Severe Storms

WW 593 SEVERE TSTM IA MN NE SD 172315Z - 180600Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 593 NWS Storm Prediction Center Norman OK 615 PM CDT Sat Aug 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northwest Iowa Southwest Minnesota Northeast Nebraska Eastern South Dakota * Effective this Saturday night and Sunday morning from 615 PM until 100 AM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Scattered large hail and isolated very large hail events to 2 inches in diameter possible A tornado or two possible SUMMARY...Ongoing storms across south-central/northeast South Dakota early this evening will continue eastward, with the possibility of additional/more isolated supercell development ahead of an evolving cluster of storms. Some tornado risk may exist for a time, particularly through mid-evening across southeast South Dakota. However, the overall most common risks should be large hail and damaging winds, which should become more of a concern later this evening as storm mergers occur and a more organized cluster/line develops. The severe thunderstorm watch area is approximately along and 130 statute miles north and south of a line from 30 miles north northeast of Worthington MN to 45 miles west southwest of Huron SD. 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 590...WW 591...WW 592... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 28025. ...Guyer Read more

WW 0591 Status Updates
STATUS REPORT ON WW 591 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NE PIT TO 30 SSE FKL TO 5 WSW DUJ TO 25 E DUJ TO 25 N UNV TO 15 NNW IPT TO 35 NE IPT TO 5 SW BGM. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1774 ..NAUSLAR..08/17/19 ATTN...WFO...PBZ...CTP... STATUS REPORT FOR WS 591 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS PAC005-031-033-035-063-065-081-113-172340- PA . PENNSYLVANIA COUNTIES INCLUDED ARE ARMSTRONG CLARION CLEARFIELD CLINTON INDIANA JEFFERSON LYCOMING SULLIVAN 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 591 SEVERE TSTM PA 172005Z - 180000Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 591 NWS Storm Prediction Center Norman OK 405 PM EDT Sat Aug 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western and northern Pennsylvania * Effective this Saturday afternoon and evening from 405 PM until 800 PM EDT. * Primary threats include... Scattered damaging wind gusts to 65 mph possible Isolated large hail events to 1.5 inches in diameter possible SUMMARY...A few supercells have developed across northwest into north-central Pennsylvania and should move east-southeast over the next few hours, before weakening across the southern portion of the state. The severe thunderstorm watch area is approximately along and 35 statute miles north and south of a line from 35 miles north northwest of Pittsburgh PA to 20 miles northeast of Williamsport PA. 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 590... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28025. ...Grams Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 55 ENE CDR TO 30 SW PHP TO 35 SSW PIR TO 30 WSW ABR TO 55 NNW VVV. ..GLEASON..08/17/19 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-013-017-025-037-049-059-065-069-071-075-085-091-095-115- 121-123-172340- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT BROWN BUFFALO CLARK DAY FAULK HAND HUGHES HYDE JACKSON JONES LYMAN MARSHALL MELLETTE SPINK TODD TRIPP 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 590 SEVERE TSTM SD 171920Z - 180200Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 590 NWS Storm Prediction Center Norman OK 220 PM CDT Sat Aug 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of South Dakota * Effective this Saturday afternoon and evening from 220 PM until 900 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...Initial storms over the Black Hills and northeast along a front in north-central South Dakota will pose a threat for mainly large hail. With time into the evening, one or more clusters is anticipated with an increasing risk for severe wind gusts. The severe thunderstorm watch area is approximately along and 85 statute miles east and west of a line from 65 miles south of Philip SD to 35 miles north northeast of Aberdeen SD. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU0). 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 26025. ...Grams Read more

MD 1774 CONCERNING SEVERE THUNDERSTORM WATCH 591... FOR WESTERN PENNSYLVANIA INTO NORTHEAST PENNSYLVANIA
