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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Mon Aug 26 2019 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not currently anticipated on Wednesday. ...Synopsis... An upper trough is expected to move eastward through the Upper Great Lakes and OH Valley on Wednesday, reaching the Northeast by early Thursday morning. Farther west, upper ridging initially extending from the Southwest into the Pacific Northwest is expected to gradually shift eastward while losing amplitude. Northwesterly flow aloft will persist over the Plains between the eastern CONUS trough and western CONUS ridge. The surface pattern early Wednesday morning will likely feature a cold front extending from the Lower Great Lakes southwestward into the Lower MS Valley then westward into west Texas. Northern/eastern portion of this front is expected to remain progressive, moving off the eastern seaboard by early Thursday morning. Southern/western portion of the front across TX will move little, becoming increasingly diffuse throughout the day as moisture return strengthens across the southern and central Plains. Showers and thunderstorms are expected along the front as well as within the diurnally destabilized air mass beneath the upper ridging over the Southwest. Given the relatively weak vertical shear in areas where instability exists, the environment does not support severe thunderstorms across CONUS. ..Mosier.. 08/26/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Mon Aug 26 2019 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not currently anticipated on Wednesday. ...Synopsis... An upper trough is expected to move eastward through the Upper Great Lakes and OH Valley on Wednesday, reaching the Northeast by early Thursday morning. Farther west, upper ridging initially extending from the Southwest into the Pacific Northwest is expected to gradually shift eastward while losing amplitude. Northwesterly flow aloft will persist over the Plains between the eastern CONUS trough and western CONUS ridge. The surface pattern early Wednesday morning will likely feature a cold front extending from the Lower Great Lakes southwestward into the Lower MS Valley then westward into west Texas. Northern/eastern portion of this front is expected to remain progressive, moving off the eastern seaboard by early Thursday morning. Southern/western portion of the front across TX will move little, becoming increasingly diffuse throughout the day as moisture return strengthens across the southern and central Plains. Showers and thunderstorms are expected along the front as well as within the diurnally destabilized air mass beneath the upper ridging over the Southwest. Given the relatively weak vertical shear in areas where instability exists, the environment does not support severe thunderstorms across CONUS. ..Mosier.. 08/26/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Mon Aug 26 2019 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not currently anticipated on Wednesday. ...Synopsis... An upper trough is expected to move eastward through the Upper Great Lakes and OH Valley on Wednesday, reaching the Northeast by early Thursday morning. Farther west, upper ridging initially extending from the Southwest into the Pacific Northwest is expected to gradually shift eastward while losing amplitude. Northwesterly flow aloft will persist over the Plains between the eastern CONUS trough and western CONUS ridge. The surface pattern early Wednesday morning will likely feature a cold front extending from the Lower Great Lakes southwestward into the Lower MS Valley then westward into west Texas. Northern/eastern portion of this front is expected to remain progressive, moving off the eastern seaboard by early Thursday morning. Southern/western portion of the front across TX will move little, becoming increasingly diffuse throughout the day as moisture return strengthens across the southern and central Plains. Showers and thunderstorms are expected along the front as well as within the diurnally destabilized air mass beneath the upper ridging over the Southwest. Given the relatively weak vertical shear in areas where instability exists, the environment does not support severe thunderstorms across CONUS. ..Mosier.. 08/26/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0224 AM CDT Mon Aug 26 2019 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not currently anticipated on Wednesday. ...Synopsis... An upper trough is expected to move eastward through the Upper Great Lakes and OH Valley on Wednesday, reaching the Northeast by early Thursday morning. Farther west, upper ridging initially extending from the Southwest into the Pacific Northwest is expected to gradually shift eastward while losing amplitude. Northwesterly flow aloft will persist over the Plains between the eastern CONUS trough and western CONUS ridge. The surface pattern early Wednesday morning will likely feature a cold front extending from the Lower Great Lakes southwestward into the Lower MS Valley then westward into west Texas. Northern/eastern portion of this front is expected to remain progressive, moving off the eastern seaboard by early Thursday morning. Southern/western portion of the front across TX will move little, becoming increasingly diffuse throughout the day as moisture return strengthens across the southern and central Plains. Showers and thunderstorms are expected along the front as well as within the diurnally destabilized air mass beneath the upper ridging over the Southwest. Given the relatively weak vertical shear in areas where instability exists, the environment does not support severe thunderstorms across CONUS. ..Mosier.. 08/26/2019 Read more

