Severe Storms

WW 573 SEVERE TSTM MT 112305Z - 120700Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 573 NWS Storm Prediction Center Norman OK 505 PM MDT Sun Aug 11 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Montana * Effective this Sunday afternoon and Monday morning from 505 PM until 100 AM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...Clusters of thunderstorms over central Montana will track east-northeastward across the watch area this evening. A few supercells and bow echoes capable of damaging winds and large hail are possible. The severe thunderstorm watch area is approximately along and 80 statute miles north and south of a line from 85 miles west southwest of Glasgow MT to 10 miles north northeast of Sidney MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). 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 569...WW 570...WW 571...WW 572... 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 500. Mean storm motion vector 26030. ...Hart Read more

MD 1705 CONCERNING SEVERE THUNDERSTORM WATCH 570... FOR EASTERN WYOMING/EASTERN COLORADO INTO THE NEBRASKA PANHANDLE
Mesoscale Discussion 1705 NWS Storm Prediction Center Norman OK 0551 PM CDT Sun Aug 11 2019 Areas affected...eastern Wyoming/eastern Colorado into the Nebraska Panhandle Concerning...Severe Thunderstorm Watch 570... Valid 112251Z - 120045Z The severe weather threat for Severe Thunderstorm Watch 570 continues. SUMMARY...Strong/locally severe thunderstorms continue across WW 570. DISCUSSION...Latest radar loop shows widespread thunderstorms -- including a few well-organized, rotating updrafts -- occurring over the central high Plains region. The storms are evolving near multiple/complex boundary interactions across the area. With low-level east-southeast flow advecting moist low-level air (60s dewpoints) into the high Plains fueling the convection, expect storms to continue for several hours. A couple of brief tornadoes have been reported over the past couple of hours, and large hail is also indicated with a couple of the most intense updrafts. These risks -- along with potential for locally damaging wind gusts -- are ongoing. With time, storms should grow upscale, and spread eastward into/across southwestern Nebraska and northwestern Kansas -- where Tornado Watch 572 is currently in effect. ..Goss/Hart.. 08/11/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...UNR...GLD...PUB...BOU...CYS... LAT...LON 38770317 38690459 40320519 41390525 41840585 43190606 43350355 42880275 40940268 38770317 Read more

MD 1704 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWESTERN NORTH DAKOTA
Mesoscale Discussion 1704 NWS Storm Prediction Center Norman OK 0519 PM CDT Sun Aug 11 2019 Areas affected...southwestern North Dakota Concerning...Severe potential...Watch unlikely Valid 112219Z - 120015Z Probability of Watch Issuance...20 percent SUMMARY...Damaging wind gusts or an isolated tornado cannot be completely ruled out with convection across the discussion area. A WW issuance is not anticipated, though convective trends continue to be monitored. DISCUSSION...A cluster of strong to isolated severe storms continues across southwestern North Dakota currently. These storms are in a moderately unstable environment (1000-2000 J/kg MUCAPE) with sufficient deep shear (35-40 kts) for updraft organization, and even though low-level wind fields are relatively weak, easterly surface winds veering to westerly with height are supporting weak updraft rotation in the strongest cores. This is apparent with recently severe-warned convection over Adams County, and with time other storms may occasionally rotate given the shear profiles. Modest increases in low-level flow after about 00-01Z or so will also enhance shear profiles and further support rotation, though storms will also encounter gradually stabilizing boundary layer thermodynamic profiles in tandem with the strengthening shear. The scenario may only support an isolated severe threat in a localized, temporally brief nature that will not necessitate any WW issuance, although convective trends will be monitored for any increase in the threat beyond current expectations. ..Cook/Hart.. 08/11/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR...BYZ...GGW... LAT...LON 46890386 47010273 47050127 46730037 46259999 45940011 45780157 45910323 45970390 46200419 46660423 46890386 Read more

