Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1139 AM CDT Mon Jul 11 2022 Valid 111700Z - 121200Z No changes have been made to the outlook, see the previous discussion below for more details. ..Dean.. 07/11/2022 .PREV DISCUSSION... /ISSUED 0104 AM CDT Mon Jul 11 2022/ ...Synopsis... Fire weather concerns will predominantly linger across central UT for today, driven by the potential for dry thunderstorms. A persistent upper ridge over the southern Rockies will likely shift slightly southwest in response to a modestly deepening trough across the Midwest. This will yield a benign surface pressure regime and low potential for wind-driven fire weather threats (though a few localized concerns may emerge). However, this will maintain isolated thunderstorm chances across the greater Four Corners region this afternoon. ...Utah/Dry-Thunderstorms... Monsoonal moisture was well sampled by regional 00 UTC soundings with PWAT values around 0.75 inches in place across AZ and UT. Nearly 3 km deep dry sub-cloud layers and 100-250 J/kg MUCAPE are also noted. This thermodynamic environment resulted in a few thunderstorms Saturday afternoon, and is expected to largely remain unchanged through this afternoon given the stagnant synoptic regime. Orographic ascent should support isolated to widely scattered thunderstorms with the potential for dry lightning strikes. Slow storm motions (generally < 10 knots) may allow for pockets of wetting rainfall, but peripheral lightning strikes over receptive fuels will maintain a fire weather concern. ...Southern Nevada and Western Texas... Hot temperatures near or above 100 F are expected this afternoon across southern NV and western TX. These hot temperatures combined with seasonal to below-seasonal dewpoints will result in 10-20% RH values by late afternoon. While pressure gradient winds will generally be between 10-15 mph, deep boundary-layer mixing may support areas of 15-20 mph winds and elevated fire weather conditions. Confidence in the duration and coverage of these conditions remains too low for additional highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Mon Jul 11 16:41:01 UTC 2022.

MD 1449 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST LOWER MI
Mesoscale Discussion 1449 NWS Storm Prediction Center Norman OK 1130 AM CDT Mon Jul 11 2022 Areas affected...Southwest Lower MI Concerning...Severe potential...Watch unlikely Valid 111630Z - 111830Z Probability of Watch Issuance...20 percent SUMMARY...Isolated damaging wind gusts are possible over the next hour or two as the line of storms moving across Lake Michigan moves into southwest Lower Michigan. DISCUSSION...Ongoing line of storms has intensified as it moves over southern Lake Michigan. Low-level stability in place suggests these storms are currently elevated. The downstream air mass across southwest Lower MI is currently characterized by upper 70s temperatures, low 60s dewpoints, and around 1000 J/kg of MUCAPE (based on recent mesoanalysis). Some additional heating/moistening of the low-levels is anticipated, but low-level stability should persist, likely limiting the overall severe potential. Even so, some isolated gusty winds appear probable as occasional downbursts penetrate the low-level stability. Limited severe coverage should preclude the need for a watch. ..Mosier/Thompson.. 07/11/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IWX...GRR... LAT...LON 41968656 42398630 42938622 43388643 43538623 43398555 43038505 42458502 41928536 41798622 41968656 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1125 AM CDT Mon Jul 11 2022 Valid 111630Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS AFTERNOON/EVENING FROM CENTRAL IL INTO SOUTHERN LOWER MI... ...SUMMARY... Thunderstorms capable of wind damage will be possible across parts of Illinois into Indiana and Lower Michigan today. Isolated strong-severe wind gusts and hail may also occur from Missouri west-southwestward into the south-central High Plains and across other parts of the upper Great Lakes. ...Central IL to Lower MI late this afternoon into early tonight... A midlevel shortwave trough over MN will progress east-southeastward over the Great Lakes by tonight, as an associated/weak surface cold front moves southeastward into KS/MO/IL/MI. An overnight MCS has largely dissipated across northern IL this morning (aside from a few elevated storms over southern Lake MI), but lingering cloud debris will slow surface heating into early afternoon. By mid-late afternoon, pockets of surface heating and eastward advection of low-level moisture along the cold front will result in sufficient destabilization and weakening of the cap to allow thunderstorm development from northern IL across northern IN into southern Lower MI by this evening. There is still some uncertainty regarding the timing and corridor of storm initiation, given lingering clouds and modest forcing for ascent. If storms do form from IL into Lower MI by this evening along the front and/or differential heating zone, moderate buoyancy and 50 kt midlevel flow will support a threat for damaging outflow gusts. ...Northeast MN into WI/northern Lower MI through