Severe Storms

MD 2085 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF MO...SOUTHEAST KS...NORTHEAST/CENTRAL OK...AND FAR NORTHWEST AR
Mesoscale Discussion 2085 NWS Storm Prediction Center Norman OK 0404 PM CDT Tue Sep 05 2023 Areas affected...Portions of MO...southeast KS...northeast/central OK...and far northwest AR Concerning...Severe potential...Watch possible Valid 052104Z - 052330Z Probability of Watch Issuance...60 percent SUMMARY...The severe-storm risk should increase during the next few hours. Severe gusts and isolated hail are both possible. A watch issuance is possible this afternoon. DISCUSSION...Latest surface analysis shows a northeast/southwest- oriented cold front extending from northwest MO into parts of central OK this afternoon -- where shallow boundary-layer cumulus is beginning to develop. Continued diurnal heating amid rich boundary-layer moisture (lower 70s surface dewpoints) along/immediately ahead of the east-southeastward-moving front should support convective initiation in the next few hours. Steep low/mid-level lapse rates and 20-30-kt midlevel west-southwesterly flow oriented oblique to the surface front (strongest across MO) will initially support semi-discrete storms capable of marginally severe hail and locally severe gusts. However, a fairly quick transition from cells to an organized line of storms is expected as storms maintain residence time in the frontal circulation amid increasing outflow generation. This mode transition will favor an increasing severe-wind threat as the front continues slowly east-southeastward into the evening hours. Currently, the potential for an organized QLCS appears greatest over parts of MO -- where deep-layer shear and large-scale ascent will be stronger compared to areas farther southwest. However, 100 deg surface temperatures and related steep low-level lapse rates will still support severe-thunderstorm gusts into central OK. A watch issuance is possible this afternoon for parts of the area. ..Weinman/Guyer.. 09/05/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LSX...SGF...EAX...TSA...ICT...OUN... LAT...LON 36569631 37239540 38389426 39019377 39809340 40159304 40189255 39939190 39489136 38849125 37679171 36929252 36239377 35159582 35069665 35229703 35569727 35839723 36569631 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Tue Sep 05 2023 Valid 052000Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY/WESTERN UPPER GREAT LAKES REGION...AND FROM MISSOURI AND VICINITY SOUTHWESTWARD INTO NORTHEASTERN OKLAHOMA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening over parts of the upper Mississippi Valley/Lake Superior region, and across the Ozarks and parts of Oklahoma. Severe wind gusts and isolated large hail are possible. ...Discussion... Along with minor line tweaks in a few areas, including some eastward expansion of thunder into parts of Wyoming for the overnight period, the only other substantive change at this time is the northward expansion of SLGT risk/15% wind into parts of northern Missouri. Here, a similar thermodynamic pre-frontal environment is indicated as compared to areas a bit farther south, and several CAM runs are indicating development along the front may extend a bit farther north than previously hinted at in the outlook. Otherwise, expectations remain similar to those in prior outlooks. ..Goss.. 09/05/2023 .PREV DISCUSSION... /ISSUED 1131 AM CDT Tue Sep 05 2023/ ...Upper Mississippi Valley... A shortwave trough over the Dakotas this morning will continue eastward toward the upper Mississippi Valley through tonight. A slight cooling of mid-level temperatures (-10C at 500 mb) will accompany this trough, while only a modest strengthening of trough-preceding winds aloft is expected, given that the trough is somewhat removed from the stronger westerlies over the Canadian prairies. While some warm-sector cloud cover persists early today regionally, the boundary layer ahead of an eastward-moving cold front should become minimally inhibited by early into mid-afternoon, with MLCAPE reaching 2500+ J/kg especially across the eastern halves of Minnesota and Iowa, as well as much of western Wisconsin and far northwest Illinois. Initial thunderstorm intensification is expected this afternoon across northern/central Minnesota, potentially with an ongoing band of storms across northern Minnesota, and more so near the aforementioned front and surface wave, with subsequent scattered development southward into southeast Minnesota/eastern Iowa and western Wisconsin through late afternoon and early evening. Severe wind gusts and hail will be possible with a mixed mode of storms including multicells and some transient supercells. Some tornado risk may exist as well, mainly across northeast Minnesota/northwest Wisconsin. ...Middle Mississippi Valley/Ozarks/southern Plains... Widely scattered mid-level convection across the region trails a shortwave trough centered generally near the confluence of the Mississippi/Ohio Rivers. This convection is atop a warm-sector boundary layer that will heat and become strongly unstable by peak heating, particularly across eastern Oklahoma into Missouri western/northern Arkansas ahead of an