Mesoscale Discussion 1774 NWS Storm Prediction Center Norman OK 0544 PM CDT Sat Aug 17 2019 Areas affected...western Pennsylvania into northeast Pennsylvania Concerning...Severe Thunderstorm Watch 591... Valid 172244Z - 180045Z The severe weather threat for Severe Thunderstorm Watch 591 continues. SUMMARY...Storms capable of marginally severe hail and wind continue to move east/southeast across western, central, and northeast Pennsylvania. DISCUSSION...As an upper-level shortwave trough moves eastward across the eastern Great Lakes and southern Ontario/Quebec, storms developed along its southern/southeast periphery across Pennsylvania. CAPPI 7 and 9 km are trending mostly downward except for the storm in far northeast Pennsylvania south/southwest of BGM. However, there still remains some potential for marginally severe wind and hail with the stronger storms. A couple of storms could move out of the watch, but a local watch extension/expansion is unlikely at this time given the recent convective trends and expected waning storm intensity after sunset. Counties will continue to be cleared behind the broken line of storms until the watch expiration at 00z. ..Nauslar/Guyer.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PHI...BGM...CTP...PBZ... LAT...LON 40277976 40647995 40987986 41137968 41227855 41337776 41497722 41857641 42027593 41957524 41837513 41247554 40517624 40377795 40297916 40277976 Read more

WW 0592 Status Updates
STATUS REPORT ON WW 592 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..GLEASON..08/17/19 ATTN...WFO...GLD... STATUS REPORT FOR WS 592 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS COC017-063-125-172340- CO . COLORADO COUNTIES INCLUDED ARE CHEYENNE KIT CARSON YUMA KSC023-039-063-065-109-137-153-179-181-193-199-172340- KS . KANSAS COUNTIES INCLUDED ARE CHEYENNE DECATUR GOVE GRAHAM LOGAN NORTON RAWLINS SHERIDAN SHERMAN THOMAS WALLACE NEC057-087-145-172340- NE . NEBRASKA COUNTIES INCLUDED ARE DUNDY HITCHCOCK RED WILLOW Read more

WW 592 SEVERE TSTM CO KS NE 172035Z - 180400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 592 NWS Storm Prediction Center Norman OK 335 PM CDT Sat Aug 17 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Far eastern Colorado Northwest Kansas Far southwestern Nebraska * Effective this Saturday afternoon and evening from 335 PM until 1100 PM CDT. * Primary threats include... Scattered damaging winds and isolated significant gusts to 80 mph possible Isolated very large hail events to 2 inches in diameter possible SUMMARY...A cluster of severe thunderstorms may develop off across the tri-state area as high-based storms spread east from the Palmer Divide in Colorado. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 35 miles west northwest of Burlington CO to 55 miles southeast of Mccook NE. 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 590...WW 591... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 70 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 27030. ...Grams Read more

MD 1773 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF FAR SOUTHEASTERN ND INTO NORTHWESTERN/NORTH-CENTRAL MN
Mesoscale Discussion 1773 NWS Storm Prediction Center Norman OK 0535 PM CDT Sat Aug 17 2019 Areas affected...Portions of far southeastern ND into northwestern/north-central MN Concerning...Severe potential...Watch unlikely Valid 172235Z - 180030Z Probability of Watch Issuance...20 percent SUMMARY...Mainly a strong/gusty wind threat should persist through the early evening. Watch issuance is unlikely. DISCUSSION...Compared to areas farther south in eastern SD, low-level moisture remains more limited late this afternoon across northwestern into north-central MN ahead of an eastward-moving cold front and attendant line of thunderstorms. Somewhat cooler surface temperatures and modest mid-level lapse rates are limiting instability across this region, with MLCAPE of 500-1500 J/kg being estimated by 22Z mesoanalysis. A recent wind gust to 36 kt was observed at KFSE in northwestern MN, and similar strong/gusty winds may occur with convective downdrafts along the front in the short term (next couple of hours). Marginally severe hail cannot be ruled out with the strongest embedded cores, but the linear mode should tend to limit the hail threat. This isolated severe threat should diminish later this evening with the loss of daytime heating and resultant gradual reduction of already weak instability. Watch issuance remains unlikely this evening due to the overall marginal nature of the severe risk. ..Gleason/Guyer.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...FGF... LAT...LON 45989705 46289727 47849582 48799503 48819459 48729418 48669379 48649313 47929351 47349411 46379516 46129600 45989705 Read more

MD 1772 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF NEW ENGLAND AND UPSTATE NEW YORK