this evening... Scattered thunderstorms are expected to spread southeastward through this afternoon/evening, from northeast MN across WI and northern Lower MI in the zone of strongest forcing for ascent preceding the midlevel shortwave trough over MN. There could be sufficient residual low-level moisture, cooling midlevel temperatures, and deep-layer vertical shear (largely straight hodographs) for some organized clusters/low-topped supercells capable of producing isolated damaging gusts and large hail. ...Southeast CO/KS/MO late this afternoon into early tonight... Isolated to widely scattered thunderstorm development is anticipated along the cold front late this afternoon/evening from MO into southern KS in conjunction with deep mixing along the cold front. Somewhat greater storm coverage expected across southeast CO/northeast NM in the upslope flow regime immediately north of the front. Vertical shear will be weak south of the front, with somewhat longer hodographs in the sheltered northeasterly low-level flow to the immediate cool side of the boundary. Primarily multicell clusters will be capable of producing isolated strong-severe outflow gusts in the hot, steep low-level lapse rate environment along the front, and convection could linger into the overnight hours in the zone of richer moisture to the cool side of the boundary. ..Thompson/Squitieri.. 07/11/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0744 AM CDT Mon Jul 11 2022 Valid 111300Z - 121200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE MIDWEST/GREAT LAKES... ...SUMMARY... Thunderstorms capable of wind damage will be possible across parts of Illinois into Indiana and Lower Michigan today. Marginally severe wind gusts and hail may also occur from Missouri west-southwestward into the south-central High Plains and across other parts of the Great Lakes. ...Midwest/Great Lakes... A relatively compact (60 miles north-south) cluster of storms, with a history of wind damage/measured severe gusts from eastern Nebraska across the middle part of Iowa, continues eastward into northwest Illinois as of 1230z/730am CDT. This cluster should continue to weaken this morning as it becomes increasingly removed from a reservoir of moisture/instability, but locally strong wind gusts and possibly some hail may continue in the short-term. For additional near-term details, see Mesoscale Discussion 1448. This MCS, and expected renewed convective development later today, are/will be influenced with a seasonally strong amplifying mid-level shortwave trough crossing the Upper Midwest and Great Lakes region today and tonight. Spatial/timing details are a bit uncertain, but areas/near south of the ongoing early morning MCS will be favored for renewed convective development near/ahead of the southeastward-moving front late this afternoon, which includes a corridor across northern Illinois into northern Indiana and southern Lower Michigan. Strong destabilization is expected particularly across north-central Illinois, although stronger deep-layer shear/forcing for ascent will be a bit compensatory for more moderate destabilization across northern Indiana into Lower Michigan. Storms that form will likely be capable of damaging wind gusts and hail. Owing to weaker overall forcing and more substantial mid-level warmth with south-southwestward extent, storm development late this afternoon/early evening should be a bit more isolated near the front from western Illinois into Missouri, although steep low-level lapse rates and ample buoyancy will yield at least a conditional or isolated potential for storms to produce severe wind gusts. ...Portions of Minnesota/Wisconsin/Upper Michigan... Marginal-related wind/hail probabilities have been introduced for the region. Amplifying shortwave trough-related seasonably cool mid-level temperatures will contribute to weak inhibition and modest boundary layer destabilization even while moisture diminishes within the post-frontal environment. Scattered semi-low-topped thunderstorms are expected to develop/increase during the afternoon with a few instances of hail and/or strong winds being possible. ...South-central Plains... Intense surface heating ahead of the southward-advancing front across the southern High Plains into Kansas will result in dry adiabatic lapse rates in the lowest 3km as temperatures soar above 100F. Low-level upslope trajectories will also influence thunderstorm development near the Raton Mesa vicinity late in the day. High cloud bases and low RH in the sub-cloud layer may support some storms capable of localized severe-caliber wind gusts with the convection late this afternoon and early evening. ..Guyer/Leitman.. 07/11/2022 Read more

