Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1121 AM CDT Mon Aug 01 2022 Valid 011630Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OH VALLEY AND MID-MO VALLEY... ...SUMMARY... Scattered severe thunderstorms, mainly in the form of damaging gusts and a tornado or two, will be possible, centered on this evening into early tonight across the Ohio Valley. A swath of mainly severe wind gusts and some hail is also possible across parts of northern Nebraska to western Iowa this evening. ...OH Valley... Decayed remnants of an early morning MCS have spread into southwest OH and northern KY. Subsidence in its wake and the southern progression of outflow render uncertainty on when/where redevelopment will occur later today. Large buoyancy will develop from the Mid-MO to Lower OH Valleys amid an elevated mixed layer extending southeast from the north-central Great Plains with peak MLCAPE approaching 4000 J/kg centered on southern IL. Weak low-level warm advection atop the residual convective outflow/baroclinic zone will likely be the primary driver for redevelopment. This will become more likely into the early to mid-evening, especially with eastern extent where mid-level lapse rates are weaker. Adequate low-level veering of the wind profile with height but backing of mid to upper flow should support predominantly cluster with embedded supercell modes. Damaging winds and marginally severe hail will be the main threats, though a tornado or two could occur with embedded supercells based on rich low-level moisture (70-74 F boundary-layer dew points) and hodograph curvature (effective SRH near 200 m2/s2). Overnight, severe potential should wane as convective outflows spread southeast away from the instability axis. ...North-central/northeast NE to the Mid-MS Valley... At least isolated thunderstorm development is expected near the intersection of the dryline, lee trough, and western flank of the Mid-MO Valley buoyancy plume. Steep low to mid-level lapse rates and boundary-layer dew points in the 60s will yield a pronounced gradient in MLCAPE, nearing 3000 J/kg over the Mid-MO Valley. Weak southerly low-level flow beneath northwesterlies that strengthen with height from the mid to upper levels will support a couple supercells initially developing with a threat for isolated large hail and severe wind gusts. With time this evening, a small cluster may spread east across the MO River into IA as warm advection intensifies. Guidance is quite varied in how this evolution will take place, likely owing to the modest large-scale ascent, robust MLCIN south of the baroclinic zone, and tight MLCAPE gradient to the north. It is plausible that a corridor of severe wind gust and hail potential may be maintained into the overnight to the east of the Mid-MS Valley. ..Grams/Lyons.. 08/01/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1036 AM CDT Mon Aug 01 2022 Valid 011700Z - 021200Z Expanded the IsoDryT slightly farther west to cover areas near the Mckinney and China2 fires where some thunderstorms are possible. These thunderstorms are expected along the moisture gradient and have the potential to be both wet and dry. Given the presence of large fire in the area, decided it would be best to expand the IsoDryT area slightly to cover this region. Also expanded the critical delineation across southeast Montana, northeast Wyoming, and far northwest South Dakota. Some of the strongest winds may actually occur in this region given the presence of a low-level jet and a passing mid-level jet maximum. ..Bentley.. 08/01/2022 .PREV DISCUSSION... /ISSUED 0200 AM CDT Mon Aug 01 2022/ ...Synopsis... A large-scale ridge will remain centered over the western CONUS, while a belt of enhanced west-northwesterly midlevel flow extends from the Pacific Northwest into the northern/central Plains along the northern periphery of the ridge. Within the west-northwesterly flow, an embedded shortwave trough and accompanying strong flow aloft will cross the northern Rockies, while a surface low deepens over eastern MT. ...Northern Rockies into the adjacent High Plains... As the belt of enhanced west-northwesterly flow overspreads the Rockies and adjacent High Plains, downslope warming/drying and deep boundary-layer mixing will result in a broad area of elevated fire-weather conditions. Along the periphery of the deepening surface low, a corridor of stronger sustained west-northwesterly surface winds near 20 mph will overlap 10-15 percent minimum RH across portions of central into eastern MT -- where critical fire-weather conditions are forecast. ...Lee of the Cascades in WA and northern OR... The enhanced west-northwesterly downslope flow will support elevated to locally critical conditions in the lee of the northern Cascades, where 15-20 mph westerly surface winds will overlap 10-15 percent RH. ...Dry Thunderstorms... Along the northern periphery of the ridge, a series of subtle midlevel impulses coupled with sufficient midlevel moisture/instability will favor high-based thunderstorms from the Cascades eastward into the northern Rockies. While many of these storms will be a hybrid wet/dry mode, any lightning strikes away from precipitation cores could lead to new fire starts owing to highly receptive fuels over the area. ...