Severe Storms

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2019 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES AND COASTAL SOUTH CAROLINA... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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. ...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. ..Guyer/Nauslar.. 09/04/2019 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1124 AM CDT Wed Sep 04 2019 Valid 041630Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE NORTHEAST STATES AND COASTAL SOUTH CAROLINA... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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. ...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. ..Guyer/Nauslar.. 09/04/2019 Read more

No watches are valid as of Wed Sep 4 15:21:01 UTC 2019.

MD 1924 CONCERNING SEVERE POTENTIAL...WATCH LIKELY FOR PORTIONS OF CENTRAL/EASTERN NY...VT...NH...WESTERN ME...MA...CT...AND FAR NORTHEAST PA
Mesoscale Discussion 1924 NWS Storm Prediction Center Norman OK 1019 AM CDT Wed Sep 04 2019 Areas affected...Portions of Central/Eastern NY...VT...NH...Western ME...MA...CT...and Far Northeast PA Concerning...Severe potential...Watch likely Valid 041519Z - 041715Z Probability of Watch Issuance...80 percent SUMMARY...Increasing thunderstorm coverage is anticipated over the next several hours. Damaging wind gusts are the primary severe threat but a couple tornadoes are also possible. A watch will eventually be needed for portions of the region. DISCUSSION...Recent surface analysis places a cold front from SLK (in far northern NY) southwestward across central NY to just east of BFD (in far north-central PA). Radar trends have shown gradually increasing intensity of the cells along the front in south-central NY as they move into a diurnally destabilizing and modestly buoyant air mass downstream. Ongoing moisture advection has lead to an 2-4 degree increase in dewpoints downstream across the Hudson Valley and this general trends is expected to continue, leading to air-mass destabilization ahead of the front as far north as northeast NY, VT, NH, and western ME. At the same time, strengthening large-scale forcing for ascent attendant to the shortwave trough moving into the Northeast will augment the frontal forcing already occurring. The combination of this increased forcing for ascent and air-mass destabilization is expected to result in expanding thunderstorm coverage over the next few hours. Even with the modest buoyancy, strong vertical shear will provide a kinematic environment supportive of organized storms. Primary threat will be damaging wind gusts associated with bowing line segments. However, given the southerly flow across southeastern NY and southern New England, some tornado threat also exists, especially with any more discrete cells ahead of the front. A watch will likely be needed by early afternoon, particularly over eastern NY and New England. ..Mosier/Guyer.. 09/04/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GYX...BOX...BTV...OKX...ALY...PHI...BGM...CTP... LAT...LON 41747693 42387681 43827469 44847352 44597056 42547148 41537287 41317494 41747693 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Sep 04 2019 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE NORTHEAST AND COASTAL SC... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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 morning Thursday. ...Mid-Atlantic States and New England... A shortwave trough from southwest QC to the Lower Great Lakes will progress east with trailing portion shifting across New England this evening. Attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with trailing portion arcing southwest across the central Appalachians. Ongoing convection within the warm conveyor just ahead of the front should persist east, with additional development expected in its immediate wake along the front by midday. Mid 60s to low 70s surface dew points are prevalent from CT/RI southwest into the Mid-Atlantic States. 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. Strong 700-500 mb southwesterlies will prevail from PA/NJ northeastward, with more modest flow to the southwest. This setup should favor multiple clusters/line segments with embedded supercell structures, most likely from eastern PA/NJ into southwest ME. Damaging winds will probably be the main threat given the strength of the low/mid-level flow, but isolated marginally severe hail could also occur. A couple tornadoes are possible, centered on the corridor with the greatest combination of moderate low-level SRH and buoyancy from southeast NY to NH. ...SC Coast and vicinity... Hurricane Dorian is expected to continue slowly north off the FL/GA coast and approach coastal SC by 12Z Thursday. The overall tornado threat is expected to remain limited through this afternoon along the GA/SC coast. Greater potential for a few tornadoes should develop this evening into the overnight across coastal SC as low-level northeasterlies substantially strengthen and hodographs enlarge within the favored northeast quadrant. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of SC into far southern NC. ...Deep South TX... TC Fernand will continue west across far northeast Mexico. 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 TX. This flow should subside during the evening, limiting the severe storm risk tonight. ...Red River Valley of the North.. 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 ND into northwest MN 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. ..Grams/Smith.. 09/04/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Sep 04 2019 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE NORTHEAST AND COASTAL SC... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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 morning Thursday. ...Mid-Atlantic States and New England... A shortwave trough from southwest QC to the Lower Great Lakes will progress east with trailing portion shifting across New England this evening. Attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with trailing portion arcing southwest across the central Appalachians. Ongoing convection within the warm conveyor just ahead of the front should persist east, with additional development expected in its immediate wake along the front by midday. Mid 60s to low 70s surface dew points are prevalent from CT/RI southwest into the Mid-Atlantic States. 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. Strong 700-500 mb southwesterlies will prevail from PA/NJ northeastward, with more modest flow to the southwest. This setup should favor multiple clusters/line segments with embedded supercell structures, most likely from eastern PA/NJ into southwest ME. Damaging winds will probably be the main threat given the strength of the low/mid-level flow, but isolated marginally severe hail could also occur. A couple tornadoes are possible, centered on the corridor with the greatest combination of moderate low-level SRH and buoyancy from southeast NY to NH. ...SC Coast and vicinity... Hurricane Dorian is expected to continue slowly north off the FL/GA coast and approach coastal SC by 12Z Thursday. The overall tornado threat is expected to remain limited through this afternoon along the GA/SC coast. Greater potential for a few tornadoes should develop this evening into the overnight across coastal SC as low-level northeasterlies substantially strengthen and hodographs enlarge within the favored northeast quadrant. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of SC into far southern NC. ...Deep South TX... TC Fernand will continue west across far northeast Mexico. 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 TX. This flow should subside during the evening, limiting the severe storm risk tonight. ...Red River Valley of the North.. 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 ND into northwest MN 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. ..Grams/Smith.. 09/04/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Sep 04 2019 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE NORTHEAST AND COASTAL SC... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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 morning Thursday. ...Mid-Atlantic States and New England... A shortwave trough from southwest QC to the Lower Great Lakes will progress east with trailing portion shifting across New England this evening. Attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with trailing portion arcing southwest across the central Appalachians. Ongoing convection within the warm conveyor just ahead of the front should persist east, with additional development expected in its immediate wake along the front by midday. Mid 60s to low 70s surface dew points are prevalent from CT/RI southwest into the Mid-Atlantic States. 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. Strong 700-500 mb southwesterlies will prevail from PA/NJ northeastward, with more modest flow to the southwest. This setup should favor multiple clusters/line segments with embedded supercell structures, most likely from eastern PA/NJ into southwest ME. Damaging winds will probably be the main threat given the strength of the low/mid-level flow, but isolated marginally severe hail could also occur. A couple tornadoes are possible, centered on the corridor with the greatest combination of moderate low-level SRH and buoyancy from southeast NY to NH. ...SC Coast and vicinity... Hurricane Dorian is expected to continue slowly north off the FL/GA coast and approach coastal SC by 12Z Thursday. The overall tornado threat is expected to remain limited through this afternoon along the GA/SC coast. Greater potential for a few tornadoes should develop this evening into the overnight across coastal SC as low-level northeasterlies substantially strengthen and hodographs enlarge within the favored northeast quadrant. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of SC into far southern NC. ...Deep South TX... TC Fernand will continue west across far northeast Mexico. 