No Mesoscale Discussions are in effect as of Sun Jul 10 16:44:10 UTC 2022.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1141 AM CDT Sun Jul 10 2022 Valid 101700Z - 111200Z The current forecast remains on track. No changes made. ... Western Kansas ... Relative humidity is still forecast to fall into the low teens this afternoon, with surface winds up to 20 mph, with gusts approaching 30 mph. However, fuel moisture should remain sufficiently high to warrant a more widespread critical fire weather threat. Thus, despite the possibility of brief, localized critical fire weather conditions being achieved, no critical highlights have been added. ..Marsh.. 07/10/2022 .PREV DISCUSSION... /ISSUED 1247 AM CDT Sun Jul 10 2022/ ...Synopsis... Fire weather concerns will continue across portions of the Great Basin and northern Rockies amid breezy conditions and dry-thunderstorm chances, but will also emerge across parts of western KS and adjacent areas of CO and NE. ...Idaho into Wyoming... Recent upper-air observations and analyses show a diffuse cold front draped across the northern Great Basin/northern Rockies associated with a passing mid-level wave. This feature will bring slightly cooler temperatures to the region, but also induce 15-20 mph westerly winds across the upper Snake River Plain in southeast ID as well as across the Wyoming Basin. Wind gusts between 25-35 mph are possible by early/mid afternoon as stronger mid-level flow mixes down to the surface. Despite the cooler temperatures, poor moisture recovery into the region and some degree of downslope flow (especially through the Wyoming Basin) will result in the RH values near 10-15%. Confidence remains high in several hours of elevated conditions, but periodic critical conditions are possible for wind-prone locations and where/when higher wind gusts occur. ...Utah/Dry-Thunderstorms... Water-vapor imagery reveals a plume of monsoonal moisture advecting northward through eastern NV and western AZ on the western periphery of the mid-level ridge. This moisture was sampled well by the 00 UTC FGZ sounding, and should reach UT/CO by early afternoon. While forcing for ascent will be modest (and should limit the coverage of storms), forecast soundings continue to show favorable thermodynamic profiles for dry thunderstorms with 100-250 J/kg MUCAPE, deep, well-mixed boundary layers, and PWAT values between 0.6 to 0.75 inches. Slow storm motions may limit the number of dry strikes, but receptive fuels across the region warrant maintaining the dry-thunderstorm risk. ...Western Kansas... A lee trough noted in early-morning surface observations along the High Plains is forecast to shift into the central Plains as an attendant surface low migrates east into the upper MS River Valley. This will augment the regional pressure gradient, resulting in sustained surface winds up to 15-20 mph. Ensemble guidance shows a strong signal for above-normal temperatures with afternoon highs between 100-105 F for western KS. This will result in widespread RH reduction to 10-20% by late afternoon. Although most fuels are only modestly dry, 1 and 10 hour fuel moisture values between 5-10% should support at least a low-end fire weather concern. A few high-based thunderstorms are possible across northwest KS this afternoon, and may result in gusty outflow winds across parts of the Elevated risk area. ...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 Sun Jul 10 2022 Valid 101630Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EARLY TONIGHT FOR PARTS OF THE NORTHERN PLAINS AND UPPER MIDWEST... ...SUMMARY... Isolated to scattered severe thunderstorms are expected across the Upper Midwest and northern Plains today into tonight. A few strong storms may also occur today from southeast Texas into southern Louisiana. ...MN and vicinity through late evening... The ongoing MCS across northern MN has been more resilient than all recent numerical model guidance (both mesoscale and CAM), and it may persist eastward into northeast MN through early afternoon as surface heating/destabilization continues to its east. Given the organized nature of the cold pool and its relatively fast motion, damaging gusts will remain possible into early afternoon. Additional thunderstorm development is possible this afternoon along the outflow boundary trailing west/southwestward from the MCS into west central MN and southeast ND. This area will likely remain capped until mid afternoon as a result of the warm elevated mixed layer noted in the 12z ABR sounding. Still, boundary-layer dewpoints of 68-70 F beneath 8-9 C/km midlevel lapse rates, in concert with daytime heating, should weaken convective inhibition and allow thunderstorm development around 21-22z. The storm environment will conditionally favor supercells capable of producing isolated very large hail and a tornado or two. Some upscale growth into a small cluster will be possible, with an attendant threat for damaging winds as the convection moves southeastward toward east central MN. ...NE WY and vicinity late this afternoon through early tonight... A midlevel shortwave trough over northwest MT this morning will crest the midlevel ridge and begin to move east-southeastward by early tonight. Residual low-level moisture, steep midlevel lapse rates, and a reinforcing cold frontal surge may be sufficient for high-based thunderstorm development by this evening, with storms subsequently spreading southeastward into early tonight. Buoyancy will be modest, but vertical shear will be favorable for supercells/small bowing segments capable of producing damaging winds and