Severe Storms

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Thu Aug 03 2023 Valid 051200Z - 111200Z ...Dry Thunderstorms - Northern Great Basin into Northwest... Monsoonal moisture will linger over the northern Great Basin and Northwest on Day 3/Saturday. While the area will generally be beneath a midlevel trough and becoming displaced from the associated large-scale ascent, sufficient instability and modest forcing along/east of the Cascades should still support isolated high-based thunderstorms over central/eastern OR into northeast CA and northwest NV. If thunderstorms can form over this area, 0.5-0.7 inch PW and inverted-V thermodynamic profiles will favor a mix of dry/wet thunderstorms capable of lightning-induced ignitions. ...Central Texas into southwest Oklahoma... A continuation of 100 deg temperatures, 10-15 mph sustained southerly winds (with higher gusts), and 20 percent RH, will support elevated to spotty critical fire-weather conditions on Day 3/Saturday -- exacerbated by critically dry fuels (97th percentile ERCs). Therefore, 40-percent Critical probabilities are in place for this risk. For Day 4/Sunday, a cold front and related northerly wind shift is expected over southern OK into north-central TX, which could impact any ongoing fires. While confidence in the development of 15 mph sustained surface winds is too low for Critical probabilities at this time, Elevated highlights could eventually be needed. For next week, a continuation of elevated fire-weather conditions is possible, though possible precipitation and the frontal passage casts uncertainty on the overall threat. ...Southwest... A warming/drying trend is expected during the extended forecast period across parts of the Southwest, as a large-scale ridge builds over southwest NM/southeast AZ. At the same time, a belt of moderate westerly midlevel flow will overspread the area along the northern periphery of the ridge. As a result, breezy surface winds and low RH should yield elevated to critical fire-weather conditions as fuels continue to dry. 40-percent Critical probabilities have been added for Days 4-5/Sunday-Monday over northwest NM into northeast AZ -- where rainfall accumulations have been limited and confidence in the overlap of dry/breezy conditions is highest. Additional probabilities could eventually be needed depending on fuel trends during the next couple of days. ..Weinman.. 08/03/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1822 CONCERNING SEVERE THUNDERSTORM WATCH 581... FOR CENTRAL PORTIONS OF ALABAMA AND GEORGIA
Mesoscale Discussion 1822 NWS Storm Prediction Center Norman OK 0324 PM CDT Thu Aug 03 2023 Areas affected...central portions of Alabama and Georgia Concerning...Severe Thunderstorm Watch 581... Valid 032024Z - 032230Z The severe weather threat for Severe Thunderstorm Watch 581 continues. SUMMARY...Risk for damaging wind gusts continues across WW 581, and will continue to expand southward with time into central portions of Alabama and Georgia. DISCUSSION...Latest radar loop shows an organized/nearly continuous band of strong/locally severe storms, extending west-to-east from northeastern Georgia to northwestern Alabama. The band is moving southeastward at 25 kt, with local gusts resulting in multiple areas of tree damage over the past hour. With gradual destabilization still underway, expect this band of storms to remain organized and continue moving southward over the next few hours. As storms encroach on the southwestern edge of the watch over the next hour or so, consideration of an areal WW extension -- or new WW issuance -- will become necessary. ..Goss.. 08/03/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CAE...GSP...FFC...TAE...BMX...MOB...MEG...JAN... LAT...LON 33778832 33638722 33708573 33948408 34268314 33708237 31768322 31638601 31818796 33778832 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Thu Aug 03 2023 Valid 041200Z - 051200Z The primary change with this update was to add an Elevated area for parts of central Texas into southwest Oklahoma. While current indications are that sustained surface winds could be slightly weaker (around 10 mph with 15-20 mph gusts) than previous days, continued 100 deg afternoon temperatures and steep low-level lapse rates amid the gusty afternoon winds will still support elevated fire-weather conditions given very dry fuels (97th percentile ERCs). Farther west, only minor adjustments were made to the Isolated Dry Thunderstorm highlights based on the latest high-resolution guidance. For details, see the previous discussion below. ..Weinman.. 