Severe Storms

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0118 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...Synopsis... A potent upper-level trough is moving into the Pacific Northwest this morning with numerous lightning being observed in northern California. Some of these storms are expected to continue into the morning hours today before a brief lull is likely during late morning and early afternoon. Additional thunderstorms are expected during the afternoon as surface temperatures warm. PWAT values across much of the Northwest will be in the 0.75" range which, combined with storm speeds around 30 mph, will support a threat for dry thunderstorms. Otherwise, light winds are expected across much of the dry portions in the western CONUS which will limit the threat for large fire spread. ..Bentley.. 09/05/2019 ...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 0118 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...Synopsis... A potent upper-level trough is moving into the Pacific Northwest this morning with numerous lightning being observed in northern California. Some of these storms are expected to continue into the morning hours today before a brief lull is likely during late morning and early afternoon. Additional thunderstorms are expected during the afternoon as surface temperatures warm. PWAT values across much of the Northwest will be in the 0.75" range which, combined with storm speeds around 30 mph, will support a threat for dry thunderstorms. Otherwise, light winds are expected across much of the dry portions in the western CONUS which will limit the threat for large fire spread. ..Bentley.. 09/05/2019 ...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 1225 AM CDT Thu Sep 05 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE NORTHERN ROCKIES... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts will be possible over a portion of the northern Rockies Friday. ...Northern Rockies region... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Boundary layer dewpoints generally in the 40s to low 50s F will support 500-1000 J/kg MLCAPE where sufficient heating of the surface layer occurs. Vertical wind profiles accompanying the upper trough with 30-35 kt effective bulk shear will generally promote multicells. Widely scattered high-based storms will likely develop over the mountains and spread east into a portion of the High Plains. Inverted-V thermodynamic profiles suggest few of the storms might produce locally strong wind gusts from mid afternoon through mid evening. ...North Carolina Coast... The center of Hurricane Dorian is forecast by the National Hurricane center to be over the NC outer banks early Friday, but will continue northeast away from shore during the day. Therefore, the more favorable quadrant for isolated tornadoes should remain offshore with minimal threat inland. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Dial.. 09/05/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Thu Sep 05 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE NORTHERN ROCKIES... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts will be possible over a portion of the northern Rockies Friday. ...Northern Rockies region... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Boundary layer dewpoints generally in the 40s to low 50s F will support 500-1000 J/kg MLCAPE where sufficient heating of the surface layer occurs. Vertical wind profiles accompanying the upper trough with 30-35 kt effective bulk shear will generally promote multicells. Widely scattered high-based storms will likely develop over the mountains and spread east into a portion of the High Plains. Inverted-V thermodynamic profiles suggest few of the storms might produce locally strong wind gusts from mid afternoon through mid evening. ...North Carolina Coast... The center of Hurricane Dorian is forecast by the National Hurricane center to be over the NC outer banks early Friday, but will continue northeast away from shore during the day. Therefore, the more favorable quadrant for isolated tornadoes should remain offshore with minimal threat inland. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Dial.. 09/05/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Thu Sep 05 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE NORTHERN ROCKIES... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts will be possible over a portion of the northern Rockies Friday. ...Northern Rockies region... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Boundary layer dewpoints generally in the 40s to low 50s F will support 500-1000 J/kg MLCAPE where sufficient heating of the surface layer occurs. Vertical wind profiles accompanying the upper trough with 30-35 kt effective bulk shear will generally promote multicells. Widely scattered high-based storms will likely develop over the mountains and spread east into a portion of the High Plains. Inverted-V thermodynamic profiles suggest few of the storms might produce locally strong wind gusts from mid afternoon through mid evening. ...North Carolina Coast... The center of Hurricane Dorian is forecast by the National Hurricane center to be over the NC outer banks early Friday, but will continue northeast away from shore during the day. Therefore, the more favorable quadrant for isolated tornadoes should remain offshore with minimal threat inland. