 0585 HAS NOT BEEN ISSUED YET Read more

WW 585 SEVERE TSTM MO 042215Z - 050400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 585 NWS Storm Prediction Center Norman OK 515 PM CDT Fri Aug 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern and Central Missouri * Effective this Friday afternoon and evening from 515 PM until 1100 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...A very warm, moist, and unstable air mass exists across northern and central Missouri this afternoon. Thunderstorms are expected to develop within this environment, with moderate vertical shear helping to organize a few of these storms into supercells. Some large hail and/or damaging gusts are possible with the strongest storms. There is a low chance for a tornado. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 50 miles northwest of Knob Noster MO to 25 miles east northeast of Columbia MO. 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 584... 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 550. Mean storm motion vector 27035. ...Mosier Read more

WW 585 SEVERE TSTM MO 042215Z - 050400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 585 NWS Storm Prediction Center Norman OK 515 PM CDT Fri Aug 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern and Central Missouri * Effective this Friday afternoon and evening from 515 PM until 1100 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...A very warm, moist, and unstable air mass exists across northern and central Missouri this afternoon. Thunderstorms are expected to develop within this environment, with moderate vertical shear helping to organize a few of these storms into supercells. Some large hail and/or damaging gusts are possible with the strongest storms. There is a low chance for a tornado. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 50 miles northwest of Knob Noster MO to 25 miles east northeast of Columbia MO. 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 584... 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 550. Mean storm motion vector 27035. ...Mosier Read more

MD 1835 CONCERNING SEVERE THUNDERSTORM WATCH 584... FOR EASTERN PENNSYLVANIA INTO THE NEW ENGLAND REGION
Mesoscale Discussion 1835 NWS Storm Prediction Center Norman OK 0513 PM CDT Fri Aug 04 2023 Areas affected...Eastern Pennsylvania into the New England region Concerning...Severe Thunderstorm Watch 584... Valid 042213Z - 050015Z The severe weather threat for Severe Thunderstorm Watch 584 continues. SUMMARY...The severe threat continues across WW 584, and may extend into portions of southern/southeastern Pennsylvania over the next couple of hours. DISCUSSION...Scattered strong to severe thunderstorms continue to develop along the cold frontal boundary draped across the New England region. Recent GOES imagery shows transient nature of some cells, possibly due to undercutting outflow from prior convection, but cooling cloud top temperatures in IR imagery as well as tight clustering of in-cloud lightning with developing storms suggest robust convection remains possible. Recent GOES-derived winds and cloud heights suggest that 40-50 knot anvil-level winds, combined with weaker low-level flow, continue to support nearly 30 knots of deep-layer shear orthogonal to the frontal axis. Given adequate buoyancy over the region, this will maintain the potential for additional discrete convection (including a few supercells) prior to the onset of stronger nocturnal stabilization later this evening. The approach of a 300 mb jet max into the Mid-Atlantic region will augment broad-scale ascent across eastern PA, and may allow for the severe threat to continue towards the MD border. Portions of WW 584 have been extended to address this concern, but further downstream watch issuance is uncertain given a diminishing thermodynamic environment towards the coast and the influence of nocturnal cooling in the coming hours. ..Moore.. 