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 1245 PM CDT Sun Jul 31 2022 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO VALLEY... ...SUMMARY... At least isolated severe storms are expected mainly across parts of the Midwest and Ohio Valley Monday afternoon and evening. ...Midwest/Ohio Valley including Indiana/Ohio/Kentucky... Have introduced a categorical Slight Risk for parts of the region, including portions of Indiana/Ohio/Kentucky. Moderate to strong destabilization is expected into Monday afternoon especially across the lower/middle Ohio River Valley, northward across eastern Indiana and western/central Ohio. This will be near/ahead of a southeastward-advancing front, and to the south-southwest of possible residual overnight convection and cloud cover that may be located over Michigan/northern Indiana vicinity Monday morning. An amplifying belt of moderately strong westerlies (30-50 kt at 500 mb) will influence forcing for ascent and probable storm development/longevity Monday afternoon and evening. This could potentially include some supercells aside from more prevalent multicells and southeastward-moving bands/linear segments. Wind damage will be the primary risk overall. ...Central Plains/Lower Missouri Valley... An initially southward-settling front will decelerate/stall and begin to return northward late Monday afternoon and Monday night. Moderately strong northwesterly winds will overlie the front. The potential for deep convective development should remain limited south of the front owing to strong capping, however isolated storm development may occur late Monday afternoon and night near/north of the boundary, particularly across portions of Nebraska where a near-boundary zone of moderate to strong destabilization should be maximized across much of central Nebraska to southeast Nebraska. Where storms do form, a few supercells could occur, along with the potential for storm organization and upscale growth near/northeast of the boundary. Large hail and damaging winds may occur, with damaging winds a viable possibility on the cool side of the front owing to the steep lapse rate environment/dry air above the more stable boundary layer. Portions of central and possibly east-central/northeast Nebraska could ultimately warrant an upgrade to a Slight Risk pending higher confidence in convective initiation/deep convective development within an otherwise severe-favorable environment. ...North Dakota... The main thunderstorm potential should be relegated to the morning and/or activity potentially crossing the international border later in the day near/north-northeast of a front across the region. A few strong to severe storms could occur given the strong wind profiles and moderate surface-based buoyancy near the front and elevated buoyancy to its east-northeast. ..Guyer.. 07/31/2022 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1245 PM CDT Sun Jul 31 2022 Valid 011200Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OHIO VALLEY... ...SUMMARY... At least isolated severe storms are expected mainly across parts of the Midwest and Ohio Valley Monday afternoon and evening. ...Midwest/Ohio Valley including Indiana/Ohio/Kentucky... Have introduced a categorical Slight Risk for parts of the region, including portions of Indiana/Ohio/Kentucky. Moderate to strong destabilization is expected into Monday afternoon especially across the lower/middle Ohio River Valley, northward across eastern Indiana and western/central Ohio. This will be near/ahead of a southeastward-advancing front, and to the south-southwest of possible residual overnight convection and cloud cover that may be located over Michigan/northern Indiana vicinity Monday morning. An amplifying belt of moderately strong westerlies (30-50 kt at 500 mb) will influence forcing for ascent and probable storm development/longevity Monday afternoon and evening. This could potentially include some supercells aside from more prevalent multicells and southeastward-moving bands/linear segments. Wind damage will be the primary risk overall. ...Central Plains/Lower Missouri Valley... An initially southward-settling front will decelerate/stall and begin to return northward late Monday afternoon and Monday night. Moderately strong northwesterly winds will overlie the front. The potential for deep convective development should remain limited south of the front owing to strong capping, however isolated storm development may occur late Monday afternoon and night near/north of the boundary, particularly across portions of Nebraska where a near-boundary zone of moderate to strong destabilization should be maximized across much of central Nebraska to southeast Nebraska. Where storms do form, a few supercells could occur, along with the potential for storm organization and upscale growth near/northeast of the boundary. Large hail and damaging winds may occur, with damaging winds a viable possibility on the cool side of the front owing to the steep lapse rate environment/dry air above the more stable boundary layer. Portions of central and possibly east-central/northeast Nebraska could ultimately warrant an upgrade to a Slight Risk pending higher confidence in convective initiation/deep convective development within an otherwise severe-favorable environment. ...North Dakota... The main thunderstorm potential should be relegated to the morning and/or activity potentially crossing the international border later in the day near/north-northeast of a front across the region. A few strong to severe storms could occur given the strong wind profiles and moderate surface-based buoyancy near the front and elevated buoyancy to its east-northeast. ..Guyer.. 07/31/2022 Read more

No watches are valid as of Sun Jul 31 17:50:02 UTC 2022.