east/southeastward-moving front. Isolated to widely scattered thunderstorms are expected to develop by mid/late afternoon near the front, and somewhat across the warm sector, potentially influenced by lingering cloud cover/zones of differential heating. While tropospheric winds will only be modest strength (effective shear less than 30 kt), strong heating, steep lapse rates, and ample buoyancy will support the potential for severe-caliber wind gusts, especially with the aforementioned corridor of greatest destabilization. Some severe hail may occur as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Tue Sep 05 2023 Valid 052000Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY/WESTERN UPPER GREAT LAKES REGION...AND FROM MISSOURI AND VICINITY SOUTHWESTWARD INTO NORTHEASTERN OKLAHOMA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening over parts of the upper Mississippi Valley/Lake Superior region, and across the Ozarks and parts of Oklahoma. Severe wind gusts and isolated large hail are possible. ...Discussion... Along with minor line tweaks in a few areas, including some eastward expansion of thunder into parts of Wyoming for the overnight period, the only other substantive change at this time is the northward expansion of SLGT risk/15% wind into parts of northern Missouri. Here, a similar thermodynamic pre-frontal environment is indicated as compared to areas a bit farther south, and several CAM runs are indicating development along the front may extend a bit farther north than previously hinted at in the outlook. Otherwise, expectations remain similar to those in prior outlooks. ..Goss.. 09/05/2023 .PREV DISCUSSION... /ISSUED 1131 AM CDT Tue Sep 05 2023/ ...Upper Mississippi Valley... A shortwave trough over the Dakotas this morning will continue eastward toward the upper Mississippi Valley through tonight. A slight cooling of mid-level temperatures (-10C at 500 mb) will accompany this trough, while only a modest strengthening of trough-preceding winds aloft is expected, given that the trough is somewhat removed from the stronger westerlies over the Canadian prairies. While some warm-sector cloud cover persists early today regionally, the boundary layer ahead of an eastward-moving cold front should become minimally inhibited by early into mid-afternoon, with MLCAPE reaching 2500+ J/kg especially across the eastern halves of Minnesota and Iowa, as well as much of western Wisconsin and far northwest Illinois. Initial thunderstorm intensification is expected this afternoon across northern/central Minnesota, potentially with an ongoing band of storms across northern Minnesota, and more so near the aforementioned front and surface wave, with subsequent scattered development southward into southeast Minnesota/eastern Iowa and western Wisconsin through late afternoon and early evening. Severe wind gusts and hail will be possible with a mixed mode of storms including multicells and some transient supercells. Some tornado risk may exist as well, mainly across northeast Minnesota/northwest Wisconsin. ...Middle Mississippi Valley/Ozarks/southern Plains... Widely scattered mid-level convection across the region trails a shortwave trough centered generally near the confluence of the Mississippi/Ohio Rivers. This convection is atop a warm-sector boundary layer that will heat and become strongly unstable by peak heating, particularly across eastern Oklahoma into Missouri western/northern Arkansas ahead of an east/southeastward-moving front. Isolated to widely scattered thunderstorms are expected to develop by mid/late afternoon near the front, and somewhat across the warm sector, potentially influenced by lingering cloud cover/zones of differential heating. While tropospheric winds will only be modest strength (effective shear less than 30 kt), strong heating, steep lapse rates, and ample buoyancy will support the potential for severe-caliber wind gusts, especially with the aforementioned corridor of greatest destabilization. Some severe hail may occur as well. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0253 PM CDT Tue Sep 05 2023 Valid 052000Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER MISSISSIPPI VALLEY/WESTERN UPPER GREAT LAKES REGION...AND FROM MISSOURI AND VICINITY SOUTHWESTWARD INTO NORTHEASTERN OKLAHOMA... ...SUMMARY... Severe thunderstorms are expected this afternoon and evening over parts of the upper Mississippi Valley/Lake Superior region, and across the Ozarks and parts of Oklahoma. Severe wind gusts and isolated large hail are possible. ...Discussion... Along with minor line tweaks in a few areas, including some eastward expansion of thunder into parts of Wyoming for the overnight period, the only other substantive change at this time is the northward expansion of SLGT risk/15% wind into parts of northern Missouri. Here, a similar thermodynamic pre-frontal environment is indicated as compared to areas a bit farther south, and several CAM runs are indicating development along the front may extend a bit farther north than previously hinted at in the outlook. Otherwise, expectations remain similar to those in prior outlooks. ..Goss.. 09/05/2023 .PREV DISCUSSION... /ISSUED 1131 AM CDT Tue Sep 