Severe Storms

WW 0660 Status Updates
STATUS REPORT ON WW 660 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..SPC..09/24/19 ATTN...WFO...DMX...FSD...ARX...OAX...MPX... STATUS REPORT FOR WT 660 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS IAC001-003-009-015-021-023-025-027-029-033-035-037-039-041-047- 049-059-063-067-069-071-073-075-077-079-081-083-085-089-091-093- 099-109-119-121-127-129-131-133-137-141-143-145-147-149-151-153- 155-159-161-165-167-169-173-175-181-187-189-193-195-197- 250040- IA . IOWA COUNTIES INCLUDED ARE ADAIR ADAMS AUDUBON BOONE BUENA VISTA BUTLER CALHOUN CARROLL CASS CERRO GORDO CHEROKEE CHICKASAW CLARKE CLAY CRAWFORD DALLAS DICKINSON EMMET FLOYD FRANKLIN FREMONT GREENE GRUNDY GUTHRIE HAMILTON HANCOCK HARDIN HARRISON HOWARD HUMBOLDT IDA JASPER KOSSUTH LYON MADISON MARSHALL MILLS MITCHELL MONONA MONTGOMERY O'BRIEN OSCEOLA PAGE PALO ALTO PLYMOUTH POCAHONTAS POLK POTTAWATTAMIE RINGGOLD SAC SHELBY Read more

MD 2009 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN/EASTERN ND AND NORTHERN MN
Mesoscale Discussion 2009 NWS Storm Prediction Center Norman OK 0516 PM CDT Tue Sep 24 2019 Areas affected...Portions of northern/eastern ND and northern MN Concerning...Severe potential...Watch unlikely Valid 242216Z - 250045Z Probability of Watch Issuance...20 percent SUMMARY...Isolated large hail and strong/gusty winds may occur through this evening. Watch issuance will probably not be needed. DISCUSSION...Storms have formed late this afternoon along a secondary cold front in southern Manitoba. A relatively cool low-level airmass is present downstream from this activity in northern/eastern ND and northern MN behind the primary surface cold front. But, cold temperatures aloft (-15 to -22 C at 500 mb) and somewhat steepened mid-level lapse rates are associated with large-scale upper troughing over central Canada and the northern Plains. Modest diurnal destabilization has occurred across this region, with 22Z mesoanalysis estimating around 500-750 J/kg of MLCAPE has developed. Latest VWP from KMVX shows generally westerly flow strengthening to around 50-60 kt through mid levels. Isolated instances of large hail may occur with any semi-discrete storms, although tendency may be for storms to grow upscale into one or more small bowing clusters this evening across eastern ND and northwestern MN. Strong/gusty winds could also be a concern. Regardless, the overall thermodynamic environment should remain marginal, and watch issuance will probably not be needed. ..Gleason/Grams.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...FGF...BIS... LAT...LON 49000087 49079522 49399521 49369482 48849454 48719417 48689383 48689333 47999357 47369442 47049553 47079717 47279864 47559954 48170021 49000087 Read more

MD 2011 CONCERNING SEVERE THUNDERSTORM WATCH 659... FOR PORTIONS OF SOUTHERN/CENTRAL KS
Mesoscale Discussion 2011 NWS Storm Prediction Center Norman OK 0630 PM CDT Tue Sep 24 2019 Areas affected...Portions of southern/central KS Concerning...Severe Thunderstorm Watch 659... Valid 242330Z - 250100Z The severe weather threat for Severe Thunderstorm Watch 659 continues. SUMMARY...Mainly an isolated large hail threat continues across Severe Thunderstorm Watch 659 this evening. DISCUSSION...Up to 2 inch diameter hail has recently been reported with a supercell in Pratt County KS. A pair of supercells in this county will likely continue moving slowly east-southeastward across southern KS this evening, posing mainly an isolated large hail threat. Additional storms have formed along a surface trough/pseudo-dryline feature in southern/central KS to the northwest of the lead supercells. This region remains on the southern fringe of stronger mid-level westerlies, but there is still sufficient veering and strengthening of the wind field per KDDC/KICT VWPs to support 30-40 kt of effective bulk shear and continued supercell structures. A modest increase in a southwesterly low-level jet is expected in the next couple of hours across OK into southern/central KS. Low-level warm air advection and related lift may maintain strong to severe storms into this evening, mainly across southern portions of Severe Thunderstorm Watch 659 (south-central KS). A narrow window for a brief/isolated tornado may also exist for the next hour or two with the lead supercells now moving slowly across Pratt County as hodograph curvature modestly increases in the 0-3 km layer in tandem with the low-level jet. ..Gleason.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ICT...DDC... LAT...LON 37030060 37670064 38849869 39189833 39179798 38939797 38559739 38449679 37049786 37030060 Read more

