Severe Storms

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0730 PM CDT Tue Sep 10 2019 Valid 110100Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF NORTHERN NEBRASKA AND PARTS OF SOUTHEAST SOUTH DAKOTA... ...SUMMARY... The threat for a couple tornadoes, damaging winds and hail will persist mainly over northern Nebraska, southeast South Dakota, and into northwest Iowa through evening. ...NE...SD...IA...MN... Numerous storms persist this evening from the WY/NE border near a dry line across northern NE and into southern SD along and north of a warm front. Previously tornadic supercells have moved out of WY, and may merge with the existing storms to the east eventually forming an MCS. Damaging winds and hail will remain possible. A tornado is still possible with any discrete cells across northern NE as the low-level jet maintains large looping hodographs. The 00Z LBF sounding shows 350+ effective SRH along with substantial instability, supportive of supercells. The very unstable air mass extends eastward into western IA and may spread into far southern MN later tonight, with damaging wind gusts possible. For more information see mesoscale discussion 1951. ..Jewell.. 09/11/2019 Read more

WW 0640 Status Updates
STATUS REPORT ON WW 640 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 NNE TOR TO 50 W RAP. ..KERR..09/11/19 ATTN...WFO...LBF...CYS...UNR... STATUS REPORT FOR WT 640 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-013-017-031-045-069-075-091-103-123-149-157-161-165-171- 110140- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOX BUTTE BROWN CHERRY DAWES GARDEN GRANT HOOKER KEYA PAHA MORRILL ROCK SCOTTS BLUFF SHERIDAN SIOUX THOMAS SDC007-047-071-095-102-121-123-110140- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT FALL RIVER JACKSON MELLETTE OGLALA LAKOTA TODD TRIPP THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more

WW 0641 Status Updates
STATUS REPORT ON WW 641 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 N AZO TO 35 WSW MBS TO 15 NW MBS TO 30 N MBS. ..SQUITIERI..09/10/19 ATTN...WFO...GRR...DTX... STATUS REPORT FOR WS 641 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MIC015-017-037-045-049-057-063-065-087-111-145-147-151-155-157- 110040- MI . MICHIGAN COUNTIES INCLUDED ARE BARRY BAY CLINTON EATON GENESEE GRATIOT HURON INGHAM LAPEER MIDLAND SAGINAW ST. CLAIR SANILAC SHIAWASSEE TUSCOLA LCZ422-LHZ421-422-441-442-443-110040- CW . ADJACENT COASTAL WATERS INCLUDED ARE ST. CLAIR RIVER OUTER SAGINAW BAY SW OF ALABASTER TO PORT AUSTIN MI TO INNER SAGINAW BAY INNER SAGINAW BAY SW OF POINT AU GRES TO BAY PORT MI Read more

WW 0642 Status Updates
STATUS FOR WATCH 0642 HAS NOT BEEN ISSUED YET Read more

WW 642 SEVERE TSTM SD 102325Z - 110300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 642 NWS Storm Prediction Center Norman OK 625 PM CDT Tue Sep 10 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Parts of southern South Dakota * Effective this Tuesday evening from 625 PM until 1000 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2.5 inches in diameter possible A tornado or two possible SUMMARY...Clusters of storms will continue to spread eastward from south central South Dakota, along the immediate cool side of a surface front. Large hail and damaging winds will be the main threats, though an isolated tornado cannot be ruled out this evening. The severe thunderstorm watch area is approximately along and 30 statute miles north and south of a line from 30 miles south southwest of Chamberlain SD to 15 miles south of Mitchell SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). 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 640...WW 641... AVIATION...A few severe thunderstorms with hail surface and aloft to 2.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 550. Mean storm motion vector 27025. ...Thompson Read more

