Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0209 PM CDT Fri Aug 11 2023 Valid 121200Z - 131200Z The overall pattern will be quite similar tomorrow in Texas as it is today. Given the state of fuels and current observations, greater weight was placed on the drier model solutions and the elevated area was expanded southward. ..Wendt.. 08/11/2023 .PREV DISCUSSION... /ISSUED 0158 AM CDT Fri Aug 11 2023/ ...Synopsis... Mid-level high pressure is forecast to remain in place across the central US while also intensifying over the western US through much of Day2/Saturday. Very warm conditions are likely over the southern Plains as monsoon moisture moves north across the Great Basin and Southwest. Hot and breezy conditions will support fire-weather concerns over parts of TX and OK, with thunderstorm chances and local fire-weather potential increasing across parts of the Northwest. ...Central TX... Another day of extreme temperatures is expected beneath the ridge focused over portions of the southern Plains. Widespread surface temperatures exceeding 100 F will continue to support extremely volatile fuels across parts of central TX and southwest OK. Dry southerly winds enhanced by a lee trough and thermal low over OK will reach 10-15 mph and higher gusts into the evening. Several hours of elevated to locally critical fire-weather conditions are expected given the volatile fuels and extremely warm/breezy conditions. ...Northern Great Basin... Monsoon moisture is forecast to slowly increase across portions of the northern Great Basin through D2/Saturday. Area model soundings show PWAT values approaching 0.5-0.6 inches across parts of northern NV, into CA, and far southern OR. While synoptic lift will be weak, isolated thunderstorms may develop along the higher terrain of the Sierra and far southern Cascades. Warm and dry surface conditions suggest any storms that do form will be high-based with low wetting rainfall potential. A few dry lightning strikes are possible within mostly receptive fuels. However, with only weak synoptic forcing present, confidence in sufficient storm coverage for IsoDryT highlights is very low. ...Northwest... Weak onshore flow from eastern Pacific high pressure will help drive northerly flow over parts of southwest WA and northwest/west-central OR. Surface wind gusts of 15-25 mph are possible, especially within terrain-enhanced areas of the central Cascades and Coastal Ranges. While surface RH values are not expected to be overly dry given the onshore wind component, minimum RH values below 35%, along with the gusty winds, may support a few hours of locally elevated fire-weather potential within dry fuels. ...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 1246 PM CDT Fri Aug 11 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTION OF THE OHIO VALLEY AND NORTHEAST...AND OVER THE SOUTHERN HIGH PLAINS VICINITY... ...SUMMARY... Severe thunderstorms are possible across portions of the Ohio Valley and Northeast, parts of the Plains region, and the Mid South/southern Appalachians on Saturday. ...Ohio Valley/Northeast... A belt of 40 to 60 kt mid-level westerlies is forecast to overspread the mid and upper Ohio Valley and Northeast on Saturday, as a short-wave trough initially over the Upper Great Lakes area shifts eastward across the region. Storms are forecast to develop by afternoon as the warm-sector airmass heats/destabilizes -- over parts of New York and northeastern PA near the warm front and evolving lake-breeze boundaries, and over northwestern Ohio and Indiana along the southeastward/moving cold front. Given moderately strong flow through the lower and middle troposphere, damaging winds are expected with stronger storms as convection moves rather quickly eastward. Some increase in storm coverage should continue through the afternoon and persist into the evening. Still, it appears that overall coverage may remain sufficiently sparse so as to limit overall coverage of severe-weather occurrences. WIth that said, this area may require upgrade to 30% wind/ENH risk, as multiple rounds of scattered storm clusters may affect some areas. ...Southern High Plains vicinity... Short-wave troughing is progged to rotate northeastward across New Mexico and the central/southern High Plains region, and then east-northeastward into Kansas and northern Oklahoma, around the western periphery of the mid-level ridge. As the afternoon airmass heats/destabilizes, storms are expected to develop from southeastern Colorado/northeastern New Mexico to the Texas Panhandle, which would then spread eastward across parts of Kansas and Oklahoma in conjunction with an