Severe Storms

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook CORR 1 NWS Storm Prediction Center Norman OK 1241 PM CDT Sun Jul 17 2022 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE MONDAY AFTERNOON AND EVENING ACROSS PARTS OF NORTHEASTERN MONTANA INTO NORTHWESTERN NORTH DAKOTA... CORRECTED FOR A COUPLE TYPOS ...SUMMARY... Strong to locally severe thunderstorm development is possible near the Canadian/U.S. border, from the Great Plains into the upper Great Lakes region, as well as across parts of the northern Mid Atlantic region, Monday afternoon into Monday night. ...Synopsis... Models indicate that lower/mid-tropospheric ridging will generally persist from the subtropical western Atlantic through much of the southern and central tier of the U.S. through this period. This will continue to include one prominent embedded mid-level high centered over the southern Rockies vicinity, and another elongated along 30N latitude across the western Atlantic, with weak mean troughing in between, roughly along an axis from the lower Mississippi Valley into the western slopes of the Appalachians. It does appear that flow may become a bit more progressive across the northern tier of the U.S., with a vigorous short wave trough and embedded low within one belt of westerlies forecast to accelerate across the northern Rockies into the northern Great Plains by late Monday night. Downstream, a more modest impulse likely will accelerate from the lower Great Lakes/upper Ohio Valley vicinity through northern New England. Both of these perturbations (preceding significant short wave impulses within a branch to the north, including one digging near or just south of southern Hudson Bay and another accelerating inland of the British Columbia coast) may be accompanied by surface cyclogenesis, with the lead cyclone probably becoming the more prominent while migrating from the lee of the lower Great Lakes into the St. Lawrence Valley. ...Northern Mid Atlantic... Pre-frontal surface troughing, extending from near the migratory low southward through the Mid Atlantic, likely will become the focus for the more prominent boundary-layer destabilization during the day Monday. The boundary-layer probably will become characterized by seasonably high moisture content, but lower/mid tropospheric lapse rates are expected to be generally weak, and most guidance suggests that CAPE may not reach 1000 J/kg. However, a belt of 30-40+ kt southwesterly flow in the 850-500 mb layer will potentially contribute to an environment conducive to organized convection given sufficient destabilization. It is possible that this could include a couple of supercells with a risk for tornadoes, particularly across the Poconos and Catskills into Hudson Valley vicinity by late Monday afternoon. ...Northern Rockies into upper Great Lakes region... In association with the short wave developments, models indicate that a lower/mid tropospheric front within an evolving deformation zone will become focused near the international border area, from the Great Plains into the upper Great Lakes region. Along and to the southwest of this front, a plume of warm and capping elevated mixed-layer air is forecast to advect east of the Rockies. At mid-levels (around 700 mb) the northeastern periphery of this air mass may generally extend from north of the international border across the Great Plains into the western Lake Superior/Upper Michigan vicinity by early Monday evening. Beneath this regime, in the presence of moderate west/northwesterly mid-level flow, there may be sufficient moisture to contribute to mixed-layer CAPE on the order of 2000+ J/kg, and the environment appears likely to become at least conditionally supportive of severe storms, potentially including isolated supercells and organizing storm clusters. However, forcing to overcome the mid-level inhibition remains unclear across much of the region. Most guidance does appear to suggest that a concentrated area of strong forcing for ascent, just to the east-northeast of the approaching mid-level low, may overcome inhibition and promote sustained thunderstorm development across parts of northeastern Montana by early Monday evening. This may be accompanied by the risk for severe wind and hail, which probably will spread into portions of northwestern and north central North Dakota through Monday night. ..Kerr.. 07/17/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1130 AM CDT Sun Jul 17 2022 Valid 171630Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE OZARK PLATEAU THROUGH THE OHIO RIVER VALLEY... ...SUMMARY... Damaging thunderstorm gusts and isolated large hail are possible today from the Ozarks to the central Appalachians, as well as across eastern North Dakota and northwest Minnesota. ...Synopsis... A pair of weak upper-level disturbances/MCVs remain evident in mid-level reflectivity mosaics across central IL and the upper OH River Valley. Embedded within a broad trough across the great Great Lakes region, these features are expected to continue to propagate to the east/northeast through the day. Widespread stratiform rain with embedded convection in the vicinity of these two features is diabatically reinforcing a stalled cold front draped through the OH River Valley into the southern Plains. This front is expected to gradually migrate southward through the day and will likely be the impetus for thunderstorm development and/or intensification later this afternoon. Across the west, ample monsoonal moisture across the Great Four Corners region and into the northern Rockies will support scattered thunderstorm development with the potential for severe downburst winds. ...Upper OH River Valley... The ongoing showers and thunderstorms across the mid to upper OH River Valley are limiting the potential for daytime heating across the region. Temperatures are currently struggling to climb above the mid 70s with few breaks in cloud cover expected through at least mid afternoon. With lift and modest, but