08/03/2023 .PREV DISCUSSION... /ISSUED 1223 AM CDT Thu Aug 03 2023/ ...Synopsis... Monsoon moisture will continue to expand west on D2/Friday with scattered wet/dry thunderstorms and an inverted-v thermal profile across portions of eastern Oregon, northeast California and northwest Nevada. ERC values in this region are mostly in the 90th percentile across this region, supporting new lightning starts. Slow storm motion and the potential for wetting rain under some cores precludes the need for a SctDryT area despite scattered storm coverage. Some dry and breezy conditions are expected across the Columbia Basin on Friday as a weak surface low develops across northeast Washington. Winds are expected to be around 10 to 15 mph with relative humidity around 15 to 20 percent. ERCs are in the 90th to 95th percentile in this region. Therefore, an Elevated delineation is warranted, given the dry and breezy conditions amid dry fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Thu Aug 03 2023 Valid 041200Z - 051200Z The primary change with this update was to add an Elevated area for parts of central Texas into southwest Oklahoma. While current indications are that sustained surface winds could be slightly weaker (around 10 mph with 15-20 mph gusts) than previous days, continued 100 deg afternoon temperatures and steep low-level lapse rates amid the gusty afternoon winds will still support elevated fire-weather conditions given very dry fuels (97th percentile ERCs). Farther west, only minor adjustments were made to the Isolated Dry Thunderstorm highlights based on the latest high-resolution guidance. For details, see the previous discussion below. ..Weinman.. 08/03/2023 .PREV DISCUSSION... /ISSUED 1223 AM CDT Thu Aug 03 2023/ ...Synopsis... Monsoon moisture will continue to expand west on D2/Friday with scattered wet/dry thunderstorms and an inverted-v thermal profile across portions of eastern Oregon, northeast California and northwest Nevada. ERC values in this region are mostly in the 90th percentile across this region, supporting new lightning starts. Slow storm motion and the potential for wetting rain under some cores precludes the need for a SctDryT area despite scattered storm coverage. Some dry and breezy conditions are expected across the Columbia Basin on Friday as a weak surface low develops across northeast Washington. Winds are expected to be around 10 to 15 mph with relative humidity around 15 to 20 percent. ERCs are in the 90th to 95th percentile in this region. Therefore, an Elevated delineation is warranted, given the dry and breezy conditions amid dry fuels. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0251 PM CDT Thu Aug 03 2023 Valid 032000Z - 041200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE CENTRAL PLAINS... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF THE TN VALLEY AND NORTHWEST NY... ...SUMMARY... The most concentrated threat for severe gusts and large hail will be later this afternoon into early tonight across parts of the central Plains. ...Discussion... The only appreciable change made to the previous convective outlook was to adjust severe probabilities across parts of TN/AL/GA based on the evolution of the broken band of storms this afternoon over AL/GA. ..Smith.. 08/03/2023 .PREV DISCUSSION... /ISSUED 1127 AM CDT Thu Aug 03 2023/ ...Central High Plains later this afternoon into tonight... A midlevel shortwave trough over northwest CO/southwest WY will begin to turn more eastward this afternoon/evening, with a belt of modestly enhanced midlevel flow expected to overspread the central High Plains this afternoon into early tonight. Residual boundary-layer dewpoints at or above 60 F in the post-frontal environment, along with daytime heating in cloud breaks, will drive moderate buoyancy this afternoon/evening from northeast CO eastward into northern KS. Diurnal convection is expected to first form by mid afternoon near or just east of the Front Range, and storms will subsequently spread eastward across east/northeast CO and southwest NE while gradually growing upscale through storm interactions. Isolated large hail will be possible the more discrete/initial storms that could have some supercell structures given modest hodograph length and effective bulk shear near 35 kt and midlevel lapse rates greater than 7 C/km. Damaging winds will become the primary threat this evening into early tonight, with a few swaths of 60-75+ mph winds possible. ...TN Valley this afternoon/evening... The remnants of an overnight MCS in MO has now progressed into southern middle TN and extreme northern AL, with a general weakening trend over the past few hours. Diurnal destabilization is ongoing to the south-southwest of the weakening storms from northeast MS across northern/central