MD 1703 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR NORTH-CENTRAL AND NORTHEASTERN MONTANA
Mesoscale Discussion 1703 NWS Storm Prediction Center Norman OK 0455 PM CDT Sun Aug 11 2019 Areas affected...north-central and northeastern Montana Concerning...Severe potential...Watch possible Valid 112155Z - 112300Z Probability of Watch Issuance...60 percent SUMMARY...Storms over central Montana will migrate northeastward into the discussion area after around 23Z or so. These storms may necessitate a WW issuance. DISCUSSION...An expanding cluster of mixed-mode (linear and cellular) storms continues to migrate northeastward across portions of central Montana (within WW 569). These storms are in a moderately unstable environment and have exhibited some upscale growth over time. Low-level easterlies veer to west-northwesterly and strengthen with height, allowing for some storm organization in this environment even though weak low-level shear is contributing largely to outflow-dominant convection. Though instability profiles are slightly less buoyant with northern extent, the expectation is that as storms continue to grow upscale and move northeastward into the discussion area, they will pose a risk of large hail and damaging wind gusts - especially if growth into a linear complex occurs as expected/depicted in latest CAMs. An isolated tornado cannot be completely ruled out either given the vertical shear profiles in place. Given these convective trends, a WW issuance is being considered around/after 23Z. ..Cook/Hart.. 08/11/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BIS...BYZ...GGW...TFX... LAT...LON 48070958 48260912 48450646 48290480 47790395 46990377 46610439 46730664 46780810 47220889 47700953 48070958 Read more

WW 0570 Status Updates
STATUS REPORT ON WW 570 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GOSS..08/11/19 ATTN...WFO...BOU...CYS... STATUS REPORT FOR WS 570 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC001-005-035-039-073-075-087-095-115-121-123-112240- CO . COLORADO COUNTIES INCLUDED ARE ADAMS ARAPAHOE DOUGLAS ELBERT LINCOLN LOGAN MORGAN PHILLIPS SEDGWICK WASHINGTON WELD NEC007-013-033-045-105-123-157-165-112240- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES KIMBALL MORRILL SCOTTS BLUFF SIOUX WYC009-015-021-027-031-112240- WY . WYOMING COUNTIES INCLUDED ARE Read more

WW 0572 Status Updates
STATUS REPORT ON WW 572 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GOSS..08/11/19 ATTN...WFO...GLD...LBF... STATUS REPORT FOR WT 572 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-063-125-112240- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIT CARSON YUMA KSC023-039-063-071-109-153-179-181-193-199-203-112240- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GREELEY LOGAN RAWLINS SHERIDAN SHERMAN THOMAS WALLACE WICHITA NEC029-049-057-063-085-087-101-111-135-145-112240- NE . NEBRASKA COUNTIES INCLUDED ARE CHASE DEUEL DUNDY FRONTIER HAYES HITCHCOCK Read more

WW 0569 Status Updates
STATUS REPORT ON WW 569 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..COOK..08/11/19 ATTN...WFO...TFX...BYZ... STATUS REPORT FOR WS 569 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC001-007-027-031-043-045-057-059-067-097-107-112240- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD BROADWATER FERGUS GALLATIN JEFFERSON JUDITH BASIN MADISON MEAGHER PARK SWEET GRASS WHEATLAND THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0571 Status Updates
STATUS REPORT ON WW 571 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..COOK..08/11/19 ATTN...WFO...BYZ...UNR... STATUS REPORT FOR WT 571 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC003-009-011-017-025-037-065-075-087-095-103-111-112240- MT . MONTANA COUNTIES INCLUDED ARE BIG HORN CARBON CARTER CUSTER FALLON GOLDEN VALLEY MUSSELSHELL POWDER RIVER ROSEBUD STILLWATER TREASURE YELLOWSTONE SDC019-033-047-063-081-093-102-103-105-112240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUTTE CUSTER FALL RIVER HARDING LAWRENCE MEADE OGLALA LAKOTA PENNINGTON PERKINS WYC005-011-033-045-112240- WY . WYOMING COUNTIES INCLUDED ARE Read more