MD 1862 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF EASTERN MO INTO WEST-CENTRAL IL
Mesoscale Discussion 1862 NWS Storm Prediction Center Norman OK 0206 AM CDT Mon Aug 26 2019 Areas affected...Portions of eastern MO into west-central IL Concerning...Severe potential...Watch unlikely Valid 260706Z - 260900Z Probability of Watch Issuance...5 percent SUMMARY...A brief/weak tornado will remain possible in the near term. Watch issuance is not expected at this time as the overall threat appears very isolated. DISCUSSION...A small line of storms has recently strengthened across east-central MO in association with a remnant MCV from prior convection located over far west-central IL at 07Z. The VWP from KLSX does show a gradually veering wind profile in the 0-3 km AGL layer. Two weak circulations have been observed so far embedded within the line. The presence of around 125-200 m2/s2 of effective bulk shear suggests that transient circulations capable of producing a brief/weak tornado may continue for the next couple of hours. However, both modest instability and weak effective bulk shear will likely tend to limit a more organized severe threat across this region through the early morning hours. Therefore, watch issuance is not anticipated at this time. ..Gleason/Edwards.. 08/26/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILX...LSX... LAT...LON 38369214 38909139 39429094 39739071 39789040 39639014 39279011 39029017 38559041 38309109 38319166 38369214 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level ridge axis will situate itself across the Pacific Northwest coast on D2/Tuesday. A surface anticyclone will continue on a southward track into central Rockies/High Plains along with the continued presence of a thermally induced pressure trough across the Oregon coast and northern California. The surface pressure pattern will continue to favor offshore flow across Oregon coast, with more of an easterly component than Monday. ...Western Oregon... Hot/dry conditions will be prevalent on Tuesday as strong heating occurs underneath the upper-level ridge. Easterly downslope flow off the Cascades will help reduce afternoon RH values to potentially below 20% in some locations, but more broadly 25-35%. Wind speed still appears to be the limiting factor to a greater threat for fire spread. However, a probable location for locally elevated concerns will be northern portions of the Willamette Valley where terrain-enhanced flow out of the Columbia Gorge will bring potential for 15-20 mph winds. Elsewhere within western Oregon, 10-15 mph are more likely. ..Wendt.. 08/26/2019 ...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 0149 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level ridge axis will situate itself across the Pacific Northwest coast on D2/Tuesday. A surface anticyclone will continue on a southward track into central Rockies/High Plains along with the continued presence of a thermally induced pressure trough across the Oregon coast and northern California. The surface pressure pattern will continue to favor offshore flow across Oregon coast, with more of an easterly component than Monday. ...Western Oregon... Hot/dry conditions will be prevalent on Tuesday as strong heating occurs underneath the upper-level ridge. Easterly downslope flow off the Cascades will help reduce afternoon RH values to potentially below 20% in some locations, but more broadly 25-35%. Wind speed still appears to be the limiting factor to a greater threat for fire spread. However, a probable location for locally elevated concerns will be northern portions of the Willamette Valley where terrain-enhanced flow out of the Columbia Gorge will bring potential for 15-20 mph winds. Elsewhere within western Oregon, 10-15 mph are more likely. ..Wendt.. 08/26/2019 ...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 0149 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level ridge axis will situate itself across the Pacific Northwest coast on D2/Tuesday. A surface anticyclone will continue on a southward track into central Rockies/High Plains along with the continued presence of a thermally induced pressure trough across the Oregon coast and northern California. The surface pressure pattern will continue to favor offshore flow across Oregon coast, with more of an easterly component than Monday. ...Western Oregon... Hot/dry conditions will be prevalent on Tuesday as strong heating occurs underneath the upper-level ridge. Easterly downslope flow off the Cascades will help reduce afternoon RH values to potentially below 20% in some locations, but more broadly 25-35%. Wind speed still appears to be the limiting factor to a greater threat for fire spread. However, a probable location for locally elevated concerns will be northern portions of the Willamette Valley where terrain-enhanced flow out of the Columbia Gorge will bring potential for 15-20 mph winds. Elsewhere within western Oregon, 10-15 mph are more likely. ..Wendt.. 