Severe Storms

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0230 AM CDT Sat Sep 14 2019 Valid 161200Z - 171200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS LATE MONDAY NIGHT ACROSS WESTERN UTAH AND ADJACENT PORTIONS OF THE GREAT BASIN... ...SUMMARY... Strong thunderstorms may impact western Utah and adjacent portions of the Great Basin late Monday night, perhaps accompanied by at least some risk for potentially damaging wind gusts. ...Discussion... Within the westerlies, models indicate substantive further amplification of mid-level ridging along an axis from the Upper Midwest into Hudson Bay during this period. As this occurs, downstream troughing is forecast to dig east-southeast of the Canadian Maritimes and north Atlantic coast, with an associated surface cold front advancing as far south as the Mid Atlantic Coast states and Ohio Valley by 12Z Tuesday. Within much weaker troughing off the south Atlantic coast, to the south of this feature, Humberto may intensify to hurricane strength, but is expected to be in the process of accelerating eastward away from the coast, through the western Atlantic. Meanwhile, as another significant short wave impulse digs southeast of the Gulf of Alaska, to the west of the British Columbia coast, initially amplified upper troughing near the Pacific coast is expected to increasingly split. One emerging short wave trough is forecast to accelerate across and northeast of the Canadian Rockies, while a more significant impulse to the south pivots inland of the Oregon and California coast, toward the northern Rockies. Strong forcing for ascent and wind fields/vertical shear associated with the trailing impulse may contribute to the best potential for any appreciable severe weather risk during this period. However, it appears that this probably will be tempered by drying over the Great Basin in the wake of a preceding short wave impulse, emerging from the lower latitudes ahead of the inland advancing troughing. Of most concern at the present time, at least some model output suggests that a return flow of monsoonal moisture could develop in a narrow plume, ahead the vigorous short wave and associated cold front, across western Utah by late Monday night. This could contribute to sufficient destabilization for the initiation of storms prior to 17/09-12Z, west of the Wasatch into the Great Salt Lake vicinity, where southwesterly flow in the 700-500 mb layer may strengthen to 40-70 kt. With relatively dry sub-cloud air contributing to evaporative cooling in downdrafts, downward mixing of higher momentum air may result in strong surface gusts. ..Kerr.. 09/14/2019 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Sat Sep 14 2019 Valid 151200Z - 161200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST NV...NORTHEAST CA...SOUTHEAST OR...SOUTHWEST ID... ...CRITICAL FIRE WEATHER AREA FOR CENTRAL/EASTERN NV... ...Synopsis... A vigorous upper trough is forecast to amplify and shift eastward across the Pacific Coast into the Great Basin/interior Northwest by Monday morning. At the surface, low pressure will deepen from the northern Great Basin into portions of the northern High Plains, with a surface trough extending southward into the central/southern High Plains. ...Great Basin and vicinity... As low/midlevel flow increases in advance of the strong upper trough, a broad area of elevated to potentially critical fire weather conditions is forecast to develop from the Great Basin and vicinity eastward into portions of southern WY. Within this region, critical conditions are likely over northwest NV and adjacent portions of northeast CA, southeast OR, and far southwest ID. In this area, sustained winds of 20-30 mph will combine with minimum RH values of 8-15%, with localized areas of extremely critical conditions possible. Another region of potentially critical conditions is forecast over portions of central/eastern NV, where sustained winds of 15-25 mph are forecast in conjunction with minimum RH values of 10-15%. The onset of critical conditions in these areas may occur as early as late morning, with critical conditions potentially persisting into late Sunday night across the westernmost critical area. ..Dean.. 09/14/2019 ...