AL into northwest GA, but there is uncertainty regarding the future evolution of the ongoing storms. One possibility is for some intensification along the leading outflow as the convection moves toward northwest GA/northeast AL through early-mid afternoon, though the storms/outflow are not phased particularly well with the more unstable warm sector. Also, the stronger midlevel flow tends to lag the initial convection, and these concerns keep confidence low in the evolution of the afternoon storms (and any resultant wind damage threat). Aside from diurnal intensification, there will be the potential for late evening/early overnight storm formation in another west-northwest/east-southeast oriented band from TN into northern AL. Given the inherent uncertainty in the forecast and at least two possible storm scenarios, will only make minor changes to the ongoing outlook. ...NY to eastern Lower MI this afternoon into tonight... An embedded speed max is rotating east-southeastward over southern ON and will reach the Saint Lawrence Valley by late evening/early tonight. Some convection is ongoing in association with this shortwave trough and a surface cold front, and some low-level warming/moistening will occur ahead of the front from ON into northwest NY through this evening. The primary convective threat will likely to spread into northwest NY near or after sunset, but there will still be some potential for isolated damaging winds, especially if an storms evolve into an organized band prior to crossing into NY late this evening into tonight. Farther west into Lower MI, thunderstorm coverage is more in question, given that the stronger forcing for ascent will pass to the north of this area. Lapse rates/buoyancy and some modest enhancement to deep-layer vertical shear will conditionally favor the potential for isolated wind damage or some hail, but storm coverage is likely to remain rather isolated. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1227 PM CDT Thu Aug 03 2023 Valid 041200Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS A PORTION OF THE NORTHEAST... ...SUMMARY... Severe thunderstorms producing hail and damaging gusts are possible across parts of the Northeast on Friday afternoon. Additional strong storms are possible along a broad arc from the central Plains to the Southeast. ...Synopsis... A mid-level trough over the Northeast will feature moderate westerly flow moving through its base during the period. A flattened mid-level anticyclone over the southwest border states will remain while a belt of modestly enhanced mid-level flow extends from the central Rockies across the central Great Plains and towards the southern Appalachians. ...Northeast... A cold front will push through the region during the period. Along this boundary, showers and a few thunderstorms will likely be ongoing Friday morning near the NY/Ontario border. Southerly low-level flow will maintain a fetch of 60s deg F dewpoints. Heating during the morning amidst cloud breaks will result in a moderately unstable airmass by midday into the early afternoon. A weak cap will erode and scattered thunderstorms are likely to develop in a broken band from PA north-northeast into New England by 17z. A mix of cells and linear structures will likely transition to mostly linear convection during the afternoon with widely scattered damaging gusts being the primary hazard. The thunderstorms will weaken by evening as they approach the coast. ...AR to Southern GA/Northern FL... Similar to Thursday morning, showers and thunderstorms will likely occur Friday morning from eastern MO southeastward into the TN Valley. Remnant outflow and a zone of differential heating related to this early day activity will be focus for thunderstorm development during the afternoon. Very moist low levels will contribute to moderate to strong instability. It remains unclear if/where a thunderstorm cluster will form during the afternoon. Damaging gusts will be possible with the stronger storms. ...Central Plains... Not much change in forecast thinking at this point compared to the previous convective outlook. Moist, upslope low-level flow within moderately unstable environment will support thunderstorm development over western portions of the central High Plains by late afternoon. A weak boundary is forecast to develop southward across NE into KS with storm coverage increasing during the evening. Several thunderstorm clusters, initially posing a risk for hail and strong gusts, are expected to develop east/southeast and likely focus the majority of the isolated severe risk. ..Smith.. 08/03/2023 Read more

No watches are valid as of Wed Aug 2 22:19:20 UTC 2023.

