Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1127 AM CDT Sat Sep 10 2022 Valid 101630Z - 111200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE SOUTHEAST AND DESERT SOUTHWEST STATES.... ...SUMMARY... Isolated, marginally severe convective gusts, or a brief tornado, may occur over parts of the southeast states, and the desert southwest. ...Southeast... A persistent upper low remains over LA today, with a plume of deep, moist southerly flow across much of the southeast states. Widespread showers and thunderstorms have been occurring this morning over the eastern Gulf of Mexico. This activity will spread inland this afternoon and affect much of FL/GA. Other more isolated storms will affect parts of the Carolinas this afternoon. Wind fields are modest, but ample moisture and localized enhancements to shear may result in locally damaging wind gusts or perhaps a tornado or two. Refer to MCDs #1773 and #1774 for further small-scale details. ...NV/CA... A band of relatively strong easterly mid-level winds extends across northern AZ into southern NV today. Most 12z CAM guidance shows increasing thunderstorm activity along this corridor this afternoon. Forecast soundings show unusually high PWAT values, promoting a risk of gusty/damaging wind gusts in the strongest cells. The area of highest threat appears to extend from northern Death Valley into the deserts of southwest NV. ..Hart/Moore.. 09/10/2022 Read more

MD 1774 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR COASTAL CAROLINAS
Mesoscale Discussion 1774 NWS Storm Prediction Center Norman OK 1116 AM CDT Sat Sep 10 2022 Areas affected...Coastal Carolinas Concerning...Severe potential...Watch unlikely Valid 101616Z - 101815Z Probability of Watch Issuance...5 percent SUMMARY...A brief/weak tornado or two is possible through the afternoon hours as thunderstorms continue to develop off the Carolina coast and move onshore. A watch is not expected given the limited nature of the threat. DISCUSSION...A pair of weak circulations have been tracked from the KLTX radar in far southeast NC over the past 20-30 minutes. These circulations are associated with largely unorganized marine convection that has begun to move onshore. However, the easterly low-level onshore flow under modest southerly winds between 2-3 km is providing sufficient low-level SRH to support weak storm rotation with the stronger updrafts. This kinematic environment is sampled well by the KTLX VWP, and likely extends northward along the NC coast. Latest visible satellite trends show additional cumulus development offshore, slowly moving towards the coast. Buoyancy will likely continue to increase through the day amid daytime heating and will support additional T-storm chances through the afternoon. Forecast soundings hint that the best kinematic environment will persist now through around 21 UTC, but the overall limited wind magnitudes will support a rather low-end waterspout/tornado threat along the coast. ..Moore/Hart.. 09/10/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MHX...ILM... LAT...LON 33517946 34137899 34817758 35147664 34867609 34507623 34147696 33717789 33477851 33347913 33517946 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1047 AM CDT Sat Sep 10 2022 Valid 101700Z - 111200Z Offshore flow across the Pacific Northwest should continue to weaken through the day as the surface pressure diffuses further. Elevated highlights have been maintained as a widespread, very dry low-level airmass remains in place, atop critically dry fuels. Despite a large-scale weaker surface wind field, at least locally stronger winds should persist in terrain-favoring areas with boundary-layer heating/mixing. Otherwise, locally Elevated conditions may still occur later this afternoon east of the Cascades into the Snake River Plain from eastern Oregon into southern Idaho. ..Squitieri.. 09/10/2022 .PREV DISCUSSION... /ISSUED 0147 AM CDT Sat Sep 10 2022/ ...Synopsis... A large-scale trough will move slowly eastward from the northern Plains into the Upper MS Valley, while a mid/upper-level ridge builds over the western CONUS. Subsidence on the backside of the trough will reinforce an expansive area of high pressure over the northern and central Rockies, while surface low pressure gradually weakens off the Pacific Northwest coast. ...Northwest... Between the surface low off the Pacific Northwest coast and high pressure over the northern/central Rockies, an enhanced surface pressure gradient will support breezy easterly surface winds across parts of the Northwest. Along and west of the Cascades, 15-20 mph sustained surface winds coupled with 15-25 percent RH will lead to elevated fire-weather conditions, given receptive fuels over the area. The strongest winds are expected through the Cascade gaps early in the period, before the regional pressure gradient weakens during the late afternoon/early evening hours. While locally critical conditions will be possible primarily over terrain-favored areas along the Cascades, these conditions appear too localized for Critical highlights at this time. East of the Cascades, locally elevated conditions will be possible in the Columbia Basin and through the Snake River Plain, though a limited overlap of breezy surface winds and low RH precludes highlights for these areas. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Fri Sep 9 17:49:02 UTC 2022.