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 0100 AM CDT Sat Sep 14 2019 Valid 151200Z - 161200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST NV...NORTHEAST CA...SOUTHEAST OR...SOUTHWEST ID... ...CRITICAL FIRE WEATHER AREA FOR CENTRAL/EASTERN NV... ...Synopsis... A vigorous upper trough is forecast to amplify and shift eastward across the Pacific Coast into the Great Basin/interior Northwest by Monday morning. At the surface, low pressure will deepen from the northern Great Basin into portions of the northern High Plains, with a surface trough extending southward into the central/southern High Plains. ...Great Basin and vicinity... As low/midlevel flow increases in advance of the strong upper trough, a broad area of elevated to potentially critical fire weather conditions is forecast to develop from the Great Basin and vicinity eastward into portions of southern WY. Within this region, critical conditions are likely over northwest NV and adjacent portions of northeast CA, southeast OR, and far southwest ID. In this area, sustained winds of 20-30 mph will combine with minimum RH values of 8-15%, with localized areas of extremely critical conditions possible. Another region of potentially critical conditions is forecast over portions of central/eastern NV, where sustained winds of 15-25 mph are forecast in conjunction with minimum RH values of 10-15%. The onset of critical conditions in these areas may occur as early as late morning, with critical conditions potentially persisting into late Sunday night across the westernmost critical area. ..Dean.. 09/14/2019 ...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 0100 AM CDT Sat Sep 14 2019 Valid 151200Z - 161200Z ...CRITICAL FIRE WEATHER AREA FOR NORTHWEST NV...NORTHEAST CA...SOUTHEAST OR...SOUTHWEST ID... ...CRITICAL FIRE WEATHER AREA FOR CENTRAL/EASTERN NV... ...Synopsis... A vigorous upper trough is forecast to amplify and shift eastward across the Pacific Coast into the Great Basin/interior Northwest by Monday morning. At the surface, low pressure will deepen from the northern Great Basin into portions of the northern High Plains, with a surface trough extending southward into the central/southern High Plains. ...Great Basin and vicinity... As low/midlevel flow increases in advance of the strong upper trough, a broad area of elevated to potentially critical fire weather conditions is forecast to develop from the Great Basin and vicinity eastward into portions of southern WY. Within this region, critical conditions are likely over northwest NV and adjacent portions of northeast CA, southeast OR, and far southwest ID. In this area, sustained winds of 20-30 mph will combine with minimum RH values of 8-15%, with localized areas of extremely critical conditions possible. Another region of potentially critical conditions is forecast over portions of central/eastern NV, where sustained winds of 15-25 mph are forecast in conjunction with minimum RH values of 10-15%. The onset of critical conditions in these areas may occur as early as late morning, with critical conditions potentially persisting into late Sunday night across the westernmost critical area. ..Dean.. 09/14/2019 ...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 1259 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...Synopsis... An upper trough is forecast to approach the Pacific Northwest by late tonight, as a downstream shortwave trough moves quickly across the northern Plains. At the surface, broad low pressure will remain in place across south-central Canada, with a surface trough extending into portions of the central/northern High Plains. ...Southern WY... Low-level westerly flow will become established across southern WY this afternoon, to the west of the surface trough over the central/northern High Plains. Drying/mixing within a westerly flow regime will result in minimum RH values dropping to 10-20% this afternoon, in conjunction with sustained winds of 15-25 mph. These conditions will result in elevated fire weather conditions, with the best chance of locally critical conditions expected across portions of southeast WY. ...Northwest Great Basin and Vicinity... In advance of the upper trough, a gradual increase in low-level southwesterly flow is expected across portions of the northwest Great Basin and vicinity. Sustained winds may approach or exceed 15 mph within a hot and dry airmass characterized by minimum RH values of 10-15%, resulting in the potential for elevated fire weather conditions. As flow continues to increase into Sunday morning, mid/high elevation regions that remain above the nocturnal inversion for a longer period of time may see elevated conditions persist into the overnight hours. ..Dean.. 09/14/2019 ...