MD 1951 CONCERNING TORNADO WATCH 640... FOR NORTHWESTERN NEBRASKA...ADJACENT PORTIONS OF EASTERN WYOMING AND SOUTHWESTERN SOUTH DAKOTA
Mesoscale Discussion 1951 NWS Storm Prediction Center Norman OK 0538 PM CDT Tue Sep 10 2019 Areas affected...Northwestern Nebraska...adjacent portions of eastern Wyoming and southwestern South Dakota Concerning...Tornado Watch 640... Valid 102238Z - 110015Z The severe weather threat for Tornado Watch 640 continues. SUMMARY...A risk for tornadic supercells is expected to continue and perhaps increase through 5-7 PM MDT across northwestern Nebraska, near/southwest of Chadron, with additional strong to severe thunderstorm development continuing near the state border vicinity, into areas near and northeast of Valentine NE. It is not clear that a new severe weather watch will be needed northeast of WW 640 in the near term, but trends are being monitored for this possibility. DISCUSSION...The environment currently most conducive to boundary-layer based thunderstorm development appears across parts of the northwest Nebraska into southeastern Wyoming, where moist southeasterly surface flow appears to be supporting mixed-layer CAPE of 1500-3000 J/kg. This is in the vicinity of the surface front, which extends eastward along and just south of the South Dakota/Nebraska border. Convection across southeastern Wyoming has been discrete, including at least one sustained tornadic supercell to the northwest through north of Goshen WY, aided by strong deep-layer shear beneath 30-40 kt southwesterly 500 mb flow. A weak mid-level perturbation is forecast to emerge from the higher terrain and progress through broader-scale anticyclonic mid-level flow across western Nebraska and South Dakota by early this evening. As it does, ongoing discrete supercell development is expected to gradually shift eastward into the northwest Nebraska Panhandle vicinity, near/southwest through south of Chadron by 23-01Z. Enlarging low-level hodographs across this region through this period may maintain or even support increasing tornadic potential, before convection increasingly consolidates into a larger convective cluster. Considerable thunderstorm activity is already ongoing near/north of the surface front downstream, into areas west through north of Valentine NE, with an intensifying southerly low-level jet forecast to focus strengthening warm advection across this region into early evening. Aided by large CAPE, in the presence of steep lapse rates, and strong deep layer shear, activity will continue to pose a risk for severe hail. Although strongest renewed convective development is expected to remain focused across northwestern/north central Nebraska and adjacent portions of southern South Dakota, some activity may at least attempt to advect northeast of the watch area before gradually weakening. ..Kerr.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...ABR...LBF...UNR...CYS... LAT...LON 43300408 43360214 43570077 43579927 42459980 42010199 41830342 41910444 42330473 43300408 Read more

WW 0641 Status Updates
STATUS FOR WATCH 0641 HAS NOT BEEN ISSUED YET Read more

WW 641 SEVERE TSTM MI LH 102225Z - 110300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 641 NWS Storm Prediction Center Norman OK 625 PM EDT Tue Sep 10 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central Lower Michigan Lake Huron * Effective this Tuesday evening from 625 PM until 1100 PM EDT. * Primary threats include... Isolated damaging wind gusts to 70 mph possible Isolated large hail events to 1 inch in diameter possible A tornado or two possible SUMMARY...Scattered thunderstorms will likely persist through late evening while spreading eastward across central Lower Michigan. The storm environment appears favorable for some supercell structures capable of producing damaging gusts, marginally severe hail, and perhaps a tornado or two. The severe thunderstorm watch area is approximately along and 40 statute miles north and south of a line from 20 miles north of Grand Rapids MI to 40 miles southeast of Bad Axe MI. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU1). 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 640... AVIATION...A few severe thunderstorms with hail surface and aloft to 1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27035. ...Thompson Read more

MD 1950 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL LOWER MICHIGAN
Mesoscale Discussion 1950 NWS Storm Prediction Center Norman OK 0458 PM CDT Tue Sep 10 2019 Areas affected...Portions of central Lower Michigan Concerning...Severe potential...Watch unlikely Valid 102158Z - 110000Z Probability of Watch Issuance...20 percent SUMMARY...A few storms may become organized and perhaps become severe over the next few hours. Isolated damaging gusts and perhaps a few marginally severe hail stones may accompany the stronger storms. Given the potentially isolated nature of the storms, a WW issuance is not currently expected. DISCUSSION...A 500 mb vort max across northern parts of Lower Michigan is currently propagating eastward while cresting a low amplitude ridge aloft, contributing to modest deep-layer ascent across central parts of Lower Michigan. An small uptick in convective coverage and organization/intensity has been noted over the past hour, particularly in the vicinity of Newaygo/Mecosta/Isabella Counties. These storms are maturing in an ambient environment characterized by modest instability and strong deep-layer shear, with up to 1500 J/kg MLCAPE and 40 knots of effective bulk shear depicted by recent Mesoanalysis. In addition, over 150 m2/s2 0-1km SRH and 300 m2/s2 0-3km SRH is present across parts of the Lower Michigan Peninsula per latest GRR and DTX VAD profiler data. As such, the ambient environment will be supportive of storm organization and at least some mid-level rotation, fostering the potential for isolated damaging wind gusts and perhaps some marginally severe hail. The severe threat however, may be rather sparse in nature, possibly precluding a WW issuance. However, given the relatively favorable overlapping kinematic and thermodynamic parameter space, convective trends will continue to be monitored through the remainder of the afternoon. ..Squitieri/Thompson.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DTX...APX...GRR... LAT...LON 42698344 42518409 42448509 42728616 43118628 43738587 44128536 43928439 43488359 43038342 42698344 Read more