No Mesoscale Discussions are in effect as of Fri Sep 9 17:49:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1210 PM CDT Fri Sep 09 2022 Valid 101200Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for organized severe thunderstorms appears generally low on Saturday. ...Synopsis and Discussion... An upper trough will progress slowly eastward across the north-central CONUS on Saturday. Limited low-level moisture ahead of a surface cold front should hinder the development of meaningful instability from the southern/central Plains into the Midwest and Great Lakes. While thunderstorms may occur along/behind the length of the front across these areas, severe convection is not expected. A weak upper low centered over the lower MS Valley Saturday morning is forecast to devolve into a trough through the day. Modestly enhanced low/mid-level flow should be present ahead of this feature across portions of the Southeast. Even with a rich low-level airmass in place from FL into GA and the Carolinas, mid-level lapse rates will likely remain quite poor. This should hinder robust updrafts to some extent, even as weak to locally moderate instability develops with daytime heating. At this point, it appears that generally modest deep-layer shear should keep thunderstorms mostly disorganized, and any strong/gusty wind threat rather isolated. Scattered to numerous thunderstorms should occur across parts of NM/AZ into the southern Great Basin Saturday afternoon and evening. The stronger low/mid-level winds associated with weakening Tropical Cyclone Kay over the eastern Pacific should be displaced from areas with greater low-level moisture and instability. Accordingly, overall severe potential across the Southwest should remain low. ..Gleason.. 09/09/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1135 AM CDT Fri Sep 09 2022 Valid 091630Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHEAST AND UPPER GREAT LAKES... ...SUMMARY... Isolated marginally severe storms may occur across parts of the Southeast and Upper Great Lakes. ...Southeast States including Florida/eastern GA/coastal SC... To the east of a persistent upper low centered over the north-central Gulf of Mexico and middle portion of the Gulf Coast region, scattered showers and thunderstorms are prevalent over the eastern Gulf of Mexico toward the western Florida Peninsula and other parts of the coastal Southeast. Ample insolation is occurring across the Florida Peninsula to the south of a front coincident with a very moist environment, although weak mid-level lapse rates will tend to temper updraft intensities. Moderately strong southwesterly low/mid-tropospheric winds will overlie the front from far northern Florida into southeast Georgia/coastal South Carolina. A few transient supercells could regionally occur, particularly in proximity to this front. A few instances of wind damage are possible aside from the potential for a brief tornado. ...Northern Wisconsin/Upper Michigan... Will maintain low severe probabilities across the region in vicinity of the southeastward-moving front. Thunderstorms may persist on an isolated basis today, with renewed development a bit more probable toward/after sunset. An instance or two of severe hail could occur. ...Southern California/southwest Arizona... It still appears that severe potential will remain low north of the international border in association with current Tropical Storm Kay. ..Guyer/Moore.. 09/09/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1106 AM CDT Fri Sep 09 2022 Valid 091700Z - 101200Z The previous forecast (see below) remains on track for the Northwest. In addition, the latest guidance consensus depicts locally Elevated/Critical conditions across much of central and eastern Utah into western Wyoming as a surface cold front sweeps across the area. The dry and breezy northwesterly surface winds should be strongest in mainly terrain-favoring areas though, precluding the introduction of any fire weather highlights. ..Squitieri.. 09/09/2022 .PREV DISCUSSION... /ISSUED 0157 AM CDT Fri Sep 09 2022/ ...Synopsis... A broad large-scale trough will shift eastward from the northern Rockies into the northern Plains/Upper MS Valley through the period. On the backside of the trough, a belt of enhanced northwesterly midlevel flow will extend from the Pacific Northwest into the northern and central Rockies. As a result, high pressure will strengthen over the northern Rockies, while an elongated area of surface low pressure extends northward along the West Coast. ...Northwest... An enhanced surface pressure gradient between the high pressure over the northern Rockies and low pressure along the West Coast will result in an expansive area of sustained east-northeasterly surface winds of 15-20 mph (with locally higher gusts) across much of the Northwest. The breezy/gusty surface winds, coupled with 10-20 percent minimum RH, will lead to elevated fire-weather conditions given receptive fuels across the region. Strong surface winds are expected to persist within the Cascade gaps into Day 2/Saturday morning, where poor overnight RH recoveries are forecast owing to the persistent offshore flow pattern. While locally critical conditions will be possible primarily over terrain-favored areas along the Cascades, these conditions appear too localized for Critical highlights at this time. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Thu Sep 8 17:44:01 UTC 2022.