Mesoscale Discussion 1772 NWS Storm Prediction Center Norman OK 0522 PM CDT Sat Aug 17 2019 Areas affected...portions of New England and Upstate New York Concerning...Severe potential...Watch unlikely Valid 172222Z - 180045Z Probability of Watch Issuance...20 percent SUMMARY...A line of storms will continue to move eastward into the evening across New England and vicinity. Storm intensity will likely begin to wane after sunset, but damaging wind and large hail hail remain possible in the next 2+ hours. A severe thunderstorm watch issuance is unlikely. DISCUSSION...A line of storms has developed ahead an upper level shortwave trough moving over the eastern Great Lakes and southern Ontario/Quebec. Given the upper-level forcing for ascent that is present, the storm mode should continue to be quasi-linear. However, given convective temperatures are being breached ahead of the line/cloud cover amid moderate instability (1000-1500 J/kg of MLCAPE) and with effective bulk shear of 30-40 knots, discrete cells are likely to continue developing ahead of the line. There is evidence of a strengthening cold pool and stronger rear inflow per KENX with strong winds remaining likely and several wind reports have been noted during the last hour. Isolated large hail is also possible along the southern periphery of the line or with any strong cell that can intensify into a weaker supercell ahead of the line. While storms are likely to continue moving east after sunset, instability will begin to weaken, and the severe threat will diminish. Given the marginal severe threat and relatively narrow window for severe wind/hail, a watch issuance is unlikely. ..Nauslar/Guyer.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM... LAT...LON 41027370 41057390 41127441 41337478 41617504 42877404 43557352 43937321 44217280 44537228 44687176 44497120 44097120 43447154 42627220 42007265 41597303 41027370 Read more

MD 1771 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PORTIONS OF EASTERN SD...FAR NORTHEASTERN NE...WEST-CENTRAL/SOUTHWESTERN MN...AND NORTHWESTERN IA
Mesoscale Discussion 1771 NWS Storm Prediction Center Norman OK 0512 PM CDT Sat Aug 17 2019 Areas affected...Portions of eastern SD...far northeastern NE...west-central/southwestern MN...and northwestern IA Concerning...Severe potential...Watch likely Valid 172212Z - 180015Z Probability of Watch Issuance...95 percent SUMMARY...The severe threat will increase this evening, with damaging winds and large hail possible. Isolated tornadoes may also occur. Watch issuance will very likely be needed within the next couple of hours. DISCUSSION...A broken line of storms has developed along a surface cold front this afternoon extending northeast-southwest across SD. 22Z surface analysis also shows a weak surface low centered along the NE/SD border, with a diffuse warm front extending eastward from this low across southeastern SD and far northeastern NE. The stronger mid-level flow associated with a large-scale upper trough appears to be lagging west of the surface cold front and associated convection, which has tended to limit the intensity of these storms so far this afternoon. Still, at least isolated damaging winds should continue to be a concern as this activity spreads eastward into eastern SD and vicinity this evening. There also appears to be some potential for discrete storm development along the warm front in southeastern SD and far northeastern NE based on latest short-term guidance and recent radar/visible satellite trends. Effective bulk shear of 35-40 kt and moderate to strong instability would initially promote supercell structures across this region, with both a large hail and damaging wind threat. Isolated tornadoes may also be a concern if a couple discrete supercells can develop along/near the warm front given a very moist low-level airmass, and backed southeasterly low-level winds supporting generally 150-250 m2/s2 of effective SRH through early evening. Watch issuance will very likely be needed within the next couple of hours as storms continue moving eastward. ..Gleason/Guyer.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MPX...FSD...OAX...ABR...LBF... LAT...LON 43019948 44569825 45719715 45709572 45069504 44199490 43499506 42819555 42449651 42429750 42599860 43019948 Read more

WW 0591 Status Updates
STATUS REPORT ON WW 591 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 15 N YNG TO 5 ESE FKL TO 15 S BFD TO 40 SW ELM TO 10 ESE ELM. ..NAUSLAR..08/17/19 ATTN...WFO...PBZ...CTP... STATUS REPORT FOR WS 591 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS PAC005-019-023-031-033-035-047-053-063-065-073-081-085-105-113- 117-121-172240- PA . PENNSYLVANIA COUNTIES INCLUDED ARE ARMSTRONG BUTLER CAMERON CLARION CLEARFIELD CLINTON ELK FOREST INDIANA JEFFERSON LAWRENCE LYCOMING MERCER POTTER SULLIVAN TIOGA VENANGO 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 0590 Status Updates
STATUS REPORT ON WW 590 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 60 WSW RAP TO 25 ESE PHP TO 55 NE PIR TO 45 NNE ABR. ..GLEASON..08/17/19 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-013-017-025-033-037-047-049-059-065-069-071-075-085-091- 095-102-115-117-119-121-123-172240- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT BROWN BUFFALO CLARK CUSTER DAY FALL RIVER FAULK HAND HUGHES HYDE JACKSON JONES LYMAN MARSHALL MELLETTE OGLALA LAKOTA SPINK STANLEY SULLY TODD TRIPP 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 0592 Status Updates