WW 0661 Status Updates
STATUS REPORT ON WW 661 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..09/24/19 ATTN...WFO...TOP...OAX... STATUS REPORT FOR WS 661 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC013-027-029-041-061-085-117-127-131-143-149-157-161-177-197- 201-250040- KS . KANSAS COUNTIES INCLUDED ARE BROWN CLAY CLOUD DICKINSON GEARY JACKSON MARSHALL MORRIS NEMAHA OTTAWA POTTAWATOMIE REPUBLIC RILEY SHAWNEE WABAUNSEE WASHINGTON NEC067-095-097-109-127-131-133-147-151-250040- NE . NEBRASKA COUNTIES INCLUDED ARE GAGE JEFFERSON JOHNSON LANCASTER NEMAHA OTOE PAWNEE RICHARDSON SALINE THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL Read more

MD 2012 CONCERNING TORNADO WATCH 660... FOR EASTERN NE...IA...SOUTHERN MN...WESTERN WI
Mesoscale Discussion 2012 NWS Storm Prediction Center Norman OK 0633 PM CDT Tue Sep 24 2019 Areas affected...Eastern NE...IA...Southern MN...Western WI Concerning...Tornado Watch 660... Valid 242333Z - 250130Z The severe weather threat for Tornado Watch 660 continues. SUMMARY...Severe threat continues across ww660. DISCUSSION...Diffluent high-level flow is spreading across the upper MS Valley ahead of a pronounced short-wave trough. In response, scattered strong/severe thunderstorms have developed ahead of the front with several supercell structures now evident from western IA into south-central MN. This activity is maturing quickly and additional supercells should emerge over the next few hours as a reservoir of moisture/instability currently extends ahead of these storms into northern WI. Latest hail algorithm suggests most supercells are producing hail in excess of 1" and long-lived supercells appear possible given the large-scale support and instability present. Tornado threat continues with these discrete supercells. ..Darrow.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ARX...MPX...DMX...FSD...OAX... LAT...LON 40739703 45559447 45549118 40759397 40739703 Read more

MD 2013 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR WI...UP MI
Mesoscale Discussion 2013 NWS Storm Prediction Center Norman OK 0652 PM CDT Tue Sep 24 2019 Areas affected...WI...UP MI Concerning...Severe potential...Watch likely Valid 242352Z - 250045Z Probability of Watch Issuance...95 percent SUMMARY...Tornado watch will be issued within the next hour to include much of northern WI and the UP of MI. DISCUSSION...Northern extent of higher moisture/instability currently extends across northern WI into the western UP of MI. Scattered severe thunderstorms are expanding in areal coverage from northwestern WI into southeast MN. This activity is strongly supported by approaching short-wave trough which will encourage ongoing storms to spread north/east of ww660. Wind profiles/buoyancy favor supercells along with a threat for a few tornadoes. ..Darrow/Grams.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MQT...GRB...DLH...ARX...MPX... LAT...LON 45729210 47278992 47388799 46258718 44378884 44209072 45729210 Read more