WW 0640 Status Updates
STATUS REPORT ON WW 640 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..KERR..09/10/19 ATTN...WFO...LBF...CYS...UNR... STATUS REPORT FOR WT 640 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-013-017-031-045-069-075-091-103-123-149-157-161-165-171- 102240- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOX BUTTE BROWN CHERRY DAWES GARDEN GRANT HOOKER KEYA PAHA MORRILL ROCK SCOTTS BLUFF SHERIDAN SIOUX THOMAS SDC007-033-047-071-095-102-121-123-102240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT CUSTER FALL RIVER JACKSON MELLETTE OGLALA LAKOTA TODD TRIPP WYC005-009-011-015-027-031-045-102240- WY Read more

WW 0640 Status Updates
STATUS REPORT ON WW 640 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..KERR..09/10/19 ATTN...WFO...LBF...CYS...UNR... STATUS REPORT FOR WT 640 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-013-017-031-045-069-075-091-103-123-149-157-161-165-171- 102240- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOX BUTTE BROWN CHERRY DAWES GARDEN GRANT HOOKER KEYA PAHA MORRILL ROCK SCOTTS BLUFF SHERIDAN SIOUX THOMAS SDC007-033-047-071-095-102-121-123-102240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT CUSTER FALL RIVER JACKSON MELLETTE OGLALA LAKOTA TODD TRIPP WYC005-009-011-015-027-031-045-102240- WY Read more

WW 640 TORNADO NE SD WY 101950Z - 110300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 640 NWS Storm Prediction Center Norman OK 150 PM MDT Tue Sep 10 2019 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Northern Nebraska Southern South Dakota Eastern Wyoming * Effective this Tuesday afternoon and evening from 150 PM until 900 PM MDT. * Primary threats include... A couple tornadoes possible Scattered large hail likely with isolated very large hail events to 3 inches in diameter possible Scattered damaging wind gusts to 70 mph likely SUMMARY...Thunderstorms will intensify this afternoon over eastern Wyoming, and along a boundary over northern Nebraska. These storms will affect the watch area through the evening, posing a risk of large hail, damaging wind gusts, and a few tornadoes. The tornado watch area is approximately along and 60 statute miles north and south of a line from 45 miles northwest of Douglas WY to 30 miles northeast of Ainsworth NE. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Tornado Watch means conditions are favorable for tornadoes and 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. && AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 3 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

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Tue Sep 10 2019 Valid 102000Z - 111200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF NORTHERN NE AND SOUTHERN SD... ...SUMMARY... An enhanced threat for severe hail and damaging winds will likely develop this afternoon and evening across parts of the north-central Plains, focused near the Nebraska/South Dakota line. A tornado threat exists in this area as well. ...20Z Update... The Enhanced Risk for damaging winds has been expanded eastward to include more of southeastern SD and northeastern NE. Storms are still expected to form and quickly strengthen across the northern and central High Plains through the remainder of this afternoon and into the evening. All severe hazards may occur with this activity as it moves eastward, as both strong shear and instability are present along/south of a front located near the NE/SD border. Damaging winds, some potentially significant, will likely become the primary threat this evening as convection grows upscale into a bowing complex in tandem with a 40-50 kt southerly low-level jet centered over KS/NE. The Slight and Marginal Risk areas have also been expanded eastward to include more of the Upper Midwest, as isolated strong to severe wind gusts may persist with the MCS through much of the overnight. For more information on the near-term severe threat across the northern/central High Plains, see Mesoscale Discussions 1947/1948, and recently issued Tornado Watch 640. ..Gleason.. 09/10/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Tue Sep 10 2019/ ...Central/Northern High Plains... A shortwave trough currently moving across UT will track into the central and northern High Plains this evening. Model guidance suggests that midlevel height falls and lift will overspread parts of western WY and the NE Panhandle after 18z, with convective initiation occurring a few hours afterward. Storms will be focused along a surface baroclinic zone that extends from northeast WY southeastward into the NE Panhandle - then eastward across NE. Forecast soundings in vicinity of the boundary show MLCAPE values around 3000 J/kg and a weak cap. Initial storm structures will likely be supercellular, with a risk of very large hail and isolated tornadoes. A consensus of CAM solutions agree that storms will congeal and grow upscale through the evening as they track eastward along the boundary across NE, with a focused area of enhanced damaging wind threat. ...ID/UT/WY/MT... Scattered thunderstorms are expected to intensify early this afternoon beneath the core of the midlevel shortwave trough over northern UT and southeast ID. These storms will be relatively fast-moving and in a steep lapse rate environment. The strongest cells in this region will pose a risk of hail and damaging wind gusts. Some activity may remain strong as it moves across northern/western WY into southern MT this evening. ...Western KS into northeast NM... Full sunshine will lead to an axis of moderate CAPE values this afternoon along the dryline from western KS into northeast NM. All model guidance shows the development of isolated thunderstorms in a deeply mixed but weakly sheared environment. A few of the storms will be capable of strong downburst winds for a few hours this afternoon and evening. ...Lower MI... A weak convectively-enhanced upper trough is moving across WI. This feature will move eastward into Lower MI this afternoon, with scattered thunderstorms likely to form. Rather strong winds aloft and sufficient CAPE suggest a risk of gusty/damaging winds in the strongest cells. Read more