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Dial.. 09/05/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1225 AM CDT Thu Sep 05 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION OF THE NORTHERN ROCKIES... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts will be possible over a portion of the northern Rockies Friday. ...Northern Rockies region... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Boundary layer dewpoints generally in the 40s to low 50s F will support 500-1000 J/kg MLCAPE where sufficient heating of the surface layer occurs. Vertical wind profiles accompanying the upper trough with 30-35 kt effective bulk shear will generally promote multicells. Widely scattered high-based storms will likely develop over the mountains and spread east into a portion of the High Plains. Inverted-V thermodynamic profiles suggest few of the storms might produce locally strong wind gusts from mid afternoon through mid evening. ...North Carolina Coast... The center of Hurricane Dorian is forecast by the National Hurricane center to be over the NC outer banks early Friday, but will continue northeast away from shore during the day. Therefore, the more favorable quadrant for isolated tornadoes should remain offshore with minimal threat inland. ...MAXIMUM RISK BY HAZARD... Tornado: <2% - None Wind: 5% - Marginal Hail: <5% - None ..Dial.. 09/05/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1244 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH TONIGHT ACROSS PARTS OF THE COASTAL CAROLINAS... ...SUMMARY... Some risk for a couple of tornadoes could develop across parts of the coastal Carolinas today through tonight in association with Hurricane Dorian. A couple of strong thunderstorms may also impact parts of the Upper Midwest, and portions of western and central Oregon, accompanied by at least some risk for severe hail and wind. ...Synopsis... The stronger westerlies will remain confined to the northern tier of the U.S. and Canada through this period. Models suggest that some amplification within this regime is possible across the northeast Pacific through the Canadian Rockies, with short wave ridging building inland of the British Columbia coast, downstream of a significant progressive short wave trough over the northeast Pacific. Preceding the latter feature, a weaker short wave is forecast to advance inland of the northern California and Oregon coast, while subtropical ridging (centered near/east of the Colorado Rockies) otherwise maintains a prominent influence across much of the remainder of the West/Rockies and Plains. Downstream of the ridging, the most prominent impulse within the westerlies appears likely to continue rapidly progressing through larger-scale mid/upper troughing, across Quebec/Newfoundland and Labrador and the Canadian Maritimes. Meanwhile, within much weaker troughing at lower latitudes, Hurricane Dorian is expected to, at least initially, continue a slow northeastward migration near the Carolina coast. However, by tonight, an acceleration toward the North Carolina Outer Banks vicinity is forecast, as at least one short wave impulse within the westerlies digs across the Canadian/U.S. border through the Upper Midwest/Great Lakes region. Seasonably moist air has largely become confined to portions of the Southwest, Deep South Texas, and Southeast coastal areas, to the north and west of Dorian, and in the wake of an initial surface front which has advanced off the New England and northern Mid Atlantic coast, as well as into the lower Ohio/lower and middle Missouri Valleys. Considerable further drying into and through the Southeast and Gulf Coast appears likely today through tonight, in the wake of Dorian. However, substantive northward moisture return does appear possible ahead of the troughing advancing inland of the Pacific coast. ...Carolina coastal areas... Potential for convection capable of producing tornadoes will largely hinge on the inland advection of tropical boundary layer moisture, now present offshore, as evolving clockwise curved low-level hodographs become characterized by strong to extreme shear in the right front quadrant (with respect to storm motion) of Dorian. Based on the most probable track of the low-level cyclonic circulation center, this may come close to coastal areas, but could remain mostly offshore through this period. There may be some window of opportunity for increasing potential for tornadoes near northeastern South Carolina and southern North Carolina coastal areas this morning into midday, then mainly near the North Carolina Outer Banks vicinity later today through tonight, as the hurricane turns northeastward and roughly parallels the coast. ...Upper Midwest... Scattered thunderstorm development, in the presence of steep lower/mid tropospheric lapse rates and strong vertical shear within the convective layer, may pose a risk for marginally severe hail and wind. This will largely be focused along a zone of enhanced lower/mid tropospheric warm advection, associated with a couple of digging shortwaves within increasingly northwesterly mid-level flow. ...Near/east of the Oregon Cascades... Stronger mid/upper forcing for ascent associated with the inland progressing short wave, in combination with strengthening southwesterly mid-level flow (30-40 kt around 500 mb), deep boundary layer mixing and destabilization aided by mid-level moistening, may provide support for scattered afternoon storms which could pose a risk for marginally severe hail and strong wind gusts. ..Kerr/Bentley.. 