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 TX. This flow should subside during the evening, limiting the severe storm risk tonight. ...Red River Valley of the North.. 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 ND into northwest MN 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. ..Grams/Smith.. 09/04/2019 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0752 AM CDT Wed Sep 04 2019 Valid 041300Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE NORTHEAST AND COASTAL SC... ...SUMMARY... Scattered damaging winds and a couple tornadoes are 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 morning Thursday. ...Mid-Atlantic States and New England... A shortwave trough from southwest QC to the Lower Great Lakes will progress east with trailing portion shifting across New England this evening. Attendant surface cold front will reach the Champlain and Hudson Valleys by afternoon with trailing portion arcing southwest across the central Appalachians. Ongoing convection within the warm conveyor just ahead of the front should persist east, with additional development expected in its immediate wake along the front by midday. Mid 60s to low 70s surface dew points are prevalent from CT/RI southwest into the Mid-Atlantic States. 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. Strong 700-500 mb southwesterlies will prevail from PA/NJ northeastward, with more modest flow to the southwest. This setup should favor multiple clusters/line segments with embedded supercell structures, most likely from eastern PA/NJ into southwest ME. Damaging winds will probably be the main threat given the strength of the low/mid-level flow, but isolated marginally severe hail could also occur. A couple tornadoes are possible, centered on the corridor with the greatest combination of moderate low-level SRH and buoyancy from southeast NY to NH. ...SC Coast and vicinity... Hurricane Dorian is expected to continue slowly north off the FL/GA coast and approach coastal SC by 12Z Thursday. The overall tornado threat is expected to remain limited through this afternoon along the GA/SC coast. Greater potential for a few tornadoes should develop this evening into the overnight across coastal SC as low-level northeasterlies substantially strengthen and hodographs enlarge within the favored northeast quadrant. This may yield a few low-topped supercells within one or more outer bands that approach the immediate coast of SC into far southern NC. ...Deep South TX... TC Fernand will continue west across far northeast Mexico. 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 TX. This flow should subside during the evening, limiting the severe storm risk tonight. ...Red River Valley of the North.. 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 ND into northwest MN 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. ..Grams/Smith.. 09/04/2019 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Wed Sep 04 2019 Valid 071200Z - 121200Z ...DISCUSSION... Model consensus is that upper synoptic pattern will transition to quasi-zonal day 4, but with general trend toward establishing a trough in the west day 5. A low-amplitude shortwave trough will emerge over the northern Plains day 4 (Saturday), but forcing with this feature should remain on cool side of a front that will reside across the central Plains. Storms developing in vicinity of this boundary might pose a marginal severe threat Saturday afternoon and evening. Day 5 (Sunday) upper ridging will build across the Plains, while a shortwave trough moves through the Great Basin and central Rockies. Warm advection storms may develop on the cool side of the stationary front across the central and northern Plains, but severe threat should remain limited. Severe potential might increase over the central/northern Plains day 6 (Monday) in association with an ejecting shortwave trough. However, antecedent conditions will be characterized by widespread storms developing north of a warm front which lowers confidence in destabilization potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Wed Sep 04 2019 Valid 071200Z - 121200Z ...DISCUSSION... Model consensus is that upper synoptic pattern will transition to quasi-zonal day 4, but with general trend toward establishing a trough in the west day 5. A low-amplitude shortwave trough will emerge over the northern Plains day 4 (Saturday), but forcing with this feature should remain on cool side of a front that will reside across the central Plains. Storms developing in vicinity of this boundary might pose a marginal severe threat Saturday afternoon and evening. Day 5 (Sunday) upper ridging will build across the Plains, while a shortwave trough moves through the Great Basin and central Rockies. Warm advection storms may develop on the cool side of the stationary front across the central and northern Plains, but severe threat should remain limited. Severe potential might increase over the central/northern Plains day 6 (Monday) in association with an ejecting shortwave trough. However, antecedent conditions will be characterized by widespread storms developing north of a warm front which lowers confidence in destabilization potential. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0345 AM CDT Wed Sep 04 2019 Valid 071200Z - 121200Z ...DISCUSSION... Model consensus is that upper synoptic pattern will transition to quasi-zonal day 4, but with general trend toward establishing a trough in the west day 5. A low-amplitude shortwave trough will emerge over the northern Plains day 4 (Saturday), but forcing with this feature should remain on cool side of a front that will reside across the central Plains. Storms developing in vicinity of this boundary might pose a marginal severe threat Saturday afternoon and evening. Day 5 (Sunday) upper ridging will build across the Plains, while a shortwave trough moves through the Great Basin and central Rockies. Warm advection storms may develop on the cool side of the stationary front across the central and northern Plains, but severe threat should remain limited. Severe potential might increase over the central/northern Plains day 6 (Monday) in association with an ejecting shortwave trough. However, antecedent conditions will be characterized by widespread storms developing north of a warm front which lowers confidence in destabilization potential. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Wed Sep 04 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST MONTANA...NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts and hail will be possible from southeast Montana, northeast Wyoming into far western South Dakota Friday. ...Southeast Montana, northeast Wyoming and western South Dakota... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Downstream from this feature, a narrow corridor of low 50s F dewpoints should reside from eastern WY, southeast MT into western SD beneath steep mid-level lapse rates supporting 1500 J/kg MLCAPE. Widely scattered storms will likely develop over the higher terrain and spread east into a portion of the High Plains. The stronger winds aloft will likely remain west of the corridor of greater instability with generally weak vertical shear supportive of multicells. A few of the storms may produce locally strong wind gusts and marginally severe hail through mid evening. ...North Carolina Coast... Dorian is forecast by the National Hurricane center to be off the northern NC coast early Friday and continue northeast away from shore during the day. Therefore, the tornado threat inland should remain low. ..Dial.. 09/04/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0208 AM CDT Wed Sep 04 2019 Valid 061200Z - 071200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHEAST MONTANA...NORTHEAST WYOMING AND WESTERN SOUTH DAKOTA... ...SUMMARY... A few thunderstorms capable of isolated strong wind gusts and hail will be possible from southeast Montana, northeast Wyoming into far western South Dakota Friday. ...Southeast Montana, northeast Wyoming and western South Dakota... A shortwave trough will suppress the northern periphery of an upper ridge and continue through the northern Rockies Friday. Downstream from this feature, a narrow corridor of low 50s F dewpoints should reside from eastern WY, southeast MT into western SD beneath steep mid-level lapse rates supporting 1500 J/kg MLCAPE. Widely scattered storms will likely develop over the higher terrain and spread east into a portion of the High Plains. The stronger winds aloft will likely remain west of the corridor of greater instability with generally weak vertical shear supportive of multicells. A few of the storms may produce locally strong wind gusts and marginally severe hail through mid evening. ...North Carolina Coast... Dorian is forecast by the National Hurricane center to be off the northern NC coast early Friday and continue northeast away from shore during the day. Therefore, the tornado threat inland should remain low. ..Dial.. 09/04/2019 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0138 AM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ..Squitieri.. 09/04/2019 ...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 0138 AM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...NO CRITICAL AREAS... ...Synopsis... A mid-level ridge will remain fortified across the western CONUS, with a pronounced mid-level shortwave trough traversing the northern California/Pacific Northwest vicinity on Day 2/Thursday. Deep-layer ascent associated with the aforementioned trough will promote isolated to potentially scattered thunderstorm development throughout much of the afternoon and evening hours, with a couple of storms producing dry strikes. ...Northern California into the Pacific Northwest and northwestern Great Basin... Isolated to potentially scattered thunderstorm development is expected by mid-afternoon, as the aforementioned shortwave trough impinges on the area. While copious lightning may accompany the longer-lived, more organized storms, precipitable water values approaching 1 inch and clustering/training of stronger storm cores suggests that wetting rainfall may be abundant, despite faster storm motions and high cloud bases. An isolated dry thunderstorm delineation was withheld at this time given the amount of wetting rains possible. Nonetheless, at least a few dry strikes may occur, with potential fire starts aggravated by erratic gusty winds associated with the stronger storms. Please see the Day 2 Convective Outlook for more information regarding the severe wind threat. ..Squitieri.. 