MD 1619 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR CENTRAL/EAST NC...FAR SOUTH-CENTRAL/SOUTHEAST VA
Mesoscale Discussion 1619 NWS Storm Prediction Center Norman OK 1138 AM CDT Sun Jul 31 2022 Areas affected...Central/East NC...Far South-Central/Southeast VA Concerning...Severe potential...Watch unlikely Valid 311638Z - 311915Z Probability of Watch Issuance...20 percent SUMMARY...Multicell thunderstorms capable of damaging wind gusts will persist across the region through the afternoon. Additionally, a supercell or two is possible later this afternoon, with an attendant risk of damaging wind gust and/or a brief tornado. DISCUSSION...The air mass across north-central/northeast NC and adjacent portions of far south-central/southeast VA has quickly destabilized amid filtered diurnal heating and ample low-level moisture. Thunderstorm coverage is expected to gradually increase over the next few hours, as modest low-level convergence persists near and south of the wavy warm front extending from south-central VA into far northeast NC. Much of this thunderstorm activity will occur south of the stronger mid-level flow, limiting the deep-layer vertical shear and likely leading to a predominantly multicellular, outflow-dominant storm mode. Primary severe risk with any of these storms is water-loaded downbursts. Later this afternoon, ascent may be augmented slightly by the shortwave trough moving through the Upper OH Valley. This shortwave will also contribute to a modest increase in the mid-level flow. While still favorable mostly multicells, these condition could also support a supercell or two. Primary risk would continue to be damaging wind gust, although a brief tornado or two could also occur. ..Mosier/Grams.. 07/31/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...AKQ...MHX...RAH...ILM...RNK... LAT...LON 34637776 35357923 35767997 36437998 36927923 36867767 36677674 36367582 35607564 34697624 34637776 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Sun Jul 31 2022 Valid 311700Z - 011200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN OREGON INTO EXTREME NORTHERN CALIFORNIA... Only minor modifications were made to the ongoing IsoDryT delineation, primarily to trim the western edge where fuels are not as favorable. ..Bentley.. 07/31/2022 .PREV DISCUSSION... /ISSUED 0222 AM CDT Sun Jul 31 2022/ ...Synopsis... Upper ridging will remain in place across the western U.S. today while a mid-level trough ejects into the Plains states during the afternoon. Downslope flow along the higher terrain in western Montana and modest surface lee troughing across the northern Plains may support at least locally dry and windy conditions for a few hours. The bigger concern for wildfire-spread potential today exists across the Pacific Northwest. Modest deep-layer ascent with passing subtle mid-level impulses will work in tandem with afternoon peak heating to support the initiation of scattered high-based thunderstorms across portions of the Pacific Northwest, where fuels have recently become highly receptive to fire spread (based on the latest observations). The previous day's storms may have slightly dampened fuels locally. However, the relatively higher number of thunderstorm expected today, combined with the critically dry fuels (especially in lower-terrain areas) necessitates the addition of scattered dry thunderstorm highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1126 AM CDT Sun Jul 31 2022 Valid 311700Z - 011200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF SOUTHERN OREGON INTO EXTREME NORTHERN CALIFORNIA... Only minor modifications were made to the ongoing IsoDryT delineation, primarily to trim the western edge where fuels are not as favorable. ..Bentley.. 07/31/2022 .PREV DISCUSSION... /ISSUED 0222 AM CDT Sun Jul 31 2022/ ...Synopsis... Upper ridging will remain in place across the western U.S. today while a mid-level trough ejects into the Plains states during the afternoon. Downslope flow along the higher terrain in western Montana and modest surface lee troughing across the northern Plains may support at least locally dry and windy conditions for a few hours. The bigger concern for wildfire-spread potential today exists across the Pacific Northwest. Modest deep-layer ascent with passing subtle mid-level impulses will work in tandem with afternoon peak heating to support the initiation of scattered high-based thunderstorms across portions of the Pacific Northwest, where fuels have recently become highly receptive to fire spread (based on the latest observations). The previous day's storms may have slightly dampened fuels locally. However, the relatively higher number of thunderstorm expected today, combined with the critically dry fuels (especially in lower-terrain areas) necessitates the addition of scattered dry thunderstorm highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1116 AM CDT Sun Jul 31 2022 Valid 311630Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EAST-CENTRAL/SOUTHEAST MN INTO WEST-CENTRAL WI... ...SUMMARY... A