09/05/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1244 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH TONIGHT ACROSS PARTS OF THE COASTAL CAROLINAS... ...SUMMARY... Some risk for a couple of tornadoes could develop across parts of the coastal Carolinas today through tonight in association with Hurricane Dorian. A couple of strong thunderstorms may also impact parts of the Upper Midwest, and portions of western and central Oregon, accompanied by at least some risk for severe hail and wind. ...Synopsis... The stronger westerlies will remain confined to the northern tier of the U.S. and Canada through this period. Models suggest that some amplification within this regime is possible across the northeast Pacific through the Canadian Rockies, with short wave ridging building inland of the British Columbia coast, downstream of a significant progressive short wave trough over the northeast Pacific. Preceding the latter feature, a weaker short wave is forecast to advance inland of the northern California and Oregon coast, while subtropical ridging (centered near/east of the Colorado Rockies) otherwise maintains a prominent influence across much of the remainder of the West/Rockies and Plains. Downstream of the ridging, the most prominent impulse within the westerlies appears likely to continue rapidly progressing through larger-scale mid/upper troughing, across Quebec/Newfoundland and Labrador and the Canadian Maritimes. Meanwhile, within much weaker troughing at lower latitudes, Hurricane Dorian is expected to, at least initially, continue a slow northeastward migration near the Carolina coast. However, by tonight, an acceleration toward the North Carolina Outer Banks vicinity is forecast, as at least one short wave impulse within the westerlies digs across the Canadian/U.S. border through the Upper Midwest/Great Lakes region. Seasonably moist air has largely become confined to portions of the Southwest, Deep South Texas, and Southeast coastal areas, to the north and west of Dorian, and in the wake of an initial surface front which has advanced off the New England and northern Mid Atlantic coast, as well as into the lower Ohio/lower and middle Missouri Valleys. Considerable further drying into and through the Southeast and Gulf Coast appears likely today through tonight, in the wake of Dorian. However, substantive northward moisture return does appear possible ahead of the troughing advancing inland of the Pacific coast. ...Carolina coastal areas... Potential for convection capable of producing tornadoes will largely hinge on the inland advection of tropical boundary layer moisture, now present offshore, as evolving clockwise curved low-level hodographs become characterized by strong to extreme shear in the right front quadrant (with respect to storm motion) of Dorian. Based on the most probable track of the low-level cyclonic circulation center, this may come close to coastal areas, but could remain mostly offshore through this period. There may be some window of opportunity for increasing potential for tornadoes near northeastern South Carolina and southern North Carolina coastal areas this morning into midday, then mainly near the North Carolina Outer Banks vicinity later today through tonight, as the hurricane turns northeastward and roughly parallels the coast. ...Upper Midwest... Scattered thunderstorm development, in the presence of steep lower/mid tropospheric lapse rates and strong vertical shear within the convective layer, may pose a risk for marginally severe hail and wind. This will largely be focused along a zone of enhanced lower/mid tropospheric warm advection, associated with a couple of digging shortwaves within increasingly northwesterly mid-level flow. ...Near/east of the Oregon Cascades... Stronger mid/upper forcing for ascent associated with the inland progressing short wave, in combination with strengthening southwesterly mid-level flow (30-40 kt around 500 mb), deep boundary layer mixing and destabilization aided by mid-level moistening, may provide support for scattered afternoon storms which could pose a risk for marginally severe hail and strong wind gusts. ..Kerr/Bentley.. 09/05/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1244 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH TONIGHT ACROSS PARTS OF THE COASTAL CAROLINAS... ...SUMMARY... Some risk for a couple of tornadoes could develop across parts of the coastal Carolinas today through tonight in association with Hurricane Dorian. A couple of strong thunderstorms may also impact parts of the Upper Midwest, and portions of western and central Oregon, accompanied by at least some risk for severe hail and wind. ...Synopsis... The stronger westerlies will remain confined to the northern tier of the U.S. and Canada through this period. Models suggest that some amplification within this regime is possible across the northeast Pacific through the Canadian Rockies, with short wave ridging building inland of the British Columbia coast, downstream of a significant progressive short wave trough over the northeast Pacific. Preceding the latter feature, a weaker short wave is forecast to advance inland of the northern California and Oregon coast, while subtropical ridging (centered near/east of the Colorado Rockies) otherwise maintains a prominent influence across much of the remainder of the West/Rockies and Plains. Downstream of the ridging, the most prominent impulse within the westerlies appears likely to continue rapidly progressing through larger-scale mid/upper