WW 0569 Status Updates
STATUS REPORT ON WW 569 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1702 ..DEAN..08/11/19 ATTN...WFO...TFX...BYZ... STATUS REPORT FOR WS 569 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC001-007-027-031-043-045-057-059-067-097-107-112140- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD BROADWATER FERGUS GALLATIN JEFFERSON JUDITH BASIN MADISON MEAGHER PARK SWEET GRASS WHEATLAND THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

WW 0572 Status Updates
STATUS FOR WATCH 0572 HAS NOT BEEN ISSUED YET Read more

MD 1702 CONCERNING SEVERE THUNDERSTORM WATCH 569... FOR SOUTHWEST INTO CENTRAL MT
Mesoscale Discussion 1702 NWS Storm Prediction Center Norman OK 0343 PM CDT Sun Aug 11 2019 Areas affected...Southwest into central MT Concerning...Severe Thunderstorm Watch 569... Valid 112043Z - 112215Z The severe weather threat for Severe Thunderstorm Watch 569 continues. SUMMARY...The threat for primarily large hail and severe wind gusts will continue through the remainder of the afternoon and spread northeast into the remainder of WW 569, with some areas seeing multiple rounds of storms. DISCUSSION...Several discrete storms are ongoing across southwest MT at 2030Z. MLCAPE of 750-1500 J/kg and effective shear of 35-45 kt will continue to support organized convection, including the potential for a few supercells. Large hail and locally severe wind gusts will the primary threat with any discrete cells through the afternoon, though a tornado cannot be ruled out with any stronger supercell, especially across the southeast portion of WW 569 where greater instability is in place. Large-scale ascent ahead of the ejecting upper trough to the west may eventually support some upscale growth, which would raise the potential for somewhat more widespread severe wind with time. Additional redevelopment within the next 1-2 hours also remains possible upstream of the ongoing activity in advance of the trough, which would result in another round of potentially severe convection for areas that have already experienced strong thunderstorms. ..Dean.. 08/11/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...TFX...MSO... LAT...LON 46041370 46271302 47171103 47750950 47570918 47010891 45920957 45191017 45081115 44721170 44671274 45121335 45731383 46041370 Read more

WW 0571 Status Updates
STATUS REPORT ON WW 571 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..08/11/19 ATTN...WFO...BYZ...UNR... STATUS REPORT FOR WT 571 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC003-009-011-017-025-037-065-075-087-095-103-111-112140- MT . MONTANA COUNTIES INCLUDED ARE BIG HORN CARBON CARTER CUSTER FALLON GOLDEN VALLEY MUSSELSHELL POWDER RIVER ROSEBUD STILLWATER TREASURE YELLOWSTONE SDC019-033-047-063-081-093-102-103-105-112140- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BUTTE CUSTER FALL RIVER HARDING LAWRENCE MEADE OGLALA LAKOTA PENNINGTON PERKINS WYC005-011-033-045-112140- WY . WYOMING COUNTIES INCLUDED ARE Read more

WW 0570 Status Updates
STATUS REPORT ON WW 570 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..08/11/19 ATTN...WFO...BOU...CYS... STATUS REPORT FOR WS 570 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC001-005-035-039-073-075-087-095-115-121-123-112140- CO . COLORADO COUNTIES INCLUDED ARE ADAMS ARAPAHOE DOUGLAS ELBERT LINCOLN LOGAN MORGAN PHILLIPS SEDGWICK WASHINGTON WELD NEC007-013-033-045-105-123-157-165-112140- NE . NEBRASKA COUNTIES INCLUDED ARE BANNER BOX BUTTE CHEYENNE DAWES KIMBALL MORRILL SCOTTS BLUFF SIOUX WYC009-015-021-027-031-112140- WY . WYOMING COUNTIES INCLUDED ARE Read more