No Mesoscale Discussions are in effect as of Thu Sep 8 17:44:01 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 PM CDT Thu Sep 08 2022 Valid 091200Z - 101200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHEAST AND SOUTHWEST... ...SUMMARY... Isolated strong to severe thunderstorms may impact parts of the Southeast and Southwest on Friday, with a risk for occasional damaging wind gusts and perhaps a brief tornado. ...Southeast... A weak upper trough/low should remain centered over the lower MS Valley on Friday. Modestly enhanced low/mid-level flow is forecast to be present on the east side of the upper low, mainly over parts of FL into southern GA and SC. A seasonably moist airmass, with surface dewpoints generally in the low to mid 70s, will likely exist across these areas along/south of a weak front. Even with mid-level lapse rates remaining poor, daytime heating should encourage the development of weak to moderate instability through Friday afternoon, with greater instability forecast with southward extent across the FL Peninsula. Most guidance indicates that thunderstorms will be ongoing Friday morning over the northeastern Gulf of Mexico, perhaps extending into parts of north/central FL. Current expectations are for loosely organized convective clusters to spread generally east/northeastward across much of FL through the day, and into southern GA and coastal SC through Friday night. With generally modest deep-layer shear around 30 kt or less, multicells should be the main convective mode. Occasional damaging winds may occur with the strongest cores, particularly where low-level lapse rates can become steepened through diurnal heating. A brief tornado also appears possible, mainly near the weak front as thunderstorms cross this boundary. ...Southwest... Hurricane Kay is forecast by the National Hurricane Center to move slowly north-northwestward Friday near the northern Baja Peninsula while gradually weakening. Consensus of 12Z guidance shows that enhanced low/mid-level east-southeasterly winds will overspread parts of southern CA/AZ through the day. Even with widespread mid/upper-level cloudiness present over these areas, it appears possible that filtered daytime heating may allow weak instability to develop on the eastern periphery of the broad precipitation shield. If even modest instability can be realized Friday afternoon, then the strong low-level flow and related 0-1 km SRH would favor updraft organization with any low-topped cells that can form in an outer rain/convective band. High-resolution guidance shows some variability on whether this scenario occurs. Regardless, opted to include low severe probabilities for strong/gusty convective winds and a brief tornado across a small part of southern CA and southwestern AZ given the favorable kinematic fields that are forecast. ..Gleason.. 09/08/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Thu Sep 08 2022 Valid 081700Z - 091200Z ...CRITICAL FIRE WEATHER AREA FOR SNAKE RIVER PLAIN... ...CRITICAL FIRE WEATHER AREA FOR SOUTHWESTERN NEBRASKA INTO SOUTHEASTERN SOUTH DAKOTA... Minimal changes where made to the ongoing forecast based on observations and ensemble guidance. Elevated fire weather conditions are possible for areas west of the Cascade crest very late in the period as the surface high intensifies in the Northwest/northern Rockies. The main impacts from these offshore winds are still expected to occur on Friday when wind speeds will peak, however. ..Wendt.. 