08/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP... LWX...PBZ... LAT...LON 40407899 41147793 42727542 44077236 43997176 43797107 43387101 42537170 40797447 39737588 39657664 39667790 39747879 39877906 40117915 40407899 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0503 PM CDT Fri Aug 04 2023 Valid 061200Z - 121200Z ...Central Texas and Southwestern Oklahoma... A cold front will sag southward Sunday and stall near the Red River through late Monday, bringing a shift to northwesterly flow across southwestern Oklahoma/northwestern and north-central Texas. This will also bring a chance for showers and thunderstorms along the front, with low confidence in wetting precipitation outside of southwestern Oklahoma into the Texas Panhandle and areas right along the Red River. Elevated to near critical fire weather will be possible before the passage of the front. However, uncertainty in where sustained winds around 15 mph or greater will be, potential cloud cover and increase in RH behind the front, and how much wetting precipitation will occur limit inclusion of any areas at this time. Lightning strikes may lead to new starts in the absence of wetting rain. The front will lift northward on Monday with warming and drying conditions to return. Across central Texas, continued dry conditions are expected with 100+ F degree temperatures forecast through the extended period. Afternoon relative humidity reductions to around 15-20 percent will be possible each day. Drought stress and extreme heat have led to rapidly drying fuels (with ERCs around the 97th percentile) within this region. Given the very critical nature of fuels, Elevated to Critical fire weather concerns can be expected each afternoon through the extended. Overall, confidence in coverage of sustained 15 mph or greater winds precludes the need to include any Critical probabilities at this time. ...Southwest and Great Basin... Westerly flow further enhanced by strengthening mid-level flow atop the ridge will bring drying conditions across the Southwest. Lingering mid-level moisture will remain south of the Mogollon Rim in Arizona. Fuels within much of the Great Basin and Southwest have seen wetting rainfall from recent monsoonal activity which will limit fire weather concerns. Less rainfall was observed across far northeastern Arizona and northern New Mexico. ERCs within this region are in the 75th-90th percentile. A 40 percent delineation has been maintained on Sunday and Monday to characterize this threat. This threat may continue Tuesday before high pressure builds back in across the four corners with moisture steadily increasing into late in the period. ..Thornton.. 08/04/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1834 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN NE...NORTHEAST CO...NORTHWEST KS
Mesoscale Discussion 1834 NWS Storm Prediction Center Norman OK 0452 PM CDT Fri Aug 04 2023 Areas affected...Western NE...Northeast CO...Northwest KS Concerning...Severe potential...Watch possible Valid 042152Z - 042315Z Probability of Watch Issuance...40 percent SUMMARY...The threat for hail and localized severe gusts may increase into this evening. Watch issuance is possible. DISCUSSION...Storms are gradually increasing in coverage and intensity late this afternoon from northeast CO into western NE, to the south of a upper-level cyclone over the northern High Plains. A surface low is located near over far southeast MT, with a surface trough extending southeastward toward the NE Sandhills region, and then southwestward toward the NE Panhandle. A secondary low-level confluence zone is noted over northeast CO. Storms will likely continue to increase near these surface features and spread eastward into this evening. Moderate buoyancy and modest effective shear (generally 25-35 kt) will support a mix of strong multicells and perhaps a marginal supercell or two, with an initial threat of isolated hail and severe gusts. An outflow-driven cluster may eventually evolve and move somewhere across northern KS/southern NE later this evening, with at least an isolated severe-wind threat. While the environment is not particularly favorable for longer-lived supercells or a well-organized MCS, watch issuance is possible given the potential for increasing coverage of storms with at least some severe hail/wind threat into this evening. ..Dean/Mosier.. 08/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...GLD...BOU...CYS... LAT...LON 41230285 42220161 42550102 42860046 42619993 42119972 40889983 40020039 39140135 38870153 38670241 39000344 41230285 Read more

MD 1832 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF NORTHERN MISSOURI