MD 1701 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PORTIONS OF EAST-CENTRAL CO...NORTHWESTERN KS...AND SOUTHWESTERN NE
Mesoscale Discussion 1701 NWS Storm Prediction Center Norman OK 0320 PM CDT Sun Aug 11 2019 Areas affected...Portions of east-central CO...northwestern KS...and southwestern NE Concerning...Severe potential...Watch likely Valid 112020Z - 112145Z Probability of Watch Issuance...95 percent SUMMARY...Severe threat will likely increase this afternoon. A couple tornadoes, large hail, and scattered damaging winds will all be possible. Watch issuance is likely. DISCUSSION...Strong heating has occurred this afternoon on both sides of a surface boundary evident on visible satellite extending from northeastern CO into northwestern KS. Low-level convergence along this boundary should encourage additional storm development across this region over the next couple of hours. This process may already be starting in Washington County in northeastern CO based on latest radar and satellite trends. Although low-level flow is not very strong across western KS at the moment per KGLD VWP, southeasterly low-level winds are forecast to increase later this afternoon into the evening as a low-level jet strengthens. MLCAPE ranges from 2000-3000 J/kg per 20Z mesoanalysis estimates, with around 35-40 kt of effective bulk shear. Supercells may initially pose a large hail threat, and isolated tornadoes could occur mainly along and immediately to the north of the surface boundary where effective SRH will be relatively greater. A bowing complex capable of producing a swath of damaging winds appears increasingly possible later this evening as storms likely grow upscale into north-central KS and south-central NE in tandem with the strengthening low-level jet. ..Gleason/Grams.. 08/11/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...GLD... LAT...LON 39220281 40030273 40320253 40420203 40970195 41010110 40980022 40440001 40059993 39350001 39100020 38790061 38790223 39220281 Read more