05 2023/ ...Upper Mississippi Valley... A shortwave trough over the Dakotas this morning will continue eastward toward the upper Mississippi Valley through tonight. A slight cooling of mid-level temperatures (-10C at 500 mb) will accompany this trough, while only a modest strengthening of trough-preceding winds aloft is expected, given that the trough is somewhat removed from the stronger westerlies over the Canadian prairies. While some warm-sector cloud cover persists early today regionally, the boundary layer ahead of an eastward-moving cold front should become minimally inhibited by early into mid-afternoon, with MLCAPE reaching 2500+ J/kg especially across the eastern halves of Minnesota and Iowa, as well as much of western Wisconsin and far northwest Illinois. Initial thunderstorm intensification is expected this afternoon across northern/central Minnesota, potentially with an ongoing band of storms across northern Minnesota, and more so near the aforementioned front and surface wave, with subsequent scattered development southward into southeast Minnesota/eastern Iowa and western Wisconsin through late afternoon and early evening. Severe wind gusts and hail will be possible with a mixed mode of storms including multicells and some transient supercells. Some tornado risk may exist as well, mainly across northeast Minnesota/northwest Wisconsin. ...Middle Mississippi Valley/Ozarks/southern Plains... Widely scattered mid-level convection across the region trails a shortwave trough centered generally near the confluence of the Mississippi/Ohio Rivers. This convection is atop a warm-sector boundary layer that will heat and become strongly unstable by peak heating, particularly across eastern Oklahoma into Missouri western/northern Arkansas ahead of an east/southeastward-moving front. Isolated to widely scattered thunderstorms are expected to develop by mid/late afternoon near the front, and somewhat across the warm sector, potentially influenced by lingering cloud cover/zones of differential heating. While tropospheric winds will only be modest strength (effective shear less than 30 kt), strong heating, steep lapse rates, and ample buoyancy will support the potential for severe-caliber wind gusts, especially with the aforementioned corridor of greatest destabilization. Some severe hail may occur as well. Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Tue Sep 05 2023 Valid 071200Z - 131200Z Fire weather potential remains limited across the country for the extended period. Upper-level ridging is forecast to re-establish over northern Mexico into the Southwest/Four Corners region through the end of the work week and into the weekend. Heading into next week, ensemble means and cluster analyses depict a de-amplification of this ridge as longwave troughing becomes established over the eastern third of the CONUS. While the resulting amplitudes of the ridge/trough are uncertain, this synoptic pattern typically favors warming/drying conditions across the Southwest, Great Basin, and West Coast with cooler temperatures and rain chances east of the Rockies. Fuels are currently unreceptive across much of the West, but may see some curing during this period. Across the Plains where fuels are dry, fire weather concerns will likely remain localized through the extended period with limited predictability at this range. ...D3/Thursday to D4/Friday - Southern High Plains... One such area of localized fire weather concern may emerge across the TX/OK Panhandles into western OK D3/Thursday and D4/Friday. A zonal to northwest flow regime over the central Rockies should foster a deepening lee trough from northeast NM into CO during this period. Increasing south/southwesterly winds with trajectories emanating from the southern Rockies may experience sufficient drying to support areas of 20-25% RH and winds near 15 mph. While deterministic solutions suggest elevated conditions will occur, considerable spread is noted in ensemble guidance, which limits confidence in the threat at this point. However, this region has maintained dry fuels with several fires noted in recent days, so trends will be monitored in subsequent outlooks for the need for highlights. ..Moore.. 09/05/2023 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0245 PM CDT Tue Sep 05 2023 Valid 071200Z - 131200Z Fire weather potential remains limited across the country for the extended period. Upper-level ridging is forecast to re-establish over northern Mexico into the Southwest/Four Corners region through the end of the work week and into the weekend. Heading into next week, ensemble means and cluster analyses depict a de-amplification of this ridge as longwave troughing becomes established over the eastern third of the CONUS. While the resulting amplitudes of the ridge/trough are uncertain, this synoptic pattern typically favors warming/drying conditions across the Southwest, Great Basin, and West Coast with cooler temperatures and rain chances east of the Rockies. Fuels are currently unreceptive across much of the West, but may see some curing during this period. Across the Plains where fuels are dry, fire weather concerns will likely remain localized through the