MD 1815 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN UTAH
Mesoscale Discussion 1815 NWS Storm Prediction Center Norman OK 0509 PM CDT Wed Aug 02 2023 Areas affected...Portions of northern Utah Concerning...Severe potential...Watch unlikely Valid 022209Z - 022345Z Probability of Watch Issuance...5 percent SUMMARY...A severe wind threat will persist for another 1 to 2 hours across northern Utah. DISCUSSION...A cluster/broken line of thunderstorms has produced severe wind gusts across portions of the southern Salt Lake Basin over the past 1 to 2 hours. These storms continue to move north into a region with temperatures in the upper 70s to near 80 and 1000 J/kg MLCAPE. This should support a continued threat for damaging wind gusts into the evening across northern Utah. Expect these storms to weaken by mid to late evening as storms move out of the greater instability and the boundary layer begins to cool. ..Bentley/Mosier.. 08/02/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...RIW...SLC... LAT...LON 40541200 40501273 40711317 41311332 41871293 41981121 41711101 40901110 40631126 40541200 Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0417 PM CDT Wed Aug 02 2023 Valid 041200Z - 101200Z ...Dry Thunderstorms - Northern Great Basin into the Northwest... A plume of monsoonal moisture will be in place across parts of the northern Great Basin into the Northwest on Days 3-4/Friday-Saturday. This midlevel moisture atop a warm/deeply mixed boundary layer will yield sufficient instability for high-based thunderstorms -- aided by a series of subtle/low-amplitude midlevel impulses and possible MCVs crossing the region. 0.5-0.7 inch PW and inverted-V thermodynamic profiles in central OR into northeast CA/northwest NV will favor isolated dry thunderstorms capable of lightning-induced ignitions on Days 3-4/Friday-Saturday. Deeper monsoonal moisture over eastern OR will promote a mix of wet/dry thunderstorms, with storms becoming increasingly wet into western ID. The primary concern with this activity is lightning strikes along the peripheries of rain cores. Strong/erratic outflow winds are possible with thunderstorms each day given the deep/dry sub-cloud layer. ...Central Texas... Slightly weaker sustained surface winds on Day 3/Friday (compared to previous days) could limit the fire-weather threat briefly over central TX. With that said, continued 100 deg afternoon temperatures and critically dry fuels will still support elevated fire-weather conditions. Thereafter, an increase in surface winds is possible on Days 4-5/Saturday-Sunday, leading to increasing fire-weather concerns. Currently, confidence in the development of critical conditions is too low to add probabilities, though highlights may eventually be needed. ...Southwest... Despite persistent thunderstorm activity across the Southwest over the last week, rainfall accumulations have generally been minimal with the exception of northwest AZ. By Day 3/Friday into next week, a warming/drying trend is expected across the Southwest, which combined with strengthening winds could result in increasing fire-weather concerns. Continued model differences on the overlap of strong winds/low RH over dry fuels casts uncertainty on where the fire-weather threat will be maximized, though probabilities/highlights could eventually be needed. ..Weinman.. 08/02/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Aug 02 2023 Valid 031200Z - 041200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF CENTRAL TEXAS INTO SOUTHWEST OKLAHOMA... Portions of central Texas into southwest Oklahoma (along/west of the I-35 corridor) were upgraded to Critical with this update. Fuels across this area are becoming increasingly dry (95th+ percentile ERCs) given the persistent 100 deg afternoon temperatures and lack of rainfall. While sustained surface winds around 15 mph would typically be borderline for Critical highlights, frequent 20-25 mph gusts and the critically dry fuels should generally compensate for this. For additional details on the Day 2 fire-weather risk, see the previous discussion below. ..Weinman.. 08/02/2023 .PREV DISCUSSION... /ISSUED 0158 AM CDT Wed Aug 02 2023/ ...Synopsis... A surface low will continue to deepen across central Kansas on Thursday which will tighten the pressure gradient across the southern Plains. Dry and breezy conditions (15 mph sustained winds and 20 to 30 percent relative humidity) are expected from central Oklahoma into central Texas with temperatures over 100F. These meteorological conditions, paired with critically dry fuels which continue to dry further each day, support an Elevated area across portions of the southern Plains on Thursday. Monsoon moisture will continue to drift west on Thursday, with isolated thunderstorms amid 0.75 to 1 inch PWAT values across portions of eastern Oregon, northeast California and northwest Nevada. These storms will be slow moving, but LCLs will be around 12kft, which will support mostly dry thunderstorms. In addition, 90th to 95th percentile ERCs should be in place across most of this region on Thursday. Therefore, an IsoDryT delineation is warranted on Thursday to cover the potential for new lightning starts. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0255 PM CDT Wed Aug 02 2023 Valid 022000Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A LARGE PART OF MISSOURI INTO FAR SOUTHERN ILLINOIS... ...SUMMARY... The greatest severe-thunderstorm potential appears to be over parts of the lower Missouri Valley region toward the lower Ohio Valley, this afternoon into evening. Severe gusts and large hail are expected, along with a marginal tornado threat. ...Discussion... The only change to the previous convective outlook was to remove low-severe probabilities in wake of the convective band over UT. ..Smith.. 