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 1259 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...Synopsis... An upper trough is forecast to approach the Pacific Northwest by late tonight, as a downstream shortwave trough moves quickly across the northern Plains. At the surface, broad low pressure will remain in place across south-central Canada, with a surface trough extending into portions of the central/northern High Plains. ...Southern WY... Low-level westerly flow will become established across southern WY this afternoon, to the west of the surface trough over the central/northern High Plains. Drying/mixing within a westerly flow regime will result in minimum RH values dropping to 10-20% this afternoon, in conjunction with sustained winds of 15-25 mph. These conditions will result in elevated fire weather conditions, with the best chance of locally critical conditions expected across portions of southeast WY. ...Northwest Great Basin and Vicinity... In advance of the upper trough, a gradual increase in low-level southwesterly flow is expected across portions of the northwest Great Basin and vicinity. Sustained winds may approach or exceed 15 mph within a hot and dry airmass characterized by minimum RH values of 10-15%, resulting in the potential for elevated fire weather conditions. As flow continues to increase into Sunday morning, mid/high elevation regions that remain above the nocturnal inversion for a longer period of time may see elevated conditions persist into the overnight hours. ..Dean.. 09/14/2019 ...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 1259 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...Synopsis... An upper trough is forecast to approach the Pacific Northwest by late tonight, as a downstream shortwave trough moves quickly across the northern Plains. At the surface, broad low pressure will remain in place across south-central Canada, with a surface trough extending into portions of the central/northern High Plains. ...Southern WY... Low-level westerly flow will become established across southern WY this afternoon, to the west of the surface trough over the central/northern High Plains. Drying/mixing within a westerly flow regime will result in minimum RH values dropping to 10-20% this afternoon, in conjunction with sustained winds of 15-25 mph. These conditions will result in elevated fire weather conditions, with the best chance of locally critical conditions expected across portions of southeast WY. ...Northwest Great Basin and Vicinity... In advance of the upper trough, a gradual increase in low-level southwesterly flow is expected across portions of the northwest Great Basin and vicinity. Sustained winds may approach or exceed 15 mph within a hot and dry airmass characterized by minimum RH values of 10-15%, resulting in the potential for elevated fire weather conditions. As flow continues to increase into Sunday morning, mid/high elevation regions that remain above the nocturnal inversion for a longer period of time may see elevated conditions persist into the overnight hours. ..Dean.. 09/14/2019 ...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 1152 PM CDT Fri Sep 13 2019 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across U.S. Sunday through Sunday night. ...Discussion... Substantial further amplification within the mid-latitude westerlies appears likely during this period. While models indicate large-scale troughing will continue to dig along an axis near/just west of the Pacific coast, downstream ridging is forecast to build across and north of the Canadian/U.S. border, east of the Rockies through Ontario and the Great Lakes region. In advance (east) of the troughing, models suggest that a much weaker perturbation emerging from the lower latitudes will gradually accelerate north of the Southwestern international border area, through the Four Corners region. Although this may be preceded by considerable lingering convectively generated cloud cover and precipitation, which appears likely to limit or slow daytime heating, destabilization in its wake may still be sufficient to support scattered afternoon and evening thunderstorm activity. Elsewhere, thunderstorms developing Saturday night, mostly in response to forcing associated with low-level warm advection, may linger into Sunday morning across parts of the Upper Midwest and Great Lakes region. However, it still appears that this activity will diminish early, with low to negligible probabilities for redevelopment as mid-level ridging builds into the region. Additionally, low probabilities for convection capable of producing lightning may develop into Washington/Oregon coastal areas by Sunday evening, in response to destabilization associated with strong mid-level cooling. There appears some risk for thunderstorms near northwest Gulf coastal areas, in association with a slow moving perturbation within the easterlies, over the western Gulf of Mexico. Isolated to widely scattered afternoon thunderstorm development may not be out of the question across parts of the Florida peninsula, well to the southwest of Humberto. With Humberto now forecast to track along a path well offshore of the Southeast coast, severe weather potential appears negligible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: <5% - None Hail: <5% - None ..Kerr.. 09/14/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CDT Fri Sep 13 2019 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across U.S. Sunday through Sunday night. ...Discussion... Substantial further amplification