extended period with limited predictability at this range. ...D3/Thursday to D4/Friday - Southern High Plains... One such area of localized fire weather concern may emerge across the TX/OK Panhandles into western OK D3/Thursday and D4/Friday. A zonal to northwest flow regime over the central Rockies should foster a deepening lee trough from northeast NM into CO during this period. Increasing south/southwesterly winds with trajectories emanating from the southern Rockies may experience sufficient drying to support areas of 20-25% RH and winds near 15 mph. While deterministic solutions suggest elevated conditions will occur, considerable spread is noted in ensemble guidance, which limits confidence in the threat at this point. However, this region has maintained dry fuels with several fires noted in recent days, so trends will be monitored in subsequent outlooks for the need for highlights. ..Moore.. 09/05/2023 ...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 0117 PM CDT Tue Sep 05 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... Fire weather concerns remain low for Wednesday across the country. Latest guidance continues to show a weak signal for localized elevated fire weather conditions across the greater Four Corners region, but the patchy nature of the threat, combined with poor fuel status, precludes any highlights. ..Moore.. 09/05/2023 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 05 2023/ ...Synopsis... Upper-level ridging will modestly intensify in the southern Rockies. A surface front will largely stall near the Red River. With cooler temperatures and lighter winds expected across areas with dry fuels, fire weather concerns will be low on Wednesday. ...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 0117 PM CDT Tue Sep 05 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... Fire weather concerns remain low for Wednesday across the country. Latest guidance continues to show a weak signal for localized elevated fire weather conditions across the greater Four Corners region, but the patchy nature of the threat, combined with poor fuel status, precludes any highlights. ..Moore.. 09/05/2023 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 05 2023/ ...Synopsis... Upper-level ridging will modestly intensify in the southern Rockies. A surface front will largely stall near the Red River. With cooler temperatures and lighter winds expected across areas with dry fuels, fire weather concerns will be low on Wednesday. ...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 0117 PM CDT Tue Sep 05 2023 Valid 061200Z - 071200Z ...NO CRITICAL AREAS... Fire weather concerns remain low for Wednesday across the country. Latest guidance continues to show a weak signal for localized elevated fire weather conditions across the greater Four Corners region, but the patchy nature of the threat, combined with poor fuel status, precludes any highlights. ..Moore.. 09/05/2023 .PREV DISCUSSION... /ISSUED 0102 AM CDT Tue Sep 05 2023/ ...Synopsis... Upper-level ridging will modestly intensify in the southern Rockies. A surface front will largely stall near the Red River. With cooler temperatures and lighter winds expected across areas with dry fuels, fire weather concerns will be low on Wednesday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0666 Status Updates
STATUS REPORT ON WW 666 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 5 SSE CYS TO 25 WSW TOR TO 55 ENE DGW TO 60 ESE GCC TO 50 ENE GCC TO 35 N GCC TO 45 W GCC TO 40 NNW CPR. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 2080 ..LYONS..09/04/23 ATTN...WFO...BYZ...CYS...UNR...RIW... STATUS REPORT FOR WS 666 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC011-075-042340- MT . MONTANA COUNTIES INCLUDED ARE CARTER POWDER RIVER NEC007-013-045-123-157-165-042340- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE DAWES MORRILL SCOTTS BLUFF SIOUX SDC019-033-047-055-063-081-093-102-103-105-137-042340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE Read more

WW 666 SEVERE TSTM MT NE SD WY 042005Z - 050200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 666 NWS Storm Prediction Center Norman OK 205 PM MDT Mon Sep 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southeast Montana Nebraska Panhandle Western South Dakota Eastern Wyoming * Effective this Monday afternoon and evening from 205 PM until 800 PM MDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Strong to severe thunderstorms are expected to develop through mid/late afternoon across the region. Storms will initially be capable of large hail and damaging winds, with severe wind potential likely to increase by evening into and across western South Dakota. The severe thunderstorm watch area is approximately along and 80 statute miles east and west of a line from 35 miles northwest of Buffalo SD to 40 miles southwest of Scottsbluff NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 23035. ...Guyer Read more