WW 0661 Status Updates
STATUS FOR WATCH 0661 HAS NOT BEEN ISSUED YET Read more

WW 661 SEVERE TSTM KS NE 242245Z - 250500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 661 NWS Storm Prediction Center Norman OK 545 PM CDT Tue Sep 24 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Kansas Southeast Nebraska * Effective this Tuesday afternoon from 545 PM until Midnight CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Isolated damaging wind gusts to 70 mph possible A tornado or two possible SUMMARY...A few supercells should develop into northeast Kansas and possibly southeast Nebraska with the primary threats being large hail and isolated severe wind gusts. The severe thunderstorm watch area is approximately along and 50 statute miles north and south of a line from 15 miles southwest of Concordia KS to 60 miles east southeast of Beatrice NE. 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 659...WW 660... 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 27035. ...Grams Read more

WW 0659 Status Updates
STATUS REPORT ON WW 659 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..09/24/19 ATTN...WFO...DDC...ICT... STATUS REPORT FOR WS 659 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS KSC007-009-025-033-047-053-057-077-079-095-097-113-115-119-145- 151-155-159-165-169-173-185-242340- KS . KANSAS COUNTIES INCLUDED ARE BARBER BARTON CLARK COMANCHE EDWARDS ELLSWORTH FORD HARPER HARVEY KINGMAN KIOWA MCPHERSON MARION MEADE PAWNEE PRATT RENO RICE RUSH SALINE SEDGWICK STAFFORD 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 659 SEVERE TSTM KS 242005Z - 250300Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 659 NWS Storm Prediction Center Norman OK 305 PM CDT Tue Sep 24 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Central Kansas * Effective this Tuesday afternoon and evening from 305 PM until 1000 PM CDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 70 mph possible SUMMARY...Thunderstorms will continue to intensify over portions of central Kansas this afternoon and early evening. The strongest cells will pose a risk of large hail and damaging wind gusts. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 45 miles west southwest of Medicine Lodge KS to 50 miles north of Hutchinson KS. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28025. ...Hart Read more

MD 2010 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR PORTIONS OF NORTHEASTERN KS...SOUTHEASTERN NE...AND FAR NORTHWESTERN MO
Mesoscale Discussion 2010 NWS Storm Prediction Center Norman OK 0530 PM CDT Tue Sep 24 2019 Areas affected...Portions of northeastern KS...southeastern NE...and far northwestern MO Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 242230Z - 242330Z Probability of Watch Issuance...80 percent SUMMARY...Storms forming in northeastern Kansas may become severe this evening, posing at least an isolated threat for large hail and damaging winds. Watch issuance is likely. DISCUSSION...Storms have begun to increase in coverage in a zone of low-level convergence along a pre-frontal trough/dryline feature across north-central/northeastern KS. The environment across this region and into southeastern NE is favorable for robust convection, with moderate to strong instability present along with 35-45 of effective bulk shear. Supercells posing at least an isolated threat for large hail appear probable, and strong to damaging downdraft winds may also occur. Even though overall storm coverage may remain somewhat isolated between ongoing convection across eastern NE/western IA and southern KS, the favorable thermodynamic and kinematic environment present ahead of the developing storms in north-central/northeastern KS suggests that Severe Thunderstorm Watch issuance will likely be needed soon. ..Gleason/Grams.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...EAX...OAX...TOP...ICT...GID... LAT...LON 39189847 41009689 40539581 40549498 38579661 38599729 38799795 39189847 Read more