tornado or two, scattered damaging winds, and isolated severe hail are most likely across a portion of the Upper Mississippi Valley between about 5 to 9 PM CDT. ...Synopsis... A low-amplitude shortwave trough centered on the MB/ND border area will progress east-southeast into the western Great Lakes region tonight. Associated surface cold front over the eastern Dakotas will similarly push east-southeast across the Upper MS Valley through this evening. ...Upper MS Valley... Low-level warm-advection-driven convection is ongoing across south-central MN to northwest IA, but decaying ahead of the cold front. Stronger surface heating and greater boundary-layer moisture in the wake of this activity will support a confined plume of moderate buoyancy with MLCAPE increasing to 1500-2000 J/kg by 21-00Z. Initial surface-based thunderstorm development is expected along the northern periphery of the buoyancy gradient in northwest to north-central MN. Convection will likely build south along the front through central to east-central MN during the early evening, with lower confidence in southern extent towards the IA border. Surface temperature-dew point spreads will be marginally large initially, but favorable low-level hodograph curvature/SRH will be sufficient for a threat of a tornado or two. Otherwise, around 30-35 kt effective bulk shear should yield a mixed cluster/embedded supercell mode, with the latter tending to be favored farther south where shear is slightly stronger and convection should be more semi-discrete. Damaging winds should be somewhat more favored in terms of coverage, but isolated severe hail is anticipated as well. Convection will likely diminish tonight as it spreads east of the confined surface-based buoyancy plume deeper into WI. ...NE/IA... A conditional supercell threat will exist across portions of northern to western IA along the surface cold front centered on early evening, in the wake of decaying elevated activity approaching the region. Isolated thunderstorms are more probable into the southwest NE area where MLCIN will be minimal at peak heating, along the western extent of the central Great Plains buoyancy plume. Weaker deep-layer shear should tend to favor a more marginal intensity threat this far west. ...NC/southern VA... A weak and wavy surface warm front has drifted north into far southwest VA and northeast NC, in advance of a low-amplitude shortwave impulse over the Upper OH Valley. The southern fringe of modestly stronger mid-level westerlies (represented by effective bulk shear near 30 kt) will overlie the baroclinic zone, where there will be some enhancement to low-level hodograph curvature (0-1 km SRH around 100 m2/s2). Despite poor mid-level lapse rates, a mix of multicell clusters and transient supercells are expected across the baroclinic zone through about dusk. A brief weak tornado and isolated damaging wind gusts in water-loaded downdrafts will be possible. ...Southern AZ... The next perturbation within the monsoonal moisture plume is aiding morning thunderstorms over a portion of northwest Sonora and will likely yield a period of mid-level drying across southeast AZ in its wake. The midlevel drying and reduction in clouds will aid surface heating, but also casts some doubt on how widespread convection will be across the higher terrain in southeast AZ this afternoon. 15-20 kt southeasterly mid-level steering flow will support potential for isolated cells and small clusters to spread across the lower deserts of south-central AZ through about dusk with isolated severe wind gusts possible. ...Lower CO Valley to OR... Very isolated severe wind gusts are possible in pulse microbursts, but overall coverage is anticipated to be less than 5 percent over such a large swath around the Great Basin mid-level anticyclone. ..Grams/Lyons.. 07/31/2022 Read more

No watches are valid as of Sat Jul 30 17:42:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sat Jul 30 17:42:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Sat Jul 30 2022 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MINNESOTA/WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms will be possible across parts of Minnesota and western Wisconsin Sunday afternoon and evening. Other more isolated severe storms could also occur across parts of the Carolinas and central Plains. ...Minnesota/western Wisconsin... Have introduced a categorical Slight Risk for parts of the region. A clipper-type shortwave trough will spread southeastward over the region amidst amplifying westerlies over the Dakotas/Upper Midwest through Sunday night. Scattered thunderstorm development seems probable near a southeastward-moving front across Minnesota Sunday afternoon. A favorable colocation of moderate buoyancy (2000+ J/kg MLCAPE) and effective shear (40 kt) is expected particularly across the southern half of Minnesota. This could support some initial supercells, with storms likely to subsequently merge and potentially grown upscale during the evening across southeast Minnesota toward western