Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Sat Sep 03 2022 Valid 031630Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE DESERT SOUTHWEST...SOUTHERN GREAT PLAINS...AND THE MID-SOUTH... ...SUMMARY... Isolated severe thunderstorms are possible across a portion of the Desert Southwest, the southern Great Plains, and the Mid-Mississippi and Lower Ohio River Valleys, mainly during the late afternoon and early evening. ...Interior Southern CA to northwest AZ... Isolated thunderstorm development is anticipated over interior southern CA and northwest AZ along the northern edge of a deep moisture plume. Although the stronger midlevel flow will reside farther south near the international border, slightly stronger mid-level easterly flow averaging 25 kts and steep low-level lapse rates will result in an environment conducive for isolated strong/severe wind gusts. ...Northern/west-central OK to far southern KS... Increasing frontal convergence and minimal CINH will contribute to isolated thunderstorm development by early evening along a slow-moving surface front. RAP/NAM forecast soundings depict a deep/well-mixed atmosphere and 1000-1500 J/kg MLCAPE by late afternoon. Within this environment, an isolated stronger storm will be capable of producing strong/potentially severe gusts. ...Mid-MS/Lower OH River Valleys... An increase in thunderstorm coverage is expected this afternoon/early evening east of a weak midlevel trough. Despite poor lapse rates, a very moist environment and modestly enhanced mid-level flow (20-25 kts) may yield a few storms capable of wet microbursts, especially where breaks in cloud cover result in locally greater buoyancy. Storms should diminish in intensity as the evening progresses. ..Bunting/Gleason.. 09/03/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1100 AM CDT Sat Sep 03 2022 Valid 031700Z - 041200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EXTREME NORTHEAST CALIFORNIA INTO SOUTHEAST OREGON...FAR NORTHWESTERN NEVADA AND FAR SOUTHWESTERN IDAHO... The previous forecast remains on track, with only minor changes made to the ongoing highlights to reflect the latest guidance consensus. Please see the previous outlook below for more details. ..Squitieri.. 09/03/2022 .PREV DISCUSSION... /ISSUED 1257 AM CDT Sat Sep 03 2022/ ...Synopsis... A progressive shortwave trough, evident in water-vapor imagery moving into northern California, will usher in strong winds to the northern Great Basin this afternoon. This will regionally bolster the fire weather potential after several days of hot/dry weather. Fire weather concerns are also expected to the east across the northern High Plains as gradient winds increase through the day over a region with dry fuels. ...Northern Great Basin... The jet axis associated with the northern CA shortwave trough is expected to shift across the northern Sierra Nevada into central ID through peak heating. The phasing of increasing 800-700 mb winds with deep boundary-layer mixing will support 15-25 mph winds at the surface with frequent gusts between 30-40 mph. Poor overnight RH recovery is noted across the northern Great Basin early this morning, and afternoon highs near 100 F are expected again this afternoon. Consequently, diurnal RH minimums near 5-15% are likely and will support widespread elevated to critical fire weather conditions. Fire activity across the region, supported by recent fuel analyses, lend further credence to the fire weather threat. ...Northern High Plains... Troughing in the lee of the northern Rockies will support increasing southeasterly gradient winds across eastern MT and the western Dakotas. Sustained winds near 15 mph, with occasional gusts to 20-25 mph, are likely. Combined with RH reductions into the low/mid teens, elevated fire weather conditions appear probable across a large swath of the northern High Plains. ...Dry Thunderstorms... Advected PWAT satellite imagery shows a plume of 700-500 mb moisture quickly advancing northward ahead of the northern CA shortwave trough. Strong ascent ahead of the wave will help steepen lapse rates and aid in ascent across WA into far western MT by this afternoon and evening. Forecast soundings hint that adequate buoyancy for convection atop a dry boundary-layer will limit precipitation accumulations and favor isolated dry thunderstorms. Given receptive fuel status across most of the region, a dry-lightning fire weather concern remains likely for today. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Fri Sep 2 17:48:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Sep 2 17:48:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1220 PM CDT Fri Sep 02 2022 Valid 031200Z - 041200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHWEST AND WEST-CENTRAL ARIZONA INTO FAR SOUTHERN NEVADA AND SOUTHEASTERN CALIFORNIA... ...SUMMARY... Strong thunderstorms are possible across the higher terrain of western Arizona by late Saturday afternoon, and may spread into parts of the lower Colorado Valley and Mojave Desert Saturday evening. ...AZ into southeast CA and far southern NV... Easterly midlevel flow will persist on Saturday across AZ and adjacent portions of southeast CA and southern NV, to the south of a stout upper ridge over the Great Basin. Some drying is expected across southern AZ (compared to D1/Friday), but low-level moisture may remain sufficient for weak to moderate destabilization from the higher terrain of west-central AZ into parts of the Colorado River Valley and Mojave Desert. Storm coverage remains uncertain during the afternoon/evening, but isolated development will be possible near the western part of the Mogollon Rim. Initial discrete development will pose a threat for strong wind gusts and perhaps isolated hail, with any upscale-growing clusters capable of strong/locally severe gusts into the evening as they spread west-southwestward within the easterly midlevel flow regime. ...Southern Plains... A cold front is forecast to move into parts of the southern Plains on Saturday, though it may tend to weaken and become increasingly ill-defined with time. While large-scale ascent appears nebulous across the region, isolated thunderstorm development will be possible near the front during the afternoon. Moderate instability and modest northerly deep-layer shear could support some organized convection, though uncertainty remains high regarding storm coverage and the primary corridor of any severe threat, so probabilities have not been introduced at this time. ...Parts of the OH/TN Valleys... Widespread convection will be possible across parts of the OH/TN Valleys on Saturday, east of a nearly stationary midlevel trough over the eastern Ozarks region. Isolated downbursts cannot be ruled out during the afternoon, but midlevel lapse rates and deep-layer shear currently appear too weak to support a more organized severe-thunderstorm threat within this regime. ..Dean.. 09/02/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Fri Sep 02 2022 Valid 021700Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE SOUTHERN CASCADES INTO THE NORTHERN SIERRA... The primary change made to this outlook was to expand Critical highlights further west into south-central Oregon, where the latest guidance consensus has trended more favorably in terms of Critical surface winds/RH overlapping for several hours late this afternoon. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 09/02/2022 .PREV DISCUSSION... /ISSUED 1254 AM CDT Fri Sep 02 2022/ ...Synopsis... Great Basin ridging is forecast to remain in place over the next several days, but will deamplify slightly as a shortwave trough impinges on its western periphery late tonight. Ahead of the approaching trough, strengthening flow over the northern Sierra will bolster low-level winds across the northern Great Basin and portions of the Northwest. At the same time, a weak cold front will move into the Plains supporting dry and breezy post-frontal conditions. Elevated to critical fire weather conditions are possible across the Great Basin and central Plains. ...Northern Great Basin to the southern Cascades... Ahead of the trough moving onshore across the West Coast, mid-level flow is forecast to increase late in the day across portions of northern CA/NV, into southern OR. Dry downslope flow from the Sierra, and warm diurnal temperatures will result in afternoon RH values of 10-15%. As flow aloft strengthens, occasional gusts of 15-25 mph should develop within the warm and dry airmass. With area fuels critically dry, spotty critical fire weather conditions appear probable into the evening hours. Farther north, enhanced westerly flow through terrain gaps in the lee of the Cascades may occasionally gust to 15-20 mph through the afternoon. With very warm temperatures expected RH values are forecast to fall to near 30%. Dry and unstable condition may support a few hours of locally elevated fire weather concerns mainly across portions of interior WA where fuels are very dry. ...Central Plains... In the wake of a cold front moving south out of the northern Plains, gusty northwest winds are expected within a modestly dry post-frontal airmass across portions of western NE and northern CO. While RH will be marginally supportive (25-30%) the gusty winds and locally dry fuels should support a few hours of elevated fire weather risk through the afternoon. Fire concerns will decrease quickly this evening and overnight as better humidity recoveries develop within the cooler air behind the front. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Fri Sep 02 2022 Valid 021630Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF ARIZONA/LOWER COLORADO RIVER VALLEY... ...SUMMARY... Isolated severe thunderstorms are possible late this afternoon and evening over parts of central/southern Arizona and the Lower Colorado River Valley, and from the central Great Plains to the Upper Great Lakes. ...Arizona/Lower Colorado Valley... Visible satellite shows relatively cloud-free skies, which will be conducive for ample insolation/heating coincident with a relatively moist air mass, with prevalent 60s F surface dewpoints in the lower elevations of southern Arizona and middle 50s F dewpoints along the Mogollon Rim as of late morning. An increase in storm coverage as compared to yesterday seems probable. Easterly mid-level/steering winds are and will remain notably strong as the upper high builds to the north over the Great Basin/central Rockies. Upwards of 25-30 kt mid-level winds are plausible across the southern half of Arizona, which would be conducive for storm organization/upscale growth and propagation onto the lower elevations/desert floor and Lower Colorado River Valley. Initial discrete development over the higher terrain/near the Rim will pose a risk for localized severe wind gusts and marginally severe hail. However, a more organized/substantial wind threat may emerge with upscale-growing/MCS development by evening. ...Central Plains to Upper Great Lakes... The primary shortwave trough over northeast Manitoba will shift east across southern Hudson Bay/far northern Ontario, with the trailing part of this trough moving across the Upper Great Lakes. A weak mid-level trough will meander east across the Ozarks. In between these features, deep-layer shear will be enhanced across the central Great Plains owing to 25-35 kt mid-level north-northwesterly winds. Weaker deep-layer shear is anticipated with northeast extent along a cold front pushing southeastward across the Upper Midwest. A greater potential for scattered thunderstorms along the front should exist in the southeast Minnesota/northern Wisconsin/Upper Michigan vicinity given more pronounced low-level convergence and trailing influence of the Ontario trough. Multicell clusters mainly producing isolated damaging winds and perhaps marginally severe hail will be the primary threats. A more isolated thunderstorm coverage is anticipated into southeast Nebraska and northern Kansas, but given the greater vertical shear and nearly perpendicular orientation of mid-level flow with respect to the front, a few transient supercells embedded within a cluster or two may develop. Isolated severe wind and hail will be possible, with increasing MLCIN after dusk being detrimental for sustaining severe potential later into the evening. ..Guyer/Bentley.. 09/02/2022 Read more

No watches are valid as of Thu Sep 1 17:49:01 UTC 2022.

No Mesoscale Discussions are in effect as of Thu Sep 1 17:49:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 PM CDT Thu Sep 01 2022 Valid 021200Z - 031200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE UPPER MIDWEST/GREAT LAKES INTO THE CENTRAL PLAINS...AND ACROSS PARTS OF CENTRAL/SOUTHERN ARIZONA... ...SUMMARY... Isolated strong to severe thunderstorms are possible Friday afternoon and evening from portions of the central Plains to the Upper Midwest, and also across central and southern Arizona. Strong wind gusts and isolated hail will be the main hazards with these storms. ...Upper Midwest into the central Great Plains... A mid/upper-level trough is forecast to move eastward across Ontario and Quebec on Friday, with the trailing part of this trough moving across the upper Great Lakes region. A weaker midlevel trough will persist to the southwest across the mid-MS Valley into the southern Plains. A cold front will move across the upper Midwest and the northern/central Plains. Moderate to locally strong buoyancy is forecast to develop along and ahead of the front by Friday afternoon. A tendency for the strongest large-scale ascent to stay north of the international border renders timing/coverage of storm initiation uncertain, but isolated development appears possible from the upper Great Lakes into the central Plains by late afternoon/early evening. Effective shear of 25-35 kt will support multicell clusters and perhaps a supercell or two, with an attendant risk of large hail and damaging wind gusts. Northerly midlevel flow may support one or more southward-moving clusters across the Plains during the mid/late evening, though the southwestward extent of any severe threat remains uncertain at this time. ...Arizona... An increase in low-level moisture is expected across parts of Arizona on Friday, which will aid in moderate diurnal destabilization from the Mogollon Rim into the