WW 0571 Status Updates
STATUS FOR WATCH 0571 HAS NOT BEEN ISSUED YET Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Sun Aug 11 2019 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHERN NE...NORTHERN KS...NORTHEAST CO...AND EAST-CENTRAL MT... ...SUMMARY... Scattered to numerous severe thunderstorms are likely across portions of the northern and central Great Plains. A few tornadoes, damaging wind gusts, and large hail are possible, mainly through this evening. ...Discussion... No appreciable change was made to the previous outlook. ..Smith.. 08/11/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 11 2019/ ...Central High Plains to Mid-MS Valley... A belt of somewhat enhanced mid-level flow extends from the southern Rockies to the Lower MO Valley around the anticyclone centered near the Red River. Within this belt, an MCV from a remnant overnight MCS is sliding eastward near the IA/MO border. Some surface-based storm development is possible near this MCV along the leading edge of the residual cold pool and perhaps in the wake of the ongoing stratiform if modest boundary-layer heating can occur. Weak mid-level lapse rates and generally modest effective shear suggests the threat for damaging winds should be localized. Farther west, a low-level upslope regime has become established north of the remnant outflow/effective front that is draped near the I-70 corridor. Recovery of low-level moisture and surface heating will yield large buoyancy north of the front with MLCAPE likely reaching 2500-3500 J/kg by late afternoon. Thunderstorm development is expected first immediately east of the Front Range in CO, while the boundary layer should remain capped through much of the afternoon in far northeast CO vicinity. Buoyancy and deep-layer vertical shear will be sufficient for a mix of supercells and multicell clusters with large hail/severe gusts possible with the initial deep convection east of the Front Range. Wind profiles will be more favorable for supercells farther east on the High Plains where low-level easterly flow and hodograph curvature will be greater, though there will be a tendency for cell interactions and upscale growth later into the evening. Any semi-discrete supercells will pose a threat for a couple of tornadoes and large hail, while the severe wind threat will increase with storm clustering into the evening. These clusters should form into a forward-propagating MCS that may develop into a longer-lived bow along the KS/NE border region tonight. Weak low-level lapse rates should be a limiting factor, but the reservoir of large buoyancy along the nose of the low-level jet lends credence to the possibility of a swath of severe wind gusts into the early overnight. ...Northern High Plains... A shortwave trough will eject from western ID to eastern MT. Easterly low-level flow will be maintained ahead of this trough and its associated cold front that will push east across MT. This flow regime will maintain a broad plume of mid 50s to mid 60s surface dew points from west to east. Rather steep mid-level lapse rates of 8-9 C/km across WY/eastern MT will contribute to a corridor of MLCAPE reaching 2000-3000 J/kg where greater surface heating is underway across southeast MT/northeast WY/western SD. Episodic thunderstorm initiation is expected during the next few hours over the high terrain of southwest MT and downstream of a leading lobe of ascent approaching the WY/MT/Dakota border region, as well as by late afternoon in an arc off the higher terrain of WY. Effective bulk shear of 35-50 kt will favor several supercells initially with large hail and a couple of tornadoes. Convection is expected to grow upscale into multiple clusters/line segments across MT into the western Dakotas with an increasing threat of severe winds. The most likely corridor for a swath of severe gusts is across parts of east-central MT along the northern periphery of the buoyancy plume where large-scale ascent should be greatest ahead of the shortwave trough. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Sun Aug 11 2019 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHERN NE...NORTHERN KS...NORTHEAST CO...AND EAST-CENTRAL MT... ...SUMMARY... Scattered to numerous severe thunderstorms are likely across portions of the northern and central Great Plains. A few tornadoes, damaging wind gusts, and large hail are possible, mainly through this evening. ...Discussion... No appreciable change was made to the previous outlook. ..Smith.. 08/11/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 11 2019/ ...Central High Plains to Mid-MS Valley... A belt of somewhat enhanced mid-level flow extends from the southern Rockies to the Lower MO Valley around the anticyclone centered near the Red River. Within this belt, an MCV from a remnant overnight MCS is sliding eastward near the IA/MO border. Some surface-based storm development is possible near this MCV along the leading edge of the residual cold pool and perhaps in the wake of the ongoing stratiform if modest boundary-layer heating can occur. Weak mid-level lapse rates and generally modest effective shear suggests the threat for damaging winds should be localized. Farther west, a low-level upslope regime has become established north of the remnant outflow/effective front that is draped near the I-70 corridor. Recovery of low-level moisture and surface heating will yield large buoyancy north of the front with MLCAPE likely