WW 666 SEVERE TSTM MT NE SD WY 042005Z - 050200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 666 NWS Storm Prediction Center Norman OK 205 PM MDT Mon Sep 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southeast Montana Nebraska Panhandle Western South Dakota Eastern Wyoming * Effective this Monday afternoon and evening from 205 PM until 800 PM MDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...Strong to severe thunderstorms are expected to develop through mid/late afternoon across the region. Storms will initially be capable of large hail and damaging winds, with severe wind potential likely to increase by evening into and across western South Dakota. The severe thunderstorm watch area is approximately along and 80 statute miles east and west of a line from 35 miles northwest of Buffalo SD to 40 miles southwest of Scottsbluff NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU6). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 23035. ...Guyer Read more

WW 0667 Status Updates
STATUS FOR WATCH 0667 HAS NOT BEEN ISSUED YET Read more

WW 0667 Status Updates
STATUS FOR WATCH 0667 HAS NOT BEEN ISSUED YET Read more

WW 667 SEVERE TSTM ND SD 042225Z - 050400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 667 NWS Storm Prediction Center Norman OK 525 PM CDT Mon Sep 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern North Dakota North-central South Dakota * Effective this Monday afternoon and evening from 525 PM until 1100 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 90 mph likely Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A small cluster over northwest South Dakota with a history of severe wind gusts should intensify and likely produce a confined swath of severe into portions of southern North Dakota through late evening. The severe thunderstorm watch area is approximately along and 85 statute miles either side of a line from 25 miles north northwest of Bismarck ND to 55 miles east southeast of Mobridge SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 666... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 80 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 24040. ...Grams Read more

WW 667 SEVERE TSTM ND SD 042225Z - 050400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 667 NWS Storm Prediction Center Norman OK 525 PM CDT Mon Sep 4 2023 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southern North Dakota North-central South Dakota * Effective this Monday afternoon and evening from 525 PM until 1100 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 90 mph likely Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A small cluster over northwest South Dakota with a history of severe wind gusts should intensify and likely produce a confined swath of severe into portions of southern North Dakota through late evening. The severe thunderstorm watch area is approximately along and 85 statute miles either side of a line from 25 miles north northwest of Bismarck ND to 55 miles east southeast of Mobridge SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU7). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 666... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 80 knots. A few cumulonimbi with maximum tops to 450. Mean storm motion vector 24040. ...Grams Read more

MD 2080 CONCERNING SEVERE THUNDERSTORM WATCH 666... FOR NORTHWEST AND NORTH-CENTRAL SD...SOUTHERN AND CENTRAL ND
Mesoscale Discussion 2080 NWS Storm Prediction Center Norman OK 0452 PM CDT Mon Sep 04 2023 Areas affected...northwest and north-central SD...southern and central ND Concerning...Severe Thunderstorm Watch 666... Valid 042152Z - 042345Z The severe weather threat for Severe Thunderstorm Watch 666 continues. SUMMARY...Scattered severe gusts are probable across the northeast part of severe thunderstorm watch #666 as a band of storms moves northeastward. A downstream severe thunderstorm watch is expected within the next hour in parts of northern SD and southern ND. Peak gusts with the most intense downdrafts are forecast to range 70-90 mph through 01 UTC (8pm CDT/7pm MDT) over northern SD and southern ND. DISCUSSION...Radar mosaic late this afternoon shows an intensifying band of storms over western SD. Surface analysis ahead of this activity indicates temperatures are in the 95-100 deg F range south of a southwest-northeast oriented surface trough. The airmass where the ongoing storms are located in western SD is adequately moist (mid 50s deg F dewpoints) but relatively dry compared to south-central ND where dewpoints are in the lower 60s. As a result, PW increases from southwest to northeast. This increase in moisture will probably result in both storms moving in a more favorable environment of buoyancy and moisture for evaporatively cooled downdrafts. It appears the most intense phase of the developing squall line will commence over the next few hours as storms move into northern SD and into southern ND. The negatively tilted mid-level shortwave trough over WY will continue to pivot eastward towards the Dakotas this evening. The combination of very steep low to mid-level lapse rates, a linear storm mode, and appreciable large-scale forcing for ascent will favor scattered severe gusts through the evening across the Dakotas with the squall line. Peak gusts are forecast to range from 70-90 mph. ..Smith.. 09/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...ABR...BIS...UNR... LAT...LON 44300172 44250220 44340250 45460364 45700370 45950357 47300105 47409982 47229892 46789830 46129834 45419893 44300172 Read more