WW 0640 Status Updates
STATUS FOR WATCH 0640 HAS NOT BEEN ISSUED YET Read more

MD 1949 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHWEST KANSAS...SOUTHEAST COLORADO...NORTHWEST TEXAS PANHANDLE...WESTERN OKLAHOMA PANHANDLE...NORTHEAST NEW MEXICO
Mesoscale Discussion 1949 NWS Storm Prediction Center Norman OK 0238 PM CDT Tue Sep 10 2019 Areas affected...Southwest Kansas...Southeast Colorado...northwest Texas Panhandle...western Oklahoma Panhandle...northeast New Mexico Concerning...Severe potential...Watch unlikely Valid 101938Z - 102145Z Probability of Watch Issuance...5 percent SUMMARY...A few isolated storms capable of strong/severe wind gusts are possible this afternoon. This diurnally-driven activity should cease after sunset. A WW is not likely. DISCUSSION...Cumulus have been deepening within the lee trough into southeast Colorado and northeast New Mexico over the past hour. Isolated storms have already developed with a few more storms possible within the next couple hours. With stronger flow/shear displaced to the northwest, storms will struggle to organize and propagate very far eastward into greater buoyancy. However, strong surface heating has steepened low-level lapse rates significantly which will allow a few strong/severe wind gusts to accompany this activity. With weak upper-level support, this disorganized activity will likely cease after sunset. A WW is not likely. ..Wendt/Hart.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD...AMA...PUB...ABQ... LAT...LON 36470371 38820207 38970169 38920116 38410076 37360091 36380167 35150271 34820358 35190416 35520435 36470371 Read more

MD 1948 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY FOR NE PANHANDLE...WESTERN/CENTRAL NE...SOUTH-CENTRAL SD
Mesoscale Discussion 1948 NWS Storm Prediction Center Norman OK 0225 PM CDT Tue Sep 10 2019 Areas affected...NE Panhandle...Western/Central NE...South-Central SD Concerning...Severe potential...Tornado Watch likely Valid 101925Z - 102130Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorm initiation is anticipated over north-central NE/south-central SD later this afternoon. All severe hazards, including tornadoes, are possible with the initial development. Upscale growth into a strong, forward-propagating MCS anticipated thereafter. DISCUSSION...Recent surface analysis places a warm front from just south of the YKN (in far southeast SD) west-southwestward across north-central NE and into far southeast WY. Moist conditions exist south of this front with dewpoints in the upper 60s/low 70s. These moist conditions combined with steep mid-level lapse rates are contributing to moderate to strong buoyancy. Additionally, southeasterly surface winds beneath increasing southwesterly flow results in a veering wind profile and strong deep layer shear. Expectation is for storm to develop quickly along and near the front once convective inhibition erodes this afternoon. An initially discrete mode is anticipated but close storm proximity suggests clustering could occur quickly. Even so, favorable low-level shear profiles and ample low-level moisture suggest tornadoes are possible. A forward-propagating MCS will likely develop out of the storm cluster as cold pools amalgamate. Given the overall environment, some significant wind gusts (i.e. 74+ mph) are possible within this MCS. ..Nauslar/Hart.. 09/10/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FSD...ABR...LBF...UNR...CYS... LAT...LON 42370311 43190254 43550192 43670060 43579968 43129893 42139884 41460004 41370260 42370311 Read more

No watches are valid as of Tue Sep 10 18:53:06 UTC 2019.