Mesoscale Discussion 1832 NWS Storm Prediction Center Norman OK 0304 PM CDT Fri Aug 04 2023 Areas affected...portions of northern Missouri Concerning...Severe potential...Watch possible Valid 042004Z - 042230Z Probability of Watch Issuance...60 percent SUMMARY...The severe threat is gradually increasing across portions of northern MO. Damaging gusts are the main threat though a tornado or two, as well as an instance of large hail, are also possible. Convective trends are being monitored for the need of a WW issuance. DISCUSSION...The remnants of an MCV continue to track eastward along the northeast KS/northwest MO border area, with clearing skies and backed surface winds preceding the MCV. Surface temperatures are rising into the low to mid 80s amid mid to upper 70s F dewpoints, contributing to 1500+ J/kg MLCAPE amid eroding MLCINH. With continued heating and further destabilization, an eventual increase in convective coverage and intensity should take place across northern MO this afternoon. 19Z mesoanalysis/1936Z EAX VAD profile shows elongated low-level hodographs, with the latest mesoanalysis also showing modest 0-3 km CAPE and vertical near-surface vorticity overlapping near the MCV center. As such, storms that manage to organize this afternoon should mature into multicells or perhaps supercells capable of damaging gusts and perhaps a tornado or two, along with an instance of large hail. Given the slower trends in increasing storm coverage and intensity, the timing for the need of a WW issuance remains uncertain. However, a WW issuance may ultimately be needed this afternoon, whenever a appreciable increase in convective trends is noted. ..Squitieri/Goss.. 08/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...EAX... LAT...LON 39289513 39909482 40119434 40229340 40129268 39749218 39319226 39029267 38879330 38909394 38959464 39059498 39289513 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Fri Aug 04 2023 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS WITHIN THE NORTHEAST...NORTHERN/CENTRAL MISSOURI...PORTIONS OF THE CENTRAL PLAINS... ...SUMMARY... Scattered severe thunderstorms remain possible across parts of the Northeast, Missouri, and the central into the southern High Plains later today through early tonight. ...20Z Update... Minor changes were made to the wind probabilities within the Mid-South/Southeast to account for observations and stabilization behind ongoing convection. The remainder of the outlook is unchanged. ..Wendt.. 08/04/2023 .PREV DISCUSSION... /ISSUED 1134 AM CDT Fri Aug 04 2023/ ...Synopsis... A broad mid-level trough continues to slowly progress across the Northeast as an upper ridge remains in place across the southern CONUS, with multiple mid-level perturbations cresting the upper ridge over the Central Plains. Though some cloud cover and showers/thunderstorms persist across the Northeast, adequate clearing through the remainder of the morning should efficiently heat the boundary layer beneath cooler mid-level temperatures and stronger flow aloft to promote strong to potentially severe thunderstorms through the afternoon. Meanwhile, residual clouds, showers, and thunderstorms should clear across the MO Valley into the Southeast today, with surface heating contributing to adequate buoyancy to support strong to potentially severe thunderstorms. These storms should initiate with the passage of the aforementioned mid-level impulses cresting the upper ridge. Lastly, upslope low-level flow will support the development of strong to potentially severe thunderstorms across the central into the southern High Plains later this afternoon and evening. ...Northeast... Scattered to potentially widespread thunderstorms are expected to initiate across the Hudson Valley late this morning into early afternoon ahead of a surface lee trough as surface heating continues across the Northeast. 16Z mesoanalysis shows modest (i.e. 6-6.5 C/km) mid-level lapse rates overspreading the Hudson Valley. Nonetheless, -14 to -15 C 500 mb temperatures and 70+ kts of 300 mb flow (in association with an approaching upper-level jet streak) will promote adequate instability (given mid 60s F surface dewpoints) and deep-layer shear to support a severe threat this afternoon. Multicells and transient supercell structures are expected, with large hail and damaging gusts the main concerns. By late afternoon, storms should congeal into one or more clusters. If this occurs, then damaging gusts will become the primary threat. ...MO Valley into the Southeast... Ongoing clouds and precipitation should gradually clear through the afternoon to support increasing buoyancy (perhaps over 3000 J/kg MLCAPE) as 7+ C/km mid-level lapse rates overspreads 70+ F surface dewpoints. The approach of an MCV from the remains of an earlier MCS will support convective initiation later this afternoon around and just east of the KC Metropolitan area. Elongated and curved hodographs (especially in the low-levels) will encourage multicell and supercell structures initially. While damaging gusts are the main threat, locally