sufficient, deep-layer flow already in place ahead of the MCVs, the greater severe threat will likely reside along and south of the OH River Valley where some destabilization is already noted. Latest CAMs support this idea and show clusters developing by late afternoon through the region. Severe probabilities have been adjusted southward to reflect this trend. ...Ozark Plateau into the lower OH River Valley... Morning showers and thunderstorms across southern MO and into adjacent parts of AR, IL, and KY will likely limit diurnal heating through at least early afternoon. Some guidance suggests sufficient clearing can take place to allow thunderstorm development across central to southern MO by mid-afternoon, and latest visible satellite imagery and surface temperature trends across western MO support this idea, but the degree of destabilization that can occur remains uncertain. Confidence in storm development is higher to the south across AR and into the mid-MS River Valley where destabilization is already ongoing with temperatures climbing into the low/mid 80s. While mid to upper-level flow will be modest, adequate deep-layer shear should be in place to support semi-discrete storms to clusters from western AR into western KY/TN to support an isolated hail/severe wind threat. A brief tornado or two appears possible across the mid-MS River Valley region where low-level helicity along and just ahead of the front will be maximized, but confidence in storm mode and coverage remains too limited for higher probabilities. ...Red River Valley of the North... Latest surface observations across northeast ND into northwest MN show surface pressure falling over the past several hours, which is resulting in a slight bolstering of generally southerly low-level flow through the region. In turn, dewpoints have increased into the 70s through the region, which is boosting MLCAPE estimates to over 2000 J/kg. Despite the improving buoyancy, 12 UTC soundings from BIS and ABR reveal some mixed-layer inhibition, which remains a concern for convective potential later this afternoon. Forecast soundings suggest this inhibition may become negligible by this afternoon, and several CAMs show discrete supercell potential as storms develop along a weak surface trough. However, some spread in guidance remains with other solutions showing little to no activity south of the international border. The Marginal risk has been expanded south to encompass much of the Red River Valley, but this is to more accurately address spatial extent of the severe threat rather than indicate an increase in the probability for thunderstorms. ...Montana... Morning soundings from MT and ID sampled 50-60 knot winds aloft ahead of a shortwave trough located across the Pacific Northwest. These soundings also sampled mid-level monsoonal moisture and fairly dry boundary layers. With daytime heating already underway, thermodynamic profiles across southern MT should be favorable for thunderstorms with strong to severe downbursts by late this afternoon. Combined ascent ahead of the shortwave trough and via orographic ascent should support isolated to scattered thunderstorms across the region. ...Nevada/Utah... Similar to southern MT, 12 UTC soundings from LKN, VEF, and SLC all sampled dry boundary layers with adequate mid-level monsoonal moisture to support thunderstorms by this afternoon. Forecast soundings show 2 to 3 km deep sub-cloud layers with steep low-level lapse rates that will be supportive of strong to severe downburst winds. Latest CAM guidance shows a strong convective signal across northeast NV into northwest UT this afternoon, which gives sufficient confidence to introduce severe wind probabilities given the expected thermodynamic environment. ..Moore/Hart.. 07/17/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1114 AM CDT Sun Jul 17 2022 Valid 171700Z - 181200Z The ongoing forecast reasoning remains valid. Locally critical fire weather remains possible in far northwest Nevada into southeastern Oregon. See the previous discussion for further information. ..Wendt.. 07/17/2022 .PREV DISCUSSION... /ISSUED 0147 AM CDT Sun Jul 17 2022/ ...Synopsis... To the northwest of a prominent anticyclone over the Southwest, a deepening Pacific trough will move ashore, overspreading strong flow aloft across the Northwest and Great Basin. At the surface, a cold front will move inland triggering isolated thunderstorms along the Cascades and northern Rockies. The strong surface flow, and dry/warm conditions across the southern Cascades/Great Basin will support several hours of elevated to near-critical fire weather conditions. ...Northern Great Basin... With flow aloft strengthening on the periphery of the upper ridge, dry downslope winds will develop off the Sierra and into the northern Great Basin this afternoon and evening. Deep mixing within the dry airmass across the region will support sustained winds of 15-20 mph and locally higher gusts. With widespread surface RH expected below 15%, the environment will easily support widespread elevated to near-critical fire weather conditions into early evening. Confidence in sustained critical conditions is lower, owing to borderline winds. However, the most likely corridor for some critical concerns appears to be across far northern NV into southeastern OR closer to the mid-level jet axis. A few hours of stronger sustained winds may develop here, but confidence remains too low for a Critical area at this time. Farther east, modest mid-level moisture on the periphery of the ridge will support a few thunderstorms across portions of central/eastern ID. Model soundings show high-based and fast-moving storms which may produce occasional lightning over dry fuels. While some risk of dry thunder likely exists given minimal wetting rain potential, storm coverage appears too low to warrant IsoDryT probabilities. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

No watches are valid as of Sat Jul 16 17:56:02 UTC 2022.