troughing, across Quebec/Newfoundland and Labrador and the Canadian Maritimes. Meanwhile, within much weaker troughing at lower latitudes, Hurricane Dorian is expected to, at least initially, continue a slow northeastward migration near the Carolina coast. However, by tonight, an acceleration toward the North Carolina Outer Banks vicinity is forecast, as at least one short wave impulse within the westerlies digs across the Canadian/U.S. border through the Upper Midwest/Great Lakes region. Seasonably moist air has largely become confined to portions of the Southwest, Deep South Texas, and Southeast coastal areas, to the north and west of Dorian, and in the wake of an initial surface front which has advanced off the New England and northern Mid Atlantic coast, as well as into the lower Ohio/lower and middle Missouri Valleys. Considerable further drying into and through the Southeast and Gulf Coast appears likely today through tonight, in the wake of Dorian. However, substantive northward moisture return does appear possible ahead of the troughing advancing inland of the Pacific coast. ...Carolina coastal areas... Potential for convection capable of producing tornadoes will largely hinge on the inland advection of tropical boundary layer moisture, now present offshore, as evolving clockwise curved low-level hodographs become characterized by strong to extreme shear in the right front quadrant (with respect to storm motion) of Dorian. Based on the most probable track of the low-level cyclonic circulation center, this may come close to coastal areas, but could remain mostly offshore through this period. There may be some window of opportunity for increasing potential for tornadoes near northeastern South Carolina and southern North Carolina coastal areas this morning into midday, then mainly near the North Carolina Outer Banks vicinity later today through tonight, as the hurricane turns northeastward and roughly parallels the coast. ...Upper Midwest... Scattered thunderstorm development, in the presence of steep lower/mid tropospheric lapse rates and strong vertical shear within the convective layer, may pose a risk for marginally severe hail and wind. This will largely be focused along a zone of enhanced lower/mid tropospheric warm advection, associated with a couple of digging shortwaves within increasingly northwesterly mid-level flow. ...Near/east of the Oregon Cascades... Stronger mid/upper forcing for ascent associated with the inland progressing short wave, in combination with strengthening southwesterly mid-level flow (30-40 kt around 500 mb), deep boundary layer mixing and destabilization aided by mid-level moistening, may provide support for scattered afternoon storms which could pose a risk for marginally severe hail and strong wind gusts. ..Kerr/Bentley.. 09/05/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1244 AM CDT Thu Sep 05 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TODAY THROUGH TONIGHT ACROSS PARTS OF THE COASTAL CAROLINAS... ...SUMMARY... Some risk for a couple of tornadoes could develop across parts of the coastal Carolinas today through tonight in association with Hurricane Dorian. A couple of strong thunderstorms may also impact parts of the Upper Midwest, and portions of western and central Oregon, accompanied by at least some risk for severe hail and wind. ...Synopsis... The stronger westerlies will remain confined to the northern tier of the U.S. and Canada through this period. Models suggest that some amplification within this regime is possible across the northeast Pacific through the Canadian Rockies, with short wave ridging building inland of the British Columbia coast, downstream of a significant progressive short wave trough over the northeast Pacific. Preceding the latter feature, a weaker short wave is forecast to advance inland of the northern California and Oregon coast, while subtropical ridging (centered near/east of the Colorado Rockies) otherwise maintains a prominent influence across much of the remainder of the West/Rockies and Plains. Downstream of the ridging, the most prominent impulse within the westerlies appears likely to continue rapidly progressing through larger-scale mid/upper troughing, across Quebec/Newfoundland and Labrador and the Canadian Maritimes. Meanwhile, within much weaker troughing at lower latitudes, Hurricane Dorian is expected to, at least initially, continue a slow northeastward migration near the Carolina coast. However, by tonight, an acceleration toward the North Carolina Outer Banks vicinity is forecast, as at least one short wave impulse within the westerlies digs across the Canadian/U.S. border through the Upper Midwest/Great Lakes region. Seasonably moist air has largely become confined to portions of the Southwest, Deep South Texas, and Southeast coastal areas, to the north and west of Dorian, and in the wake of an initial surface front which has advanced off the New England and northern Mid Atlantic coast, as well as into the lower Ohio/lower and middle Missouri Valleys. Considerable further drying into and through the Southeast and Gulf Coast appears likely today through tonight, in the wake of Dorian. However, substantive northward moisture return does appear possible ahead of the troughing advancing inland of the Pacific coast. ...Carolina coastal areas... Potential for convection capable of producing tornadoes will largely hinge on the inland advection of tropical boundary layer moisture, now present offshore, as