backed low-level winds ahead of the MCV track may encourage a localized tornado threat for a few hours. However, storms should merge into one or more MCSs later this afternoon, with severe gusts the primary concern. Across the southeast, thunderstorm clusters should develop along the eastern periphery of the upper ridge. Given rich low-level moisture and strong buoyancy (with the 16Z mesoanalysis already showing up to 5000 J/kg SBCAPE in place), water-loaded downdrafts may accompany the stronger storm cores, and at least isolated damaging gusts are possible later this afternoon. ...Central into the Southern High Plains... Upslope flow induced by a surface lee trough, along with diurnal heating, will support the development of at least isolated to potentially scattered thunderstorms late this afternoon, from western SD to the TX Panhandle. A plume of 7-8 C/km mid-level lapse rates will advect over the central High Plains in tandem with the ejection of a subtle 700 mb impulse. 2000+ J/kg MLCAPE and an increase in deep-layer shear will result, with modestly lengthening hodographs (and 40 kts of effective bulk shear) expected. Multicells and supercells are expected to be the initial storm modes, with both severe hail wind the primary threats. By evening though, weak low-level shear should encourage outflow and subsequent cold pool mergers, with severe gusts then becoming the dominant severe threat. A few outflow-dominant thunderstorms may also develop along the surface trough across portions of the southern High Plains by afternoon peak heating. These storms will develop atop a dry, mixed boundary layer, with a couple of severe gusts possible. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Fri Aug 04 2023 Valid 051200Z - 061200Z No changes are needed to the Day 2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 08/04/2023 .PREV DISCUSSION... /ISSUED 0206 AM CDT Fri Aug 04 2023/ ...Synopsis... Elevated fire weather concerns will continue for Saturday across the southern Plains and parts of the Southwest/Four Corners. Isolated dry thunderstorms are also expected across parts of the Pacific Northwest and into the northern Great Basin. ...Southern High Plains... Medium-range guidance shows good agreement in the gradual ejection of the northern Rockies upper low into the Plains through the day Saturday. Lee troughing, coupled with thermally-driven pressure falls, should yield a modest surface low over the western OK/northwest TX where temperatures are expected to climb into the 100-105 F range. Ensemble guidance suggests the probability of sustained 15+ mph winds is generally low across central TX where fuels are currently most critical. A stronger pressure gradient near the surface low may support 15 mph winds (and hence the greatest fire weather concern) across northwest TX/southwest OK during peak heating. However, this region may also see afternoon thunderstorms per latest forecast soundings and ensemble QPF probabilities, which casts uncertainty into the duration and coverage of the fire weather threat. While elevated concerns appear most likely at this time, the potential for critical conditions will be monitored considering the critical nature of the fuels. ...Arizona into New Mexico... The aforementioned surface low over the Panhandles region will also augment westerly flow across northern AZ into northern NM. Sustained winds near 15-20 mph coupled with 15-20% RH appear likely based on both deterministic solutions and ensemble probabilities. While elevated conditions appear most probable, drier/windier solutions hint at the potential for critical conditions. Scattered pockets of wetting rain over the past 7 days complicate fuel status to some degree, but at least low-end fire weather concerns appear likely. ...Dry Thunderstorms... A slow-moving upper trough is expected to linger over the Pacific Northwest through the day Saturday. An influx of mid-level Pacific moisture and lift associated with this feature will result in another day of isolated to scattered thunderstorms. Forecast soundings continue to show PWAT values near 0.6 to 0.75 inches with deep, well-mixed boundary layers conducive for a mix of wet and dry thunderstorms from northwest NV into OR and adjacent areas of northern CA. Dry thunderstorms are also possible across parts of eastern UT and western CO, but recent rainfall appears to have mitigated fuel status based on recent fuel guidance. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0584 Status Updates