09/08/2022 .PREV DISCUSSION... /ISSUED 0139 AM CDT Thu Sep 08 2022/ ...Synopsis... An upper trough moving onshore across the Pacific Northwest is forecast to strengthen today as high pressure is broken down over the Southwest. Moderate mid-level flow will spill eastward into the central/northern Rockies and over the High Plains. A lee low over the eastern Plains is expected to strengthen, dragging a cold front south through WY and the Dakotas. Moderate flow aloft and increasing surface pressure gradients driven by the low will support strong surface wind fields across the central Rockies and High Plains into tonight. With unseasonably hot temperatures and very dry fuels, widespread elevated to critical fire weather conditions are expected. ...Central Idaho... As the upper trough continues eastward, moderate flow aloft will linger across central ID behind a cold front. Gusty west winds will develop across the central Rockies and the Snake River Valley, with gusts to 25 mph possible this afternoon and evening. While temperatures will be cooler behind the front, poor overnight humidity recoveries will allow for low diurnal RH values of 15-20%. Fuels remain extremely dry and recent lightning/fire activity lends high confidence to critical fire weather concerns given the favorable RH and wind combinations. ...Wyoming onto the central High Plains... Ahead of the cold front near the surface low, winds are forecast to reach 20-30 mph in the afternoon across portions of eastern CO, NE and southeastern SD. Very hot daytime temperatures should support low afternoon humidity values below 20% along with the strong wind gusts. Widespread elevated and critical fire weather conditions appear likely given very dry fuels. Farther north across central NE and portions of northern CO, the lower humidity may be short lived as the cold front quickly moves south. Some fire weather risk may linger for a few hours behind the front given gusty winds near the surface low. While humidity values should quickly begin to rise, the strong wind shift and very dry fuels may still allow for a few hours of elevated fire weather concerns following frontal passage. Isolated high-based thunderstorms may also develop near and behind the cold front across portions of central and eastern WY. Initially dry, a few lightning strikes and strong outflow winds are possible through the afternoon and early evening. Storm coverage is expected to be relatively low, and strong forcing from the upper trough should eventually support more widespread rainfall limiting the risk for dry strikes. ...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 Thu Sep 08 2022 Valid 081630Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST...WYOMING/BLACK HILLS...FLORIDA...AND MIDDLE TEXAS COASTAL PLAIN... ...SUMMARY... Isolated severe hail and locally damaging winds may occur this evening into the overnight across parts of the Upper Midwest. Isolated severe wind gusts are possible across parts of Florida, the middle Texas Coast, as well as Wyoming and the Black Hills vicinity during the mid to late afternoon. ...Upper Midwest... No changes warranted for this region. Low/mid-level warm advection is expected from a stout upstream EML regime, emanating from where record high temperatures have been set in prior days over a large portion of the interior West. This, in combination with a return-flow process that lacks robust connection to the western Gulf and therefore limits rich boundary-layer moisture, should keep an impinging cold front capped from thunderstorm development through late afternoon. By evening, mid-level height falls should overspread the front in advance of a broad upper trough reaching the Prairie Provinces to northern Great Plains. Strengthening low-level convergence and low-level arm/moist advection may provide sufficient ascent to weaken the EML and yield isolated thunderstorms initially from west-central to northeast Minnesota. Some guidance suggest this process will be more pronounced overnight and thus displaced southward. Regardless, convection is most likely to be rooted on and to the cool side of the southeast-progressing cold front. Deep-layer winds will largely be stronger deeper into the stable air mass away from the immediate front, but still adequate to support rotating updrafts amid moderate elevated buoyancy. Isolated large hail is the primary threat, but locally damaging winds from strong gusts are possible. ...Wyoming/Black Hills vicinity... The trailing portion of a cold front will move