Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 27 2019 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF WEST TX AND ACROSS WI/UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...WI/Upper MI this afternoon/evening... An embedded shortwave trough will move from MN across WI/Upper MI this afternoon/evening, around the southern periphery of a developing closed low over MB/western ON. Surface heating and residual boundary-layer dewpoints in the low-mid 50s, beneath 500 mb temperatures near -20 C, will result in low-midlevel lapse rates of 7-8 C/km and MLCAPE near 500 J/kg. Scattered low-topped thunderstorms are expected in the corridor immediately preceding the shortwave trough this afternoon/evening, and a few of the storms could produce strong outflow gusts and hail approaching one inch in diameter. ...Elsewhere... The richer low-level moisture has been shunted south of the stronger midlevel flow by a surface cold front and multiple convective outflows from overnight convection that have now spread southward to the I-20 corridor from north TX to central MS. Boundary-layer dewpoints of 76-80 F are present south of the outflow boundaries from southeast TX eastward, but vertical shear is weak and there is little focus for storm initiation aside from the outflows. Isolated strong gusts could occur with downbursts, but the overall severe threat is too limited to warrant introduction of any damaging wind probabilities. Farther west, very steep lapse rates were observed at MAF, though surface temperatures in excess of 105 F are needed to eliminate convective inhibition. There will be some threat for storms late this afternoon into early tonight along the surface front/stalling outflow, with isolated strong downbursts possible in the steep lapse rate environment. ..Thompson/Cook.. 08/27/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 27 2019 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF WEST TX AND ACROSS WI/UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...WI/Upper MI this afternoon/evening... An embedded shortwave trough will move from MN across WI/Upper MI this afternoon/evening, around the southern periphery of a developing closed low over MB/western ON. Surface heating and residual boundary-layer dewpoints in the low-mid 50s, beneath 500 mb temperatures near -20 C, will result in low-midlevel lapse rates of 7-8 C/km and MLCAPE near 500 J/kg. Scattered low-topped thunderstorms are expected in the corridor immediately preceding the shortwave trough this afternoon/evening, and a few of the storms could produce strong outflow gusts and hail approaching one inch in diameter. ...Elsewhere... The richer low-level moisture has been shunted south of the stronger midlevel flow by a surface cold front and multiple convective outflows from overnight convection that have now spread southward to the I-20 corridor from north TX to central MS. Boundary-layer dewpoints of 76-80 F are present south of the outflow boundaries from southeast TX eastward, but vertical shear is weak and there is little focus for storm initiation aside from the outflows. Isolated strong gusts could occur with downbursts, but the overall severe threat is too limited to warrant introduction of any damaging wind probabilities. Farther west, very steep lapse rates were observed at MAF, though surface temperatures in excess of 105 F are needed to eliminate convective inhibition. There will be some threat for storms late this afternoon into early tonight along the surface front/stalling outflow, with isolated strong downbursts possible in the steep lapse rate environment. ..Thompson/Cook.. 08/27/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 27 2019 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF WEST TX AND ACROSS WI/UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...WI/Upper MI this afternoon/evening... An embedded shortwave trough will move from MN across WI/Upper MI this afternoon/evening, around the southern periphery of a developing closed low over MB/western ON. Surface heating and residual boundary-layer dewpoints in the low-mid 50s, beneath 500 mb temperatures near -20 C, will result in low-midlevel lapse rates of 7-8 C/km and MLCAPE near 500 J/kg. Scattered low-topped thunderstorms are expected in the corridor immediately preceding the shortwave trough this afternoon/evening, and a few of the storms could produce strong outflow gusts and hail approaching one inch in diameter. ...Elsewhere... The richer low-level moisture has been shunted south of the stronger midlevel flow by a surface cold front and multiple convective outflows from overnight convection that have now spread southward to the I-20 corridor from north TX to central MS. Boundary-layer dewpoints of 76-80 F are present south of the outflow boundaries from southeast TX eastward, but vertical shear is weak and there is little focus for storm initiation aside from the outflows. Isolated strong gusts could occur with downbursts, but the overall severe threat is too limited to warrant introduction of any damaging wind probabilities. Farther west, very steep lapse rates were observed at MAF, though surface temperatures in excess of 105 F are needed to eliminate convective inhibition. There