lower deserts, and a likely increase in storm coverage (compared to previous days) from late afternoon into the evening. Initial semi-discrete development across the higher terrain may pose a threat of isolated strong wind gusts and hail. Modestly enhanced midlevel easterly flow along the southern periphery of an upper ridge will support the potential for outflow-driven clusters to spread into the lower deserts, posing a threat of isolated severe gusts Friday evening. ..Dean.. 09/01/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1054 AM CDT Thu Sep 01 2022 Valid 011630Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms are not forecast across the contiguous United States through tonight. ...Synopsis... Tropical moisture, with boundary-layer dewpoints in the low-mid 70s and PW values greater than 2 inches, will persist across the Southeast. Primarily diurnal convection will be focused across south GA/north FL by a weak midlevel low and local sea breeze/differential heating zones. Farther west into the southern Plains, similar moisture exists with embedded/weak midlevel troughs over southwest OK and northern Mexico. The southwest OK wave will move slowly east-northeastward through tonight, in response to an upstream trough digging south-southeastward over KS. Embedded thunderstorms are expected across central OK with the ejecting wave, but lightning may be more prevalent around the northern-eastern-southern periphery of the midlevel trough, with diurnal convection in the zones of differential heating on the edge of the thicker clouds. Otherwise, a larger-scale midlevel trough will move east-southeastward over AB/SK/MB, as a smaller-scale lead wave ejects generally eastward over MT today. Low-level moisture will be limited across the northern Plains, with only a small chance for thunderstorms with the ejecting shortwave trough and a cold front this evening into tonight. ..Thompson/Guyer.. 09/01/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1044 AM CDT Thu Sep 01 2022 Valid 011700Z - 021200Z The previous forecast remains on track, with only minor changes made to the ongoing highlights to account for the latest guidance consensus. Please see the previous forecast below for more details. ..Squitieri.. 09/01/2022 .PREV DISCUSSION... /ISSUED 1256 AM CDT Thu Sep 01 2022/ ...Synopsis... Fire weather concerns are expected across the northern Rockies and northern High Plains this afternoon as an upper wave translates across the region. A pair of upper troughs, noted over the northern Rockies and northwestern Canadian Prairies in morning water-vapor imagery, are expected to phase as they crest a Great Basin upper ridge. This phasing will enhance mid-level flow and shift a Canadian surface low into the Plains through the day. The passage of an associated cold front across the northern Plains, coupled with strengthening flow, will support breezy conditions over a region with receptive fuels and antecedent dry conditions. ...Montana... Latest guidance has delayed the passage of the Canadian cold front across northern/central MT until later in the afternoon/evening compared to previous model runs. While strong surface winds may be less expansive than anticipated, a deepening lee trough and strengthening zonal flow off the Rockies will foster breezy downslope winds. Temperatures in the 90s and RH minimums in the teens to 20s remain likely and will maintain the potential for elevated fire weather conditions. A wind shift to the north/northwest associated with the frontal passage is still expected later today, but may occur just after peak daytime heating during the 00-03 UTC time frame. ...Snake River Plain and Wyoming... 00 UTC soundings from BOI and RIW sampled very dry boundary-layer conditions across ID and WY. Recent surface observations show overnight RH values are struggling to recover out of the 20-30% range. Such conditions are conducive for another day of deep boundary-layer mixing, which will aid in downward transfer of the strengthening mid-level flow over the region this afternoon. Sustained winds between 15-20 mph with gusts between 20-30 mph appear likely. Confidence remains high in elevated, to briefly critical, conditions through the Snake River Plain. To the east across WY, fire weather concerns are possible across much of the state, but may manifest as numerous pockets of somewhat transient elevated conditions. An Elevated risk area has been introduced for portions of WY that are most likely to see sustained and sufficiently widespread elevated conditions - namely in the lee of prominent ranges. Further refinement of this risk area is possible as guidance comes into better agreement over the next 12 hours. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Wed Aug 31 17:56:02 UTC 2022.

