Severe Storms

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

WW 0591 Status Updates
STATUS FOR WATCH 0591 HAS NOT BEEN ISSUED YET Read more

MD 1770 CONCERNING SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY FOR NORTHEAST CO...SOUTHWEST NE AND NORTHWEST KS
Mesoscale Discussion 1770 NWS Storm Prediction Center Norman OK 0234 PM CDT Sat Aug 17 2019 Areas affected...northeast CO...southwest NE and northwest KS Concerning...Severe potential...Severe Thunderstorm Watch likely Valid 171934Z - 172130Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms capable of strong, damaging gusts and hail will increase in the coverage through the afternoon and shift east/southeast through this evening. DISCUSSION...Isolated thunderstorms were developing this afternoon near the higher terrain of north-central CO as a subtle shortwave impulse ejects across the area. Surface dewpoints increase from meager 30s F near the I-25 corridor to the mid 60s just east of the CO/NE/KS tri-state area. Meanwhile, a plume of very steep midlevel lapse rates reside across the region, resulting in MLCAPE values increasing from around 500-1000 J/KG near the Palmer Divide to 2000 J/kg across parts of western into central KS/NE. With continued destabilization, high-based convection is expected to increase in coverage. On the southern fringes of strong deep-layer flow, bulk shear values around 25-35 kt should help to sustain organized cells. While steep lapse rates will support hail production, damaging wind is also possible. Strong downdrafts/downward transport will be supported by a deeply-mixed sub-cloud layer and light low level winds. As such, a swath of damaging wind is possible across parts of southwest NE/northeast CO/northwest KS this afternoon and evening. A severe thunderstorm watch likely will be needed in the next couple of hours. ..Leitman/Grams.. 08/17/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GID...LBF...GLD...PUB...BOU...CYS... LAT...LON 41810257 41590190 41290117 40560005 39859982 39270012 38800069 38750159 38840297 38950425 39200460 39870475 41060437 41620408 41830353 41810257 Read more

WW 0590 Status Updates
STATUS FOR WATCH 0590 HAS NOT BEEN ISSUED YET Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0152 PM CDT Sat Aug 17 2019 Valid 181200Z - 191200Z Minor adjustments were made to the Elevated area, but the forecast reasoning remains unchanged. Confidence in meeting critical wind criteria remains too low for an upgrade at this time. See the previous discussion below for more details. ..Dean.. 08/17/2019 .PREV DISCUSSION... /ISSUED 0145 AM CDT Sat Aug 17 2019/ ...Synopsis... Upper-level ridging begins to amplify across the western CONUS behind a shortwave trough moving over the Upper Midwest and Great Lakes tomorrow. Mid-level westerly flow of 25-50 knots will likely remain from southern Idaho into the central/northern High Plains. Once again, daytime heating will deepen the boundary layer and allow stronger winds to mix to the surface resulting in elevated to locally critical conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%). This will be the fourth consecutive day for dry/windy conditions across the area and ERCs are now mostly between the 70th and 90th percentile. Hot/dry conditions will continue across much of the Intermountain West. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0152 PM CDT Sat Aug 17 2019 Valid 181200Z - 191200Z Minor adjustments were made to the Elevated area, but the forecast reasoning remains unchanged. Confidence in meeting critical wind criteria remains too low for an upgrade at this time. See the previous discussion below for more details. ..Dean.. 08/17/2019 .PREV DISCUSSION... /ISSUED 0145 AM CDT Sat Aug 17 2019/ ...Synopsis... Upper-level ridging begins to amplify across the western CONUS behind a shortwave trough moving over the Upper Midwest and Great Lakes tomorrow. Mid-level westerly flow of 25-50 knots will likely remain from southern Idaho into the central/northern High Plains. Once again, daytime heating will deepen the boundary layer and allow stronger winds to mix to the surface resulting in elevated to locally critical conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%). This will be the fourth consecutive day for dry/windy conditions across the area and ERCs are now mostly between the 70th and 90th percentile. Hot/dry conditions will continue across much of the Intermountain West. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0152 PM CDT Sat Aug 17 2019 Valid 181200Z - 191200Z Minor adjustments were made to the Elevated area, but the forecast reasoning remains unchanged. Confidence in meeting critical wind criteria remains too low for an upgrade at this time. See the previous discussion below for more details. ..Dean.. 08/17/2019 .PREV DISCUSSION... /ISSUED 0145 AM CDT Sat Aug 17 2019/ ...Synopsis... Upper-level ridging begins to amplify across the western CONUS behind a shortwave trough moving over the Upper Midwest and Great Lakes tomorrow. Mid-level westerly flow of 25-50 knots will likely remain from southern Idaho into the central/northern High Plains. Once again, daytime heating will deepen the boundary layer and allow stronger winds to mix to the surface resulting in elevated to locally critical conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%). This will be the fourth consecutive day for dry/windy conditions across the area and ERCs are now mostly between the 70th and 90th percentile. Hot/dry conditions will continue across much of the Intermountain West. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0152 PM CDT Sat Aug 17 2019 Valid 181200Z - 191200Z Minor adjustments were made to the Elevated area, but the forecast reasoning remains unchanged. Confidence in meeting critical wind criteria remains too low for an upgrade at this time. See the previous discussion below for more details. ..Dean.. 08/17/2019 .PREV DISCUSSION... /ISSUED 0145 AM CDT Sat Aug 17 2019/ ...Synopsis... Upper-level ridging begins to amplify across the western CONUS behind a shortwave trough moving over the Upper Midwest and Great Lakes tomorrow. Mid-level westerly flow of 25-50 knots will likely remain from southern Idaho into the central/northern High Plains. Once again, daytime heating will deepen the boundary layer and allow stronger winds to mix to the surface resulting in elevated to locally critical conditions (westerly sustained surface winds of 15-20 mph, RH values of 10-20%). This will be the fourth consecutive day for dry/windy conditions across the area and ERCs are now mostly between the 70th and 90th percentile. Hot/dry conditions will continue across much of the Intermountain West. ...Please see www.spc.noaa.gov/fire for graphic product... Read more