040- STATUS REPORT ON WW 584 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 E DUJ TO 35 NNW IPT TO 30 NNE BGM TO 40 NNE UCA TO 25 ENE MSS. ..LYONS..08/04/23 ATTN...WFO...BOX...ALY...GYX...PHI...BGM...BUF...BTV...OKX... CTP... STATUS REPORT FOR WS 584 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC003-005-042040- CT . CONNECTICUT COUNTIES INCLUDED ARE HARTFORD LITCHFIELD MEC031-042040- ME . MAINE COUNTIES INCLUDED ARE YORK MAC003-009-011-013-015-017-025-027-042040- MA . MASSACHUSETTS COUNTIES INCLUDED ARE BERKSHIRE ESSEX FRANKLIN HAMPDEN HAMPSHIRE MIDDLESEX Read more

WW 584 SEVERE TSTM CT MA ME NH NJ NY PA VT CW 041605Z - 050000Z
0- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 584 NWS Storm Prediction Center Norman OK 1205 PM EDT Fri Aug 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwestern Connecticut Much of Massachusetts Far southern Maine Central and southern New Hampshire Northwestern New Jersey Central and eastern New York Parts of central and eastern Pennsylvania Central and southern Vermont Coastal Waters * Effective this Friday afternoon and evening from 1205 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are forecast to continue to develop across portions of Pennsylvania and New York and into New England early this afternoon, intensifying and evolving into clusters/bands of storms with time. Large hail up to golf ball size, and wind gusts locally exceeding 60 MPH are expected with the strongest storms. The severe thunderstorm watch area is approximately along and 110 statute miles east and west of a line from 25 miles north northwest of Lebanon NH to 35 miles southeast of State College PA. 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 55 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 27030. ...Goss Read more

WW 584 SEVERE TSTM CT MA ME NH NJ NY PA VT CW 041605Z - 050000Z
0- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 584 NWS Storm Prediction Center Norman OK 1205 PM EDT Fri Aug 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwestern Connecticut Much of Massachusetts Far southern Maine Central and southern New Hampshire Northwestern New Jersey Central and eastern New York Parts of central and eastern Pennsylvania Central and southern Vermont Coastal Waters * Effective this Friday afternoon and evening from 1205 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Scattered large hail events to 1.5 inches in diameter possible SUMMARY...Thunderstorms are forecast to continue to develop across portions of Pennsylvania and New York and into New England early this afternoon, intensifying and evolving into clusters/bands of storms with time. Large hail up to golf ball size, and wind gusts locally exceeding 60 MPH are expected with the strongest storms. The severe thunderstorm watch area is approximately along and 110 statute miles east and west of a line from 25 miles north northwest of Lebanon NH to 35 miles southeast of State College PA. 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 55 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 27030. ...Goss Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Fri Aug 04 2023 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE CENTRAL PLAINS INTO THE MISSOURI VALLEY... ...SUMMARY... Severe thunderstorms are expected across portions of the central Plains to the Lower Missouri/Middle Mississippi Valley vicinity on Saturday. Damaging gusts (some 75+ mph) and large hail (some 2+ inches) will be the primary severe weather hazards. ...Synopsis... A closed upper low currently within the northern Plains is expected to become more of an open wave and move southward/southeastward on Saturday. Mid/upper-level winds will increase through the period within the central High Plains eastward into the Missouri Valley as a result. Farther east, an MCV is forecast to track into the mid-Mississippi/lower Ohio Valley vicinity. At the surface, a remnant stationary boundary, perhaps reinforced by warm-advection precipitation, will remain from Missouri into the southern Plains. To the north, a surface low will deepen in South Dakota and eventually move into the Midwest along with its parent shortwave trough. This will act to push a cold front into the central Plains by Sunday morning. A secondary surface low is also forecast to develop in the southern High Plains. ...Central High Plains into Kansas... Upslope flow into the terrain is expected to be maintained ahead of the cold front which should approach by late afternoon. Upper 50s F to low 60s F dewpoints should be sufficient for a cluster or two of storms to develop within the terrain and