marginally severe hail. ...NE late this afternoon into early tonight... Strong surface heating and deep mixing along a cold front will promote high-based thunderstorm development late this afternoon, and storms will spread east-northeastward along the front toward IA into early tonight. Vertical shear will generally be weak, but inverted-v profiles and large DCAPE (~1500 J/kg) will favor strong-severe outflow gusts. ...Northwest Gulf Coast this afternoon... A weak cold front is sagging southward across the Gulf Coast states in association with a weak midlevel trough moving southward around the eastern periphery of a midlevel high over the southern High Plains. A hot/humid boundary layer persists south of the front from southeast TX into southern LA, where Large CAPE (> 3000 J/kg) and DCAPE > 1000 J/kg will support isolated strong/damaging downbursts with pulse-type cells and loosely organized, southward moving clusters this afternoon. ..Thompson/Squitieri.. 07/10/2022 Read more

WW 0455 Status Updates
STATUS REPORT ON WW 455 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 SE DTL TO 35 S RRT. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1436 ..MOSIER..07/10/22 ATTN...WFO...FGF... STATUS REPORT FOR WS 455 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC007-057-101640- MN . MINNESOTA COUNTIES INCLUDED ARE BELTRAMI HUBBARD THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0456 Status Updates
STATUS FOR WATCH 0456 HAS NOT BEEN ISSUED YET Read more

WW 456 SEVERE TSTM MN 101515Z - 101900Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 456 NWS Storm Prediction Center Norman OK 1015 AM CDT Sun Jul 10 2022 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of North central and northeast Minnesota * Effective this Sunday morning and afternoon from 1015 AM until 200 PM CDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible SUMMARY...An ongoing convective system is expected to continue eastward across northern Minnesota for the next few hours, with the threat for damaging winds of 60-70 mph and isolated large hail to near 1 inch in diameter. The severe thunderstorm watch area is approximately along and 65 statute miles east and west of a line from 20 miles east northeast of International Falls MN to 35 miles east southeast of Brainerd MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 455... 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 500. Mean storm motion vector 27045. ...Thompson Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 AM CDT Sun Jul 10 2022 Valid 101300Z - 111200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST AND NORTHERN HIGH PLAINS... ...SUMMARY... Isolated to scattered severe thunderstorms are expected across the Upper Midwest and northern Plains today into tonight. A few strong storms may also occur today from southeast Texas into southern Louisiana, as well as other parts of the Southeast. ...Upper Midwest/North Dakota... Initially, a severe fast-moving (50+ kt) MCS is ongoing early this morning from far eastern North Dakota into northern Minnesota. Severe-caliber wind gusts will remain possible for a time, but the system should eventually weaken this morning as inflow diminishes. That said, given the large-scale support aloft, complete dissipation is not expected and the primary question is to what degree/where robust convection develops in the wake of the MCS debris field along the advancing frontal zone. This currently appears most probable across northern Minnesota along the southern edge of the ongoing MCS where differential heating/frontal convergence should be adequate for renewed convective development by around mid-afternoon. Strong shear suggests supercells are possible, with the potential for large hail, damaging winds, and possibly a tornado. Farther west, additional strong/severe storms, at least on an isolated basis, may develop/move southeastward across the international border into northern North Dakota later this afternoon and evening. With moderate recovery in the wake of the MCS early today, at least isolated severe storms capable of wind/hail may occur and have maintained the ongoing Slight Risk for this post-MCS/later-day severe potential. ...Northern High Plains... Surface pressure rises across Montana will create a narrow corridor of favorable low-level upslope flow along the Montana/Wyoming border by late afternoon as a secondary surface boundary strengthens and advances south during the evening. While PW values will not be particularly moist (around 1 inch), strong surface heating and orographic influences should aid at least isolated robust development. Forecast soundings suggest strongly sheared storms could generate gusty winds as high-based supercells spread southeast toward the Black Hills region. ...Southeast Texas/southern Louisiana... Strengthening northwesterly flow across the Mississippi Valley into the Mid-South region will ensure a surface boundary sags south across Louisiana, arcing west into south-central Texas. Very strong surface heating will allow temperatures to soar above 100F across southeast Texas with mid 90s into southwest Louisiana. While deep-layer flow will be weak along this corridor, high PW values and warm temperatures should contribute to a few robust updrafts. Forecast soundings across southeast Texas suggest cloud bases may be near 3km AGL and this may contribute to gusty downdrafts due to relatively low sub-cloud RH values. ...Coastal Carolinas and vicinity... Although cloud cover is semi-prevalent early today, a few strong to locally severe storms may occur into the afternoon across South Carolina and nearby parts of Georgia/coastal North Carolina. Moderate diurnal destabilization ahead of an upstream shortwave trough will influence the potential for these stronger updrafts/downdrafts, with some localized wind damage a possibility. ..Guyer/Leitman.. 07/10/2022 Read more