evolving clockwise curved low-level hodographs become characterized by strong to extreme shear in the right front quadrant (with respect to storm motion) of Dorian. Based on the most probable track of the low-level cyclonic circulation center, this may come close to coastal areas, but could remain mostly offshore through this period. There may be some window of opportunity for increasing potential for tornadoes near northeastern South Carolina and southern North Carolina coastal areas this morning into midday, then mainly near the North Carolina Outer Banks vicinity later today through tonight, as the hurricane turns northeastward and roughly parallels the coast. ...Upper Midwest... Scattered thunderstorm development, in the presence of steep lower/mid tropospheric lapse rates and strong vertical shear within the convective layer, may pose a risk for marginally severe hail and wind. This will largely be focused along a zone of enhanced lower/mid tropospheric warm advection, associated with a couple of digging shortwaves within increasingly northwesterly mid-level flow. ...Near/east of the Oregon Cascades... Stronger mid/upper forcing for ascent associated with the inland progressing short wave, in combination with strengthening southwesterly mid-level flow (30-40 kt around 500 mb), deep boundary layer mixing and destabilization aided by mid-level moistening, may provide support for scattered afternoon storms which could pose a risk for marginally severe hail and strong wind gusts. ..Kerr/Bentley.. 09/05/2019 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0746 PM CDT Wed Sep 04 2019 Valid 050100Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS LATE TONIGHT ACROSS NORTHEASTERN SOUTH CAROLINA AND SOUTHERN NORTH CAROLINA COASTAL AREAS... ...SUMMARY... The potential for a couple of tornadoes may increase late tonight near northeastern South Carolina and southern North Carolina coastal areas. ...01Z Outlook Update... ...South Atlantic Coast... At least some evaporative cooling, within steady convective precipitation to the north and west of the center of Dorian, is maintaining a relatively cool and stable (as suggested by latest observational data and objective analysis) boundary layer across much of South Carolina and Georgia coastal areas and offshore waters. Based on the expected slow north-northeastward motion of Dorian, there might not be much change overnight. However, toward 12Z, near surface flow may gradually take on a more substantive easterly component (as opposed to northeasterly) near northeastern South Carolina/southern North Carolina coastal areas, accompanied by an influx of tropical boundary layer air (including mid/upper 70s surface dew points ) which could become more conducive to tornado potential in the presence of enlarging low-level hodographs (becoming characterized by strong to extreme shear). ...Northern Plains... A low amplitude short wave trough over southern Saskatchewan is forecast to turn eastward and southeastward across into the eastern North Dakota/Minnesota international border area by daybreak. Models suggest that this may be accompanied by a zone of strengthening lower/mid tropospheric warm advection across parts of eastern North Dakota into northwestern Minnesota by 06-08Z, with CAPE for moistening parcels rooted within this layer increasing in excess of 1000 J/kg. Coupled with moderately strong, unidirectional shear within the convective layer, the environment could become conducive storms posing at least some risk for severe hail. ..Kerr.. 09/05/2019 Read more

WW 0634 Status Updates
000-050040- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 S ABE TO 15 SSE EWR TO 5 SW JFK TO 25 W BDR TO 10 N BDR TO 15 WNW GON TO 20 NNE GON TO 5 WSW PVD. ..GLEASON..09/04/19 ATTN...WFO...OKX...BOX...ALY...GYX...PHI...BGM...BTV... STATUS REPORT FOR WS 634 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-007-009-011-050040- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD MIDDLESEX NEW HAVEN NEW LONDON NJC021-023-025-050040- NJ . NEW JERSEY COUNTIES INCLUDED ARE MERCER MIDDLESEX MONMOUTH NYC059-103-050040- NY . NEW YORK COUNTIES INCLUDED ARE NASSAU SUFFOLK Read more

WW 634 SEVERE TSTM CT MA ME NH NJ NY PA RI VT CW 041650Z - 050100Z
0-050100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 634 NWS Storm Prediction Center Norman OK 1250 PM EDT Wed Sep 4 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Massachusetts Southern Maine New Hampshire Northern New Jersey Southern and Eastern New York Eastern Pennsylvania Rhode Island Southern Vermont Coastal Waters * Effective this Wednesday afternoon and evening from 1250 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...Multiple corridors of intensifying thunderstorm development are expected this afternoon along and ahead of a cold front. Adequate instability along with very strong deep-layer winds will yield the potential for storms capable of damaging winds and some hail. A tornado or two cannot be ruled out mainly across southeast New York into southern New England. The severe risk will diminish from west to east across the region by early/mid-evening. The severe thunderstorm watch area is approximately along and 100 statute miles east and west of a line from 30 miles north of Laconia NH to 35 miles east southeast of Allentown PA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 450. Mean storm motion vector 28030. ...Guyer Read more

No Mesoscale Discussions are in effect as of Wed Sep 4 22:36:06 UTC 2019.