reaching 2500-3500 J/kg by late afternoon. Thunderstorm development is expected first immediately east of the Front Range in CO, while the boundary layer should remain capped through much of the afternoon in far northeast CO vicinity. Buoyancy and deep-layer vertical shear will be sufficient for a mix of supercells and multicell clusters with large hail/severe gusts possible with the initial deep convection east of the Front Range. Wind profiles will be more favorable for supercells farther east on the High Plains where low-level easterly flow and hodograph curvature will be greater, though there will be a tendency for cell interactions and upscale growth later into the evening. Any semi-discrete supercells will pose a threat for a couple of tornadoes and large hail, while the severe wind threat will increase with storm clustering into the evening. These clusters should form into a forward-propagating MCS that may develop into a longer-lived bow along the KS/NE border region tonight. Weak low-level lapse rates should be a limiting factor, but the reservoir of large buoyancy along the nose of the low-level jet lends credence to the possibility of a swath of severe wind gusts into the early overnight. ...Northern High Plains... A shortwave trough will eject from western ID to eastern MT. Easterly low-level flow will be maintained ahead of this trough and its associated cold front that will push east across MT. This flow regime will maintain a broad plume of mid 50s to mid 60s surface dew points from west to east. Rather steep mid-level lapse rates of 8-9 C/km across WY/eastern MT will contribute to a corridor of MLCAPE reaching 2000-3000 J/kg where greater surface heating is underway across southeast MT/northeast WY/western SD. Episodic thunderstorm initiation is expected during the next few hours over the high terrain of southwest MT and downstream of a leading lobe of ascent approaching the WY/MT/Dakota border region, as well as by late afternoon in an arc off the higher terrain of WY. Effective bulk shear of 35-50 kt will favor several supercells initially with large hail and a couple of tornadoes. Convection is expected to grow upscale into multiple clusters/line segments across MT into the western Dakotas with an increasing threat of severe winds. The most likely corridor for a swath of severe gusts is across parts of east-central MT along the northern periphery of the buoyancy plume where large-scale ascent should be greatest ahead of the shortwave trough. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Sun Aug 11 2019 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHERN NE...NORTHERN KS...NORTHEAST CO...AND EAST-CENTRAL MT... ...SUMMARY... Scattered to numerous severe thunderstorms are likely across portions of the northern and central Great Plains. A few tornadoes, damaging wind gusts, and large hail are possible, mainly through this evening. ...Discussion... No appreciable change was made to the previous outlook. ..Smith.. 08/11/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 11 2019/ ...Central High Plains to Mid-MS Valley... A belt of somewhat enhanced mid-level flow extends from the southern Rockies to the Lower MO Valley around the anticyclone centered near the Red River. Within this belt, an MCV from a remnant overnight MCS is sliding eastward near the IA/MO border. Some surface-based storm development is possible near this MCV along the leading edge of the residual cold pool and perhaps in the wake of the ongoing stratiform if modest boundary-layer heating can occur. Weak mid-level lapse rates and generally modest effective shear suggests the threat for damaging winds should be localized. Farther west, a low-level upslope regime has become established north of the remnant outflow/effective front that is draped near the I-70 corridor. Recovery of low-level moisture and surface heating will yield large buoyancy north of the front with MLCAPE likely reaching 2500-3500 J/kg by late afternoon. Thunderstorm development is expected first immediately east of the Front Range in CO, while the boundary layer should remain capped through much of the afternoon in far northeast CO vicinity. Buoyancy and deep-layer vertical shear will be sufficient for a mix of supercells and multicell clusters with large hail/severe gusts possible with the initial deep convection east of the Front Range. Wind profiles will be more favorable for supercells farther east on the High Plains where low-level easterly flow and hodograph curvature will be greater, though there will be a tendency for cell interactions and upscale growth later into the evening. Any semi-discrete supercells will pose a threat for a couple of tornadoes and large hail, while the severe wind threat will increase with storm clustering into the evening. These clusters should form into a forward-propagating MCS that may develop into a longer-lived bow along the KS/NE border region tonight. Weak low-level lapse rates should be a limiting factor, but the reservoir of large buoyancy along the nose of the low-level jet lends credence to the possibility of a swath of severe wind gusts into the early overnight. ...Northern High Plains... A shortwave trough will eject from western ID to eastern MT. Easterly low-level flow will be maintained ahead of this trough and its associated cold front that will push east across MT. This flow regime will maintain a broad plume of mid 50s to mid 60s surface dew