enhanced belt of mid-level westerlies accompanying the aforementioned short-wave troughing. Given a relatively deep mixed layer anticipated during the afternoon and early evening, locally damaging wind gusts appear to be the primary severe threat, along with some hail risk. Storms may increase in coverage during the evening/overnight as a southwesterly low-level jet develops. Convection may spread eastward into Missouri late, though likely with diminishing severe risk due to diurnal stabilization of the boundary layer. ...Mid South/southern Appalachians... An MCS is forecast to be ongoing at the start of the period, moving eastward across the Mid Mississippi Valley vicinity. As the downstream airmass destabilizes through the day, storms will likely be maintained, with some reintensification possible -- aided by presence of increasing mid-level west-northwesterly flow with northward extent. Locally damaging wind gusts and hail will be possible with the strongest storms/storm clusters as convection moves across the Mid South/Tennessee Valley region, with some hints that a southeastward advance into/across the southern Appalachians may occur. As such, have expanded MRGL risk into northern parts of Alabama/Georgia, and into the western Carolinas/western Virginia, to cover any local/isolated severe risk. ...South Dakota/Nebraska area... Weak height falls associated with a short-wave trough advancing southeastward from the Canadian Rockies, in conjunction with low-level warm advection, should result in isolated afternoon storm development as ample diurnal destabilization occurs. Given sufficient shear expected over the area, a couple of the strongest storms will likely become capable of producing hail and a damaging gust or two. As a southerly low-level jet evolves through the evening, a continuation of isolated storms is expected, with some increase in coverage possible. Local severe risk may persist into the overnight hours with the strongest storms. ..Goss.. 08/11/2023 Read more

WW 0623 Status Updates
STATUS FOR WATCH 0623 HAS NOT BEEN ISSUED YET Read more

WW 623 SEVERE TSTM MN ND SD 102155Z - 110400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 623 NWS Storm Prediction Center Norman OK 455 PM CDT Thu Aug 10 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Extreme west central Minnesota Southeast North Dakota Eastern South Dakota * Effective this Thursday afternoon and evening from 455 PM until 1100 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...Scattered severe storms are expected through late evening across eastern South Dakota and adjacent areas of North Dakota and west central Minnesota. Large hail of 1.5 to 2 inches in diameter and severe outflow gusts of 60-70 mph will be the main threats, though an isolated tornado or two may occur with storms near the surface warm front across extreme northeast South Dakota. The severe thunderstorm watch area is approximately along and 65 statute miles east and west of a line from 80 miles north northeast of Aberdeen SD to 50 miles south of Mitchell SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). 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 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27020. ...Thompson Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0435 PM CDT Thu Aug 10 2023 Valid 121200Z - 181200Z ...Central Texas... Strong ridging across the southwestern/south-central US will continue to bring very warm temperatures and dry conditions across central Texas. Occasional breezes around 10-15 mph (gusting 20 mph) will be possible D3 - Saturday and D4 - Sunday as weak lee troughing east of the Rockies continues. A cold front will sag southward late D4 - Sunday into D5 - Monday with a shift to northerly winds across north-central Texas. Temperatures will be a few degrees cooler with slightly higher afternoon relative humidity near the Red River Valley. South of the front, triple digit highs will continue. Beneath the influence of the ridge, lighter winds are forecast for D5 - Mon through D8 - Thursday. Afternoon relative humidity reductions to 15-25 percent will remain possible. Given extremely dry fuels, multiple periods of Elevated fire weather concerns will be possible. ...Pacific Northwest... Building high pressure will bring warming across the Pacific Northwest. Initial thunderstorm development will be possible as tropical moisture extends northward D3 - Saturday lingering into D6 - Tuesday (detailed below). Beyond the early week thunderstorm activity, thermal troughing may increase. This may lead to increased fire weather concerns in the extended. Confidence is low at