MD 2009 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NORTHERN/EASTERN ND AND NORTHERN MN
Mesoscale Discussion 2009 NWS Storm Prediction Center Norman OK 0516 PM CDT Tue Sep 24 2019 Areas affected...Portions of northern/eastern ND and northern MN Concerning...Severe potential...Watch unlikely Valid 242216Z - 250045Z Probability of Watch Issuance...20 percent SUMMARY...Isolated large hail and strong/gusty winds may occur through this evening. Watch issuance will probably not be needed. DISCUSSION...Storms have formed late this afternoon along a secondary cold front in southern Manitoba. A relatively cool low-level airmass is present downstream from this activity in northern/eastern ND and northern MN behind the primary surface cold front. But, cold temperatures aloft (-15 to -22 C at 500 mb) and somewhat steepened mid-level lapse rates are associated with large-scale upper troughing over central Canada and the northern Plains. Modest diurnal destabilization has occurred across this region, with 22Z mesoanalysis estimating around 500-750 J/kg of MLCAPE has developed. Latest VWP from KMVX shows generally westerly flow strengthening to around 50-60 kt through mid levels. Isolated instances of large hail may occur with any semi-discrete storms, although tendency may be for storms to grow upscale into one or more small bowing clusters this evening across eastern ND and northwestern MN. Strong/gusty winds could also be a concern. Regardless, the overall thermodynamic environment should remain marginal, and watch issuance will probably not be needed. ..Gleason/Grams.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...FGF...BIS... LAT...LON 49000087 49079522 49399521 49369482 48849454 48719417 48689383 48689333 47999357 47369442 47049553 47079717 47279864 47559954 48170021 49000087 Read more

WW 0660 Status Updates
STATUS FOR WATCH 0660 HAS NOT BEEN ISSUED YET Read more

WW 660 TORNADO IA MN NE WI 242145Z - 250500Z
URGENT - IMMEDIATE BROADCAST REQUESTED Tornado Watch Number 660 NWS Storm Prediction Center Norman OK 445 PM CDT Tue Sep 24 2019 The NWS Storm Prediction Center has issued a * Tornado Watch for portions of Western and central Iowa Southern and east-central Minnesota Eastern Nebraska West-central Wisconsin * Effective this Tuesday afternoon from 445 PM until Midnight CDT. * Primary threats include... A few tornadoes likely with a couple intense tornadoes possible Scattered large hail and isolated very large hail events to 3 inches in diameter likely Scattered damaging winds likely with isolated significant gusts to 80 mph possible SUMMARY...Several supercells are expected to develop from eastern Nebraska and western Iowa northeast across southern Minnesota into west-central Wisconsin this evening, capable of producing all severe thunderstorm hazards. The greater tornado threat should exist from northern Iowa across southern Minnesota into west-central Wisconsin. The tornado watch area is approximately along and 80 statute miles east and west of a line from 5 miles west of Shenandoah IA to 50 miles north northeast of Minneapolis MN. 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. && OTHER WATCH INFORMATION...CONTINUE...WW 659... AVIATION...Tornadoes and a few severe thunderstorms with hail surface and aloft to 3 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 26040. ...Grams Read more