points from west to east. Rather steep mid-level lapse rates of 8-9 C/km across WY/eastern MT will contribute to a corridor of MLCAPE reaching 2000-3000 J/kg where greater surface heating is underway across southeast MT/northeast WY/western SD. Episodic thunderstorm initiation is expected during the next few hours over the high terrain of southwest MT and downstream of a leading lobe of ascent approaching the WY/MT/Dakota border region, as well as by late afternoon in an arc off the higher terrain of WY. Effective bulk shear of 35-50 kt will favor several supercells initially with large hail and a couple of tornadoes. Convection is expected to grow upscale into multiple clusters/line segments across MT into the western Dakotas with an increasing threat of severe winds. The most likely corridor for a swath of severe gusts is across parts of east-central MT along the northern periphery of the buoyancy plume where large-scale ascent should be greatest ahead of the shortwave trough. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0244 PM CDT Sun Aug 11 2019 Valid 112000Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS SOUTHERN NE...NORTHERN KS...NORTHEAST CO...AND EAST-CENTRAL MT... ...SUMMARY... Scattered to numerous severe thunderstorms are likely across portions of the northern and central Great Plains. A few tornadoes, damaging wind gusts, and large hail are possible, mainly through this evening. ...Discussion... No appreciable change was made to the previous outlook. ..Smith.. 08/11/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sun Aug 11 2019/ ...Central High Plains to Mid-MS Valley... A belt of somewhat enhanced mid-level flow extends from the southern Rockies to the Lower MO Valley around the anticyclone centered near the Red River. Within this belt, an MCV from a remnant overnight MCS is sliding eastward near the IA/MO border. Some surface-based storm development is possible near this MCV along the leading edge of the residual cold pool and perhaps in the wake of the ongoing stratiform if modest boundary-layer heating can occur. Weak mid-level lapse rates and generally modest effective shear suggests the threat for damaging winds should be localized. Farther west, a low-level upslope regime has become established north of the remnant outflow/effective front that is draped near the I-70 corridor. Recovery of low-level moisture and surface heating will yield large buoyancy north of the front with MLCAPE likely reaching 2500-3500 J/kg by late afternoon. Thunderstorm development is expected first immediately east of the Front Range in CO, while the boundary layer should remain capped through much of the afternoon in far northeast CO vicinity. Buoyancy and deep-layer vertical shear will be sufficient for a mix of supercells and multicell clusters with large hail/severe gusts possible with the initial deep convection east of the Front Range. Wind profiles will be more favorable for supercells farther east on the High Plains where low-level easterly flow and hodograph curvature will be greater, though there will be a tendency for cell interactions and upscale growth later into the evening. Any semi-discrete supercells will pose a threat for a couple of tornadoes and large hail, while the severe wind threat will increase with storm clustering into the evening. These clusters should form into a forward-propagating MCS that may develop into a longer-lived bow along the KS/NE border region tonight. Weak low-level lapse rates should be a limiting factor, but the reservoir of large buoyancy along the nose of the low-level jet lends credence to the possibility of a swath of severe wind gusts into the early overnight. ...Northern High Plains... A shortwave trough will eject from western ID to eastern MT. Easterly low-level flow will be maintained ahead of this trough and its associated cold front that will push east across MT. This flow regime will maintain a broad plume of mid 50s to mid 60s surface dew points from west to east. Rather steep mid-level lapse rates of 8-9 C/km across WY/eastern MT will contribute to a corridor of MLCAPE reaching 2000-3000 J/kg where greater surface heating is underway across southeast MT/northeast WY/western SD. Episodic thunderstorm initiation is expected during the next few hours over the high terrain of southwest MT and downstream of a leading lobe of ascent approaching the WY/MT/Dakota border region, as well as by late afternoon in an arc off the higher terrain of WY. Effective bulk shear of 35-50 kt will favor several supercells initially with large hail and a couple of tornadoes. Convection is expected to grow upscale into multiple clusters/line segments across MT into the western Dakotas with an increasing threat of severe winds. The most likely corridor for a swath of severe gusts is across parts of east-central MT along the northern periphery of the buoyancy plume where large-scale ascent should be greatest ahead of the shortwave trough. Read more

WW 0569 Status Updates
STATUS REPORT ON WW 569 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..08/11/19 ATTN...WFO...TFX...BYZ... STATUS REPORT FOR WS 569 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC001-007-027-031-043-045-057-059-067-097-107-112040- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD BROADWATER FERGUS GALLATIN JEFFERSON JUDITH BASIN MADISON MEAGHER PARK SWEET GRASS WHEATLAND THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more