this time in placement and strength and as a result impacts. ...Dry Thunderstorms... Potential remnants of tropical storm activity will spread northward into California and southern Oregon beginning D3 - Saturday through D6 - Tuesday. Recent model runs continue to trend slower and drier. Initial activity across central/northern California will likely be isolated, with low potential for a dry thunderstorm or two. Potential for thunderstorms will increase into D4 - Sunday and D5 - Monday as better instability spreads across northern California. A mix of wet/dry storms, mainly tied to the high terrain, with gusty and erratic winds may be possible. Confidence in coverage remains too low to include any areas at this time but this will be monitored in the coming days. ..Thornton.. 08/10/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1937 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF CENTRAL TEXAS
Mesoscale Discussion 1937 NWS Storm Prediction Center Norman OK 0439 PM CDT Thu Aug 10 2023 Areas affected...Parts of central Texas Concerning...Severe potential...Watch unlikely Valid 102139Z - 102345Z Probability of Watch Issuance...20 percent SUMMARY...The risk of locally severe gusts will persist through the afternoon. A watch is not expected. DISCUSSION...Isolated high-based thunderstorms are evolving across parts of central Texas this afternoon, where surface temperatures have climbed into the 105-110 range amid upper 50s/lower 60s dewpoints. The associated deeply mixed boundary layer (deep inverted-V thermodynamic profile) beneath steep midlevel lapse rates will support strong to locally severe gusts and possibly sporadic/marginally severe hail with any stronger updrafts that develop through the afternoon. Given weak deep-layer flow/shear and minimal large-scale ascent across the area, updraft longevity and the potential for organized upscale growth should generally be limited. Therefore, a watch is not expected at this time. ..Weinman/Thompson.. 08/10/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN...SJT...LUB...MAF... LAT...LON 32260210 32650205 33000177 33280111 33529998 33579939 33589885 33429837 33129828 32879837 32439907 31730037 31490108 31540169 31790200 32260210 Read more

MD 1936 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF EASTERN NORTH CAROLINA
Mesoscale Discussion 1936 NWS Storm Prediction Center Norman OK 0437 PM CDT Thu Aug 10 2023 Areas affected...portions of eastern North Carolina Concerning...Severe potential...Watch possible Valid 102137Z - 102300Z Probability of Watch Issuance...40 percent SUMMARY...Isolated severe storms, including a few supercells, are possible this evening. Damaging gusts, isolated hail and a couple of tornadoes are possible with the strongest storms. A weather watch is possible, but uncertain. DISCUSSION...As of 2130 UTC, regional radar and satellite analysis showed renewed convective development ongoing across parts of southeastern and eastern North Carolina. Located ahead of a weak cold front/ wind shift, incipient storms are expected to continue to intensify through this evening. Very moist surface conditions ( dewpoints in the mid to upper 70s F) were supporting 2000-2500 J/kg of MLCAPE despite modest mid-level lapse rates. Area VADs show enhanced mid-level flow around 50 kt was aiding in sufficient deep-layer shear for supercells and or short bowing segments, with a risk for damaging wind gusts and isolated hail. While low-level winds are slightly veered, 0-1 km SRH of 100-200 m2/s2 may support a few stronger low-level mesocyclones and a risk for a couple of tornadoes this evening. Storm coverage remains the primary uncertainty in the wake of previous convection. Confidence in a more sustained severe risk is greatest farther south where the air mass has better recovered. However, conditions are being monitored for a possible weather watch over much of eastern North Carolina this evening. ..Lyons/Thompson.. 08/10/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...ILM... LAT...LON 33917823 34087858 34257868 34627876 34887883 35017874 35097859 35257826 35757722 36217609 36307582 35687544 35307547 35007563 34737608 34397686 34137752 34007792 33917823 Read more

MD 1934 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR EASTERN AR...NORTHERN MS