within the mid-latitude westerlies appears likely during this period. While models indicate large-scale troughing will continue to dig along an axis near/just west of the Pacific coast, downstream ridging is forecast to build across and north of the Canadian/U.S. border, east of the Rockies through Ontario and the Great Lakes region. In advance (east) of the troughing, models suggest that a much weaker perturbation emerging from the lower latitudes will gradually accelerate north of the Southwestern international border area, through the Four Corners region. Although this may be preceded by considerable lingering convectively generated cloud cover and precipitation, which appears likely to limit or slow daytime heating, destabilization in its wake may still be sufficient to support scattered afternoon and evening thunderstorm activity. Elsewhere, thunderstorms developing Saturday night, mostly in response to forcing associated with low-level warm advection, may linger into Sunday morning across parts of the Upper Midwest and Great Lakes region. However, it still appears that this activity will diminish early, with low to negligible probabilities for redevelopment as mid-level ridging builds into the region. Additionally, low probabilities for convection capable of producing lightning may develop into Washington/Oregon coastal areas by Sunday evening, in response to destabilization associated with strong mid-level cooling. There appears some risk for thunderstorms near northwest Gulf coastal areas, in association with a slow moving perturbation within the easterlies, over the western Gulf of Mexico. Isolated to widely scattered afternoon thunderstorm development may not be out of the question across parts of the Florida peninsula, well to the southwest of Humberto. With Humberto now forecast to track along a path well offshore of the Southeast coast, severe weather potential appears negligible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: <5% - None Hail: <5% - None ..Kerr.. 09/14/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1152 PM CDT Fri Sep 13 2019 Valid 151200Z - 161200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... The risk for severe thunderstorms appears negligible across U.S. Sunday through Sunday night. ...Discussion... Substantial further amplification within the mid-latitude westerlies appears likely during this period. While models indicate large-scale troughing will continue to dig along an axis near/just west of the Pacific coast, downstream ridging is forecast to build across and north of the Canadian/U.S. border, east of the Rockies through Ontario and the Great Lakes region. In advance (east) of the troughing, models suggest that a much weaker perturbation emerging from the lower latitudes will gradually accelerate north of the Southwestern international border area, through the Four Corners region. Although this may be preceded by considerable lingering convectively generated cloud cover and precipitation, which appears likely to limit or slow daytime heating, destabilization in its wake may still be sufficient to support scattered afternoon and evening thunderstorm activity. Elsewhere, thunderstorms developing Saturday night, mostly in response to forcing associated with low-level warm advection, may linger into Sunday morning across parts of the Upper Midwest and Great Lakes region. However, it still appears that this activity will diminish early, with low to negligible probabilities for redevelopment as mid-level ridging builds into the region. Additionally, low probabilities for convection capable of producing lightning may develop into Washington/Oregon coastal areas by Sunday evening, in response to destabilization associated with strong mid-level cooling. There appears some risk for thunderstorms near northwest Gulf coastal areas, in association with a slow moving perturbation within the easterlies, over the western Gulf of Mexico. Isolated to widely scattered afternoon thunderstorm development may not be out of the question across parts of the Florida peninsula, well to the southwest of Humberto. With Humberto now forecast to track along a path well offshore of the Southeast coast, severe weather potential appears negligible. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: <5% - None Hail: <5% - None ..Kerr.. 09/14/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MS VALLEY AND CENTRAL PLAINS AND OVER PARTS OF AZ... ...SUMMARY... A few strong-severe storms are possible across portions of the upper Mississippi Valley, extending southwest into the central Plains. Locally damaging winds are the primary risk along with marginally severe hail. Gusty winds may also accompany storms in the lower desert regions of AZ. ...Upper MS Valley to Central Plains... Notable short-wave trough over the northern Rockies is forecast to progress across the Dakotas into the upper MS Valley by 15/00z. While southern extent of this feature should influence northern portions of the MRGL Risk late this afternoon, large-scale height rises are expected across much of the central US, including the Plains and MS Valley. Partly in response to this feature, LLJ should increase across the central Plains before veering into WI by early evening. This will allow higher-PW air mass to advance north, then east into southern MN/IA by peak heating. Even so, forecast soundings suggest surface parcels will struggle to reach convective temperatures and low-level warm advection may ultimately be the primary forcing mechanism for potential robust convective development. Latest models support this with most guidance suggesting warm-sector convection struggling to organize in the presence of height rises and marginal low-level lapse rates. However, isentropic ascent across southern MN into southwest WI should encourage slightly elevated convection along nose of LLJ. Some of this activity could produce gusty winds and perhaps some hail. Farther southwest across KS, strong boundary-layer heating will be noted across the High Plains where surface temperatures should soar into the mid 90s. Forecast soundings suggest convective temperatures will be breached by 23z and isolated high-based convection is expected to develop across southwest KS which could spread/develop northeast along the boundary into south-central NE. Gusty winds and hail are the primary threats with the diurnally-driven activity. ...AZ... A considerable amount of deep convection developed over the higher terrain of northwestern Mexico ahead of what appears to be a weak short-wave trough. This low-latitude wave should drift toward the Gulf of California which will allow for more favorable trajectories to transport moisture north of the international border into AZ. With PWs expected to climb well above 1", strong boundary-layer heating should contribute to increasing buoyancy that will prove supportive of robust convection. Forecast soundings suggest deep convection will develop as early as 19z across southeast AZ, then spread/develop west toward the lower deserts. A considerable amount of convection may ultimately evolve across this region and gusty winds are certainly possible given the increasingly wet downdrafts. ..Darrow/Dean.. 09/14/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MS VALLEY AND CENTRAL PLAINS AND OVER PARTS OF AZ... ...SUMMARY... A few strong-severe storms are possible across portions of the upper Mississippi Valley, extending southwest into the central Plains. Locally damaging winds are the primary risk along with marginally severe hail. Gusty winds may also accompany storms in the lower desert regions of AZ. ...Upper MS Valley to Central Plains... Notable short-wave trough over the northern Rockies is forecast to progress across the Dakotas into the upper MS Valley by 15/00z. While southern extent of this feature should influence northern portions of the MRGL Risk late this afternoon, large-scale height rises are expected across much of the central US, including the Plains and MS Valley. Partly in response to this feature, LLJ should increase across the central Plains before veering into WI by early evening. This will allow higher-PW air mass to advance north, then east into southern MN/IA by peak heating. Even so, forecast soundings suggest surface parcels will struggle to reach convective temperatures and low-level warm advection may ultimately be the primary forcing mechanism for potential robust convective development. Latest models support this with most guidance suggesting warm-sector convection struggling to organize in the presence of height rises and marginal low-level lapse rates. However, isentropic ascent across southern MN into southwest WI should encourage slightly elevated convection along nose of LLJ. Some of this activity could produce gusty winds and perhaps some hail. Farther southwest across KS, strong boundary-layer heating will be noted across the High Plains where surface temperatures should soar into the mid 90s. Forecast soundings suggest convective temperatures will be breached by 23z and isolated high-based convection is expected to develop across southwest KS which could spread/develop northeast along the boundary into south-central NE. Gusty winds and hail are the primary threats with the diurnally-driven activity. ...AZ... A considerable amount of deep convection developed over the higher terrain of northwestern Mexico ahead of what appears to be a weak short-wave trough. This low-latitude wave should drift toward the Gulf of California which will allow for more favorable trajectories to transport moisture north of the international border into AZ. With PWs expected to climb well above 1", strong