08/26/2019 ...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 0149 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level ridge axis will situate itself across the Pacific Northwest coast on D2/Tuesday. A surface anticyclone will continue on a southward track into central Rockies/High Plains along with the continued presence of a thermally induced pressure trough across the Oregon coast and northern California. The surface pressure pattern will continue to favor offshore flow across Oregon coast, with more of an easterly component than Monday. ...Western Oregon... Hot/dry conditions will be prevalent on Tuesday as strong heating occurs underneath the upper-level ridge. Easterly downslope flow off the Cascades will help reduce afternoon RH values to potentially below 20% in some locations, but more broadly 25-35%. Wind speed still appears to be the limiting factor to a greater threat for fire spread. However, a probable location for locally elevated concerns will be northern portions of the Willamette Valley where terrain-enhanced flow out of the Columbia Gorge will bring potential for 15-20 mph winds. Elsewhere within western Oregon, 10-15 mph are more likely. ..Wendt.. 08/26/2019 ...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 0149 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...NO CRITICAL AREAS... ...Synopsis... The upper-level ridge axis will situate itself across the Pacific Northwest coast on D2/Tuesday. A surface anticyclone will continue on a southward track into central Rockies/High Plains along with the continued presence of a thermally induced pressure trough across the Oregon coast and northern California. The surface pressure pattern will continue to favor offshore flow across Oregon coast, with more of an easterly component than Monday. ...Western Oregon... Hot/dry conditions will be prevalent on Tuesday as strong heating occurs underneath the upper-level ridge. Easterly downslope flow off the Cascades will help reduce afternoon RH values to potentially below 20% in some locations, but more broadly 25-35%. Wind speed still appears to be the limiting factor to a greater threat for fire spread. However, a probable location for locally elevated concerns will be northern portions of the Willamette Valley where terrain-enhanced flow out of the Columbia Gorge will bring potential for 15-20 mph winds. Elsewhere within western Oregon, 10-15 mph are more likely. ..Wendt.. 08/26/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0621 Status Updates
STATUS REPORT ON WW 621 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 10 N LBF TO 30 SE MHN TO 35 E MHN TO 45 WNW MHN TO 55 WNW VTN. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1861 ..GLEASON..08/26/19 ATTN...WFO...LBF... STATUS REPORT FOR WS 621 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS NEC009-015-017-031-041-071-089-103-113-115-149-171-183-260740- NE . NEBRASKA COUNTIES INCLUDED ARE BLAINE BOYD BROWN CHERRY CUSTER GARFIELD HOLT KEYA PAHA LOGAN LOUP ROCK THOMAS WHEELER 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 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW VTN TO 30 N PIR. WW 620 WILL BE ALLOWED TO EXPIRE AT 260700Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1861 ..GLEASON..08/26/19 ATTN...WFO...UNR... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-055-071-095-121-123-260700- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT HAAKON JACKSON MELLETTE 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 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW VTN TO 30 N PIR. WW 620 WILL BE ALLOWED TO EXPIRE AT 260700Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1861 ..GLEASON..08/26/19 ATTN...WFO...UNR... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-055-071-095-121-123-260700- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT HAAKON JACKSON MELLETTE 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 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW VTN TO 30 N PIR. WW 620 WILL BE ALLOWED TO EXPIRE AT 260700Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1861 ..GLEASON..08/26/19 ATTN...WFO...UNR... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-055-071-095-121-123-260700- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT HAAKON JACKSON MELLETTE 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 0620 Status Updates