Mesoscale Discussion 1934 NWS Storm Prediction Center Norman OK 0338 PM CDT Thu Aug 10 2023 Areas affected...eastern AR...northern MS Concerning...Severe potential...Watch unlikely Valid 102038Z - 102245Z Probability of Watch Issuance...20 percent SUMMARY...Additional storm development is possible. An isolated severe hail/wind threat may develop. DISCUSSION...Radar/visible satellite composite shows a thunderstorm over eastern AR with an increasingly optically deep stratocumulus field over northern MS. Water-vapor imagery shows a weak mid-level perturbation moving east across eastern AR this afternoon. Surface temperatures across northern MS into far eastern AR range from the lower 80s south to the lower 90s on the southern periphery of a residual baroclinic zone. Objective analysis indicates a very unstable airmass resides over the northern MS/southeast AR vicinity (MLCAPE 3000-4000 J/kg). Effective shear due largely in part to large veering of flow with height will aid in some multicell organization. A few stronger storms may develop and pose a risk for isolated marginally severe hail/damaging gusts through early evening. The expected coverage/magnitude of the severe threat will probably preclude a severe thunderstorm watch. However, will monitor convective trends for a low possibility the severe threat is more organized than anticipated, perhaps prompting a small severe thunderstorm watch. ..Smith/Guyer.. 08/10/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MEG...JAN...LZK... LAT...LON 34599144 34759097 34348921 33968914 33668930 33568984 33999146 34359159 34599144 Read more

MD 1933 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF SOUTHEAST WYOMING INTO EXTREME NORTHEAST COLORADO...FAR SOUTHWESTERN SOUTH DAKOTA AND THE NEBRASKA PANHANDLE
Mesoscale Discussion 1933 NWS Storm Prediction Center Norman OK 0314 PM CDT Thu Aug 10 2023 Areas affected...portions of southeast Wyoming into extreme northeast Colorado...far southwestern South Dakota and the Nebraska Panhandle Concerning...Severe potential...Watch unlikely Valid 102014Z - 102245Z Probability of Watch Issuance...5 percent SUMMARY...A couple instances of severe hail/wind may accompany the stronger storms. A WW issuance is not expected. DISCUSSION...Convective initiation/intensification is underway across the Higher Terrain of WY/CO. Ahead of the developing storms, a well-mixed boundary layer has materialized, characterized by 30 F surface temperature/dewpoint spreads and 9-10 C/km 0-3 km lapse rates (per 20Z mesoanalysis). Forecast soundings depict around 500 J/kg of tall/thin MLCAPE, distributed in roughly the 700-300 mb layer. Given elongated hodographs, storms that can mature in this environment may produce a couple instances of severe hail/wind. However, the severe threat should be sparse and a WW issuance is not anticipated. ..Squitieri/Guyer.. 08/10/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...UNR...GLD...BOU...CYS... LAT...LON 40140221 40290348 40450419 40930471 41900547 42770588 43240579 43460519 43540445 43400372 43050327 42420276 41750235 40960217 40140221 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Thu Aug 10 2023 Valid 102000Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID MISSOURI VALLEY AND VICINITY... ...SUMMARY... Isolated severe thunderstorms remain possible over parts of the eastern and central states this afternoon into tonight, including eastern North Carolina/southeast Virginia and parts of the Upper Midwest vicinity. ...Discussion... The main outlook adjustment being implemented in this update, aside from minor/local tweaks of the areal outlines, is an expansion of MRGL risk across the Iowa vicinity. Expectations are that an at least loosely organized MCS will move across the Iowa vicinity overnight, and that local/low-end severe potential may accompany the strongest cells. Otherwise, no appreciable changes appear necessary at this time. ..Goss.. 08/10/2023 .PREV DISCUSSION... /ISSUED 1139 AM CDT Thu Aug 10 2023/ ...Eastern Carolinas/southeast Virginia... A convectively augmented shortwave trough over the southern/central Appalachians will continue eastward today. A cluster of thunderstorms, likely MCV aided, is ongoing across coastal areas of the Carolinas at late morning. Although considerable cloud cover immediately preceding the cluster may be a thermodynamic hindrance, more appreciable destabilization is expected in more immediate coastal areas. Where storms intensify, a seasonally strong/cyclonically curved belt of westerlies (50+ kt at 500 mb) would support organized storms including the possibility of a few supercells and well-organized/moderately fast-moving clusters capable of wind damage and some tornado risk. Although uncertain, there is a scenario is which a secondary round of regional convective development occurs late this afternoon near the southeastward-moving weak front and/or preceding surface trough. While deep-layer shear will tend to weaken late this afternoon/early evening, wind