08/02/2023 .PREV DISCUSSION... /ISSUED 1129 AM CDT Wed Aug 02 2023/ ...MO and vicinity this afternoon through tonight... Overnight convection (associated with low-level warm advection) has been slowly weakening through the morning over MO. A couple of MCVs emanating from the overnight convection will continue to move east-southeastward through the afternoon. There is some uncertainty regarding the potential for diurnal convection along the residual front/outflow boundary across MO/northeast KS, given the presence of substantial cloud cover and the need for surface temperatures to warm well into the 90s to reduce convective inhibition. Will maintain the outlook area with no changes in this update, but will have to monitor for late afternoon storm development near the KS/MO border close to I-70. If storms form in this area, the environment will conditionally favor the potential for large hail/damaging winds, and perhaps an isolated tornado, with a mix of supercells and multicell clusters. Convection is expected to persist overnight with a renewed strengthening of a southwesterly low-level jet and warm advection. ...Central High Plains this afternoon/evening... Lingering low-level moisture across the central High Plains and surface heating in cloud breaks may again support scattered thunderstorm development to the east of the higher terrain later this afternoon into this evening. Vertical shear will be relatively weak, though a few strong outflow gusts will be possible. ...UT/northern AZ today... A well-defined MCV with associated convection is moving slowly northeastward from the lower CO River Valley toward UT. Strong surface heating/mixing will occur in advance of the ongoing convection, which will also coincide with a belt of modestly enhanced midlevel flow. The net result will be the potential for a few strong-severe outflow gusts with a broken band of convection spreading northeastward through the afternoon. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Wed Aug 02 2023 Valid 031200Z - 041200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR FAR NORTHEAST COLORADO...FAR SOUTHWEST NEBRASKA...AND NORTHWEST KANSAS... ...SUMMARY... Scattered severe thunderstorms are possible over the central High Plains beginning Thursday afternoon and continuing through late Thursday evening. Severe gusts in the 60-80 mph range are the primary hazard. ...Synopsis... The mean upper flow regime on Thursday will be characterized by a ridge oriented over the Great Plains and a trough centered over the lower Great Lakes/Northeast. A convectively-aided mid-level shortwave trough is forecast to move from the OH/MS River confluence into GA through the late evening. Another convectively-aided disturbance is forecast to move from eastern UT/southwest WY east into the north-central High Plains. Embedded within the larger-scale southeast Canada mid-level trough, an impulse is forecast to move southeast through its base during the period. These three features will focus strong to severe thunderstorm potential on Thursday/Thursday night. ...Central High Plains vicinity... Mid/upper westerly flow around 30-40 kt is forecast as the mid-level perturbation ejects eastward through the afternoon/evening. East/southeasterly low-level flow will maintain 60s F surface dewpoints across the region, supporting a corridor of 1500-3000 J/kg MLCAPE. Effective-shear magnitudes around 35-45 kt will support organized cells capable of large hail initially and an increasing risk for severe gusts with time. Steep 700-500 mb lapse rates will overspread the Enhanced Risk categorical area over eastern CO/western KS as 0-2 km lapse rates become adequately steep by the 22-00z timeframe. Models are is relatively good agreement in showing an organized thunderstorm cluster developing over eastern CO and becoming more expansive as it encounters increasingly rich moisture and larger CAPE. The latest CAM guidance shows a focused corridor where severe gusts are most probable and a risk for significant gusts (exceeding 75 mph) may be realized during the MCS's mature phase during the evening centered over northwest KS. This activity will continue east into central KS with a gradually reducing wind hazard into the late night. ...TN Valley vicinity... There is high confidence for a corridor of showers/thunderstorms to be ongoing Thursday morning over the lower OH Valley into TN. On the southern and western periphery of cloud debris/convective outflow, differential heating will favor additional storm development during the day across the TN Valley with more isolated storm coverage along the trailing baroclinic zone perhaps extending into the Ozarks. Appreciably strong northwesterly mid/upper flow will aid in storm organization once robust storms develop. It seems probable at least some linear configuration will evolve with the diurnal storm activity centered over northern AL. Strong heating amidst a moist/mixed boundary layer will lend potential for damaging gusts with this threat peaking during the mid-late afternoon. If uncertainty regarding mesoscale details is reduced in terms of placement of the most intense storms, additional refinement of severe probabilities may become necessary. ...Great Lakes/Northeast vicinity... Model guidance doesn't show much change to the previously issued forecast in showing a shortwave impulse embedded in the larger-scale eastern trough moving across the Great Lakes much of the period. A belt of 30-40 kt midlevel flow will overlap a seasonally moist boundary layer ahead of a south/southeast-advancing cold front. MLCAPE generally less than 1500 J/kg is forecast amid modest midlevel lapse rates. Low-level flow will be fairly light, but speed shear will support effective-shear magnitudes around 25-35 kt. Forecast soundings show elongated/straight hodographs, and marginally severe hail will be possible with stronger updrafts. Strong heating will result in steep low-level lapse rates, and strong outflow winds also will be possible. ..Smith.. 08/02/2023 Read more

No Mesoscale Discussions are in effect as of Tue Aug 1 22:16:06 UTC 2023.