Wisconsin. Large hail and damaging winds should be the primary hazards. ...Nebraska/western Iowa... The region will be influenced by the southern periphery of the amplifying shortwave trough over the Dakotas/Upper Midwest. Heating/convergence near the southeastward-moving front (and pre-frontal trough) should be conducive for at least isolated thunderstorm development Sunday late afternoon/early evening, some of which could produce hail and/or severe-caliber wind gusts. ...Carolinas/southern Appalachians... The persistent/convectively reinforced front across the region may transition a bit northward into Sunday, with a moist airmass remaining near the boundary and to its south. Although the details of destabilization and preferred corridors of more appreciable thunderstorm development are a bit uncertain, it currently appears that destabilization will be regionally maximized across the Carolinas. This should coincide with a modestly enhanced belt of westerlies aloft. Some of the stronger updrafts/downdrafts could produce wet microbursts capable of localized wind damage Sunday afternoon through early evening. ...Southern Arizona/Lower Colorado River Valley... The southern CONUS upper ridge should build a bit westward toward the region on Sunday, with some potential for a further enhancement to east-southeasterly mid-level winds particularly across southern Arizona. Some questions exist regarding the lingering influence/cloud cover of thunderstorms from later today and tonight into Sunday. However, if confidence increases in boundary layer recovery/destabilization, microburst-related severe wind probabilities could be warranted in later outlooks. ..Guyer.. 07/30/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1138 AM CDT Sat Jul 30 2022 Valid 301700Z - 311200Z Expanded the IsoDryT delineation slightly farther north in Oregon and a bit farther south across northern California based on morning forecast soundings and CAM guidance. Otherwise, no changes were necessary. See previous discussion below. ..Bentley.. 07/30/2022 .PREV DISCUSSION... /ISSUED 0146 AM CDT Sat Jul 30 2022/ ...Synopsis... An upper ridge will persist across the western U.S. through the day today, with a mid-level impulse expected to pivot around the ridge over the northern Rockies. The mid-level impulse will support dry and breezy surface conditions across eastern Montana during the afternoon, where fuels are becoming receptive to wildfire spread, necessitating the addition of Elevated highlights. Meanwhile, upslope flow of a marginally unstable airmass along the southern Cascades may support isolated high-based thunderstorm development during the afternoon. Fuels continue to efficiently dry in this area, supporting lightning ignition potential and warranting the addition of isolated dry thunderstorm highlights. ...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 1100 AM CDT Sat Jul 30 2022 Valid 301630Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF NORTHEASTERN MONTANA AND THE DAKOTAS... ...SUMMARY... Isolated damaging gusts and large hail may occur this afternoon into tonight across northeastern Montana into central North/South Dakota. ...Northern Plains... A shortwave trough along the northern periphery of a western US mid-level anticyclone will move out of southern Canada across portions of northern MT and ND late this afternoon and evening. At the surface, a lee trough will develop ahead of the emerging shortwave, drawing low 60s F surface dewpoints north across the Dakotas. Strong heating and mixing of the airmass along the surface trough may support isolated storms this afternoon. While generally less than 25 kt, effective shear may favor organized multi-cell clusters with an isolated risk for damaging wind gusts and or hail. Overall confidence in severe coverage is low, but the highest likelihood of severe wind/hail within this regime will be from southern ND into central SD where hi-res guidance does show some convective signal. As the main shortwave emerges later in the evening, a cold front and associated surface low will move from southern SK into northeastern MT and far western ND. While poorly timed with the diurnal cycle, strong frontal convergence may still support isolated storms along and behind the front where low 60s F surface dewpoints should pool. 500-1000 J/kg of MUCAPE and 30-40kt of effective shear may allow some storm organization with the potential for damaging wind gusts and or severe hail. However, uncertainty on severe potential/coverage remains high given the poor timing of the main shortwave and the anafrontal nature of any convection that can develop. ...Southern US... Evident on morning visible imagery, a weak quasi stationary front will serve as a focus for another day of diurnal thunderstorms from the southern Plains into the southeastern US. Warm and moist through much of the lower atmosphere along and south of the boundary, the weakly sheared airmass will support scattered to numerous thunderstorms from eastern OK to the Carolinas. While an occasional gust may occur with any more concentrated storm clusters, overall predictability remains too low for the inclusion of severe probabilities. ..Lyons/Grams.. 07/30/2022 Read more