STATUS FOR WATCH 0592 HAS NOT BEEN ISSUED YET Read more

WW 0592 Status Updates
STATUS FOR WATCH 0592 HAS NOT BEEN ISSUED YET Read more

WW 0590 Status Updates
STATUS REPORT ON WW 590 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..ELLIOTT..08/17/19 ATTN...WFO...UNR...ABR... STATUS REPORT FOR WS 590 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-013-017-025-033-037-045-047-049-055-059-065-069-071-075- 085-089-091-093-095-102-103-107-115-117-119-121-123-172140- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT BROWN BUFFALO CLARK CUSTER DAY EDMUNDS FALL RIVER FAULK HAAKON HAND HUGHES HYDE JACKSON JONES LYMAN MCPHERSON MARSHALL MEADE MELLETTE OGLALA LAKOTA PENNINGTON POTTER SPINK STANLEY SULLY TODD TRIPP 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

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Aug 17 2019 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHEASTERN SOUTH DAKOTA INTO NORTHWEST IOWA AND SOUTHWEST MINNESOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEW YORK INTO NORTHERN PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms with damaging winds and large hail as the primary threats are expected across a large portion of the northern to central Great Plains into the Midwest, generally during the late afternoon into tonight. Damaging winds are also possible into early evening in parts of the Northeast States. ...Discussion... Only a few changes were made to the previous outlook for this outlook update. 1) Added a 65-kt or greater risk area for wind for adjacent parts of southern NE into northern KS. Recent HRRR time-lagged members indicate the possibility for a bowing system moving eastward within a plume of steep 700-500mb lapse rates (in excess of 8 degrees C/km) and a wind profile supportive of organized storms. Uncertainty remains regarding this scenario and therefore will keep at a Slight Risk for this outlook update. 2) Reduced severe probabilities west of the squall line over NY where convective overturning will limit the magnitude of destabilization and the potential for severe later this afternoon into the early evening. 3) With passage of an MCV and the stabilizing influence of a thunderstorm line that moved through IL into eastern IN, have reduced hail/wind probabilities into a Marginal-Risk highlight. 4) Nudged higher severe probabilities westward into east-central CO to account for ongoing and expected storm development forecast to move east off the Palmer Divide towards the northwest KS vicinity. ..Smith.. 08/17/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 17 2019/ ...Northern Great Plains/Upper Midwest... A broad positive-tilt shortwave trough will advance east across the southern Prairie Provinces and MT to ND through tonight. A surface front well in advance of this wave extends from the Red River Valley southwest towards the Black Hills and should remain quasi-stationary before accelerating south/east tonight. The bulk of stronger mid-level west-southwesterlies accompanying the wave will remain confined to the cool side of the front, while a separate belt of enhanced westerlies is confined south across NE. In addition, the northern periphery of steeper mid-level lapse rates from an elevated mixed-layer will probably only overlap the SD portion of the front. Low to mid 60s F surface dew points are expected along the front and should support moderate buoyancy with MLCAPE around 1500-2500 J/kg. Owing to a lack of stronger capping, at least scattered thunderstorms will develop in the late afternoon. A few transient supercells should develop initially, but hodographs do not appear particularly elongated or enlarged given modest low-level winds and weakness aloft in the split flow regime. Given the frontal forcing and predominance of outflow consolidation, broader clusters fusing into one or more lines are expected with eastern extent tonight. Some risk for damaging winds will probably continue across southern MN and northern IA along the northern extent of the larger buoyancy plume. ...Central Great Plains... High-based convection that develops off the Front Range this afternoon should impinge on the recovering moist sector near the CO/KS/NE border towards early evening. On the southern periphery of a belt of enhanced mid-level westerlies centered from southern WY across NE amid a very steep lapse rate environment, a swath of severe wind gusts will be possible into north-central KS tonight. ...Mid-MS Valley to IN vicinity... An MCV is centered near the MO/IA/IL border area and should drift east. Several CAMs indicate redevelopment of scattered storms ahead of this feature. This will be highly dependent on more robust destabilization occurring in the wake of a leading MCS in IN. At least a conditional threat for damaging winds and severe hail exists, mainly during the evening. Warm-advection storms overnight may also pose an isolated severe risk. ...Northeast... A low-amplitude shortwave impulse over southern Ontario should slowly move across the Saint Lawrence Valley. Scattered convection is ongoing in association with this wave and will likely persist through the afternoon as further surface-based destabilization occurs downstream. Weak low-level winds and modest mid-level lapse rates will be limiting factors. Most of the stronger speed shear should be confined to the upper portion of the buoyancy profile. Setup should foster a risk of isolated marginally severe hail and scattered damaging winds. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Aug 17 2019 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHEASTERN SOUTH DAKOTA INTO NORTHWEST IOWA AND SOUTHWEST MINNESOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEW YORK INTO NORTHERN PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms with damaging winds and large hail as the primary threats are expected across a large portion of the northern to central Great Plains into the Midwest, generally during the late afternoon into tonight. Damaging winds are also possible into early evening in parts of the Northeast States. ...Discussion... Only a few changes were made to the previous outlook for this outlook update. 1) Added a 65-kt or greater risk area for wind for adjacent parts of southern NE into northern KS. Recent HRRR time-lagged members indicate the possibility for a bowing system moving eastward within a plume of steep 700-500mb lapse rates (in excess of 8 degrees C/km) and a wind profile supportive of organized storms. Uncertainty remains regarding this scenario and therefore will keep at a Slight Risk for this outlook update. 2) Reduced severe probabilities west of the squall line over NY where convective overturning will limit the magnitude of destabilization and the potential for severe later this afternoon into the early evening. 3) With passage of an MCV and the stabilizing influence of a thunderstorm line that moved through IL into eastern IN, have reduced hail/wind probabilities into a Marginal-Risk highlight. 4) Nudged higher severe probabilities westward into east-central CO to account for ongoing and expected storm development forecast to move east off the Palmer Divide towards the northwest KS vicinity. ..Smith.. 08/17/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 17 2019/ ...Northern Great Plains/Upper Midwest... A broad positive-tilt shortwave trough will advance east across the southern Prairie Provinces and MT to ND through tonight. A surface front well in advance of this wave extends from the Red River Valley southwest towards the Black Hills and should remain quasi-stationary before accelerating south/east tonight. The bulk of stronger mid-level west-southwesterlies accompanying the wave will remain confined to the cool side of the front, while a separate belt of enhanced westerlies is confined south across NE. In addition, the northern periphery of steeper mid-level lapse rates from an elevated mixed-layer will probably only overlap the SD portion of the front. Low to mid 60s F surface dew points are expected along the front and should support moderate buoyancy with MLCAPE around 1500-2500 J/kg. Owing to a lack of stronger capping, at least scattered thunderstorms will develop in the late afternoon. A few transient supercells should develop initially, but hodographs do not appear particularly elongated or enlarged given modest low-level winds and weakness aloft in the split flow regime. Given the frontal forcing and predominance of outflow consolidation, broader clusters fusing into one or more lines are expected with eastern extent tonight. Some risk for damaging winds will probably continue across southern MN and northern IA along the northern extent of the larger buoyancy plume. ...Central Great Plains... High-based convection that develops off the Front Range this afternoon should impinge on the recovering moist sector near the CO/KS/NE border towards early evening. On the southern periphery of a belt of enhanced mid-level westerlies centered from southern WY across NE amid a very steep lapse rate environment, a swath of severe wind gusts will be possible into north-central KS tonight. ...Mid-MS Valley to IN vicinity... An MCV is centered near the MO/IA/IL border area and should drift east. Several CAMs indicate redevelopment of scattered storms ahead of this feature. This will be highly dependent on more robust destabilization occurring in the wake of a leading MCS in IN. At least a conditional threat for damaging winds and severe hail exists, mainly during the evening. Warm-advection storms overnight may also pose an isolated severe risk. ...Northeast... A low-amplitude shortwave impulse over southern Ontario should slowly move across the Saint Lawrence Valley. Scattered convection is ongoing in association with this wave and will likely persist through the afternoon as further surface-based destabilization occurs downstream. Weak low-level winds and modest mid-level lapse rates will be limiting factors. Most of the stronger speed shear should be confined to the upper portion of the buoyancy profile. Setup should foster a risk of isolated marginally severe hail and scattered damaging winds. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Aug 17 2019 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHEASTERN SOUTH DAKOTA INTO NORTHWEST IOWA AND SOUTHWEST MINNESOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEW YORK INTO NORTHERN PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms with damaging winds and large hail as the primary threats are expected across a large portion of the northern to central Great Plains into the Midwest, generally during the late afternoon into tonight. Damaging winds are also possible into early evening in parts of the Northeast States. ...Discussion... Only a few changes were made to the previous outlook for this outlook update. 1) Added a 65-kt or greater risk area for wind for adjacent parts of southern NE into northern KS. Recent HRRR time-lagged members indicate the possibility for a bowing system moving eastward within a plume of steep 700-500mb lapse rates (in excess of 8 degrees C/km) and a wind profile supportive of organized storms. Uncertainty remains regarding this scenario and therefore will keep at a Slight Risk for this outlook update. 2) Reduced severe probabilities west of the squall line over NY where convective overturning will limit the magnitude of destabilization and the potential for severe later this afternoon into the early evening. 3) With passage of an MCV and the stabilizing influence of a thunderstorm line that moved through IL into eastern IN, have reduced hail/wind probabilities into a Marginal-Risk highlight. 4) Nudged higher severe probabilities westward into east-central CO to account for ongoing and expected storm development forecast to move east off the Palmer Divide towards the northwest KS vicinity. ..Smith.. 08/17/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 17 2019/ ...Northern Great Plains/Upper Midwest... A broad positive-tilt shortwave trough will advance east across the southern Prairie Provinces and MT to ND through tonight. A surface front well in advance of this wave extends from the Red River Valley southwest towards the Black Hills and should remain quasi-stationary before accelerating south/east tonight. The bulk of stronger mid-level west-southwesterlies accompanying the wave will remain confined to the cool side of the front, while a separate belt of enhanced westerlies is confined south across NE. In addition, the northern periphery of steeper mid-level lapse rates from an elevated mixed-layer will probably only overlap the SD portion of the front. Low to mid 60s F surface dew points are expected along the front and should support moderate buoyancy with MLCAPE around 1500-2500 J/kg. Owing to a lack of stronger capping, at least scattered thunderstorms will develop in the late afternoon. A few transient supercells should develop initially, but hodographs do not appear particularly elongated or enlarged given modest low-level winds and weakness aloft in the split flow regime. Given the frontal forcing and predominance of outflow consolidation, broader clusters fusing into one or more lines are expected with eastern extent tonight. Some risk for damaging winds will probably continue across southern MN and northern IA along the northern extent of the larger buoyancy plume. ...Central Great Plains... High-based convection that develops off the Front Range this afternoon should impinge on the recovering moist sector near the CO/KS/NE border towards early evening. On the southern periphery of a belt of enhanced mid-level westerlies centered from southern WY across NE amid a very steep lapse rate environment, a swath of severe wind gusts will be possible into north-central KS tonight. ...Mid-MS Valley to IN vicinity... An MCV is centered near the MO/IA/IL border area and should drift east. Several CAMs indicate redevelopment of scattered storms ahead of this feature. This will be highly dependent on more robust destabilization occurring in the wake of a leading MCS in IN. At least a conditional threat for damaging winds and severe hail exists, mainly during the evening. Warm-advection storms overnight may also pose an isolated severe risk. ...Northeast... A low-amplitude shortwave impulse over southern Ontario should slowly move across the Saint Lawrence Valley. Scattered convection is ongoing in association with this wave and will likely persist through the afternoon as further surface-based destabilization occurs downstream. Weak low-level winds and modest mid-level lapse rates will be limiting factors. Most of the stronger speed shear should be confined to the upper portion of the buoyancy profile. Setup should foster a risk of isolated marginally severe hail and scattered damaging winds. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0304 PM CDT Sat Aug 17 2019 Valid 172000Z - 181200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHEASTERN SOUTH DAKOTA INTO NORTHWEST IOWA AND SOUTHWEST MINNESOTA... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR CENTRAL NEW YORK INTO NORTHERN PENNSYLVANIA... ...SUMMARY... Scattered severe thunderstorms with damaging winds and large hail as the primary threats are expected across a large portion of the northern to central Great Plains into the Midwest, generally during the late afternoon into tonight. Damaging winds are also possible into early evening in parts of the Northeast States. ...Discussion... Only a few changes were made to the previous outlook for this outlook update. 1) Added a 65-kt or greater risk area for wind for adjacent parts of southern NE into northern KS. Recent HRRR time-lagged members indicate the possibility for a bowing system moving eastward within a plume of steep 700-500mb lapse rates (in excess of 8 degrees C/km) and a wind profile supportive of organized storms. Uncertainty remains regarding this scenario and therefore will keep at a Slight Risk for this outlook update. 2) Reduced severe probabilities west of the squall line over NY where convective overturning will limit the magnitude of destabilization and the potential for severe later this afternoon into the early evening. 3) With passage of an MCV and the stabilizing influence of a thunderstorm line that moved through IL into eastern IN, have reduced hail/wind probabilities into a Marginal-Risk highlight. 4) Nudged higher severe probabilities westward into east-central CO to account for ongoing and expected storm development forecast to move east off the Palmer Divide towards the northwest KS vicinity. ..Smith.. 08/17/2019 .PREV DISCUSSION... /ISSUED 1130 AM CDT Sat Aug 17 2019/ ...Northern Great Plains/Upper Midwest... A broad positive-tilt shortwave trough will advance east across the southern Prairie Provinces and MT to ND through tonight. A surface front well in advance of this wave extends from the Red River Valley southwest towards the Black Hills and should remain quasi-stationary before accelerating south/east tonight. The bulk of stronger mid-level west-southwesterlies accompanying the wave will remain confined to the cool side of the front, while a separate belt of enhanced westerlies is confined south across NE. In addition, the northern periphery of steeper mid-level lapse rates from an elevated mixed-layer will probably only overlap the SD portion of the front. Low to mid 60s F surface dew points are expected along the front and should support moderate buoyancy with MLCAPE around 1500-2500 J/kg. Owing to a lack of stronger capping, at least scattered thunderstorms will develop in the late afternoon. A few transient supercells should develop initially, but hodographs do not appear particularly elongated or enlarged given modest low-level winds and weakness aloft in the split flow regime. Given the frontal forcing and predominance of outflow consolidation, broader clusters fusing into one or more lines are expected with eastern extent tonight. Some risk for damaging winds will probably continue across southern MN and northern IA along the northern extent of the larger buoyancy plume. ...Central Great Plains... High-based convection that develops off the Front Range this afternoon should impinge on the recovering moist sector near the CO/KS/NE border towards early evening. On the southern periphery of a belt of enhanced mid-level westerlies centered from southern WY across NE amid a very steep lapse rate environment, a swath of severe wind gusts will be possible into north-central KS tonight. ...Mid-MS Valley to IN vicinity... An MCV is centered near the MO/IA/IL border area and should drift east. Several CAMs indicate redevelopment of scattered storms ahead of this feature. This will be highly dependent on more robust destabilization occurring in the wake of a leading MCS in IN. At least a conditional threat for damaging winds and severe hail exists, mainly during the evening. Warm-advection storms overnight may also pose an isolated severe risk. ...Northeast... A low-amplitude shortwave impulse over southern Ontario should slowly move across the Saint Lawrence Valley. Scattered convection is ongoing in association with this wave and will likely persist through the afternoon as further surface-based destabilization occurs downstream. Weak low-level winds and modest mid-level lapse rates will be limiting factors. Most of the stronger speed shear should be confined to the upper portion of the buoyancy profile. Setup should foster a risk of isolated marginally severe hail and scattered damaging winds. Read more