MD 1492 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE MID-ATLANTIC INTO NORTHERN NC
Mesoscale Discussion 1492 NWS Storm Prediction Center Norman OK 1236 PM CDT Sat Jul 16 2022 Areas affected...Portions of the Mid-Atlantic into northern NC Concerning...Severe potential...Watch unlikely Valid 161736Z - 162030Z Probability of Watch Issuance...20 percent SUMMARY...Thunderstorms capable of producing isolated hail and damaging winds should spread slowly eastward this afternoon. Watch issuance appears unlikely at this time. DISCUSSION...There are rather prevalent low/mid-level clouds associated with a weak mid-level shortwave trough over parts of western/northern VA into western MD. To the east of these clouds, filtered diurnal heating should continue this afternoon along/south of a weak boundary that extends across southern portions of the Mid-Atlantic. As surface temperatures climb further into the 80s and 90s across the warm sector, weak to moderate instability will aid thunderstorm development. This process has already begun across parts of south-central VA into northern/central NC. Low/mid-level flow should remain fairly modest across these regions, but some enhancement to the mid-level westerlies (around 20-30 kt) associated with the weak shortwave trough could foster convective organization this afternoon. A mix of pulse thunderstorms and loosely organized multicells should spread slowly eastward over the next few hours. Isolated gusty to perhaps damaging downdraft winds should be the main threat as low-level lapse rates become steepened. Occasional marginally severe hail may also occur, as mid-level temperatures are seasonably cool. Current expectations are for the overall severe threat to remain rather isolated/marginal through the rest of the afternoon, and watch issuance appears unlikely at this time. ..Gleason/Hart.. 07/16/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...AKQ...LWX...RAH...RNK... LAT...LON 39647710 39657641 39607586 39197541 38707560 37697621 37017671 36197743 35817813 35767862 35957935 36177997 36677979 37157932 37687859 38807763 39647710 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Sat Jul 16 2022 Valid 171200Z - 181200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SUNDAY AFTERNOON AND EVENING ACROSS PARTS OF THE LOWER OHIO VALLEY INTO ALLEGHENY PLATEAU...OZARK PLATEAU/MID SOUTH...AND NORTHERN ROCKIES... ...SUMMARY... Strong thunderstorms may impact parts of the Ohio Valley and Allegheny Plateau into the Ozark Plateau and Mid South, as well as portions of the northern Rockies vicinity Sunday afternoon and evening, accompanied by at least some risk for damaging wind gusts. ...Synopsis... Lower/mid-tropospheric ridging will generally be maintained from the lower latitude western Atlantic through much of the U.S., including a couple of prominent embedded mid-level high centers over the Four Corners states and subtropical western Atlantic. Mid-level ridging within the westerlies to the north of the Four Corners high may become suppressed as far east as the northern Rockies, as a mid-level low turns inland of the Pacific Northwest coast. To the east of this ridging, a couple of digging perturbations may contribute to the evolution of larger-scale mid-level troughing east of the upper Mississippi Valley through the upper Ohio Valley and lower Great Lakes, accompanied by influxes of cooler and/or drier low-level air. ...Upper Ohio Valley into Allegheny Plateau... Preceding one lead short wave perturbation within the evolving larger-scale mid-level troughing, low-level moistening may contribute to a corridor of mixed-layer CAPE on the order of 1000-2000 J/kg by Sunday afternoon with daytime heating. Thermodynamic profiles may be characterized by generally modest to weak lower/mid-tropopheric lapse rates and a high degree of saturation. However, a corridor of stronger thunderstorm development appears possible near the leading edge of the stronger mid-level forcing for ascent, which may coincide with 30-40+ kt flow on the southern fringe of the westerlies. This may be accompanied by the evolution of a slow moving squall line with the potential to produce damaging wind gusts, aided by heavy precipitation loading and downward momentum transport, before convection weakens by Sunday evening. ...Ozark Plateau/Mid South vicinity... Severe probabilities have been adjusted some to more closely align with a zone of stronger differential heating forecast to develop beneath a plume of warm elevated mixed-layer air emanating from the Great Plains. It remains unclear the extent to which forcing for ascent associated with digging perturbations upstream of the larger-scale mid-level trough axis will impact this developing boundary, and low-level warm advection along it may remain weak. However, given the presence of at least modestly steep mid-level lapse rates, sizable CAPE in excess of 2000 J/kg, and modest deep-layer shear, the environment probably will become at least conditionally supportive