will be some threat for storms late this afternoon into early tonight along the surface front/stalling outflow, with isolated strong downbursts possible in the steep lapse rate environment. ..Thompson/Cook.. 08/27/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1120 AM CDT Tue Aug 27 2019 Valid 271630Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON/EVENING FOR PARTS OF WEST TX AND ACROSS WI/UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...WI/Upper MI this afternoon/evening... An embedded shortwave trough will move from MN across WI/Upper MI this afternoon/evening, around the southern periphery of a developing closed low over MB/western ON. Surface heating and residual boundary-layer dewpoints in the low-mid 50s, beneath 500 mb temperatures near -20 C, will result in low-midlevel lapse rates of 7-8 C/km and MLCAPE near 500 J/kg. Scattered low-topped thunderstorms are expected in the corridor immediately preceding the shortwave trough this afternoon/evening, and a few of the storms could produce strong outflow gusts and hail approaching one inch in diameter. ...Elsewhere... The richer low-level moisture has been shunted south of the stronger midlevel flow by a surface cold front and multiple convective outflows from overnight convection that have now spread southward to the I-20 corridor from north TX to central MS. Boundary-layer dewpoints of 76-80 F are present south of the outflow boundaries from southeast TX eastward, but vertical shear is weak and there is little focus for storm initiation aside from the outflows. Isolated strong gusts could occur with downbursts, but the overall severe threat is too limited to warrant introduction of any damaging wind probabilities. Farther west, very steep lapse rates were observed at MAF, though surface temperatures in excess of 105 F are needed to eliminate convective inhibition. There will be some threat for storms late this afternoon into early tonight along the surface front/stalling outflow, with isolated strong downbursts possible in the steep lapse rate environment. ..Thompson/Cook.. 08/27/2019 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1016 AM CDT Tue Aug 27 2019 Valid 271700Z - 281200Z ...NO CRITICAL AREAS... Locally elevated conditions are possible in western Oregon into western Washington as hot/dry/unstable/breezy conditions are expected along/near the thermally-induced surface pressure trough. Northerly to easterly surface winds of 10-15 mph with minimum RH values of 10-30% are expected to develop this afternoon. Otherwise, the forecast remains on track, and please see the discussion below for more details. ..Nauslar.. 08/27/2019 .PREV DISCUSSION... /ISSUED 0118 AM CDT Tue Aug 27 2019/ ...Synopsis... An upper-level ridge will shift eastward over the West Coast while amplifying slightly today. Hot/dry conditions are expected much of the areas west of the Continental Divide. At the surface, high pressure over the central Rockies/High Plains in combination with a thermally-driven surface trough along the west coast of Oregon will drive easterly downslope flow for much of western Oregon. Some locations may see afternoon RH below 20%, but most areas will likely fall between 20-35%. Winds will generally be light (10-15 mph). However, areas near the Columbia Gorge in the northern Willamette Valley could see terrain enhanced flow of 15+ mph. As the spatial extent of elevated conditions is expected to remain small, no areas will be introduced. A few lightning strikes may occur along and just into the eastern slopes of the Sierra in central California. There is currently too much uncertainty as to whether these storms will impact areas outside of the highest peaks for greater fire weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1016 AM CDT Tue Aug 27 2019 Valid 271700Z - 281200Z ...NO CRITICAL AREAS... Locally elevated conditions are possible in western Oregon into western Washington as hot/dry/unstable/breezy conditions are expected along/near the thermally-induced surface pressure trough. Northerly to easterly surface winds of 10-15 mph with minimum RH values of 10-30% are expected to develop this afternoon. Otherwise, the forecast remains on track, and please see the discussion below for more details. ..Nauslar.. 08/27/2019 .PREV DISCUSSION... /ISSUED 0118 AM CDT Tue Aug 27 2019/ ...Synopsis... An upper-level ridge will shift eastward over the West Coast while amplifying slightly today. Hot/dry conditions are expected much of the areas west of the Continental Divide. At the surface, high pressure over the central Rockies/High Plains in combination with a thermally-driven surface trough along the west coast of Oregon will drive easterly downslope flow for much of western Oregon. Some locations may see afternoon RH below 20%, but most areas will likely fall between 20-35%. Winds will generally be light (10-15 mph). However, areas near the Columbia Gorge in the northern Willamette Valley could see terrain enhanced flow of 15+ mph. As the spatial extent of elevated conditions is expected to remain small, no areas will be introduced. A few lightning strikes may occur along and just into the eastern slopes of the Sierra in central California. There is currently too much uncertainty as to whether these storms will impact areas outside of the highest peaks for greater fire weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1016 AM CDT Tue Aug 27 2019 Valid 271700Z - 281200Z ...NO CRITICAL AREAS... Locally elevated conditions are possible in western Oregon into western Washington as hot/dry/unstable/breezy conditions are expected along/near the thermally-induced surface pressure trough. Northerly to easterly surface winds of 10-15 mph with minimum RH values of 10-30% are expected to develop this afternoon. Otherwise, the forecast remains on track, and please see the discussion below for more details. ..Nauslar.. 