MD 1753 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR MUCH OF CENTRAL NEBRASKA
Mesoscale Discussion 1753 NWS Storm Prediction Center Norman OK 1254 PM CDT Wed Aug 31 2022 Areas affected...much of central Nebraska Concerning...Severe potential...Watch unlikely Valid 311754Z - 312030Z Probability of Watch Issuance...20 percent SUMMARY...A few severe gusts are possible with the stronger storms. The severe threat is expected to remain relatively isolated through the afternoon. DISCUSSION...MRMS mosaic radar imagery depicts an increase in convective coverage and intensity across northwest NE as a small mid-level impulse grazes the central Plains. Ahead of the storms, strong diurnal heating is contributing to surface temperatures exceeding 90 F, with a dry boundary layer growing to 600 mb and low-level lapse rates steepening past 9 C/km. As such, continued intensification of the ongoing storms amid the warm/dry low-level environment should promote enough evaporative cooling to support strong wind gusts, and a few gusts exceeding 50 kts are possible. Nonetheless, shear and upper support are expected to remain weak, so storm organization should remain fairly limited, with any severe gusts being isolated. ..Squitieri/Guyer.. 08/31/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...OAX...GID...LBF... LAT...LON 41170157 41940101 42210045 42549950 42609838 42359706 41709713 41249770 40849831 40549890 40449935 40480062 40500127 41170157 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1217 PM CDT Wed Aug 31 2022 Valid 011200Z - 021200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The severe-thunderstorm threat is expected to be relatively low on Thursday. ...Synopsis... An upper ridge will persist over the West on Thursday, while an upper trough may amplify slightly from the central/southern Great Plains into the upper Great Lakes region. A seasonably deep upper trough initially over New England will move northeastward away from the region through the day. In general, generally weak deep-layer flow/shear will tend to limit the threat of organized convection through the period. Northerly midlevel flow across parts of the central/southern High Plains may support sufficient deep-layer shear for some modest storm organization, but uncertainty remains high regarding the extent of destabilization and coverage of storms in this area. Elsewhere, high-based convection could produce locally gusty winds across parts of the northern Plains and also across Arizona. Scattered to numerous thunderstorms will be possible across parts of central/north TX into southern OK, and also across parts of the Southeast, but these storms are expected to remain relatively disorganized. ..Dean.. 08/31/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Wed Aug 31 2022 Valid 311630Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL PLAINS...NORTHERN NEW YORK...AND MAINE... ...SUMMARY... Isolated strong to severe thunderstorms may occur over parts of the central Plains this afternoon and evening. Isolated hail and locally damaging wind gusts are also possible over parts of Maine and northern New York. ...Maine... In the wake of abating early day precipitation and cloud cover, isolated thunderstorms may redevelop this afternoon across west/central Maine within a narrow zone of modest destabilization near the eastward-moving front. While overall buoyancy will be modest, sufficient heating/boundary layer mixing in conjunction with moderately strong low/mid-level westerlies could yield some stronger wind gusts related to thunderstorms. ...Northern New York... While boundary-layer mixing will continue to occur within the warming post-frontal environment, sufficient residual low-level moisture (50s F surface dewpoints) in the presence of relatively cool mid-level temperatures (around -16C at 500 mb) will support modest destabilization and minimal inhibition by mid-afternoon. Some stronger low-topped storms may develop over the region and/or spread east-southeastward out of Ontario. While not overly hot, sufficient boundary-layer mixing and semi-strong westerlies could yield some strong/locally severe storms with wind gusts, until around sunset. ...Central Plains... To the east of ongoing early day storms, additional thunderstorm development through late this afternoon/early evening is expected across Nebraska and northeast Colorado/northwest Kansas. This should semi-focus along a weak surface low and southwest/northeast-oriented boundary. Hot temperatures and deeply mixed boundary layers will be supportive of some stronger downdrafts amid modest-strength wind profiles. Strong to severe wind gusts will be possible with the multicells/clusters of storms that develop and spread southeastward late this afternoon and evening. ..Guyer/Squitieri.. 08/31/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1046 AM CDT Wed Aug 31 2022 Valid 311700Z - 011200Z No changes to the ongoing forecast. ..Wendt.. 