south from eastern Montana into northern Wyoming this afternoon. As this occurs, isolated to scattered thunderstorms should develop over the higher terrain of far southern Montana and northwest/north-central Wyoming and then spread east-southeast. Moisture will be poor with surface dewpoints generally in the 30s F, but steep low/mid-level lapse rates should support meager MLCAPE to around 300 J/kg. High-based, skeletal convection may produce isolated severe gusts, augmented by momentum transport from strengthening mid-level winds, and small hail. This threat should diminish rapidly near sunset. ...Central/south Florida Peninsula... To the east of a low centered over the northern Gulf of Mexico, scattered, semi-organized, slow-moving thunderstorms will move across the Florida Peninsula through late afternoon and evening. While low/mid-level winds are not overly strong, ample veering and as much as 20-25 kt effective shear may support a couple of weak/transient supercells, and more prevalently, semi-organized linear segments otherwise. A localized severe storm or two could occur mainly through the afternoon. ...Middle Texas coast/South-Central Texas... In a somewhat similar regime to yesterday across east Texas, modestly enhanced northerly winds aloft in conjunction with moderate buoyancy could yield a few stronger storms this afternoon, with localized wind damage the most probable hazard. ..Guyer/Bentley.. 09/08/2022 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1224 PM CDT Wed Sep 07 2022 Valid 081200Z - 091200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MIDWEST/GREAT LAKES... ...SUMMARY... Isolated thunderstorms may impact parts of the Upper Midwest and Great Lakes vicinity late Thursday afternoon through Thursday night, posing some risk for hail and strong/gusty winds. ...Upper Midwest/Great Lakes... A large-scale upper trough will move eastward across western/central Canada and the northwestern into north-central CONUS on Thursday. As a surface low over central Canada develops towards Ontario, a trailing cold front will sweep southeastward across the northern Plains into the Upper Midwest through the period. A narrow plume of low-level moisture should be present ahead of the front, mainly across MN into WI and the U.P. of MI. Steep mid-level lapse rates associated with a pronounced EML will overspread the warm sector, with a cap likely acting to inhibit convective development through much of Thursday afternoon. As diurnal heating occurs, weak to moderate instability should develop along and just ahead of the cold front. Owing to lingering convective inhibition associated with the stout EML, a fair amount of uncertainty remains regarding overall thunderstorm coverage late Thursday afternoon into the evening across the Upper Midwest. Still, current expectations are for isolated attempts at convection to occur along the length of the front across MN as modest mid-level height falls and ascent overspread this area ahead of the approaching upper trough. Any thunderstorms that can be sustained should be capable of producing isolated severe hail and strong/gusty winds given favorable deep-layer shear as they move generally east-northeastward Thursday evening/night. ...Wyoming into the Northern/Central High Plains... The trailing portion of the upper trough and related surface cold front are forecast to overspread much of WY into the northern and central High Plains on Thursday. Low-level moisture should remain quite meager across these areas, which will likely limit instability. Any thunderstorms that develop Thursday afternoon along or ahead of the cold front may be capable of producing occasional strong/gusty winds given a fairly dry and deeply mixed boundary layer. But, the overall severe wind potential will probably be tempered by the rather weak instability forecast. ..Gleason.. 09/07/2022 Read more

No Mesoscale Discussions are in effect as of Wed Sep 7 17:29:02 UTC 2022.

No watches are valid as of Wed Sep 7 17:29:02 UTC 2022.