profiles should conditionally remain supportive of well-organized storms, potentially including a few supercells. This could yield some storms capable of damaging winds, hail, and possibly a tornado, prior to the risk abating/shifting offshore by mid-evening. ...Dakotas/Upper Midwest and eastern Nebraska... As a mid/upper ridge shifts east, a low-amplitude trough will overspread the northern Great Plains. This will help induce a weak surface cyclone over western North Dakota with a surface trough arcing south into central Nebraska and a warm front extending southeast through southern Minnesota. Relatively modest boundary-layer moisture and deep-layer shear will be limiting factors to a more prolific severe threat across the region. But steeper mid-level lapse rates within an elevated mixed layer will spread east across most of South Dakota and much of Nebraska by early evening and support a confined corridor of moderate buoyancy with MLCAPE of 1000-2000 J/kg. Effective bulk shear of 25-35 kts should support a mixed mode of a few supercells and multicell clusters. The most likely zone for scattered thunderstorm development in the late afternoon should be near the surface trough/warm front intersection in the northeast South Dakota border area with ND/MN. Increasingly isolated development should trail south along the trough. A mix of large hail and severe wind gusts will be the main threats, with some potential that an MCS evolves and continues southeastward this evening. ...Mid-South/Tennessee Valley... Modifying outflow from early day thunderstorms should serve as a focus for redevelopment later this afternoon, along the remnant front to the north. Additionally, another round of low-level warm theta-e advection-driven storms should occur after sunset tonight. A modest combination of mid-level lapse rates and vertical shear should support a mainly isolated severe threat, with sporadic instances of damaging gusts and marginal hail possible. ...Coastal Mid-Atlantic/southern New England... Low-level warm theta-e advection will strengthen today and translate northeast from the Mid-Atlantic across New England this afternoon and evening. Low-topped convection (perhaps void of lighting flashes in some cases) should develop amid meager surface-based instability as thermodynamic profiles become saturated. Aside from localized wind damage, the potential for a brief tornado also exists owing to enlarged low-level hodograph curvature. ...Central High Plains... Isolated high-based thunderstorms should develop off the higher terrain of southeast Wyoming and far north-central Colorado near a lee surface trough. A deep mixed boundary layer along the adjacent High Plains could support a few severe wind gusts during the late afternoon to early evening. ...West-central/northwest Texas... Hot surface temperatures along the dryline may support isolated thunderstorm development late this afternoon and early evening. Should deep convection become sustained, the very deeply mixed boundary layer could yield a few severe-caliber wind gusts. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0247 PM CDT Thu Aug 10 2023 Valid 111200Z - 121200Z There are no changes needed to the current D2 Fire Weather Outlook. See previous discussion below. ..Thornton.. 08/10/2023 .PREV DISCUSSION... /ISSUED 0152 AM CDT Thu Aug 10 2023/ ...Synopsis... Fire weather concerns will persist across parts of Texas on Friday with more localized concerns possible over northern Montana. Broad northwesterly flow aloft over the northern half of the country will continue to support breezy conditions at the surface. Across the southern CONUS, monsoonal thunderstorms are expected across the Southwest with another day of anomalously hot temperatures over the southern Plains. ...Texas... Weak lee troughing along the High Plains will induce a broad southerly flow regime across the southern Plains. This will advect unseasonably hot temperatures northward into northwest TX/western OK where high temperatures are expected to peak near 105 F. Forecast guidance suggests winds will be regionally augmented in proximity to a thermal low over northwest TX and/or the TX Panhandle, which will increase the fire weather potential. Maximum sustained winds near 15 mph appear probable with afternoon RH in the 20-30% range. Recent reports from the region indicate that these wind/RH conditions are sufficient for active fire behavior, warranting highlights. Thunderstorms developing along the lee trough and/or in proximity to the low will pose a threat for gusty outflow winds and perhaps dry lightning strikes (ensemble guidance shows low probability