WW 0454 Status Updates
STATUS REPORT ON WW 454 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 55 NNE ABR TO 30 ENE JMS TO 45 WSW HCO. ..LEITMAN..07/10/22 ATTN...WFO...FGF...BIS... STATUS REPORT FOR WS 454 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NDC003-017-035-073-091-097-101340- ND . NORTH DAKOTA COUNTIES INCLUDED ARE BARNES CASS GRAND FORKS RANSOM STEELE TRAILL THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Sat Jul 09 2022 Valid 091700Z - 101200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF THE GREAT BASIN... The ongoing forecast remains on track. No changes needed. ..Marsh.. 07/09/2022 .PREV DISCUSSION... /ISSUED 1250 AM CDT Sat Jul 09 2022/ ...Synopsis... Fire weather concerns will persist across parts of the Great Basin for today. Early-morning water vapor imagery reveals a mid-level trough moving onshore across northern CA. This feature will shift into the northern Rockies through the day, augmenting mid and low-level flow over the Great Basin and central Rockies in response. The combination of an antecedent dry air mass, receptive fuels, and increasing winds will result in critical to elevated fire weather conditions. ...Great Basin... 00 UTC soundings from NV and UT sampled a very dry low-level air mass Friday evening with RH values in the single digits. This air mass will largely remain in place and promote afternoon RH values near 10% as low-level trajectories continue to emanate largely from southern CA desert and/or off the Sierra Nevada. Stronger mid and upper-level winds were also noted in soundings along the West Coast ahead of the approaching shortwave trough. These winds will overspread the Great Basin by peak daytime heating, and when combined with deep boundary-layer mixing, will support sustained 15-20 mph winds with frequent gusts between 25-35 mph. Guidance continues to show increasing confidence in sustained critical conditions across eastern NV into western and northwestern UT. Brief critical conditions may extend into southeast ID as winds gusts to near 30 mph, but these conditions should remain somewhat localized/transient. Elevated conditions are probable across northwest NV as well as central WY, but latest fuel guidance continues to show only marginally dry fuels. ...Central High Plains... Localized elevated fire weather conditions appear possible this afternoon across parts of the central High Plains, most notably across the SD/WY/NE tri-state region where winds between 15-20 mph are possible and RH values may fall into the low teens. However, recent rainfall across this region has allowed ERC values to fall to near seasonal normal, mitigating the need for additional highlights. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sat Jul 9 16:38:01 UTC 2022.

No Mesoscale Discussions are in effect as of Sat Jul 9 16:38:01 UTC 2022.

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sat Jul 09 2022 Valid 091630Z - 101200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS EVENING INTO TONIGHT FROM CENTRAL MT INTO WESTERN ND... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FROM CENTRAL AL INTO CENTRAL/NORTHERN MS... ...SUMMARY... Scattered severe thunderstorms are expected later this afternoon through tonight across Montana into North Dakota, with damaging winds and large hail likely. Occasional damaging gusts will also be possible this afternoon/evening across parts of Alabama and Mississippi. ...MT/ND late this afternoon through tonight... Similar to the previous two days, midlevel shortwave troughs will move around the northwest periphery of the Four Corners midlevel high, from the interior Northwest across MT to ND through tonight. Despite overnight convection, boundary-layer dewpoints remain in the mid 50s to near the higher terrain in west/southwest MT (somewhat higher dewpoints across eastern MT). Steep midlevel lapse rates will again be replenished from the southwest, which in concert with daytime heating, will result in MLCAPE near 1500 J/kg this afternoon/evening. Deep-layer vertical shear will be fairly strong, with long hodographs and effective bulk shear in excess of 45 kt. Much like yesterday, scattered thunderstorm development is expected near or just after 21z, over and immediately northeast of the mountains in southwest MT. Some of these storms could develop supercell structures with an attendant threat for large hail of 2+ inches in diameter. Later this evening, some