08/27/2019 .PREV DISCUSSION... /ISSUED 0118 AM CDT Tue Aug 27 2019/ ...Synopsis... An upper-level ridge will shift eastward over the West Coast while amplifying slightly today. Hot/dry conditions are expected much of the areas west of the Continental Divide. At the surface, high pressure over the central Rockies/High Plains in combination with a thermally-driven surface trough along the west coast of Oregon will drive easterly downslope flow for much of western Oregon. Some locations may see afternoon RH below 20%, but most areas will likely fall between 20-35%. Winds will generally be light (10-15 mph). However, areas near the Columbia Gorge in the northern Willamette Valley could see terrain enhanced flow of 15+ mph. As the spatial extent of elevated conditions is expected to remain small, no areas will be introduced. A few lightning strikes may occur along and just into the eastern slopes of the Sierra in central California. There is currently too much uncertainty as to whether these storms will impact areas outside of the highest peaks for greater fire weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1016 AM CDT Tue Aug 27 2019 Valid 271700Z - 281200Z ...NO CRITICAL AREAS... Locally elevated conditions are possible in western Oregon into western Washington as hot/dry/unstable/breezy conditions are expected along/near the thermally-induced surface pressure trough. Northerly to easterly surface winds of 10-15 mph with minimum RH values of 10-30% are expected to develop this afternoon. Otherwise, the forecast remains on track, and please see the discussion below for more details. ..Nauslar.. 08/27/2019 .PREV DISCUSSION... /ISSUED 0118 AM CDT Tue Aug 27 2019/ ...Synopsis... An upper-level ridge will shift eastward over the West Coast while amplifying slightly today. Hot/dry conditions are expected much of the areas west of the Continental Divide. At the surface, high pressure over the central Rockies/High Plains in combination with a thermally-driven surface trough along the west coast of Oregon will drive easterly downslope flow for much of western Oregon. Some locations may see afternoon RH below 20%, but most areas will likely fall between 20-35%. Winds will generally be light (10-15 mph). However, areas near the Columbia Gorge in the northern Willamette Valley could see terrain enhanced flow of 15+ mph. As the spatial extent of elevated conditions is expected to remain small, no areas will be introduced. A few lightning strikes may occur along and just into the eastern slopes of the Sierra in central California. There is currently too much uncertainty as to whether these storms will impact areas outside of the highest peaks for greater fire weather concerns. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Tue Aug 27 2019 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEST TX AND EAST-CENTRAL MN TO UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...West TX... A decaying, southward-moving MCS is ongoing across north-central to northeast TX. Guidance generally agrees that this MCS will further decay as it shifts into progressively weaker upper-level flow with southern extent and becomes separated from isentropic ascent focused across the low-level baroclinic zone that lingers farther northwest in OK. Potential for late afternoon to evening thunderstorm development should be focused farther west from western North Texas to the Permian Basin. Reinvigorated low-level warm advection on the cool side of the front might support a cluster of elevated convection, with possibly a separate area of development farther southwest where convergence should be maximized along the surface front. Deep-layer shear will be modest and weaker with southwest extent despite veering of the wind profile with height. Steep mid-level lapse rates will support an isolated severe hail risk, while hot surface temperatures south of the front may yield a few severe wind gusts, mainly in the evening. ...Upper Great Lakes... As pronounced mid-level DCVA occurs ahead of a shortwave impulse moving from the SD/MN border to eastern WI, scattered low-topped convection will develop this afternoon. The bulk of strong southwesterlies aloft should reside in the upper portion of the weak buoyancy profile, which would curb effective shear values. Steepening low-level lapse rates will support mixing of moderate 700-mb flow despite predominant west-southwesterly boundary-layer winds. Setup could foster locally damaging winds from strong gusts along with marginally severe hail. ...Lower MS Valley to OH... Scattered thunderstorms should redevelop along residual outflows from remnant early-day convection, most likely across the Lower MS to TN Valleys where boundary-layer heating should be more pronounced. Weak deep-layer shear in these regions should preclude an organized severe risk, but pulse microbursts are possible. Farther north into OH, pervasive cloudiness in morning visible imagery should limit boundary-layer heating. Given weak mid-level lapse rates, buoyancy will likely remain below 1000 J/kg. In combination with modest deep-layer speed shear, overall setup appears unlikely to yield an appreciable organized severe risk. ..Grams/Mosier.. 