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1155 AM CDT Wed Sep 07 2022 Valid 071700Z - 081200Z ...EXTREMELY CRITICAL FIRE WEATHER AREA FOR NORTH-CENTRAL MONTANA... ...CRITICAL FIRE WEATHER AREA FOR SOUTHEASTERN OREGON AND VICINITY... ...CRITICAL FIRE WEATHER AREA FOR PARTS OF WESTERN AND CENTRAL MONTANA... ...CRITICAL FIRE WEATHER AREA FOR SCATTERED DRY THUNDERSTORMS IN EAST-CENTRAL OREGON...CENTRAL IDAHO...SOUTHWEST MONTANA... The ongoing forecast remains on track with minimal changes to the isolated dry thunder area based on observations. A multi-faceted and high-impact fire weather day is still expected across the Northwest into the northern Great Basin and northern Rockies. In the short term, thunderstorm activity is most likely to occur from central into east-central Oregon as a weak disturbance moves north and east. Greater storm coverage can be expected as heating occurs through the afternoon and mid-level ascent increases late afternoon into the evening. Sustained winds and strong gusts will also increase across north-central Montana later today as the boundary layer deepens substantially. See the previous forecast for more details. ..Wendt.. 09/07/2022 .PREV DISCUSSION... /ISSUED 0104 AM CDT Wed Sep 07 2022/ ...Synopsis... A strong pattern shift is forecast across much of the western CONUS today and tonight as the prominent ridge of high pressure is broken down by a strengthening Pacific trough. Unseasonably strong winds aloft along with increasing forcing for ascent will overspread the Pacific Northwest and Northern Rockies, while a cold front sweeps out of southern Canada. Ahead of the front, an unstable atmosphere along with very warm temperatures and strong winds will support weather conditions favorable for dry thunderstorms as well as extreme fire behavior. ...Northern Rockies and adjacent plains... Across portions of northern ID and MT, westerly winds are forecast to increase early this morning and through much of the day ahead of the approaching cold front. Enhanced by strong surface pressure gradients from the deepening lee low across the southern Canadian Rockies, west-southwest surface winds of 25-35 mph are likely by early afternoon. Deep vertical mixing to 600 mb evident on regional model soundings also shows potential for stronger surface gusts (40-50+ mph) as 50-65 kt of flow aloft approaches. Coincident with peak heating, the well-mixed boundary layer, very warm surface temperatures, and downsloping westerly flow will support low teens to single digit RH values. The combination of hot, dry and windy conditions within very dry fuels lends high confidence to widespread critical and extremely critical fire weather conditions across portions of northern and central MT. Extreme fire weather conditions should continue through the afternoon ahead of the fast-moving cold front arriving after dark. While cooler temperatures and increasing humidity will accompany the frontal passage, a rapid wind direction change to northerly flow is also expected. Fire weather concerns may linger for a few hours overnight before winds gradually decrease and surface humidity recovers. ...Dry Thunderstorms... Ahead of the cold front, dynamic ascent and modest mid-level moisture associated with the approaching upper trough will support isolated to scattered thunderstorms from northern CA, through portions of the northern Great Basin, into the northern Rockies. Forecast sounding show generally 0.5 to 0.75 in PWAT values with 100-500 J/kg of MUCAPE. Below the unstable layers, high LCLs (2-3 km AGL) and with fast storm motions will favor poor precipitation efficiency and the potential for strong outflow winds over much of the West. Recent fire activity indicates that fuels remain highly receptive across the region and will support critical lightning-driven fire weather concerns. Storm coverage is expected to be greatest along the cold front from portions of eastern OR, central ID, into western MT. HREF lightning probabilities show high confidence in the potential for scattered strike coverage atop highly receptive fuels in this area. Additionally, the risk for convective outflow gusts greater than 60 mph also suggests a high probability of critical fire weather concerns across this region given the expected storm potential. A Scattered dry thunderstorm area was introduced, and additional information related to the severe weather risk is available in the Day1 Convective Outlook. ...Cascades and northern Great Basin... Across the Cascades and Great Basin westerly flow will remain strong in the wake of the cold front farther east. Bolstered by increasing flow aloft from the upper trough, widespread 15-25 mph surface winds are expected along with low humidity. Widespread elevated fire weather conditions are expected within dry fuels. Critical fire weather conditions will also be possible across portions of the northern Great Basin across southern OR, and far northern CA/NV. Here, higher confidence in winds greater than 25 mph exists along with afternoon humidity values below 15%. ...