boundary-layer heating should contribute to increasing buoyancy that will prove supportive of robust convection. Forecast soundings suggest deep convection will develop as early as 19z across southeast AZ, then spread/develop west toward the lower deserts. A considerable amount of convection may ultimately evolve across this region and gusty winds are certainly possible given the increasingly wet downdrafts. ..Darrow/Dean.. 09/14/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1240 AM CDT Sat Sep 14 2019 Valid 141200Z - 151200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MS VALLEY AND CENTRAL PLAINS AND OVER PARTS OF AZ... ...SUMMARY... A few strong-severe storms are possible across portions of the upper Mississippi Valley, extending southwest into the central Plains. Locally damaging winds are the primary risk along with marginally severe hail. Gusty winds may also accompany storms in the lower desert regions of AZ. ...Upper MS Valley to Central Plains... Notable short-wave trough over the northern Rockies is forecast to progress across the Dakotas into the upper MS Valley by 15/00z. While southern extent of this feature should influence northern portions of the MRGL Risk late this afternoon, large-scale height rises are expected across much of the central US, including the Plains and MS Valley. Partly in response to this feature, LLJ should increase across the central Plains before veering into WI by early evening. This will allow higher-PW air mass to advance north, then east into southern MN/IA by peak heating. Even so, forecast soundings suggest surface parcels will struggle to reach convective temperatures and low-level warm advection may ultimately be the primary forcing mechanism for potential robust convective development. Latest models support this with most guidance suggesting warm-sector convection struggling to organize in the presence of height rises and marginal low-level lapse rates. However, isentropic ascent across southern MN into southwest WI should encourage slightly elevated convection along nose of LLJ. Some of this activity could produce gusty winds and perhaps some hail. Farther southwest across KS, strong boundary-layer heating will be noted across the High Plains where surface temperatures should soar into the mid 90s. Forecast soundings suggest convective temperatures will be breached by 23z and isolated high-based convection is expected to develop across southwest KS which could spread/develop northeast along the boundary into south-central NE. Gusty winds and hail are the primary threats with the diurnally-driven activity. ...AZ... A considerable amount of deep convection developed over the higher terrain of northwestern Mexico ahead of what appears to be a weak short-wave trough. This low-latitude wave should drift toward the Gulf of California which will allow for more favorable trajectories to transport moisture north of the international border into AZ. With PWs expected to climb well above 1", strong boundary-layer heating should contribute to increasing buoyancy that will prove supportive of robust convection. Forecast soundings suggest deep convection will develop as early as 19z across southeast AZ, then spread/develop west toward the lower deserts. A considerable amount of convection may ultimately evolve across this region and gusty winds are certainly possible given the increasingly wet downdrafts. ..Darrow/Dean.. 09/14/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Fri Sep 13 2019 Valid 140100Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OH VALLEY... ...SUMMARY... Scattered strong storms will linger across northern Ohio into extreme northwest Pennsylvania this evening. Isolated damaging winds may be noted for the next few hours. ...OH Valley... Large-scale height falls are spreading east across ON/QC ahead of a pronounced mid-level short-wave trough. Southern influence of this trough is affecting the international border region from northern OH into upstate NY. Convection that developed ahead of the front over southeastern lower MI/western OH has shifted downstream, utilizing an air mass that is characterized by steep low-level lapse rates with MLCAPE on the order of 1500 J/kg. 00z sounding from ILN supports this along with deep-layer shear of roughly 30kt. Ongoing activity will soon shift east of instability corridor, and loss of daytime heating should also serve to negatively influence convective updrafts. For these reasons will only maintain 5% severe probs for the next few hours. ..Darrow.. 09/14/2019 Read more

WW 0652 Status Updates