WW 0578 Status Updates
STATUS REPORT ON WW 578 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..08/01/23 ATTN...WFO...FGF...GGW...BIS... STATUS REPORT FOR WS 578 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MNC005-027-029-051-087-089-107-111-113-119-125-167-012240- MN . MINNESOTA COUNTIES INCLUDED ARE BECKER CLAY CLEARWATER GRANT MAHNOMEN MARSHALL NORMAN OTTER TAIL PENNINGTON POLK RED LAKE WILKIN MTC021-083-085-109-012240- MT . MONTANA COUNTIES INCLUDED ARE DAWSON RICHLAND ROOSEVELT WIBAUX NDC001-003-007-011-015-017-021-025-027-029-031-033-035-037-039- 041-043-045-047-051-053-055-057-059-061-063-065-073-077-081-083- 085-087-089-091-093-097-103-105-012240- ND . NORTH DAKOTA COUNTIES INCLUDED ARE Read more

WW 578 SEVERE TSTM MN MT ND 012050Z - 020500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 578 NWS Storm Prediction Center Norman OK 350 PM CDT Tue Aug 1 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwest Minnesota Extreme northeast Montana North Dakota * Effective this Tuesday afternoon from 350 PM until Midnight CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Widely scattered thunderstorm development is expected this afternoon from northwest Minnesota westward across North Dakota, where the environment will favor splitting supercells capable of producing large hail and damaging winds. Additional storm development is expected near the Montana/North Dakota border, with the potential for these storms to grow into a cluster with damaging winds while moving east-southeastward through early tonight. The severe thunderstorm watch area is approximately along and 65 statute miles north and south of a line from 65 miles south southwest of Williston ND to 25 miles northeast of Detroit Lakes MN. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU8). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 30020. ...Thompson Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Tue Aug 01 2023 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF CENTRAL TEXAS INTO SOUTHWEST OKLAHOMA... The Critical area was expanded slightly based on the latest high-resolution guidance. Farther west, locally elevated fire-weather conditions are possible in the Cascade gaps, though these conditions appear too localized for highlights. For additional details, see the previous discussion below. ..Weinman.. 08/01/2023 .PREV DISCUSSION... /ISSUED 1225 AM CDT Tue Aug 01 2023/ ...Synopsis... A surface cyclone will continue to slowly deepen across the central Plains on Wednesday as the upper-level ridge continues to deamplify. This will maintain a pressure gradient across the southern Plains, with a strengthening low-level jet late Wednesday afternoon and Wednesday evening. As a result, 15 to 20 mph winds are expected from central Texas into northern Oklahoma with relative humidity of 20 to 30 percent. While these conditions are well within the range of Elevated fire-weather criteria, they are borderline for a Critical area. However, fuels are very dry in the region and with temperatures over 100F, are expected to continue to dry further. Therefore, sustained Elevated conditions may be more capable of large-fire potential than typical Critical fire-weather conditions due to the fuel status. This warrants a Critical delineation for areas along and west of I-35 in central and northern Texas and into far southwest Oklahoma. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0249 PM CDT Tue Aug 01 2023 Valid 012000Z - 021200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON THROUGH EARLY TONIGHT FOR PARTS OF THE NORTHERN PLAINS AND CENTRAL HIGH PLAINS... ...SUMMARY... Severe-thunderstorm gusts are most probable over parts of the central High Plains and much of North Dakota to northwestern Minnesota, along with at least isolated large hail. ...20Z Update... Overall forecast remains on track with no changes needed to the existing outlook. Late afternoon thunderstorm development is still anticipated over ND, both along the front in north-central ND and in the MT/ND border vicinity. The environmental conditions still support supercells capable of large hail and damaging gusts. Additionally, ongoing thunderstorms across central CO as are still expected to grow upscale later this evening, with an attendant threat for severe outflow gusts and isolated large hail. ..Mosier.. 