08/27/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Tue Aug 27 2019 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEST TX AND EAST-CENTRAL MN TO UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...West TX... A decaying, southward-moving MCS is ongoing across north-central to northeast TX. Guidance generally agrees that this MCS will further decay as it shifts into progressively weaker upper-level flow with southern extent and becomes separated from isentropic ascent focused across the low-level baroclinic zone that lingers farther northwest in OK. Potential for late afternoon to evening thunderstorm development should be focused farther west from western North Texas to the Permian Basin. Reinvigorated low-level warm advection on the cool side of the front might support a cluster of elevated convection, with possibly a separate area of development farther southwest where convergence should be maximized along the surface front. Deep-layer shear will be modest and weaker with southwest extent despite veering of the wind profile with height. Steep mid-level lapse rates will support an isolated severe hail risk, while hot surface temperatures south of the front may yield a few severe wind gusts, mainly in the evening. ...Upper Great Lakes... As pronounced mid-level DCVA occurs ahead of a shortwave impulse moving from the SD/MN border to eastern WI, scattered low-topped convection will develop this afternoon. The bulk of strong southwesterlies aloft should reside in the upper portion of the weak buoyancy profile, which would curb effective shear values. Steepening low-level lapse rates will support mixing of moderate 700-mb flow despite predominant west-southwesterly boundary-layer winds. Setup could foster locally damaging winds from strong gusts along with marginally severe hail. ...Lower MS Valley to OH... Scattered thunderstorms should redevelop along residual outflows from remnant early-day convection, most likely across the Lower MS to TN Valleys where boundary-layer heating should be more pronounced. Weak deep-layer shear in these regions should preclude an organized severe risk, but pulse microbursts are possible. Farther north into OH, pervasive cloudiness in morning visible imagery should limit boundary-layer heating. Given weak mid-level lapse rates, buoyancy will likely remain below 1000 J/kg. In combination with modest deep-layer speed shear, overall setup appears unlikely to yield an appreciable organized severe risk. ..Grams/Mosier.. 08/27/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Tue Aug 27 2019 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEST TX AND EAST-CENTRAL MN TO UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...West TX... A decaying, southward-moving MCS is ongoing across north-central to northeast TX. Guidance generally agrees that this MCS will further decay as it shifts into progressively weaker upper-level flow with southern extent and becomes separated from isentropic ascent focused across the low-level baroclinic zone that lingers farther northwest in OK. Potential for late afternoon to evening thunderstorm development should be focused farther west from western North Texas to the Permian Basin. Reinvigorated low-level warm advection on the cool side of the front might support a cluster of elevated convection, with possibly a separate area of development farther southwest where convergence should be maximized along the surface front. Deep-layer shear will be modest and weaker with southwest extent despite veering of the wind profile with height. Steep mid-level lapse rates will support an isolated severe hail risk, while hot surface temperatures south of the front may yield a few severe wind gusts, mainly in the evening. ...Upper Great Lakes... As pronounced mid-level DCVA occurs ahead of a shortwave impulse moving from the SD/MN border to eastern WI, scattered low-topped convection will develop this afternoon. The bulk of strong southwesterlies aloft should reside in the upper portion of the weak buoyancy profile, which would curb effective shear values. Steepening low-level lapse rates will support mixing of moderate 700-mb flow despite predominant west-southwesterly boundary-layer winds. Setup could foster locally damaging winds from strong gusts along with marginally severe hail. ...Lower MS Valley to OH... Scattered thunderstorms should redevelop along residual outflows from remnant early-day convection, most likely across the Lower MS to TN Valleys where boundary-layer heating should be more pronounced. Weak deep-layer shear in these regions should preclude an organized severe risk, but pulse microbursts are possible. Farther north into OH, pervasive cloudiness in morning visible imagery should limit boundary-layer heating. Given weak mid-level lapse rates, buoyancy will likely remain below 1000 J/kg. In combination with modest deep-layer speed shear, overall setup appears unlikely to yield an appreciable organized severe risk. ..Grams/Mosier.. 