MD 2080 CONCERNING SEVERE THUNDERSTORM WATCH 666... FOR NORTHWEST AND NORTH-CENTRAL SD...SOUTHERN AND CENTRAL ND
Mesoscale Discussion 2080 NWS Storm Prediction Center Norman OK 0452 PM CDT Mon Sep 04 2023 Areas affected...northwest and north-central SD...southern and central ND Concerning...Severe Thunderstorm Watch 666... Valid 042152Z - 042345Z The severe weather threat for Severe Thunderstorm Watch 666 continues. SUMMARY...Scattered severe gusts are probable across the northeast part of severe thunderstorm watch #666 as a band of storms moves northeastward. A downstream severe thunderstorm watch is expected within the next hour in parts of northern SD and southern ND. Peak gusts with the most intense downdrafts are forecast to range 70-90 mph through 01 UTC (8pm CDT/7pm MDT) over northern SD and southern ND. DISCUSSION...Radar mosaic late this afternoon shows an intensifying band of storms over western SD. Surface analysis ahead of this activity indicates temperatures are in the 95-100 deg F range south of a southwest-northeast oriented surface trough. The airmass where the ongoing storms are located in western SD is adequately moist (mid 50s deg F dewpoints) but relatively dry compared to south-central ND where dewpoints are in the lower 60s. As a result, PW increases from southwest to northeast. This increase in moisture will probably result in both storms moving in a more favorable environment of buoyancy and moisture for evaporatively cooled downdrafts. It appears the most intense phase of the developing squall line will commence over the next few hours as storms move into northern SD and into southern ND. The negatively tilted mid-level shortwave trough over WY will continue to pivot eastward towards the Dakotas this evening. The combination of very steep low to mid-level lapse rates, a linear storm mode, and appreciable large-scale forcing for ascent will favor scattered severe gusts through the evening across the Dakotas with the squall line. Peak gusts are forecast to range from 70-90 mph. ..Smith.. 09/04/2023 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FGF...ABR...BIS...UNR... LAT...LON 44300172 44250220 44340250 45460364 45700370 45950357 47300105 47409982 47229892 46789830 46129834 45419893 44300172 Read more

WW 0666 Status Updates
STATUS REPORT ON WW 666 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..LYONS..09/04/23 ATTN...WFO...BYZ...CYS...UNR...RIW... STATUS REPORT FOR WS 666 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC011-075-042240- MT . MONTANA COUNTIES INCLUDED ARE CARTER POWDER RIVER NEC007-013-045-123-157-165-042240- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE DAWES MORRILL SCOTTS BLUFF SIOUX SDC019-033-047-055-063-081-093-102-103-105-137-042240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUTTE CUSTER FALL RIVER HAAKON HARDING LAWRENCE MEADE OGLALA LAKOTA PENNINGTON PERKINS ZIEBACH Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Mon Sep 04 2023 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHERN PLAINS/NORTHERN AND CENTRAL HIGH PLAINS... ...SUMMARY... Isolated severe wind gusts and large hail remain possible over parts of the northern Plains this afternoon and evening, particularly from parts of eastern Wyoming to the Dakotas. ...Discussion... Little change appears necessary to the ongoing outlook at this time, as the convective scenario across the U.S. continues to largely evolve as expected. The primary change has been to extend severe risk southward across more of the central High Plains region. Here, scant low-level moisture and limited CAPE, but a dry sub-cloud layer may support gusty/isolated damaging wind gusts where storms are currently developing. ..Goss.. 09/04/2023 .PREV DISCUSSION... /ISSUED 1141 AM CDT Mon Sep 04 2023/ ...Northern Plains... An upper trough over the Intermountain West/north-central Rockies will continue northeastward toward the Dakotas, with thunderstorms expected to increase near/behind an advancing cold front this afternoon, initially across interior/eastern portions of Wyoming and far southeast Montana. Strengthening winds aloft, steep lapse rates, and modest overall buoyancy will support high-based storms capable of large hail and strong wind gusts. Storms will likely further increase, aggregate, and grow upscale into northeast Wyoming/western South Dakota and eventually North Dakota this evening, with the potential for severe-caliber wind gusts expected to steadily increase accordingly. This also includes some potential for significant wind gusts (65+ kt). ...Ozarks/Mid-South... Widely scattered to scattered, multicellular thunderstorms are expected to increase across the region this afternoon with the potential for localized wind damage, and possibly some sporadic hail near severe limits. This will be as the upper low transitions northeastward toward the region and interfaces with a moderately to strongly unstable boundary layer, with moderately strong winds aloft (25-30 kt at 500 mb? likely contributing to some semi-sustained multicells. Any such severe risk should diminish by around sunset. Read more