STATUS REPORT ON WW 652 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NE MIE TO 15 NNE TOL TO 10 SSE DTW TO 60 ESE MTC. ..DEAN..09/13/19 ATTN...WFO...IWX...DTX...CLE... STATUS REPORT FOR WS 652 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OHC033-043-063-077-095-123-143-147-173-175-132340- OH . OHIO COUNTIES INCLUDED ARE CRAWFORD ERIE HANCOCK HURON LUCAS OTTAWA SANDUSKY SENECA WOOD WYANDOT LEZ142-143-144-162-163-164-132340- CW . ADJACENT COASTAL WATERS INCLUDED ARE MAUMEE BAY TO RENO BEACH OH RENO BEACH TO THE ISLANDS OH THE ISLANDS TO VERMILION OH DETROIT RIVER LT. TO MAUMEE BAY OH TO RENO BEACH OH BEYOND 5NM OFFSHORELINE TO US-CANADIAN BORDER Read more

WW 652 SEVERE TSTM IN MI OH LE LH 131845Z - 140100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 652 NWS Storm Prediction Center Norman OK 245 PM EDT Fri Sep 13 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Indiana Southeast Lower Michigan Northwest Ohio Lake Erie Lake Huron * Effective this Friday afternoon and evening from 245 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered thunderstorms developing from northeast Indiana to southeast Lower Michigan should spread east-northeast through the rest of the afternoon into early evening. Scattered damaging winds are the main threat, but a tornado or two will also be possible across southeast Lower Michigan through late afternoon. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles southwest of Findlay OH to 85 miles north northeast of Mount Clemens MI. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24030. ...Grams Read more

MD 1974 CONCERNING SEVERE THUNDERSTORM WATCH 652... FOR NORTHERN OH...EXTREME EAST-CENTRAL IN
Mesoscale Discussion 1974 NWS Storm Prediction Center Norman OK 0616 PM CDT Fri Sep 13 2019 Areas affected...Northern OH...Extreme east-central IN Concerning...Severe Thunderstorm Watch 652... Valid 132316Z - 140045Z The severe weather threat for Severe Thunderstorm Watch 652 continues. SUMMARY...Thunderstorms capable of locally damaging winds and perhaps marginally severe hail will remain possible this evening, with a gradual weakening trend expected with time. DISCUSSION...A general weakening trend has been noticed recently the longer-lived convective cluster across north-central OH, with some redevelopment noted further west from east-central IN into northwest OH. MLCAPE of 1000-1500 J/kg and effective shear of 25-35 kt may support some organization with the strongest cells, with some threat for isolated damaging wind and/or marginally severe hail. However, as large-scale ascent associated with the upper trough over the Upper Great Lakes lifts away from the region and MLCINH increases this evening, a gradual decrease in the severe thunderstorm threat is expected with time, and downstream watch issuance is not currently anticipated. ..Dean/Goss.. 09/13/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CLE...ILN...DTX...IWX...IND... LAT...LON 40158536 40768468 41078436 41418406 42038336 42018274 41898183 41478160 40918214 40608257 40408315 40258383 40068453 40158536 Read more

WW 0652 Status Updates
STATUS REPORT ON WW 652 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 NE MIE TO 15 NNE TOL TO 10 SSE DTW TO 60 ESE MTC. ..DEAN..09/13/19 ATTN...WFO...IWX...DTX...CLE... STATUS REPORT FOR WS 652 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS OHC033-043-063-077-095-123-143-147-173-175-132340- OH . OHIO COUNTIES INCLUDED ARE CRAWFORD ERIE HANCOCK HURON LUCAS OTTAWA SANDUSKY SENECA WOOD WYANDOT LEZ142-143-144-162-163-164-132340- CW . ADJACENT COASTAL WATERS INCLUDED ARE MAUMEE BAY TO RENO BEACH OH RENO BEACH TO THE ISLANDS OH THE ISLANDS TO VERMILION OH DETROIT RIVER LT. TO MAUMEE BAY OH TO RENO BEACH OH BEYOND 5NM OFFSHORELINE TO US-CANADIAN BORDER Read more

WW 652 SEVERE TSTM IN MI OH LE LH 131845Z - 140100Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 652 NWS Storm Prediction Center Norman OK 245 PM EDT Fri Sep 13 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northeast Indiana Southeast Lower Michigan Northwest Ohio Lake Erie Lake Huron * Effective this Friday afternoon and evening from 245 PM until 900 PM EDT. * Primary threats include... Scattered damaging wind gusts to 70 mph possible Isolated large hail events to 1.5 inches in diameter possible A tornado or two possible SUMMARY...Scattered thunderstorms developing from northeast Indiana to southeast Lower Michigan should spread east-northeast through the rest of the afternoon into early evening. Scattered damaging winds are the main threat, but a tornado or two will also be possible across southeast Lower Michigan through late afternoon. The severe thunderstorm watch area is approximately along and 60 statute miles east and west of a line from 40 miles southwest of Findlay OH to 85 miles north northeast of Mount Clemens MI. 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. && AVIATION...A few severe thunderstorms with hail surface and aloft to 1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 24030. ...Grams Read more

No Mesoscale Discussions are in effect as of Fri Sep 13 22:56:05 UTC 2019.