upscale growth into one or more clusters is expected, with an increase in the threat for damaging winds of 75+ mph. Embedded supercells will remain possible, especially on the southern flank of the convection, as the cluster(s) move eastward across ND tonight. ...Southeast into TX this afternoon/evening... Downstream from a midlevel high centered near the Four Corners, a broad zone of cyclonic flow aloft persists from the MS Valley to the Mid-Atlantic/Carolinas. Embedded perturbations within this cyclonic flow, enhanced by prior convection, will continue to move east-southeastward over the Southeast, as a surface cold front drifts slowly southward across VA/KY/TN/AR and north TX. Morning clouds/convection across north GA/northeast AL will produce weak outflow and differential heating zones that will drive afternoon thunderstorm development farther south and west from central AL into the Mid-South along the cold front. Hot afternoon temperatures of 95-100 F and boundary-layer dewpoints in the mid 70s will boost MLCAPE to 3000 J/kg or greater, with thunderstorm development expected by early-mid afternoon. Convection will likely grow upscale into a couple of clusters/lines and spread southward through late afternoon/evening. Though flow aloft will be weak, the large buoyancy and DCAPE near 1000 J/kg will support occasional damaging downbursts. Farther east, the morning convection across GA may persist into the afternoon while spreading southeastward, and additional storms are expected to form along the differential heating zone across the Piedmont, and along the cold front moving southward into NC. Vertical shear will remain rather weak (slightly stronger along the front in NC), and thermodynamic profiles from GA into the Carolinas will not be quite as supportive of downbursts compared to MS/AL. Thus, isolated strong/damaging outflow winds will be possible with multicell clusters this afternoon from GA into NC. Strong surface heating (afternoon temperatures well above 100 F) and inverted-v profiles along the slow-moving front across north TX will support the threat for high-based thunderstorms with isolated severe outflow winds for a few hours later this afternoon/evening. ..Thompson/Dean.. 07/09/2022 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0751 AM CDT Sat Jul 09 2022 Valid 091300Z - 101200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MONTANA TO NORTH DAKOTA/NORTHWEST MINNESOTA... ...SUMMARY... Scattered severe thunderstorms are expected this afternoon through tonight across Montana into North Dakota, with damaging winds and large hail likely. Marginally severe storms may also occur from parts of Texas into much of the Southeast States, with locally damaging wind gusts a possibility. ...Montana/North Dakota to Minnesota... An early morning MCS across central North Dakota will likely persist east-southeastward with the potential for some stronger wind gusts, but it will likely tend to weaken into midday as elevated inflow diminishes. The remnants of this MCS could subsequently serve as a focus for isolated robust redevelopment across eastern North Dakota and/or northern Minnesota later this afternoon as the boundary layer destabilizes. Otherwise, another semi-active scenario is anticipated across the region later today, including the possibility of a somewhat higher severe potential across Montana/western North Dakota as compared to yesterday. A wind/hail-related Enhanced Risk may be warranted in subsequent Day 1 Outlook updates. Late day/nighttime height falls along with a strengthening of deep-layer westerlies are expected from Idaho/Montana into North Dakota late this afternoon and tonight in advance of a consequential shortwave trough emerging from the Pacific Northwest. Convection will again initially develop over the mountains of northern Idaho and southwest Montana. Forecast soundings suggest convective initiation will occur by 21z-22z as convective temperatures are breached. These storms will evolve beneath a belt of 40-50kt of mid-level flow that will encourage upscale growth of scattered supercells into central Montana. Seasonally strong buoyancy, steep lapse rates, and strong shear suggest one or more MCSs may evolve. This activity should focus along a corridor from central Montana into west-central North Dakota this evening into the overnight. Initial supercells may produce very large hail, but with time, the severe wind threat may increase as bow-type structures are likely to evolve with a maturing MCS. ...Deep South to Carolinas/eastern Virginia... On the eastern periphery of the Great Plains upper ridge, modestly strong west-northwesterly flow aloft will prevail across much of the Deep South and Southeast States. A southward-moving front, aided by weak support aloft, along with pre-existing early day storm clusters/outflows across the Tennessee Valley, should encourage at scattered to numerous thunderstorms especially this afternoon within a high PW environment. Some of these storms are likely to produce localized microbursts capable of wind damage. ...Texas/ArkLaTex... A very hot/humid air mass with afternoon temperatures in excess of 100F in many locations could support some strong/locally severe wind gusts as thunderstorms develop this afternoon near/south of the front across the region. ..Guyer/Leitman.. 