spread eastward into eastern Colorado and western Kansas. There continues to be some uncertainty as to potential convection within southern Kansas into northern Oklahoma overnight Friday into Saturday morning. Weak warm advection is still predicted by most guidance even into the afternoon. What impact this activity will have on the forecast does remain unclear. Even so, moderate to strong buoyancy is expected within eastern Colorado and south of areas impacted by early precipitation. Winds at mid/upper levels will be increasing into early evening. Hodographs will consequently become more favorable for supercells and large/very-large hail. It is not clear how quickly upscale growth will occur, but an increase in 850 mb flow from the south across West Texas will likely promote increasing storm coverage during the evening. Strong/severe wind gusts will also be possible with supercells, including gusts in excess of 75 mph. The spatial extent of significant gust potential will be conditional on degree and timing of upscale growth. Damaging wind potential will persist into the evening in some fashion across Kansas into perhaps western Missouri. ...Mid-Missouri Valley... Near the surface low, storm development appears likely from southeast South Dakota into eastern Nebraska. Shear will decrease with northern extent, as will buoyancy, with the mid-level jet being generally near the Nebraska/Kansas border. However, some supercell structures appear possible that will be capable of large hail and damaging winds. A narrow corridor of backed surface winds near the low could support a risk for a tornado as well, but hodographs at mid/upper-levels do not appear favorable for sustained/strong mesocyclones. ...Lower Ohio Valley Vicinity... An MCV now in the Mid-Missouri Valley region is expected to progress into Illinois by early Saturday morning. Cloud cover and precipitation with this feature will mean some uncertainty in the magnitude and location of severe risk during the afternoon. The degree of surface heating will be the key and not all models suggest it will occur. However, there appears to be a conditionally favorable environment for marginal supercell structures capable of isolated damaging winds and a brief tornado or two. ..Wendt.. 08/04/2023 Read more

MD 1823 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR LOWER MICHIGAN
Mesoscale Discussion 1823 NWS Storm Prediction Center Norman OK 0449 PM CDT Thu Aug 03 2023 Areas affected...Lower Michigan Concerning...Severe potential...Watch unlikely Valid 032149Z - 032345Z Probability of Watch Issuance...5 percent SUMMARY...Scattered thunderstorms may pose an isolated threat for sporadic severe/damaging winds and large hail across lower Michigan through the evening hours. Given the limited nature of the threat, watch issuance is not anticipated. DISCUSSION...A broken line of cells moving onshore across northwest Lower MI have demonstrated transient signs of organization over the past hour per KGRR and KAPX imagery. This activity, including a cell along the eastern WI shore, has produced near-severe wind/hail over the past couple of hours, including a 57 mph wind gust and 0.75 inch hail. The regional thermodynamic and kinematic environment appear adequate for convective maintenance with 1500-2000 J/kg MLCAPE and 0-6 km bulk wind difference values approaching 30 knots. The somewhat disorganized/clustered nature of the convection and modest deep-layer shear will modulate the overall severe threat to some degree, but sporadic severe hail and damaging winds appear possible over the next few hours as these storms spread southeast across Lower MI. ..Moore/Mosier.. 08/03/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX...APX...GRR... LAT...LON 44038642 45028578 44878500 44458410 44038312 43678269 42858248 42348307 42208371 42518489 42948569 43178614 43398642 43688652 44038642 Read more

WW 0582 Status Updates
STATUS REPORT ON WW 582 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/03/23 ATTN...WFO...BOU...PUB...GLD...CYS...LBF... STATUS REPORT FOR WS 582 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC001-005-011-017-025-039-061-063-073-075-087-089-095-099-115- 121-123-125-032240- CO . COLORADO COUNTIES INCLUDED ARE ADAMS ARAPAHOE BENT CHEYENNE CROWLEY ELBERT KIOWA KIT CARSON LINCOLN LOGAN MORGAN OTERO PHILLIPS PROWERS SEDGWICK WASHINGTON WELD YUMA NEC007-013-033-045-049-069-105-123-157-161-165-032240- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES DEUEL GARDEN KIMBALL MORRILL SCOTTS BLUFF SHERIDAN SIOUX WYC015-021-032240- Read more