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 1134 AM CDT Wed Sep 07 2022 Valid 071630Z - 081200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE INTERIOR NORTHWEST/NORTHERN ROCKIES... ...SUMMARY... Scattered thunderstorms may yield scattered severe wind gusts, a few of which could be significant, across portions of the interior Northwest and northern Rockies, centered on mid-afternoon through early evening. ...Interior Northwest/northern Rockies... A high-impact to extreme fire weather day is anticipated this afternoon into the evening. Please see the latest Day 1 Fire Weather Outlook for details on all hazards. Upper ridge will break down over the region as a vigorous shortwave trough over British Columbia amplifies and shifts east-southeastward toward the Canadian Rockies. Mid-level height falls accompanying this wave will overspread the interior Northwest as a belt of 50-kt 500-mb westerlies becomes centered from northeast Oregon/eastern Washington across northern Montana into southern Saskatchewan. Modest moisture along with record warmth will yield very deeply mixed boundary layers, especially east of the Rockies in Montana and across the Idaho Snake River Valley into southeast Oregon. Dry thunderstorms will increase in coverage this afternoon as both the boundary layer deepens and large-scale forcing for ascent strengthens. While buoyancy will be quite meager with MLCAPE of 300 J/kg or less, the extreme lapse rate profiles to 500 mb will support dry downbursts mixing to the surface from high-based/low-topped convection. Latest convection-allowing guidance are consistent in suggesting severe wind gusts will be prevalent within this fast-moving, skeletal activity. The eastern extent of this threat may include amalgamating convective outflows which could maintain severe gusts into eastern Montana despite diminishing lightning flashes this evening. ...Southeast/south-central Texas and southwest Louisiana... A minor mid-level impulse evident in water vapor imagery over the Ark-La-Tex will gradually move south-southwest into south Texas by this evening. A pocket of relatively cooler mid-level temperatures and steeper lapse rates attendant to this impulse should support a plume of moderate to large MLCAPE of 1500-3000 J/kg. While deep-layer shear will be modest and generally offset west of the greater instability/buoyancy, isolated marginally severe hail and strong to localized severe wind gusts will be possible as scattered thunderstorms develop this afternoon. ..Guyer/Bentley.. 09/07/2022 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Tue Sep 06 2022 Valid 071200Z - 081200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PARTS OF EASTERN OREGON...CENTRAL IDAHO...WESTERN/CENTRAL MONTANA... ...SUMMARY... Thunderstorms capable of isolated severe wind gusts will be possible from eastern Oregon into central Idaho and western and central Montana, mainly Wednesday afternoon and evening. ...Interior Northwest into the northern Rockies/High Plains... A partial breakdown of the highly amplified western upper ridge is expected across the Northwest and northern Rockies on Wednesday, as a vigorous midlevel shortwave trough moves across British Columbia and Alberta through the day. Moisture will generally remain rather limited across the Northwest, but may become sufficient to support convection within a hot and well-mixed environment across the interior Northwest into parts of Montana. Very limited buoyancy will tend to limit storm intensity, but the thermodynamic environment will be quite favorable for isolated downburst winds with any sustained storms. There will also be some potential for outflows to consolidate and move east-northeastward with a threat for gusty winds, even if convection attendant to the outflow remains relatively disorganized. A Marginal Risk was added in a corridor from eastern OR through central ID into western/central MT, where there appears to be the greatest potential for possibly multiple rounds of convection with strong/locally severe gusts from late afternoon into the evening. ...Central/east TX... A low-amplitude midlevel shortwave trough is forecast to move southward into parts of central/east TX on Wednesday, around the eastern periphery of the western upper ridge. While this shortwave may tend to weaken and not be ideally timed with the diurnal cycle, it may still aid in the development of scattered thunderstorms during the afternoon. While northerly midlevel flow may support the potential for weakly organized cells/clusters, the severe potential remains uncertain, with generally weak midlevel lapse rates and low-level flow expected. Storms capable of isolated strong gusts and/or marginal hail cannot be ruled out, but confidence is too low to add probabilities at this time. ..Dean.. 09/06/2022 Read more

No watches are valid as of Tue Sep 6 17:34:02 UTC 2022.