of organized convection with the potential to produce damaging wind gusts sometime late Sunday afternoon into Sunday night. ...Northern Rockies... Due to limited moisture, models suggest that CAPE may only reach 500 J/kg or so by late Sunday afternoon, within a deeply mixed boundary layer across the higher terrain of southwestern into central Montana. However, forcing for ascent, aided by orography, downstream of the inland migrating low, coupled with shear beneath 30-50 kt flow in the 500-300 mb layer, might become conducive to organized convective development spreading northeastward off the higher terrain accompanied by potential to produce strong surface gusts by Sunday evening. ..Kerr.. 07/16/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Sat Jul 16 2022 Valid 161700Z - 171200Z No changes to the ongoing forecast. ..Wendt.. 07/16/2022 .PREV DISCUSSION... /ISSUED 0136 AM CDT Sat Jul 16 2022/ ...Synopsis... Ridging will remain dominant across much of the western and central US as very warm and very dry conditions persist. A shortwave trough along the northwestern periphery of the mid-level anticyclone will move ashore across the West Coast later in the day. Accompanying stronger mid-level flow should gradually expand across the Great Basin and southern Cascades, bolstering modest surface winds for a few hours. Across the Southwest, monsoon thunderstorms are expected to remain mostly wet, while very warm conditions (temperatures 100F+) and weak winds will continue across the Plains. ...Northern Great Basin and southern Cascades... Modest westerly winds through the higher terrain are forecast across much of northern NV and southeastern OR today. Mid-level flow is forecast to slowly weaken through the morning before rebounding ahead of the trough moving onshore across the Pacific Northwest. As a result, low-level winds should remain modest through the first half of the day. However, hi-res guidance does show increasing probabilities for sustained 15-20 mph winds later in the afternoon coincident with sub 15% RH across the northern Great Basin/southern Cascades. Given dry area fuels, elevated fire weather conditions may develop later this afternoon, persisting into the evening. ...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 1121 AM CDT Sat Jul 16 2022 Valid 161630Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE CENTRAL PLAINS...LOWER MISSOURI VALLEY...MD/DC/VA REGION...AND SOUTHERN AZ... ...SUMMARY... Isolated severe thunderstorms are possible over the central Plains this afternoon and evening, and possibly across the lower Missouri Valley overnight. Damaging to isolated severe gusts are also expected this afternoon from Maryland southward across Virginia, and over southern Arizona. ...Central NE... A broad upper ridge is present over much of the central/southern Plains and Rockies today. Several minor shortwave troughs are traversing the northern periphery of the ridge across the WY/NE vicinity. These features will interact with a weak surface boundary extending from central MO into central NE, resulting in scattered afternoon and evening thunderstorms. Most 12z CAM solutions show a cluster of thunderstorms forming by late afternoon over central NE. These storms will track southeastward toward the KS border during the evening. A SLGT risk area was considered for this area. However, abundant mid-level clouds will slow daytime heating, and mid-level winds and temperatures are not particularly favorable for severe storms. Locally gusty/damaging winds will be possible with the stronger cells, but the overall coverage/intensity of these storms is uncertain. Therefore will maintain MRGL risk at this time and reconsider at the 20z update. ...Eastern CO/western KS... Hot surface temperatures will result in steep low-level lapse rates and a deeply mixed boundary layer this afternoon over parts of eastern CO and western KS. Scattered high-based thunderstorms are expected to develop and spread slowly eastward across this area through the evening. Gusty outflow winds are expected, but weak flow aloft and limited large scale forcing should limit the areal coverage of severe threat. ...VA/MD... Warm/humid conditions over eastern VA/MD will result in isolated to widely scattered afternoon thunderstorms. Forecast soundings show poor mid-level lapse rates and weak flow in the lowest 6-7km, which should limit convective organization and intensity. Nevertheless, a few cells may occasionally result in strong/damaging wind gusts through early evening. ...AZ... Water vapor imagery shows a weak vort max and plume of mid-level moisture moving across northern Mexico. This feature will likely result in scattered high-based showers and thunderstorms across parts of southern and central AZ this afternoon and evening. Hot surface temperatures and a deeply mixed boundary layer will support a risk of gusty/damaging winds in the strongest cells. ..Hart/Dean.. 07/16/2022 Read more

No watches are valid as of Fri Jul 15 17:56:02 UTC 2022.