08/01/2023 .PREV DISCUSSION... /ISSUED 1119 AM CDT Tue Aug 01 2023/ ...Northern Plains through tonight... A midlevel shortwave trough is cresting the midlevel ridge and will continue east-southeastward over southern SK/AB toward ON, as an associated weak cold front moves southeastward into ND. Convection is ongoing in a few clusters near the ND/MT/SK border and northwest MN along the north edge of the unstable warm sector. Some form of these storms could persist through the afternoon, though the main severe threat is expected to be additional development along the front and/or outflow boundaries by mid-late afternoon. Steep midlevel lapse rates, boundary-layer dewpoints in the 65-70 F range and daytime heating will boost MLCAPE to 2000 J/kg or greater as convective inhibition weakens. Low-level flow will be weak beneath moderately strong mid-upper westerly flow, resulting in small low-level hodographs and longer hodographs above about 4 km AGL. This environment will support a mix of multicell clusters and some supercells capable of producing large hail and damaging winds as convection spreads southeastward late this afternoon into early tonight. ...Central High Plains this evening... Within the monsoonal moisture plume, convectively-enhanced waves will move slowly eastward from UT/WY/CO toward NE. Thunderstorms are expected to form later this afternoon near and just east of the Front Range in a weak upslope flow regime in CO, and convection will subsequently grow upscale into a cluster or two across northeast CO and vicinity this evening. Moderate buoyancy and relatively weak vertical shear will mainly favor multicell clusters capable of producing occasional severe outflow gusts and isolated large hail. ...MO area through tonight... Elevated convection persists late this morning over central MO in a low-level warm advection regime, though this convection is expected to diminish as warm advection weakens this afternoon. There will be a low chance for afternoon storm development on the west edge of the cloud debris and northeast edge of the hot surface temperatures/deeper mixing near the KS/MO border, with a conditional wind/hail threat. The more probable scenario will be for renewed thunderstorm development tonight as warm advection increases again on the nose of a southwesterly low-level jet. The overnight storms will be capable of producing isolated large hail and possibly a few strong outflow gusts. ...Carolinas to FL this afternoon... Surface heating with lingering low-level moisture, beneath midlevel drying, will result in moderate destabilization across the eastern Carolinas, where isolated thunderstorms are expected this afternoon along the sea breeze and subtle terrain influences inland. Buoyancy will be larger to the south (>2500 J/kg MLCAPE from southeast GA southward) where widely scattered afternoon thunderstorms are expected mainly inland from the west coast sea breeze. The moderate buoyancy, DCAPE near 1000 J/kg, and some modest enhancement to vertical shear from north FL northward will support a low-end threat for strong/damaging downburst winds. Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1226 PM CDT Tue Aug 01 2023 Valid 021200Z - 031200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL MISSOURI INTO SOUTHERN ILLINOIS... ...SUMMARY... Thunderstorms capable of damaging gusts are possible from central Missouri into southern Illinois Wednesday afternoon through evening. Isolated strong to severe thunderstorms capable of producing damaging gusts and hail are also possible across the Upper Great Lakes region and central High Plains. ...Synopsis... Upper ridging is forecast to remain in place over the southern Plains and Lower MS Valley, keeping that region hot and dry. Some modestly enhanced mid-level flow will exist from the northern Plains/Upper Midwest through the Mid-Atlantic, between the southern Plains ridge and an upper low over the Hudson Bay. A shortwave trough and associated surface low will likely move through this enhanced flow across Ontario. An attendant cold front is expected to move into the northern Plains, Upper Midwest, and Upper Great Lakes, with some thunderstorms possible along the front during afternoon and evening. Additionally, a convectively induced vorticity maximum will likely track eastward over the central Plains and into the Mid/Lower MO Valley. Some thunderstorms are possible from the Mid MO Valley into the Mid MS Valley as this vorticity maximum interacts with the moist and buoyant air mass over the region. ...Mid MO Valley into the Mid MS Valley... Numerous showers and thunderstorms will likely be ongoing Wednesday morning in an arc from far eastern NE to southeast MO/southern IL/far western KY, remnant from overnight storms from the Mid MO Valley into the Mid MS Valley. These storms will likely dissipate by late