for wetting rainfall Friday afternoon). ...Northern Montana... Dry northwesterly low to mid-level flow will persist across north-central MT from Thursday into Friday afternoon. A few deterministic solutions suggest that elevated fire weather conditions are possible with 15-20 mph winds and RH values falling into the low 20s. However, ensemble guidance shows considerably more spread in the wind/RH forecast with limited probability for sustained elevated conditions. This hinders confidence in a robust fire threat, but receptive fuels over northern MT will support a fire concern if confidence in elevated conditions improves. ...Dry Thunderstorms... Monsoonal moisture will linger across AZ into western NM with decreasing column moisture with northern extent into NV, UT, and CO. While wetting thunderstorms are probable across the Southwest, PWAT values between 0.5 to 0.75 inches over the Great Basin/central Rockies will support another day of dry thunderstorm potential. Upper ridging over the region will limit broad scale ascent, but orographic lift will be sufficient for isolated thunderstorms. Although current fuel moisture values are sufficiently high to preclude a more robust fire concern, fuel trends will be monitored and may necessitate highlights if they become sufficiently receptive to lightning starts. ...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 1234 PM CDT Thu Aug 10 2023 Valid 111200Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MID AND UPPER MISSISSIPPI AND LOWER MISSOURI VALLEYS... ...SUMMARY... Severe thunderstorms capable of large hail, damaging gusts, and perhaps a tornado or two are possible across portions of the Mid and Upper Mississippi Valley and Lower Missouri Valley areas on Friday. ...Mid and Upper Mississippi/Lower Missouri Valleys... Ongoing thunderstorms -- and some lingering severe potential -- are expected at the start of the period over the southern Wisconsin/eastern Iowa/northwestern Illinois/northern Missouri vicinity. This convection is forecast to continue moving east/southeastward across the central Illinois vicinity through midday. The strongest storms may be capable of producing locally damaging winds and marginal hail. Over southern portions of the SLGT risk area -- i.e. the Mid Mississippi and Lower Missouri Valleys and vicinity -- redevelopment of convection near a roughly west-to-east outflow is expected during the afternoon, and continuing into the evening (aided by southwesterly low-level jet development). With moderate (30 to 40 kt) mid-level northwesterlies, organized/locally severe storms are expected, with locally damaging wind gusts and hail expected. Risk may persist into the overnight hours as storms move southeastward. Farther north, over the Upper Mississippi Valley area, afternoon storm redevelopment is expected, as short-wave mid-level troughing shifts southeastward out of Canada. With daytime heating resulting in ample destabilization, and strong (40 to 50 kt) mid-level northwesterly flow, organized storms capable of producing locally damaging wind gusts and hail are expected to evolve, spreading eastward/southeastward through the evening. Local risk may extend as far east as Lower Michigan into the overnight hours. ...The Southeast... As a weak short-wave trough crosses the Southeast, and a very weak/outflow-reinforced surface front lingers, afternoon heating of the moist boundary layer in place will result in moderate destabilization. This will help to foster redevelopment of storms from the central Gulf Coast states eastward to the southern Atlantic Coast. With moderate lower- to mid-level west-southwesterly flow (around 30 kt), some potential for upscale linear growth/forward propagation is evident, which suggests strong/gusty winds across the area, including a few gusts which may approach severe levels during the afternoon and into the evening hours. ..Goss.. 08/10/2023 Read more

MD 1922 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR THE RED RIVER VALLEY REGION