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1219 PM CDT Fri Jul 15 2022 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS CENTERED ACROSS THE CENTRAL PLAINS AREA... ...SUMMARY... Isolated severe thunderstorms are possible over the central Plains vicinity on Saturday. ...Synopsis... A relatively stagnant upper flow regime will persist across the U.S. Saturday, as a ridge remains dominant across the western and south-central states. Meanwhile, a trough will shift slowly eastward across western Canada and the Pacific Northwest, while a second trough over eastern North America continues making gradual eastward progress. Within the northwesterly flow between the western ridge and eastern trough, a series of vorticity maxima -- loosely functioning as a broader-scale short-wave trough -- will move southeastward out of the northern Plains and across the Upper Midwest through the period. At the surface, a cold front will move slowly across the Pacific Northwest, while a second/weaker front sags slowly southeastward across the Midwest and central Plains. ...Central High Plains to northern Missouri... Scattered showers and thunderstorms are forecast to be ongoing at the start of the period across portions of the northern and central Plains, with lingering convection and associated boundaries a complicating factor with respect to storm evolution/severe potential later in the day Saturday. While limited severe risk may linger across the Dakotas and Minnesota during the day, uncertainty prevails, precluding any severe-weather probabilities across this region in this update. From a larger-scale perspective, a surface front progged to extend east-to-west across the central Plains will be a focus for convective development. Isolated storms may initially develop across the central High Plains, while warm advection to the cool side of the boundary also suggests late afternoon storm development, as daytime heating contributes to a corridor of moderate destabilization. As a south-southwesterly low-level jet develops during the evening, isolated storms moving eastward across the High Plains may interact/congeal with convection farther east, potentially yielding an eastward-/southeastward-moving MCS across Kansas. While this scenario remains uncertain, the strengthening low-level jet beneath 40 kt west-northwesterly mid-level flow suggests this potential. In any case, gusty/locally damaging winds will be possible from afternoon into the overnight hours, with any stronger storms. ..Goss.. 07/15/2022 Read more

MD 1486 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PARTS OF WESTERN INTO CENTRAL MONTANA
Mesoscale Discussion 1486 NWS Storm Prediction Center Norman OK 1221 PM CDT Fri Jul 15 2022 Areas affected...Parts of western into central Montana Concerning...Severe potential...Watch likely Valid 151721Z - 151915Z Probability of Watch Issuance...80 percent SUMMARY...A developing cluster of thunderstorms is expected to intensify and become better organized east of the Continental Divide. This may be accompanied by a developing swath of strong to severe wind gusts across and south of the Great Falls vicinity into central Montana (north through south of Lewistown) by 2-4 PM MDT. DISCUSSION...Downstream of one notable short wave perturbation progressing northeast of the Oregon Cascades, forcing for ascent has supported a sustained cluster of thunderstorms now spreading into and across the Continental Divide vicinity of western Montana. This activity appears to be focused near the nose of a 40-50 kt jet streak around 500 mb, with associated momentum contributing to a current forward propagation up to 40-45 kt. As forcing for ascent spread east of the higher terrain into areas near and south of the Great Falls vicinity within the next few hours, the environment appears likely to become increasingly conducive to renewed, intensifying thunderstorm development along an associated strengthening surface cold pool. In advance of the cold pool, forecast soundings suggest that further insolation will contribute to a seasonably warm and well-mixed boundary layer, including large surface temperature/dew point spreads up to around 40 F, but also characterized by CAPE on the order of 1000-1500 J/kg. Coupled with strengthening deep-layer shear, the evolution of an increasingly organized convective system seems possible, accompanied by increasing potential to produce strong to severe wind gusts while spreading into central Montana by 20-22Z. ..Kerr/Hart.. 07/15/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...GGW...TFX... LAT...LON 47601241 48121135 48380993 47750874 46800882 46250920 45451212 46481174 47601241 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1107 AM CDT Fri Jul 15 2022 Valid 151700Z - 161200Z The forecast remains unchanged. See the previous discussion for greater details. ..Wendt.. 07/15/2022 .PREV DISCUSSION... /ISSUED 0157 AM CDT Fri Jul 15 2022/ ...Synopsis... Across the western US, the mid-level flow pattern will remain dominated by a prominent anticyclone centered over the Southwest and southern High Plains. To the west of the ridge, a Pacific trough will move shoreward, bolstering mid-level southwesterly flow across the Cascades and northern Rockies. Beneath the ridge, a strong monsoonal surge will support scattered to widespread thunderstorms across the Southwest. Meanwhile, very warm and dry conditions are expected across the southern and central High Plains with temperatures exceeding 100F. ...Northern Great Basin... Modest southwesterly flow along the periphery of the ridge will support dry downslope flow off the Sierra across portions of northern NV, southeastern OR and eastern ID. Surface RH below 15% and winds near 15 mph will support elevated fire weather concerns given area fuel ERC values above the 90th percentile. Winds should gradually weaken overnight as the shortwave and stronger flow aloft move quickly northeastward. To the south and east, monsoonal moisture will support scattered thunderstorms across portions of central and northeastern NV. Along the northwestern fringe of the monsoonal plume, model soundings show initially dry sub-cloud layers greater than 2km deep supporting dry strikes over receptive fuels. Storm coverage and PWATs are forecast to gradually increase through the day, supporting wetter storms. However, the potential for a few drier strikes initially within receptive fuels necessitates continuation of the IsoDryT area across north/northeastern NV. ...Southwest KS and the Panhandles... Beneath the center of a strong and sustained mid-level anticyclone, a very warm airmass should develop across portions of the southern and central High Plains this afternoon. Low-level southerly flow bolstered by a weak lee trough/decaying cold front may support gusty winds to 15-25 mph coincident with surface RH below 20%. Ongoing drought and excessive heat (temps greater than 100F) will favor curing of short-hour fuels and the possibility of Elevated fire weather conditions. ...Southern Cascades... A gradual increase in low-level westerly flow is forecast today as mid and upper-level winds strengthen with the passing trough. Hi-res guidance indicates at least localized potential for winds greater than 15 mph through terrain gaps and in the immediate lee of the southern Cascades. Dry and warm conditions with humidity below 30% may coincide with these gustier winds, supporting locally elevated fire weather conditions across portions of OR. However, uncertainty on the areal coverage of sustained elevated fire weather conditions remains high, precluding any Elevated delineations. ...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 1103 AM CDT Fri Jul 15 2022 Valid 151630Z - 161200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MONTANA INTO WESTERN NORTH DAKOTA... ...SUMMARY... Scattered strong to severe storms, including a risk of damaging winds and hail, will be possible across parts of the northern Rockies and High Plains today and tonight. ...MT/ND... Morning water vapor imagery shows a well-defined shortwave trough moving across eastern OR. This feature and its associated mid-level speed max will track across ID into MT this afternoon. Large-scale lift ahead of the trough is already resulting in scattered thunderstorms over the mountains of western MT, which will spread eastward into central/eastern MT this afternoon and evening. Hot surface temperatures in the 90s or low 100s are expected, yielding a deeply mixed boundary layer with 500-1000 J/kg of MLCAPE. This will support high-based convection capable of locally damaging wind gusts. This activity will likely spread into western ND after dark. Winds aloft weaken with southward extent, but at least isolated strong to severe wind gusts will be possible into parts of northern/eastern WY and western NE/SD this afternoon. ..Hart/Kerr.. 07/15/2022 Read more

No watches are valid as of Thu Jul 14 18:02:02 UTC 2022.