WW 0634 Status Updates
000-042340- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 NNW PHL TO 25 SSW POU TO 25 SSW ORH TO 30 NNW BOS TO 25 SE PSM. ..GLEASON..09/04/19 ATTN...WFO...OKX...BOX...ALY...GYX...PHI...BGM...BTV... STATUS REPORT FOR WS 634 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-007-009-011-013-015-042340- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MAC009-017-027-042340- MA . MASSACHUSETTS COUNTIES INCLUDED ARE ESSEX MIDDLESEX WORCESTER NJC003-013-017-019-021-023-025-027-031-035-039-042340- NJ . NEW JERSEY COUNTIES INCLUDED ARE BERGEN ESSEX HUDSON HUNTERDON MERCER MIDDLESEX Read more

WW 634 SEVERE TSTM CT MA ME NH NJ NY PA RI VT CW 041650Z - 050100Z
0-050100- URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 634 NWS Storm Prediction Center Norman OK 1250 PM EDT Wed Sep 4 2019 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Connecticut Massachusetts Southern Maine New Hampshire Northern New Jersey Southern and Eastern New York Eastern Pennsylvania Rhode Island Southern Vermont Coastal Waters * Effective this Wednesday afternoon and evening from 1250 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...Multiple corridors of intensifying thunderstorm development are expected this afternoon along and ahead of a cold front. Adequate instability along with very strong deep-layer winds will yield the potential for storms capable of damaging winds and some hail. A tornado or two cannot be ruled out mainly across southeast New York into southern New England. The severe risk will diminish from west to east across the region by early/mid-evening. The severe thunderstorm watch area is approximately along and 100 statute miles east and west of a line from 30 miles north of Laconia NH to 35 miles east southeast of Allentown PA. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU4). 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 450. Mean storm motion vector 28030. ...Guyer Read more

WW 0634 Status Updates
000-042140- STATUS REPORT ON WW 634 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 SE IPT TO 10 WNW POU TO 15 ESE PSF TO 15 SE MWN. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1925 ..MOSIER..09/04/19 ATTN...WFO...OKX...BOX...ALY...GYX...PHI...BGM...BTV... STATUS REPORT FOR WS 634 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS CTC001-003-005-007-009-011-013-015-042140- CT . CONNECTICUT COUNTIES INCLUDED ARE FAIRFIELD HARTFORD LITCHFIELD MIDDLESEX NEW HAVEN NEW LONDON TOLLAND WINDHAM MEC005-031-042140- ME . MAINE COUNTIES INCLUDED ARE CUMBERLAND YORK MAC009-011-013-015-017-027-042140- MA . MASSACHUSETTS COUNTIES INCLUDED ARE Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Sep 04 2019 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHEAST/NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a couple tornadoes remain possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Discussion... Latest forecast areas, and reasoning, appear to remain valid for this outlook update. Aside from tweaks of the probability areas over the Northeast, to account for progression of ongoing convection, no substantive changes to the outlook appear necessary at this time. ..Goss.. 09/04/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Wed Sep 04 2019/ ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Sep 04 2019 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHEAST/NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a couple tornadoes remain possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Discussion... Latest forecast areas, and reasoning, appear to remain valid for this outlook update. Aside from tweaks of the probability areas over the Northeast, to account for progression of ongoing convection, no substantive changes to the outlook appear necessary at this time. ..Goss.. 09/04/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Wed Sep 04 2019/ ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0258 PM CDT Wed Sep 04 2019 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE NORTHEAST/NEW ENGLAND... ...SUMMARY... Scattered damaging winds and a couple tornadoes remain possible through about 8 PM EDT across parts of the Mid-Atlantic States and New England. A few tornadoes may occur along the coast of South Carolina, mainly tonight through early Thursday morning. ...Discussion... Latest forecast areas, and reasoning, appear to remain valid for this outlook update. Aside from tweaks of the probability areas over the Northeast, to account for progression of ongoing convection, no substantive changes to the outlook appear necessary