morning/early afternoon, but residual cloud cover and resulting differential heating will help induce a warm-front-like boundary across MO. Dewpoints are expected to be in the mid 70s in the vicinity of this boundary Wednesday afternoon, contributing to moderate/strong buoyancy. Even with strong daytime heating south/west of the boundary, some convective inhibition will likely persist, particularly with southwestward extent, where mixing will be greatest. However, convergence along this differential heating zone, combined with slightly higher dewpoints and less overall mixing, as well as ascent from the approaching vorticity maximum, is expected to result in convective initiation. Strong buoyancy will support a risk for hail within the first hour or so of development, before cell interactions and outflow-dominant structures influence a more linear storm mode. Additionally, given the presence of a surface boundary and some more southeasterly surface winds, a tornado or two cannot be entirely ruled out. However, a somewhat quick transition to a predominantly linear mode is anticipated, with at least some chance for cold pool organization into a coherent linear convective system. This system should then track southeastward along the buoyancy gradient into southeast MO, southern IL, and potentially even far western KY. ...Upper Midwest into the Upper Great Lakes... Moderate buoyancy is anticipated ahead of the approaching cold front mentioned in the synopsis. Convergence along the boundary will be modest, with higher storm coverage expected across Upper MI versus farther west across northern WI and northeast MN. Even so, expected moderate buoyancy will combine with 30-40 kt of effective bulk shear to support organized thunderstorms. Forecast soundings show modestly steep midlevel lapse rates and elongated/straight hodographs above around 1-2 km. This suggests isolated hail potential with the strongest storms. Where stronger heating occurs, steep low-level lapse rates will foster isolated strong/damaging gusts as well. ...Central High Plains... Afternoon thunderstorms across the higher terrain are forecast to progress eastward into the lower elevations of the central High Plains during the late afternoon/early evening. Steep low-level lapse rates and high cloud bases will likely support a few stronger gusts as this activity moves eastward into western KS. ..Mosier.. 08/01/2023 Read more

No watches are valid as of Mon Jul 31 22:16:01 UTC 2023.

MD 1800 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PARTS OF CENTRAL/NORTH ND
Mesoscale Discussion 1800 NWS Storm Prediction Center Norman OK 0511 PM CDT Mon Jul 31 2023 Areas affected...Parts of central/north ND Concerning...Severe potential...Watch unlikely Valid 312211Z - 312345Z Probability of Watch Issuance...20 percent SUMMARY...Isolated severe storms will be possible this evening, with a threat of large hail and localized severe gusts. Watch issuance is currently considered unlikely, but will become possible if storm coverage becomes greater than expected. DISCUSSION...A small cluster of storms has recently developed over southwest Manitoba, with attempts at convective initiation noted across far northeast Bottineau County, ND, and increasing cumulus across north-central ND. Modest diurnal heating amid relatively rich low-level moisture is supporting moderate buoyancy (MLCAPE of 1500-3000 J/kg), while northwesterly midlevel flow is supporting effective shear of 35-45 kt across the region. As a result, the environment is conditionally favorable for supercell development. The primary uncertainty this evening is storm coverage. While multiple mid/upper-level shortwave troughs are moving across the Canadian Prairies, most of ND is under the influence of an upper ridge, and large-scale ascent will likely remain limited. However, a weak warm-advection regime may continue to support isolated storm development, with any mature storms tending to propagate southeastward along the primary instability gradient. As a result, a supercell or two may develop and move across parts of north and central ND this evening, with a threat of large hail and localized severe gusts. Watch issuance is currently considered unlikely due to the expectation for the threat to remain isolated, but will become possible if short-term trends support a greater coverage of storms than currently anticipated. ..Dean/Grams.. 07/31/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...BIS... LAT...LON 48990147 48989982 48299952 47629936 47379944 47120011 47250081 47710124 48100147 48660158 48990147 Read more