MD 2008 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PARTS OF NORTHERN IOWA...SOUTHEASTERN MINNESOTA AND WESTERN WISCONSIN
Mesoscale Discussion 2008 NWS Storm Prediction Center Norman OK 0313 PM CDT Tue Sep 24 2019 Areas affected...Parts of northern Iowa...southeastern Minnesota and western Wisconsin Concerning...Severe potential...Watch possible Valid 242013Z - 242245Z Probability of Watch Issuance...60 percent SUMMARY...Increasing thunderstorm development which may pose a risk for tornadoes, large hail and damaging wind gusts appears probable by early this evening. Although it currently appears that a watch issuance may not be needed until around or shortly after 7 PM CDT, it is possible that one could be needed sooner. DISCUSSION...Surface troughing continues to deepen south of the international border through the central U.S. Plains, including sustained 2-hourly surface pressure falls now evident along an axis from Sioux City IA through Minneapolis MN and Hayward WI. This appears generally beneath the pre-cold frontal 850 mb thermal ridge axis, where latest Rapid Refresh suggests deep boundary layer moistening has yet to take place. However, between now and 22-00Z, southwesterly 850 mb flow is forecast to strengthen from 30-50 kt along this corridor, which appears likely to allow for more rapid low-level moistening. This should be accompanied by substantive further destabilization (including mixed-layer CAPE on the order of 2000+ J/kg) and weakening of inhibition, which is expected to eventually support the initiation of vigorous thunderstorm development. Although some uncertainty remains, it currently appears that stronger mid/upper forcing for ascent may not begin impacting the developing instability axis until after 25/00Z. Once activity initiates, there appears at least a window of opportunity for scattered discrete supercell storms, in the presence of strong deep layer shear beneath 50+ kt westerly 500 mb flow. Given sizable clockwise curved low-level hodographs, strongest storms may pose potential for tornadoes, in addition to the risk for severe hail and strong surface gusts. ..Kerr/Hart.. 09/24/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GRB...DLH...ARX...MPX...DMX...FSD... LAT...LON 43429537 44859320 45539217 45408978 43659060 42749218 42369321 42659531 43429537 Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Tue Sep 24 2019 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms will threaten parts of the central Plains and Midwest today. Large hail, damaging gusts and a few tornadoes are possible. ...Discussion... Primary change to previous outlook has been to reintroduce a small 10% tornado probability for southeast MN into western WI. Moisture return has been robust along a 30 kt southwesterly low-level jet with corridor of 70 F dewpoints now approaching the southern MN border. The low-level jet will strengthen in pre-frontal warm sector this evening downstream from an amplifying northern-stream trough. Vertical wind profiles will become increasingly favorable for organized storms with effective bulk shear up to 50 kt and 0-1 km storm relative helicity from 200-300 m2/s2 in presence of a moistening boundary layer and moderate to strong instability (2000-3000 J/kg MLCAPE). Storms are expected to develop along and ahead of the cold front from southeast MN, western WI into IA by early evening and spread east. Discrete supercells will probably be the initial storm mode before upscale growth into line segments occurs. While the parameter space will be favorable for supercells capable of producing a few tornadoes, overall tornado threat will be dependent in part on duration of discrete storm modes. Otherwise, damaging wind and large to very large hail will be likely with some of the storms into this evening. ..Dial.. 09/24/2019 .PREV DISCUSSION... /ISSUED 1105 AM CDT Tue Sep 24 2019/ ...IA to WI... A strong upper trough and associated midlevel jet will move into the northern Plains today, with height falls and large-scale forcing overspreading parts of MN/IA/WI/Upper MI. A surface cold front extends from western MN into eastern SD, and will track eastward into IA later today. This boundary will be the focus for afternoon thunderstorm development. Visible satellite imagery shows strong heating is occurring in this region. Dewpoints are only in the 50s to lower 60s, but are forecast to climb into the mid/upper 60s by mid-late afternoon as advection occurs from the southwest. This will result in a corridor of strong instability across much of IA into southeast MN and western WI. Initial storm mode will likely be supercellular, given strong deep-layer vertical shear, relatively steep midlevel lapse rates, and high CAPE values. Very large hail will be main threat with these storms, although damaging winds and a few tornadoes are possible. The main tornado threat appears to be over parts of western/central WI, but is contingent on robust low-level moisture return depicted in model guidance. Storms will likely congeal into linear segments by early evening and spread eastward into WI with a continued risk of damaging winds and a few tornadoes. ...KS... The aforementioned cold front extends southward into KS, where ample low-level moisture