WW 0507 Status Updates
STATUS FOR WATCH 0507 HAS NOT BEEN ISSUED YET Read more

WW 507 SEVERE TSTM MD VA CW 291730Z - 300000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 507 NWS Storm Prediction Center Norman OK 130 PM EDT Fri Jul 29 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern Maryland Southern and eastern Virginia Coastal Waters * Effective this Friday afternoon and evening from 130 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely SUMMARY...Initial cluster in central Virginia should pose the primary threat for damaging winds as it spreads east towards the southern Delmarva Peninsula. An additional cluster may form across southwest Virginia and spread towards southeast Virginia as well. The severe thunderstorm watch area is approximately along and 75 statute miles east and west of a line from 15 miles northeast of Patuxent River MD to 25 miles west of South Hill VA. 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 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 26030. ...Grams Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1212 PM CDT Fri Jul 29 2022 Valid 301200Z - 311200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms associated with strong winds will be possible on Saturday afternoon from parts of Oklahoma and far northeast Texas into Arkansas. ...Synopsis and Discussion... Expansive subtropical ridging is forecast to extend across the Southeast and southern Plains early Saturday morning, with another upper ridge centered near the northern CA/NV and covering much of the western CONUS. This dominance of upper ridging will lead to predominantly weak flow aloft across the majority of the CONUS. The only exceptions are early in the period across the Northeast, before the shortwave trough extended over the region moves eastward, and over the northern High Plains/northern Plains during from late Saturday afternoon into Sunday morning. This second area will be coincident with a modest shortwave trough moving through the Canadian Prairie Provinces and adjacent northern High Plains/northern Plains. Surface pattern is expected to feature a large ridge centered over the OH Valley, and modest lee troughing across the High Plains. A frontal zone will exist between the more continental air associated with the ridging and moist air mass across much of the southern Plains and Southeast. This frontal zone will be fairly broad, with some more defined portions possible due to potential augmentation via thunderstorm outflow, and is expected to act as the corridor for additional thunderstorms development during the afternoon and evening. Weakly sheared nature of the environment suggests a predominantly multicellular mode with limited updraft strength and duration. Given the very moist character of the air mass (i.e. PW values of 2-2.25"), a few isolated water-loaded downbursts capable of damaging wind gusts could occur. However, widely spaced character of events and overall marginal nature of the threat merits keeping severe wind probabilities below 5% for this outlook. ..Mosier.. 07/29/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Fri Jul 29 2022 Valid 291700Z - 301200Z No changes. See previous discussion below. ..Bentley.. 07/29/2022 .PREV DISCUSSION... /ISSUED 0200 AM CDT Fri Jul 29 2022/ ...Synopsis... A large-scale ridge will remain centered over the western CONUS, while a low-amplitude shortwave trough tracks southeastward across the northern Rockies. Beneath the upper ridge, hot/dry conditions will result in widespread 10-15 percent minimum RH east of the Cascades into the northern Rockies. The low RH, coupled with breezy northerly surface winds over southeast OR, southwest ID, and northern NV will promote elevated fire-weather conditions during the afternoon -- especially owing to highly receptive fuels over the area. In addition, large-scale ascent ahead of the shortwave trough and favorable midlevel moisture/instability will support isolated to widely scattered high-based thunderstorms over the northern Rockies. As these storms overspread a hot/dry boundary layer and critically dry fuels, lightning-induced ignitions will be possible. Farther west, upslope flow and adequate instability will also support very isolated high-based thunderstorms along the Cascades in northern CA into southern OR -- where isolated ignitions remain a concern. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1610 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR CENTRAL/EASTERN VIRGINIA TO EASTERN MARYLAND/SOUTHERN DELAWARE