08/27/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0737 AM CDT Tue Aug 27 2019 Valid 271300Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS WEST TX AND EAST-CENTRAL MN TO UPPER MI... ...SUMMARY... Isolated severe thunderstorms are possible across parts of west Texas during the late afternoon and evening, and from east-central Minnesota to Upper Michigan this afternoon. ...West TX... A decaying, southward-moving MCS is ongoing across north-central to northeast TX. Guidance generally agrees that this MCS will further decay as it shifts into progressively weaker upper-level flow with southern extent and becomes separated from isentropic ascent focused across the low-level baroclinic zone that lingers farther northwest in OK. Potential for late afternoon to evening thunderstorm development should be focused farther west from western North Texas to the Permian Basin. Reinvigorated low-level warm advection on the cool side of the front might support a cluster of elevated convection, with possibly a separate area of development farther southwest where convergence should be maximized along the surface front. Deep-layer shear will be modest and weaker with southwest extent despite veering of the wind profile with height. Steep mid-level lapse rates will support an isolated severe hail risk, while hot surface temperatures south of the front may yield a few severe wind gusts, mainly in the evening. ...Upper Great Lakes... As pronounced mid-level DCVA occurs ahead of a shortwave impulse moving from the SD/MN border to eastern WI, scattered low-topped convection will develop this afternoon. The bulk of strong southwesterlies aloft should reside in the upper portion of the weak buoyancy profile, which would curb effective shear values. Steepening low-level lapse rates will support mixing of moderate 700-mb flow despite predominant west-southwesterly boundary-layer winds. Setup could foster locally damaging winds from strong gusts along with marginally severe hail. ...Lower MS Valley to OH... Scattered thunderstorms should redevelop along residual outflows from remnant early-day convection, most likely across the Lower MS to TN Valleys where boundary-layer heating should be more pronounced. Weak deep-layer shear in these regions should preclude an organized severe risk, but pulse microbursts are possible. Farther north into OH, pervasive cloudiness in morning visible imagery should limit boundary-layer heating. Given weak mid-level lapse rates, buoyancy will likely remain below 1000 J/kg. In combination with modest deep-layer speed shear, overall setup appears unlikely to yield an appreciable organized severe risk. ..Grams/Mosier.. 08/27/2019 Read more

WW 0625 Status Updates
STATUS REPORT ON WW 625 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NNW CHK TO 20 S OKC TO 10 NW ADM TO 20 ESE ADM TO 10 NNE DUA. WW 625 WILL BE ALLOWED TO EXPIRE AT 271100Z. ..MOSIER..08/27/19 ATTN...WFO...LZK...TSA...SGF...OUN... STATUS REPORT FOR WS 625 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OKC013-015-019-051-067-085-095-127-137-271100- OK . OKLAHOMA COUNTIES INCLUDED ARE BRYAN CADDO CARTER GRADY JEFFERSON LOVE MARSHALL PUSHMATAHA STEPHENS 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 625 SEVERE TSTM AR MO OK 270350Z - 271100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 625 NWS Storm Prediction Center Norman OK 1050 PM CDT Mon Aug 26 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Western and northern Arkansas Southern Missouri Southern and Eastern Oklahoma * Effective this Monday night and Tuesday morning from 1050 PM until 600 AM CDT. * Primary threats include... Scattered damaging winds likely with isolated significant gusts to 75 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Multiple clusters of storms will continue to steadily progress southeastward across the region late this evening and overnight, with damaging winds continuing to be a concern. These storms have a history of producing very strong winds across central/northeast Oklahoma this evening. Isolated severe hail may also occur. The severe thunderstorm watch area is approximately along and 70 statute miles north and south of a line from 50 miles south southwest of Chickasha OK to 35 miles east northeast of West Plains MO. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU5). 