and strong heating will be present today. Large-scale forcing is much weaker this far south, but weak frontal convergence and a weak cap will likely result in widely scattered storms over central KS this afternoon. Sufficient vertical shear suggests rotating storms are possible with a risk of large hail and gusty winds. The primary severe risk with this activity should diminish by mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Tue Sep 24 2019 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms will threaten parts of the central Plains and Midwest today. Large hail, damaging gusts and a few tornadoes are possible. ...Discussion... Primary change to previous outlook has been to reintroduce a small 10% tornado probability for southeast MN into western WI. Moisture return has been robust along a 30 kt southwesterly low-level jet with corridor of 70 F dewpoints now approaching the southern MN border. The low-level jet will strengthen in pre-frontal warm sector this evening downstream from an amplifying northern-stream trough. Vertical wind profiles will become increasingly favorable for organized storms with effective bulk shear up to 50 kt and 0-1 km storm relative helicity from 200-300 m2/s2 in presence of a moistening boundary layer and moderate to strong instability (2000-3000 J/kg MLCAPE). Storms are expected to develop along and ahead of the cold front from southeast MN, western WI into IA by early evening and spread east. Discrete supercells will probably be the initial storm mode before upscale growth into line segments occurs. While the parameter space will be favorable for supercells capable of producing a few tornadoes, overall tornado threat will be dependent in part on duration of discrete storm modes. Otherwise, damaging wind and large to very large hail will be likely with some of the storms into this evening. ..Dial.. 09/24/2019 .PREV DISCUSSION... /ISSUED 1105 AM CDT Tue Sep 24 2019/ ...IA to WI... A strong upper trough and associated midlevel jet will move into the northern Plains today, with height falls and large-scale forcing overspreading parts of MN/IA/WI/Upper MI. A surface cold front extends from western MN into eastern SD, and will track eastward into IA later today. This boundary will be the focus for afternoon thunderstorm development. Visible satellite imagery shows strong heating is occurring in this region. Dewpoints are only in the 50s to lower 60s, but are forecast to climb into the mid/upper 60s by mid-late afternoon as advection occurs from the southwest. This will result in a corridor of strong instability across much of IA into southeast MN and western WI. Initial storm mode will likely be supercellular, given strong deep-layer vertical shear, relatively steep midlevel lapse rates, and high CAPE values. Very large hail will be main threat with these storms, although damaging winds and a few tornadoes are possible. The main tornado threat appears to be over parts of western/central WI, but is contingent on robust low-level moisture return depicted in model guidance. Storms will likely congeal into linear segments by early evening and spread eastward into WI with a continued risk of damaging winds and a few tornadoes. ...KS... The aforementioned cold front extends southward into KS, where ample low-level moisture and strong heating will be present today. Large-scale forcing is much weaker this far south, but weak frontal convergence and a weak cap will likely result in widely scattered storms over central KS this afternoon. Sufficient vertical shear suggests rotating storms are possible with a risk of large hail and gusty winds. The primary severe risk with this activity should diminish by mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Tue Sep 24 2019 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms will threaten parts of the central Plains and Midwest today. Large hail, damaging gusts and a few tornadoes are possible. ...Discussion... Primary change to previous outlook has been to reintroduce a small 10% tornado probability for southeast MN into western WI. Moisture return has been robust along a 30 kt southwesterly low-level jet with corridor of 70 F dewpoints now approaching the southern MN border. The low-level jet will strengthen in pre-frontal warm sector this evening downstream from an amplifying northern-stream trough. Vertical wind profiles will become increasingly favorable for organized storms with effective bulk shear up to 50 kt and 0-1 km storm relative helicity from 200-300 m2/s2 in presence of a moistening boundary layer and moderate to strong instability (2000-3000 J/kg MLCAPE). Storms are expected to develop along and ahead of the cold front from southeast MN, western WI into IA by early evening and spread east. Discrete supercells will probably be the initial storm mode before upscale growth into line segments occurs. While the parameter space will be favorable for supercells capable of producing a few tornadoes, overall tornado threat will be dependent in part on duration of discrete storm modes. Otherwise, damaging wind and large to very large hail will be likely with some of the storms into this evening. ..Dial.. 09/24/2019 .PREV DISCUSSION... /ISSUED 1105 AM CDT Tue Sep 24 2019/ ...IA to