Mesoscale Discussion 1610 NWS Storm Prediction Center Norman OK 1124 AM CDT Fri Jul 29 2022 Areas affected...Central/eastern Virginia to eastern Maryland/southern Delaware Concerning...Severe potential...Watch possible Valid 291624Z - 291830Z Probability of Watch Issuance...60 percent SUMMARY...Thunderstorms are expected to develop/increase this afternoon initially across Virginia near the Blue Ridge and spread eastward toward/across the Chesapeake bay vicinity. Isolated wind damage may occur with the strongest storms. Trends are being monitored for a possible Severe Thunderstorm Watch. DISCUSSION...Strong heating and ample insolation/boundary layer destabilization are occurring across the southern half of Virginia to the south of a southwest/northeast-oriented effective front from the central Appalachians toward the Delmarva, although buoyancy will be somewhat tempered by warm mid-level temperatures (-4 to -5C at 500mb) and poor mid-level lapse rates. Regardless, thunderstorms will develop and increase through mid-afternoon over the mountains and Blue Ridge vicinity and subsequently spread eastward. Influenced by the upper trough over the Great Lakes, a belt of moderately strong westerlies is noted, particularly with northward extent near/north of the frontal zone. This will support sustained multicells/linear segments as thunderstorms develop, and possibly even some transient supercells across east-central Virginia/eastern Maryland and Chesapeake Bay vicinity. A very moist boundary layer and steepening low-level lapse rates could yield some downbursts capable of isolated wind damage as the most probable severe hazard. ..Guyer/Grams.. 07/29/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RNK... LAT...LON 36897666 36587907 37507911 38817740 38597490 37177583 36897666 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1108 AM CDT Fri Jul 29 2022 Valid 291630Z - 301200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS VA AND CHESAPEAKE BAY VICINITY... ...SUMMARY... Potential for scattered damaging winds from strong to locally severe gusts is greatest across parts of Virginia and the Chesapeake Bay vicinity through early evening. ...VA and Chesapeake Bay vicinity... South of a slow-moving surface cold front, a southwest to northeast-oriented zone of differential boundary-layer heating is apparent from southwest VA to the Chesapeake. Scattered thunderstorms are expected to develop along this corridor through the afternoon. On the fringe of 35-40 kt mid-level westerlies in conjunction with a pronounced buoyancy gradient, a mix of multicell clusters and transient supercell structures are anticipated. Amid weak mid-level lapse rates, strong to locally severe gusts producing mainly tree damage should be the primary threat into early evening. ...Southern Appalachians to the Mid-South... Scattered thunderstorms are again expected along the composite outflow/differential heating corridors south of the quasi-stationary surface front. Isolated strong/damaging downbursts will be possible with water-loaded downdrafts on the fringe of modest mid-level westerlies. ...Red River Valley and TX Panhandle... Isolated to scattered thunderstorms are expected from late afternoon into mid-evening both along the surface cold front near the Red River and in a post-frontal regime over the TX Panhandle. Deep-layer shear will be weak across the region, especially for convection along the front. The latter will be compensated by a deeply mixed thermodynamic profile with hot temperatures south of the front. Isolated strong/damaging downbursts will be possible with water-loaded downdrafts. Farther west, slow-moving cells/clusters may contain a threat of both isolated, marginally severe wind/hail. ...Southern Great Basin... Around the southeast periphery of a mid-level anticyclone centered over northern CA, modest northeasterly flow of 15-20 kt will be maintained over southern NV. Boundary-layer dewpoints are generally in the low to mid 60s this morning and gradual clearing of clouds will allow strong surface heating this afternoon with MLCAPE increasing to 500-1500 J/kg. Isolated to scattered thunderstorms are expected to form by late afternoon close to the NV/UT border, and storms will subsequently spread south-southwestward on outflow into southern NV and adjacent areas of southeast CA. Given the modest buoyancy and steep low-level lapse rates, isolated severe outflow gusts up to around 70 mph will be possible with multicell clusters. ...Northern MT... A low-amplitude shortwave impulse over southeast BC will drift east across southern AB. Though moisture will be limited, deep boundary-layer mixing will occur as surface temperatures warm through the 90s. Weak ascent preceding the upper trough and weak low-level convergence along a surface trough will support isolated to scattered thunderstorms later this afternoon. Though low to mid-level flow will remain weak, deep inverted-v profiles will favor isolated strong outflow gusts of 50-60 mph. ...NE Panhandle vicinity... Isolated thunderstorms may develop along the northern periphery of the High Plains moisture plume during the late afternoon/early evening. Adequate veering of the wind profile with height (weak low-level southerlies to modest mid-level northwesterlies) will support a short-duration and very isolated threat for marginally severe hail/wind. ..Grams/Lyons.. 07/29/2022 Read more