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 624... AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 65 knots. A few cumulonimbi with maximum tops to 600. Mean storm motion vector 34030. ...Guyer Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 27 2019 Valid 301200Z - 041200Z ...DISCUSSION... ...Days 4/5 - Fri/Sat -- Central and Southern Plains Vicinity... At least some potential for strong to severe storms appears possible heading into the weekend as a stalled cold front in the vicinity of southern NE/northern KS progresses southward as an upper shortwave impulse shifts southeast across the northern Plains and Upper Midwest. Southerly low level flow will continue to bring rich Gulf moisture northward across the southern/central Plains. At this time, aside from the surface boundary, forcing for ascent appears weak as does forecast shear. Guidance also varies in location/timing and extent of convection. As a result, uncertainty is too great to include severe probabilities at this time. ...Days 5/6 - Saturday/Sunday -- Southeastern U.S... By late Saturday into Sunday, some guidance brings current Tropical Storm Dorian toward Florida. Depending on the exact track, this could bring an attendant tropical cyclone tornado threat to portions of the southeastern U.S. Trends will be monitored closely along with future collaboration with the National Hurricane Center to address any possible threats approaching the mainland U.S. in the coming days. ...Days 7/8 - Monday/Tuesday -- Northern/Central Plains to the Upper Midwest... By the end of the period, forecast guidance brings a shortwave trough across the northern Rockies toward the northern Plains. A strengthening lee surface low over the northern High Plains and attendant cold front will shift east/southeast and could be a focus for severe potential early next week. Questions remain regarding moisture return this far north as well as timing differences in the arrival of the trough and surface cold front. As such, confidence is too low to introduce severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 27 2019 Valid 301200Z - 041200Z ...DISCUSSION... ...Days 4/5 - Fri/Sat -- Central and Southern Plains Vicinity... At least some potential for strong to severe storms appears possible heading into the weekend as a stalled cold front in the vicinity of southern NE/northern KS progresses southward as an upper shortwave impulse shifts southeast across the northern Plains and Upper Midwest. Southerly low level flow will continue to bring rich Gulf moisture northward across the southern/central Plains. At this time, aside from the surface boundary, forcing for ascent appears weak as does forecast shear. Guidance also varies in location/timing and extent of convection. As a result, uncertainty is too great to include severe probabilities at this time. ...Days 5/6 - Saturday/Sunday -- Southeastern U.S... By late Saturday into Sunday, some guidance brings current Tropical Storm Dorian toward Florida. Depending on the exact track, this could bring an attendant tropical cyclone tornado threat to portions of the southeastern U.S. Trends will be monitored closely along with future collaboration with the National Hurricane Center to address any possible threats approaching the mainland U.S. in the coming days. ...Days 7/8 - Monday/Tuesday -- Northern/Central Plains to the Upper Midwest... By the end of the period, forecast guidance brings a shortwave trough across the northern Rockies toward the northern Plains. A strengthening lee surface low over the northern High Plains and attendant cold front will shift east/southeast and could be a focus for severe potential early next week. Questions remain regarding moisture return this far north as well as timing differences in the arrival of the trough and surface cold front. As such, confidence is too low to introduce severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 27 2019 Valid 301200Z - 041200Z ...DISCUSSION... ...Days 4/5 - Fri/Sat -- Central and Southern Plains Vicinity... At least some potential for strong to severe storms appears possible heading into the weekend as a stalled cold front in the vicinity of southern NE/northern KS progresses southward as an upper shortwave impulse shifts southeast across the northern Plains and Upper Midwest. Southerly low level flow will continue to bring rich Gulf moisture northward across the southern/central Plains. At this time, aside from the surface boundary, forcing for ascent appears weak as does forecast shear. Guidance also varies in location/timing and extent of convection. As a result, uncertainty is too great to include severe probabilities at this time. ...Days 5/6 - Saturday/Sunday -- Southeastern U.S... By late Saturday into Sunday, some guidance brings current Tropical Storm Dorian toward Florida. Depending on the exact track, this could bring an attendant tropical cyclone tornado threat to portions of the southeastern U.S. Trends will be monitored closely along with future collaboration with the National Hurricane Center to address any possible threats approaching the mainland U.S. in the coming days. ...Days 7/8 - Monday/Tuesday -- Northern/Central Plains to the Upper Midwest... By the end of the period, forecast guidance brings a shortwave trough across the northern Rockies toward the northern Plains. A strengthening lee surface low over the northern High Plains and attendant cold front will shift east/southeast and could be a focus for severe potential early next week. Questions remain regarding moisture return this far north as well as timing differences in the arrival of the trough and surface cold front. As such, confidence is too low to introduce severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 27 2019 Valid 301200Z - 041200Z ...DISCUSSION... ...Days 4/5 - Fri/Sat -- Central and Southern Plains Vicinity... At least some potential for strong to severe storms appears possible heading into the weekend as a stalled cold front in the vicinity of southern NE/northern KS progresses southward as an upper shortwave impulse shifts southeast across the northern Plains and Upper Midwest. Southerly low level flow will continue to bring rich Gulf moisture northward across the southern/central Plains. At this time, aside from the surface boundary, forcing for ascent appears weak as does forecast shear. Guidance also varies in location/timing and extent of convection. As a result, uncertainty is too great to include severe probabilities at this time. ...Days 5/6 - Saturday/Sunday -- Southeastern U.S... By late Saturday into Sunday, some guidance brings current Tropical Storm Dorian toward Florida. Depending on the exact track, this could bring an attendant tropical cyclone tornado threat to portions of the southeastern U.S. Trends will be monitored closely along with future collaboration with the National Hurricane Center to address any possible threats approaching the mainland U.S. in the coming days. ...Days 7/8 - Monday/Tuesday -- Northern/Central Plains to the Upper Midwest... By the end of the period, forecast guidance brings a shortwave trough across the northern Rockies toward the northern Plains. A strengthening lee surface low over the northern High Plains and attendant cold front will shift east/southeast and could be a focus for severe potential early next week. Questions remain regarding moisture return this far north as well as timing differences in the arrival of the trough and surface cold front. As such, confidence is too low to introduce severe probabilities. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0358 AM CDT Tue Aug 27 2019 Valid 301200Z - 041200Z ...DISCUSSION... ...Days 4/5 - Fri/Sat -- Central and Southern Plains Vicinity... At least some potential for strong to severe storms appears possible heading into the weekend as a stalled cold front in the vicinity of southern NE/northern KS progresses southward as an upper shortwave impulse shifts southeast across the northern Plains and Upper Midwest. Southerly low level flow will continue to bring rich Gulf moisture northward across the southern/central Plains. At this time, aside from the surface boundary, forcing for ascent appears weak as does forecast shear. Guidance also varies in location/timing and extent of convection. As a result, uncertainty is too great to include severe probabilities at this time. ...Days 5/6 - Saturday/Sunday -- Southeastern U.S... By late Saturday into Sunday, some guidance brings current Tropical Storm Dorian toward Florida. Depending on the exact track, this could bring an attendant tropical cyclone tornado threat to portions of the southeastern U.S. Trends will be monitored closely along with future collaboration with the National Hurricane Center to address any possible threats approaching the mainland U.S. in the coming days. ...Days 7/8 - Monday/Tuesday -- Northern/Central Plains to the Upper Midwest... By the end of the period, forecast guidance brings a shortwave trough across the northern Rockies toward the northern Plains. A strengthening lee surface low over the northern High Plains and attendant cold front will shift east/southeast and could be a focus for severe potential early next week. Questions remain regarding moisture return this far north as well as timing differences in the arrival of the trough and surface cold front. As such, confidence is too low to introduce severe probabilities. Read more

MD 1879 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR FAR NORTH-CENTRAL TX
Mesoscale Discussion 1879 NWS Storm Prediction Center Norman OK 0355 AM CDT Tue Aug 27 2019 Areas affected...Far North-Central TX Concerning...Severe potential...Watch unlikely Valid 270855Z - 271030Z Probability of Watch Issuance...20 percent SUMMARY...Isolated damaging wind gusts are possible far north-central TX but the ongoing storm cluster is expected to weaken, keeping the threat isolated and precluding the need for a downstream watch. DISCUSSION...Recent gusts around 45-50 mph have been reported with the surging storm cluster across far south-central OK. Current storm motion on this cluster is south-southeastward at 38 kt. This cluster is already near the edge of Severe Thunderstorm Watch 625 along the TX/OK border. Downstream air mass across far north-central TX is characterized by temperatures in the low to mid 80s, dewpoints in the low to mid 70s, and strong buoyancy. RAP forecast soundings also show a deep warm layer and strong convective inhibition. While this cluster is currently quite strong (with 55 dbz over 30kft), the strong downstream convective inhibition is expected to lead to gradual storm weakening. Isolated strong wind gusts are possible with this cluster but the expected weakening limits the spatial and temporal extent of this threat. As such, a downstream watch across far north-central TX is not currently anticipated. ..Mosier/Grams.. 08/27/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...OUN... LAT...LON 33569834 34039802 34359714 34179641 33749592 33209602 32939615 32669717 32839825 33569834 Read more