MD 1480 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE FL PENINSULA
Mesoscale Discussion 1480 NWS Storm Prediction Center Norman OK 1256 PM CDT Thu Jul 14 2022 Areas affected...Portions of the FL Peninsula Concerning...Severe potential...Watch unlikely Valid 141756Z - 142100Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe hail and damaging winds may occur with the strongest thunderstorms this afternoon. Watch issuance appears unlikely at this time. DISCUSSION...Convection has recently developed along both sea breezes on the west and east coasts of the FL Peninsula. MLCAPE of 2500-3000 J/kg will be common across this area with continued robust diurnal heating. Seasonably cool mid-level temperatures associated with a weak upper low over northern Cuba and the Bahamas are also contributing to this substantial buoyancy. Even though low-level winds will remain weak, some modest enhancement to the mid and upper-level flow field was noted in 12Z soundings from MFL/KEY due to the proximity of the upper low. Some anvil-level venting should occur with scattered to numerous thunderstorms that will develop over much of the FL Peninsula in the next few hours. This venting, along with the cool mid-level temperatures and moderate to strong instability, should aid in the production of isolated marginally severe hail with the more robust updrafts. Occasional strong to damaging downdraft winds may also occur as low-level lapse rates continue to steepen with daytime heating and as DCAPE increases to around 1000 J/kg. Still, current expectations are for the overall severe threat to remain isolated/marginal owing to the weak deep-layer shear. Accordingly, watch issuance appears unlikely at this time. ..Gleason/Thompson.. 07/14/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW...JAX... LAT...LON 27798290 28548272 29148276 29398208 29138141 28378084 27628052 26968019 26128041 25438091 25398121 25818172 26538224 27798290 Read more

MD 1480 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF THE FL PENINSULA
Mesoscale Discussion 1480 NWS Storm Prediction Center Norman OK 1256 PM CDT Thu Jul 14 2022 Areas affected...Portions of the FL Peninsula Concerning...Severe potential...Watch unlikely Valid 141756Z - 142100Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe hail and damaging winds may occur with the strongest thunderstorms this afternoon. Watch issuance appears unlikely at this time. DISCUSSION...Convection has recently developed along both sea breezes on the west and east coasts of the FL Peninsula. MLCAPE of 2500-3000 J/kg will be common across this area with continued robust diurnal heating. Seasonably cool mid-level temperatures associated with a weak upper low over northern Cuba and the Bahamas are also contributing to this substantial buoyancy. Even though low-level winds will remain weak, some modest enhancement to the mid and upper-level flow field was noted in 12Z soundings from MFL/KEY due to the proximity of the upper low. Some anvil-level venting should occur with scattered to numerous thunderstorms that will develop over much of the FL Peninsula in the next few hours. This venting, along with the cool mid-level temperatures and moderate to strong instability, should aid in the production of isolated marginally severe hail with the more robust updrafts. Occasional strong to damaging downdraft winds may also occur as low-level lapse rates continue to steepen with daytime heating and as DCAPE increases to around 1000 J/kg. Still, current expectations are for the overall severe threat to remain isolated/marginal owing to the weak deep-layer shear. Accordingly, watch issuance appears unlikely at this time. ..Gleason/Thompson.. 07/14/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW...JAX... LAT...LON 27798290 28548272 29148276 29398208 29138141 28378084 27628052 26968019 26128041 25438091 25398121 25818172 26538224 27798290 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Thu Jul 14 2022 Valid 151200Z - 161200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHERN ROCKIES/NORTHERN HIGH PLAINS...AND ACROSS PARTS OF THE UPPER MIDWEST VICINITY... ...SUMMARY... Isolated severe storms, including local risk for strong wind gusts and hail, will be possible across parts of the northern High Plains on Friday. Local severe risk may also occur across portions of the Upper Midwest during the day. ...Synopsis... A generally stagnant pattern aloft will persist Friday, with pronounced western and central U.S. ridging flanked by northeastern Pacific and eastern North America troughing. Weak short-wave features progressing through anticyclonic flow aloft will continue to support weak surface frontal progressions across the northern Rockies and northern Plains through the period. ...Northern Rockies/northern High Plains area... Another day of heating/modest destabilization is expected over the northern Intermountain region, ahead of another in a series of short-wave troughs progressing eastward within the belt of stronger, anticyclonic flow around the northern periphery of stout/persistent upper ridging. As in prior days, this will result in renewed, isolated convective development across the region. Given ample flow aloft to support locally organized, eastward-progressing storms, a few stronger convective elements will again become capable of producing gusty/damaging