07/09/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1129 AM CDT Fri Jul 08 2022 Valid 081700Z - 091200Z No changes have been made to the outlook, see the previous discussion below for more details. ..Dean.. 07/08/2022 .PREV DISCUSSION... /ISSUED 1240 AM CDT Fri Jul 08 2022/ ...Synopsis... Southwesterly flow aloft over the western CONUS will persist for the next 24 hours ahead of an approaching mid-level wave. This will maintain dry and breezy conditions across much of the Great Basin for today, resulting in areas of elevated fire weather conditions. Unseasonably hot and dry conditions are expected across much of central TX. While winds will generally be benign, very low humidity and curing grasses will yield at least a low-end fire weather concern for the region. ...Great Basin... Fire weather concerns will once again focus across portions of the Great Basin for this afternoon. Early-morning water vapor imagery shows a dry, subsident air mass in place from Baja CA into the eastern Great Basin, which was sampled well by regional 00 UTC soundings. While some mid/upper-level moisture will advect into the region in the form of scattered high clouds today, mostly sunny skies coupled with the antecedent dry air mass will result in another day of widespread 10-20% RH. Latest fuel guidance continues to show high ERCs above the 90th percentile across eastern NV into adjacent areas of UT and ID. While this region will be on the periphery of the stronger southwesterly flow aloft, deep diurnal mixing will maintain 15-20 mph winds with frequent gusts to 25 mph. Consequently, elevated conditions appear likely with sporadic critical conditions possible. ...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 1126 AM CDT Fri Jul 08 2022 Valid 081630Z - 091200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING ACROSS KY AND VICINITY...AND LATE THIS AFTERNOON INTO TONIGHT ACROSS MT/WESTERN ND... ...SUMMARY... Isolated very large hail and significant outflow gusts are possible late this afternoon into early tonight across Montana, and occasional damaging winds will be possible this afternoon across Kentucky and vicinity. ...OH Valley into the Southeast this afternoon/evening... An expansive midlevel ridge will dominate the Southwest and southern Plains through the period, with mostly weak west-northwesterly flow over the upper MS and OH Valleys. Weak convectively-enhanced perturbations in the west-northwest flow, with associated convective clusters, will continue to move east-southeastward through the afternoon from southern IN into KY. These storm clusters will move along the southern fringe of the 30 kt midlevel flow, and along a baroclinic zone coincident with the northern edge of the warmest boundary layer, where dewpoints will range from the low to mid 70s. Though midlevel lapse rates will not be steep, the warm/moist boundary layer will drive MLCAPE values in the 2000-3000 J/kg range, which will help maintain the ongoing clusters, and support additional storm development to the southwest along the trailing outflow near the confluence of the MS/OH Rivers. The modest midlevel flow and steepening low-level lapse rates during the afternoon will support occasional strong/damaging outflow gusts as the main threat across KY and vicinity. Scattered diurnal thunderstorms are expected in the weak northwest flow regime into the Carolinas/GA this afternoon, with storm development focused along diffuse boundaries/differential heating zones. The weak flow and poor midlevel lapse rates suggest that pulse storm downbursts with outflow winds near or above 50 kt will be sparse. ...MT area later this afternoon into western ND tonight... Clusters of high-based thunderstorms are expected to form from southwest into central/north central MT later this afternoon/evening, in association with surface heating/deep mixing and embedded speed maxima moving around the northwest periphery of the Southwest/southern Plains ridge aloft. Steep midlevel lapse rates will be replenished from the southwest during the day, and surface heating will boost MLCAPE to 2000-3000 J/kg. Long hodographs with effective shear in excess of 40 kt, in combination with the steep lapse rates and strong buoyancy will support clusters with embedded supercells and bowing segments, capable of producing isolated very large hail (2 to 2.5 inches in diameter) and isolated significant outflow gusts up to 75 mph. ...High Plains area this afternoon/evening... Isolated to widely scattered thunderstorms are expected this afternoon/evening east of the high terrain from eastern WY into northeast CO. Forcing for ascent will be weak, but terrain circulations and weak upslope low-level flow should support storm development. Deep-layer, northwesterly vertical shear/hodograph length will be sufficient for supercells and small clusters capable of producing isolated strong-severe outflow gusts and hail late this afternoon through late evening. ..Thompson/Squitieri.. 07/08/2022 Read more