STATUS REPORT ON WW 620 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 WNW VTN TO 30 N PIR. WW 620 WILL BE ALLOWED TO EXPIRE AT 260700Z. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1861 ..GLEASON..08/26/19 ATTN...WFO...UNR... STATUS REPORT FOR WS 620 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS SDC007-055-071-095-121-123-260700- SD . SOUTH DAKOTA COUNTIES INCLUDED ARE BENNETT HAAKON JACKSON MELLETTE 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 Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0112 AM CDT Mon Aug 26 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ..Wendt.. 08/26/2019 ...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 0112 AM CDT Mon Aug 26 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ..Wendt.. 08/26/2019 ...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 0112 AM CDT Mon Aug 26 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ..Wendt.. 08/26/2019 ...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 0112 AM CDT Mon Aug 26 2019 Valid 261200Z - 271200Z ...NO CRITICAL AREAS... ...Synopsis... A broad upper-level trough will continue to move east through the central Rockies today, with remnant enhanced mid-level flow along the back edge of this feature. An upper-level ridge will again build across the Pacific Northwest coast. At the surface, an anticyclone will build within the northern Rockies as a thermally induced pressure trough sets up across northern California into parts of the Oregon coast. While fire weather concerns will be greatly reduced from Sunday, a few areas of locally elevated conditions are probable. ...Southwestern Wyoming and Central Utah... With some stronger northwesterly flow aloft, areas of southwestern Wyoming and within the lee of the Wasatch range may experience 15-20 mph winds, with potentially higher gusts, during the afternoon. These conditions, however, are not expected to be widespread or long-lasting as surface pressure gradient remains weak under the influence of the anticyclone. ...Willamette Valley Vicinity... The surface pressure pattern will favor offshore flow across much of the Oregon coast, particularly during the evening and overnight hours. Guidance differs on how low the RH will fall (most likely 25-35%), but there is ample agreement that sustained 15 mph winds will be localized in nature. Dry offshore flow may also occur in southwestern Oregon, but confidence in even locally elevated conditions is less farther south. ..Wendt.. 08/26/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1246 AM CDT Mon Aug 26 2019 Valid 271200Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM NORTHWEST TEXAS/SOUTHWEST OKLAHOMA SOUTHEASTWARD INTO WESTERN LOUISIANA... ...SUMMARY... Isolated severe thunderstorms are possible from northwest Texas/southwest Oklahoma southeastward into western Louisiana on Tuesday. ...Synopsis... Maturing mid-latitude cyclone, centered near the southern Manitoba/Ontario border early Tuesday morning, is expected continue eastward into far northwest Ontario. Expansive cyclonic flow throughout the base of this system (and attendant enhanced westerly flow aloft) will also progress eastward over the upper/middle MS Valleys into the OH Valley. Surface low attendant to this upper system is expected to be centered over northwestern Ontario Tuesday morning. A cold front will extend southeastward from this low into the Upper Great Lakes then southwestward through the middle MS Valley into southwest TX. Northern/eastern portion of this front will remain progressive, continuing eastward through the OH Valley and Lower Great Lakes. Southern/western portion of this front will be less progressive with outflow from an MCS likely becoming the effective boundary across southern OK/northern TX. ...Far Northwest TX/Southeast OK into Western LA... Showers and thunderstorm will likely be ongoing at the beginning of the period as a decaying MCS moves into the region. Isolated damaging wind gusts are possible with the strongest cells along the outflow boundary. Warm and moist conditions are anticipated south of the composite outflow boundary Tuesday afternoon. Mid-level temperatures will be relatively warm, but the warm and moist low-levels will likely result in an erosion of any convective inhibition. Convergence along the boundary will then lead to thunderstorm development. However, given the mesoscale nature of this boundary, its location is hard to ascertain with much confidence at this point. Most of the convection-allowing guidance suggests a more southerly boundary location during the afternoon and the 5% threat area was adjusted accordingly. The lack of stronger vertical shear suggests minimal storm organization and a predominantly multicellular mode. Even so, strong water-loaded downbursts are possible with the strongest updrafts. ...Upper Midwest... A shortwave trough embedded within the base of the larger parent mid-latitude cyclone is expected to move into the region during the afternoon. Cool mid-level temperatures and large-scale forcing for ascent associated with this trough will led to thunderstorm development. Given the weak instability, storms are generally expected to remain sub-severe with some small hail possible within the strongest updrafts. ...MAXIMUM RISK BY HAZARD... Tornado: 2% - Marginal Wind: 5% - Marginal Hail: 5% - Marginal ..Mosier.. 08/26/2019 Read more