winds and marginally severe hail locally. During the evening, development of a southeasterly low-level jet over the northern High Plains may aid in continuation of ongoing storms, potentially spreading into the western Dakotas through evening, along with possible/local severe risk. ...Parts of the Upper Midwest vicinity... A rather pronounced mid-level trough cresting the ridge and shifting southeastward across the Upper Mississippi Valley region at the start of the period may be supporting ongoing/warm-advection-aided convection Friday morning. Minimal/local risk for gusty winds may then continue through the morning, spreading southeastward across southeastern Minnesota/northeastern Iowa and roughly the southern half of Wisconsin and adjacent northern Illinois. As the associated cold front shifts southeastward through the day, some southwestward development of convection may occur, perhaps into portions of west-central Illinois and northeastern Missouri through the afternoon and evening. Locally gusty/damaging winds and hail would be possible, before diminishing during the evening hours. ..Goss.. 07/14/2022 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook CORR 2 NWS Storm Prediction Center Norman OK 1203 PM CDT Thu Jul 14 2022 Valid 141630Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON INTO TONIGHT FOR PARTS OF THE DAKOTAS AND WESTERN MN... CORRECTED FOR OUTLOOK GRAPHICS (GEN TSTM LINE/SEVERE WIND PROBS) ...SUMMARY... The greatest conditional severe-weather concern is across parts of the Dakotas and western Minnesota, where large hail and damaging gusts are possible from late afternoon through tonight. ...Northern Plains this afternoon into tonight... A midlevel shortwave trough over southern SK/MB is cresting the midlevel ridge and will begin to move southeastward toward MN this evening into tonight. Some elevated convection is ongoing as of late morning over northeast ND, in a zone of weak warm advection near a northwest-southeast oriented warm front. The potential for diurnal, surface-based convection is in question along the front, given that surface temperatures will need to warm to 90F or above to remove convective inhibition across east/southeast ND, and clouds are upstream from this area now. If storms manage to form, the environment will conditionally favor supercells capable of producing large hail/damaging winds, and perhaps a tornado. However, the more probable scenario will be for slightly elevated storms/clusters to form along the immediate cool side of the front tonight, and spread southeastward toward western MN, with an attendant threat for large hail/damaging winds. ...Southern MT vicinity this afternoon through tonight... Daytime heating and local terrain circulations are expected to initiate at least widely scattered thunderstorms this afternoon across southern MT, in conjunction with subtle speed maxima within the monsoonal moisture plume around the northern periphery of the Four Corners high aloft. Westerly midlevel flow with relatively long/straight hodographs, deep mixing/inverted-v profiles, and modest buoyancy will support the potential for isolated severe outflow gusts and marginally severe hail with small clusters and high-based supercells from southern MT this afternoon into northeastern WY this evening. ...TX area this afternoon/evening... A cluster of storms is ongoing as of late morning across northeast/east central TX, in association with a diffuse midlevel trough and pocket of slightly cooler midlevel temperatures. Given the organized nature of the cold pool with these storms and weak northeasterly midlevel steering flow, the storms will likely persist through the afternoon while spreading southwestward. The 12z FWD sounding depicted a hybrid microburst environment, and strong surface heating in advance of the storms will result in steepening low-level lapse rates, moderate buoyancy (MLCAPE around 1500 J/kg), and DCAPE in the range of 1000-1500 J/kg. A few damaging/severe outflow gusts will be the main threat this afternoon through late evening. ...Southeast/FL this afternoon/evening... A weak midlevel trough persists from GA to the Carolinas, and a separate closed low is moving westward over the north coast of Cuba. Somewhat enhanced midlevel west-southwesterly flow will support the potential for semi-organized storms/clusters and isolated wind damage from southeast GA to the Carolina coasts this afternoon. Sea breeze convection is likely across the FL peninsula, with easterly flow aloft favoring storm motion and subsequent outflow mergers inland from the southeast FL coast to the west coast sea breeze. The strongest storms will be capable of producing isolated damaging downbursts, as well as marginally severe hail, given the strong buoyancy (MLCAPE near or above 3000 J/kg), DCAPE near 1000 J/kg, and slightly cooler midlevel temperatures compared to previous days. ...Eastern MA to southeastern ME this afternoon... Pockets of stronger surface heating, weak low-level convergence along a cold front and local sea breeze boundaries could support widely scattered thunderstorm development this afternoon. Though buoyancy will remain modest, somewhat enhanced midlevel flow and effective bulk shear in excess of 30 kt could support isolated strong/damaging gusts. ..Thompson.. 