WI... A strong upper trough and associated midlevel jet will move into the northern Plains today, with height falls and large-scale forcing overspreading parts of MN/IA/WI/Upper MI. A surface cold front extends from western MN into eastern SD, and will track eastward into IA later today. This boundary will be the focus for afternoon thunderstorm development. Visible satellite imagery shows strong heating is occurring in this region. Dewpoints are only in the 50s to lower 60s, but are forecast to climb into the mid/upper 60s by mid-late afternoon as advection occurs from the southwest. This will result in a corridor of strong instability across much of IA into southeast MN and western WI. Initial storm mode will likely be supercellular, given strong deep-layer vertical shear, relatively steep midlevel lapse rates, and high CAPE values. Very large hail will be main threat with these storms, although damaging winds and a few tornadoes are possible. The main tornado threat appears to be over parts of western/central WI, but is contingent on robust low-level moisture return depicted in model guidance. Storms will likely congeal into linear segments by early evening and spread eastward into WI with a continued risk of damaging winds and a few tornadoes. ...KS... The aforementioned cold front extends southward into KS, where ample low-level moisture and strong heating will be present today. Large-scale forcing is much weaker this far south, but weak frontal convergence and a weak cap will likely result in widely scattered storms over central KS this afternoon. Sufficient vertical shear suggests rotating storms are possible with a risk of large hail and gusty winds. The primary severe risk with this activity should diminish by mid-evening. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Tue Sep 24 2019 Valid 242000Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHERN IOWA INTO SOUTHEAST MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms will threaten parts of the central Plains and Midwest today. Large hail, damaging gusts and a few tornadoes are possible. ...Discussion... Primary change to previous outlook has been to reintroduce a small 10% tornado probability for southeast MN into western WI. Moisture return has been robust along a 30 kt southwesterly low-level jet with corridor of 70 F dewpoints now approaching the southern MN border. The low-level jet will strengthen in pre-frontal warm sector this evening downstream from an amplifying northern-stream trough. Vertical wind profiles will become increasingly favorable for organized storms with effective bulk shear up to 50 kt and 0-1 km storm relative helicity from 200-300 m2/s2 in presence of a moistening boundary layer and moderate to strong instability (2000-3000 J/kg MLCAPE). Storms are expected to develop along and ahead of the cold front from southeast MN, western WI into IA by early evening and spread east. Discrete supercells will probably be the initial storm mode before upscale growth into line segments occurs. While the parameter space will be favorable for supercells capable of producing a few tornadoes, overall tornado threat will be dependent in part on duration of discrete storm modes. Otherwise, damaging wind and large to very large hail will be likely with some of the storms into this evening. ..Dial.. 09/24/2019 .PREV DISCUSSION... /ISSUED 1105 AM CDT Tue Sep 24 2019/ ...IA to WI... A strong upper trough and associated midlevel jet will move into the northern Plains today, with height falls and large-scale forcing overspreading parts of MN/IA/WI/Upper MI. A surface cold front extends from western MN into eastern SD, and will track eastward into IA later today. This boundary will be the focus for afternoon thunderstorm development. Visible satellite imagery shows strong heating is occurring in this region. Dewpoints are only in the 50s to lower 60s, but are forecast to climb into the mid/upper 60s by mid-late afternoon as advection occurs from the southwest. This will result in a corridor of strong instability across much of IA into southeast MN and western WI. Initial storm mode will likely be supercellular, given strong deep-layer vertical shear, relatively steep midlevel lapse rates, and high CAPE values. Very large hail will be main threat with these storms, although damaging winds and a few tornadoes are possible. The main tornado threat appears to be over parts of western/central WI, but is contingent on robust low-level moisture return depicted in model guidance. Storms will likely congeal into linear segments by early evening and spread eastward into WI with a continued risk of damaging winds and a few tornadoes. ...KS... The aforementioned cold front extends southward into KS, where ample low-level moisture and strong heating will be present today. Large-scale forcing is much weaker this far south, but weak frontal convergence and a weak cap will likely result in widely scattered storms over central KS this afternoon. Sufficient vertical shear suggests rotating storms are possible with a risk of large hail and gusty winds. The primary severe risk with this activity should diminish by mid-evening. Read more

WW 0659 Status Updates
STATUS FOR WATCH 0659 HAS NOT BEEN ISSUED YET Read more