at this time. ..Goss.. 09/04/2019 .PREV DISCUSSION... /ISSUED 1124 AM CDT Wed Sep 04 2019/ ...Mid-Atlantic/Northeast States and New England... At least isolated severe thunderstorms are expected across the region this afternoon into early/mid-evening. A shortwave trough centered over Lake Ontario at midday will steadily progress eastward toward northern New England by early evening. An attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with the trailing portion extending southwest across the central Appalachians through peak heating. Ahead of the cold front, mid 60s F surface dew points are prevalent from Connecticut/Rhode Island southwest into the Mid-Atlantic States where low 70s F are more common. As a plume of steeper mid-level lapse rates sampled by the 12Z Pittsburgh sounding spreads east, MLCAPE of 750-1500 J/kg should develop amid pockets of greater insolation in the lee of the Appalachians. Consistent with upstream regional 12Z soundings, strengthening mid-level (700-500 mb) southwesterly winds will overspread the region, particularly from Pennsylvania/New Jersey northeastward, with more modest flow aloft to the southwest. As storms develop/mature, the setup will support some initial supercells, and otherwise, multiple clusters/line segments with embedded supercell structures, particularly from northeast Pennsylvania/northern New Jersey across southern New England. Damaging winds will be the most common risk given the strength of the low/mid-level winds, but isolated marginally severe hail could also occur. There is also the potential for a couple of tornadoes, mainly across interior southeast New York and much of southern New England where the greatest combination of moderate low-level SRH and buoyancy are expected. The severe risk should gradually wane/move offshore by the mid-evening hours. ...Coastal Georgia/Carolinas... Hurricane Dorian will continue slowly north off the Florida/Georgia coast and approach coastal South Carolina by 12Z Thursday; reference NHC for the latest forecast details. The overall tornado threat is expected to remain limited along the Georgia/South Carolina coast through the afternoon. A greater potential for a few tornadoes should develop this evening into the overnight across coastal South Carolina as low-level northeasterly winds substantially strengthen and hodographs enlarge within the favored northeast quadrant of Dorian. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of South Carolina into far southern North Carolina. ...Deep South TX... TC Fernand will continue west across far northeast Mexico per latest NHC forecasts. Moderate low-level easterly flow will support adequate SRH for perhaps a brief tornado and/or isolated thunderstorm wind damage with scattered convection that persists from the northwest Gulf across Deep South Texas. This flow should gradually subside during the evening, limiting the severe storm risk tonight onward. ...North Dakota/northern Minnesota... A low-amplitude shortwave trough near the BC/AB/MT border will move east along the international border towards the Lake of the Woods region by 12Z Thursday. 700-mb warm advection will strengthen across northeast North Dakota into northwest Minnesota tonight. A cluster of elevated storms may evolve southeast from southeast SK/southwest MB overnight. Thin buoyancy will be a limiting factor, but robust speed shear within the cloud-bearing layer could support a few instances of marginally severe hail. ...Central High Plains... While particularly organized/sustained severe storms are not currently expected, a very isolated severe storm or two cannot be ruled across the region late this afternoon and early evening near the surface boundary/lee trough across the region. Neither deep-layer shear/buoyancy will be strong, but adequate moisture coincident with steep lapse rates and 25-30 kt effective shear could support some stronger updrafts/downdrafts capable of marginally severe hail and/or wind gusts. Any such risk appears most probable across northeast Colorado into southeast Wyoming and the southern Nebraska Panhandle. ...Arizona/Lower Colorado River Valley... Thunderstorm coverage may remain limited across the lower elevations of Arizona where a relatively greater reservoir of moisture/buoyancy will exist (particularly southwest Arizona). However, if/where storms develop later today, modest easterly steering flow and the hot/well-mixed nature of the boundary layer could conditionally support some stronger wind gusts, although the overall organized severe potential currently appears low. Read more