Mesoscale Discussion 1922 NWS Storm Prediction Center Norman OK 0520 PM CDT Wed Aug 09 2023 Areas affected...The Red River Valley region Concerning...Severe potential...Watch possible Valid 092220Z - 100015Z Probability of Watch Issuance...40 percent SUMMARY...Thunderstorms developing along the Red River Valley will pose a risk for severe winds over the next several hours. Watch issuance is possible. DISCUSSION...Robust convective initiation is underway along a surface trough draped from eastern OK into north/northwest TX. 12 UTC soundings from OUN and FWD sampled high PWAT values generally near 1.75 inches, but recent surface observations are showing high dewpoint depressions on the order of 40-50 F. This suggests that the low-level thermodynamic environment is very deeply mixed and should support accelerating downdrafts. A mix of wet/dry downbursts appear possible with an attendant risk for severe winds. Trends will be monitored, and watch issuance is possible if it becomes evident the severe threat will be sufficiently widespread and persistent. ..Moore/Thompson.. 08/09/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...SHV...TSA...FWD...OUN...SJT... LAT...LON 33159767 32589859 32239920 32089977 32310009 32679983 33419888 33959814 34249771 34629699 34709622 34639533 34019517 33439542 33289645 33159767 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0452 PM CDT Wed Aug 09 2023 Valid 111200Z - 171200Z ...Texas... Extremely dry and warm conditions, with daily highs 100+ F degrees, will continue across central and southern Texas through the extended period. While light rainfall will be possible across portions of southwest/north central Texas, much of central Texas will likely remain dry through D8. High pressure building in across the Four Corners to the Southern Plains will keep winds mostly light, though locally breezy conditions may occur. Elevated to locally Critical fire weather concerns will be likely daily, with low confidence in any one corridor where sustained winds will support Critical risk probabilities. Though the winds will largely stay below criteria, expect continued potential for new fire starts and rapid fire growth in hot and unstable conditions and extremely critically dry fuels. ...Pacific Northwest... Building high pressure will bring warming across the Pacific Northwest. Initial thunderstorm development will be possible as tropical moisture extends northward D4 - Saturday lingering into D7 - Tuesday (detailed below). Beyond the early week thunderstorm activity, thermal troughing may increase. This may lead to increased fire weather concerns in the extended. Confidence is low at this time in placement and strength and as a result impacts. ...Dry Thunderstorms... Potential remnants of tropical storm activity will spread northward into California and southern Oregon beginning D2 - Thursday through D3 - Friday. Recent model runs have been slower and drier with northern extent of the incoming moisture. Initial activity across central/northern California will likely be isolated, with low potential for a dry thunderstorm or two. Potential for thunderstorms will increase into D4 - Saturday and D5 - Sunday as better instability spreads across northern California. A mix of wet/dry storms with gusty and erratic winds may be possible. Confidence in coverage remains too low to include any areas at this time but this will be monitored in the coming days. ..Thornton.. 08/09/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0617 Status Updates
STATUS REPORT ON WW 617 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 SSE MKL TO 15 W CHA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1920 ..WEINMAN..08/09/23 ATTN...WFO...BMX...HUN...MEG...OHX... STATUS REPORT FOR WS 617 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ALC009-019-033-043-049-055-057-059-071-075-077-079-083-089-093- 095-103-127-133-092340- AL . ALABAMA COUNTIES INCLUDED ARE BLOUNT CHEROKEE COLBERT CULLMAN DEKALB ETOWAH FAYETTE FRANKLIN JACKSON LAMAR LAUDERDALE LAWRENCE LIMESTONE MADISON MARION MARSHALL MORGAN WALKER WINSTON MSC003-057-117-141-092340- MS . MISSISSIPPI COUNTIES INCLUDED ARE ALCORN ITAWAMBA PRENTISS TISHOMINGO Read more

WW 617 SEVERE TSTM AL MS TN 091850Z - 100100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 617 NWS Storm Prediction Center Norman OK 150 PM CDT Wed Aug 9 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Alabama Northeast Mississippi Middle Tennessee * Effective this Wednesday afternoon and evening from 150 PM until 800 PM CDT. * Primary threats include... Scattered damaging wind gusts to 65 mph likely Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Storms are expected to increase and intensify along a warm front/instability gradient across the region, with wind profiles supportive of a few supercells and bowing segments. The severe thunderstorm watch area is approximately along and 55 statute miles north and south of a line from 40 miles west northwest of Muscle Shoals AL to 50 miles north northeast of Gadsden AL. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). 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 550. Mean storm motion vector 28025. ...Guyer Read more

WW 0618 Status Updates
STATUS FOR WATCH 0618 HAS NOT BEEN ISSUED YET Read more