08/31/2022 .PREV DISCUSSION... /ISSUED 0103 AM CDT Wed Aug 31 2022/ ...Synopsis... Fire weather concerns will remain confined to the northern Great Basin and Pacific Northwest for today as winds increase in response to a weak upper disturbance moving into the region. Early-morning water-vapor imagery depicts a low-amplitude upper wave approaching the northern CA coast. This feature will continue to move northeast through the day, and will foster increasing mid-level flow and thunderstorm chances over the region. ...Northern Great Basin and Columbia Gorge... Elevated fire weather conditions are expected from northeast CA/northwest NV into southern OR and through the Columbia Gorge. 00 UTC soundings along the West Coast sampled increasing mid/upper-level winds associated with the approaching upper wave. Such winds will overspread the northern Great Basin and Pacific Northwest through the day and support sustained surface winds between 15-20 mph. Deep boundary-layer mixing will foster frequent gusts between 25-35 mph, especially near terrain features. The driest conditions are expected across northeast CA/northwest NV into southern OR with afternoon RH minimums in the teens likely. To the north through the Columbia Gorge, better overnight RH recovery is noted, and some moisture advection through the Gorge will moderate RH reductions to some degree. However, minimum RH values in the low to mid 20s appear probable based on latest ensemble guidance, and should support elevated fire weather conditions. ...Dry thunderstorms... The 00 UTC BOI sounding sampled modest mid-level moisture, which is noted in water-vapor imagery advecting northward ahead of the approaching wave. This moisture should support 150-300 J/KG MUCAPE by late afternoon across northern WA into northern ID/northwest MT. Forecast soundings depict a deep, dry boundary layer over this region with PWAT values near 0.7 inch, which favors dry thunderstorms. Given the dry fuel status across the area (ERCs generally above the 90th percentile), a dry-lightning threat appears likely with any thunderstorm. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Tue Aug 30 17:57:01 UTC 2022.

MD 1751 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR VA..MD
Mesoscale Discussion 1751 NWS Storm Prediction Center Norman OK 1255 PM CDT Tue Aug 30 2022 Areas affected...VA..MD Concerning...Severe potential...Watch unlikely Valid 301755Z - 302000Z Probability of Watch Issuance...5 percent SUMMARY...Isolated damaging wind gusts are possible this afternoon. DISCUSSION...Surface observations reveal temperatures have climbed into the low 90s amid low 70s dewpoints across much of MD and VA. This heating has helped erode convective inhibition across the region ahead of the approaching shortwave trough and attendant surface trough. Thunderstorms have developed along the leading edge of the large-scale forcing for ascent (as evidenced by the relatively sharp gradient in cloud cover). Given the downstream destabilization, the ongoing storms are expected to persist eastward into more of VA and MD. Even so, relatively warm thermodynamic profiles will temper instability, likely keeping storms near their current intensity. Primary risk with any of these storms is expected to be damaging wind gusts associated with water-loaded downbursts. ..Mosier/Thompson.. 08/30/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RNK... LAT...LON 37308053 39537840 39567631 38847597 37907669 36687858 36628063 37308053 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1228 PM CDT Tue Aug 30 2022 Valid 311200Z - 011200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe wind gusts may occur with thunderstorms across parts of the central Plains Wednesday afternoon and evening. ...Central Plains... On the east side of a prominent upper ridge over the western CONUS, a weak mid-level perturbation should move southeastward across parts of the central Plains on Wednesday. Modest low-level moisture is forecast to return northward through the day across the central High Plains on the western periphery of a surface high centered over eastern KS and MO. Scattered thunderstorms should develop from northeastern CO into NE Wednesday afternoon along and south of a weak boundary. Strong daytime heating will act to deeply mix the boundary layer across these regions, with forecast soundings showing inverted-v type soundings. Even though instability should remain fairly weak, with MLCAPE generally 500-1000 J/kg, substantial DCAPE should promote a risk for isolated strong to severe wind gusts with convective downdrafts as thunderstorms spread southeastward through the early evening. Around 20-30 kt of deep-layer shear should also foster some convective organization, with loosely organized clusters possible. ...Western New York... An amplified upper trough will continue eastward over the Northeast and eastern Canada on Wednesday. A mid-level shortwave embedded within this upper trough should overspread Ontario, southern Quebec, and NY through the day. Enhanced mid-level winds will accompany this feature, with strong deep-layer shear also present. Most guidance shows a band of thunderstorms developing and spreading quickly eastward across parts of western/northern NY Wednesday afternoon. Some risk for strong/gusty winds may accompany this convection, but instability is forecast to remain rather weak. Given the potential thermodynamic limitations, have opted to not include low severe wind probabilities at this time. But, trends will be monitored. ..Gleason.. 08/30/2022 Read more