07/14/2022 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1136 AM CDT Thu Jul 14 2022 Valid 141700Z - 151200Z Minor changes were made to the fire weather highlights to reflect the latest guidance consensus. Otherwise, the previous forecast (see below) remains on track. ..Squitieri.. 07/14/2022 .PREV DISCUSSION... /ISSUED 0109 AM CDT Thu Jul 14 2022/ ...Synopsis... The dominant upper ridge over the Four Corners region will remain in place for the next several days and will limit overall boundary-layer and surface wind speeds. However, this feature will also promote hot conditions across the Southern Plains into the Southwest and diurnal thunderstorm chances across the Great Basin and Four Corners region. This synoptic regime will limit the potential for widespread fire weather concerns, but will support regional threats across parts of Nevada and western Kansas. ...Nevada... Despite a generally weak synoptic regime, deep diurnal boundary-layer mixing, coupled with downslope flow off the Sierra Nevada, will likely result in sustained winds around 15 mph across northwest to north-central NV this afternoon. Poor overnight RH recovery is noted across this region, and afternoon RH values should once again fall into the teens for much of the risk area. While critical wind speeds are not expected given weak flow aloft, fuels remain receptive across the region and will support areas of elevated fire weather conditions. Such conditions may overlap with parts of northeast NV that received lightning strikes Wednesday afternoon, posing a threat for holdover fires, though confidence in the northeastern extent of dry/windy conditions is somewhat low. ...West Kansas... A low-amplitude mid-level wave cresting the upper ridge is supporting modest lee pressure falls along the northern High Plains. This trough is expected to consolidate into a weak low over the central Plains, and will support another day of a dry return-flow pattern across western KS. The low wind-speed bias that is common in most guidance under this type of pattern is noted in yesterday's surface observations with observed gusts coming in stronger than anticipated by most deterministic and ensemble solutions. For today, a slightly stronger regional pressure gradient should yield winds closer to 15-20 mph with gusts up to 30 mph (after accounting for the noted low bias). Afternoon minimum RH values in the low 20s appear likely over a region with ERC values near or above the 80th percentile (outside of where thunderstorms tracked Wednesday evening). This should support areas of elevated conditions this afternoon. ...Dry Thunderstorms... Regional 00 UTC soundings continue to sample steep mid-level lapse rates and ample monsoonal moisture across the Four Corners region and diminishing moisture quality with western extent into Nevada. This matches well with latest satellite-based total precipitable water estimates, which show PWAT values between 0.75 to 0.9 inches across eastern NV. This thermodynamic regime supported a mix of wet and dry thunderstorms yesterday (Wednesday) across NV and western UT. Rainfall amounts increased with eastward extent into central UT (per MRMS QPE estimates). A similar regime is expected for today with isolated dry/wet thunderstorms across central to eastern NV where PWAT values near or below 0.75 inches are expected, and fuels remain receptive after receiving only localized pockets of wetting rainfall on Wednesday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1479 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL TX
Mesoscale Discussion 1479 NWS Storm Prediction Center Norman OK 1120 AM CDT Thu Jul 14 2022 Areas affected...Portions of central TX Concerning...Severe potential...Watch unlikely Valid 141620Z - 141845Z Probability of Watch Issuance...20 percent SUMMARY...A loosely organized complex of thunderstorms may pose an isolated threat for strong to damaging winds through the afternoon. Watch issuance appears unlikely at this time. DISCUSSION...A cluster of convection developed overnight across northeast TX on the eastern periphery of an upper ridge centered over the Southwest. This cluster has persisted through the morning while moving slowly southwestward. Although low/mid-level flow across much of TX is expected to remain modest, around 15-25 kt of northeasterly mid-level winds should encourage the ongoing thunderstorms to continue progressing southwestward across parts of central TX through the early afternoon. A rather moist airmass is in place ahead of this activity, with surface dewpoints generally in the upper 60s to low 70s. Strong diurnal heating will likely continue over the next several hours based on recent visible satellite trends, and instability should further increase in tandem with steepening low-level lapse rates. Even with deep-layer shear remaining modest, the moderate to strong instability forecast to develop, including substantial DCAPE with inverted-v forecast soundings, should support an isolated risk for strong to damaging winds. Still, current expectations are for this damaging wind threat to remain fairly isolated, and watch issuance appears unlikely at this time. ..Gleason/Thompson.. 07/14/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...HGX...FWD...EWX...SJT... LAT...LON 31079524 30099569 29959660 30039761 30559855 31389908 32149912 32879871 33099799 33079691 32549686 31669638 31079524 Read more