WW 618 TORNADO AR KS MO OK 092105Z - 100300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 618 NWS Storm Prediction Center Norman OK 405 PM CDT Wed Aug 9 2023 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northwest Arkansas Far Southeast Kansas Southwest Missouri Eastern Oklahoma * Effective this Wednesday afternoon and evening from 405 PM until 1000 PM CDT. * Primary threats include... A couple tornadoes possible Scattered damaging wind gusts to 65 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...The air mass in the wake of storms earlier today continues to gradually destabilize, with severe storms expected to increase mainly near a front through late afternoon and early evening. Strong wind profiles will support initial supercells. The tornado watch area is approximately along and 65 statute miles east and west of a line from 40 miles north northeast of Springfield MO to 30 miles south southeast of Mcalester OK. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). 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 617... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 28025. ...Guyer Read more

MD 1921 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EXTREME EASTERN MONTANA...SOUTHERN NORTH DAKOTA...NORTHERN SOUTH DAKOTA
Mesoscale Discussion 1921 NWS Storm Prediction Center Norman OK 0359 PM CDT Wed Aug 09 2023 Areas affected...portions of extreme eastern Montana...southern North Dakota...northern South Dakota Concerning...Severe potential...Watch unlikely Valid 092059Z - 092330Z Probability of Watch Issuance...5 percent SUMMARY...An instance or two of severe hail or wind may occur later this afternoon into early evening. The severe threat should remain isolated and a WW issuance is not expected. DISCUSSION...Agitated cumulus, along with sparse areas of convective initiation, are underway ahead of a diffuse trailing cold front from extreme eastern MT, eastward along the SD/ND border. Ample heating has mixed the boundary layer, with observed upper 70s/low 80s F temperatures amid low 60s F dewpoints, overspread by 8.5+ C/km boundary-layer lapse rates (20Z mesoanalysis). Given the dry boundary layer, RAP forecast soundings depict the 1000 J/kg MLCAPE (currently in place) distributed in tall/skinny profiles, though unidirectional speed shear is in place. As such, a few multicells or transient supercells may become sustained and support an instance or two of severe hail/wind. Since the severe threat should be sparse, a WW issuance is not expected. ..Squitieri/Guyer.. 08/09/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...ABR...BIS...UNR...BYZ...GGW... LAT...LON 47890494 47620358 46419934 46079728 45589689 45069696 44809822 44880039 45290175 46080364 46640481 47450509 47890494 Read more

MD 1920 CONCERNING SEVERE THUNDERSTORM WATCH 617... FOR PORTIONS OF NORTHERN ALABAMA...SOUTHERN TENNESSEE...NORTHWEST GEORGIA
Mesoscale Discussion 1920 NWS Storm Prediction Center Norman OK 0342 PM CDT Wed Aug 09 2023 Areas affected...Portions of northern Alabama...southern Tennessee... northwest Georgia Concerning...Severe Thunderstorm Watch 617... Valid 092042Z - 092245Z The severe weather threat for Severe Thunderstorm Watch 617 continues. SUMMARY...The primary hazard within WW 617 will remain damaging wind gusts with an organized linear segment along the AL/TN border. A new severe thunderstorm watch may be needed downstream as the airmass destabilizes further. A tornado threat may also be developing along the outflow from this cluster from northeast Mississippi into northern Alabama. DISCUSSION...An organized cluster/linear segment of storms continues east along the Alabama/Tennessee border. With temperatures warming into the mid/upper 80s F in parts of southeastern Tennessee and northwest Georgia, this activity may be able to persist and pose a threat for wind damage into these areas. A downstream severe thunderstorm watch may be needed later this afternoon into parts of southeast Tennessee and northwest Georgia. Along the outflow to the southwest, one storm has initiated in northeast Mississippi with other deepening cumulus in the vicinity. These storms will likely be more discrete and pose a threat for a tornado or two as well as large hail and damaging winds. Convective trends will need to be monitored with this activity to determine if a more substantive tornado threat will develop in the next few hours. ..Wendt.. 08/09/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MRX...FFC...OHX...BMX...HUN...MEG... LAT...LON 34188860 34928766 35218742 35698727 35418465 35168400 34328389 33728433 33688649 33998834 34188860 Read more