09/04/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0110 AM CDT Wed Sep 04 2019 Valid 041200Z - 051200Z CORRECTED FOR GRAPHIC ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ..Squitieri.. 09/04/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0110 AM CDT Wed Sep 04 2019 Valid 041200Z - 051200Z CORRECTED FOR GRAPHIC ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ..Squitieri.. 09/04/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook CORR 1 NWS Storm Prediction Center Norman OK 0110 AM CDT Wed Sep 04 2019 Valid 041200Z - 051200Z CORRECTED FOR GRAPHIC ...Synopsis... A mid-level ridge will hold firm across the western CONUS. Nonetheless, a mid-level shortwave trough embedded in the larger scale flow will crest the ridge and traverse the northern Rockies, encouraging a mass response for surface dry, breezy conditions, which may be favorable for some wildfire-spread. Also, a second mid-level impulse will impinge on the California coastline, promoting deep-layer ascent across northern portions of California into the western Great Basin, where at least isolated thunderstorm potential will exist. ...Northern and central Rockies... By peak afternoon heating, the surface isallobaric response to a glancing mid-level shortwave, combined with boundary layer mixing of the stronger flow aloft to the surface, will foster 15-20 mph sustained westerly surface winds and 15-25% RH. Finer fuels have sufficiently dried across the region to support at least modest wildfire-spread potential, with an elevated area remaining in place across parts of northern Montana. At least localized elevated conditions may also occur farther south to the Montana/Idaho border, but the patchy and brief nature of these conditions precludes a delineation across this area at this time. Widespread 10-15 mph westerly winds and critically low RH are expected across portions of central into eastern Wyoming during the afternoon as well. While fuels have recently become receptive to fire spread across portions of this area, model guidance struggles to show more widespread winds exceeding 15 mph, hence no elevated delineation at this time, though trends will continue to be monitored for a possible elevated area addition in the next forecast update. ...Northern California into the western Great Basin... Storms are first expected to initiate mainly across northern Nevada by afternoon peak heating. Later, storms are expected to initiate across northern California during the evening/overnight hours. Modest storm motions and wetting rainfall may be the biggest inhibiting factors to a more robust lightning-induced fire threat. Nonetheless, precipitable water values in the 0.50-0.75 inch range will foster at least isolated dry strikes on the peripheral of updrafts atop near-critical to critically dry fuels. As such, maintaining an isolated dry thunderstorm delineation across northern California into the western Great Basin appears warranted. ..Squitieri.. 09/04/2019 ...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 1229 AM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EXTREME NORTHEAST SOUTH CAROLINA COAST THROUGH COASTAL NORTH CAROLINA... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Eastern Carolinas... Hurricane Dorian is forecast by the National Hurricane Center (NHC) to be located just off the central South Carolina coast Thursday morning and off southeast North Carolina coast Thursday evening. Based on this forecast, increasingly large low-level hodographs north of the center will evolve across northeast South Carolina and eastern North Carolina where very moist onshore winds will result in modest buoyancy. Mini supercells developing north of the center over the Gulf Stream and moving onshore will be capable of producing isolated tornadoes, especially along and inland of the North Carolina coast. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream from a shortwave trough that will move inland later Thursday afternoon and evening. Dewpoints will mix down into the 40s F during the day with inverted-V boundary layers and MLCAPE of 500 J/kg. Destabilization and increasing forcing for ascent downstream from the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. Effective bulk shear will increase to 35-40 kt with approach of the trough supporting potential for a few storms to develop mid-level rotation. Isolated downburst winds and possibly hail may occur with the stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Dial.. 09/04/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 AM CDT Wed Sep 04 2019 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE EXTREME NORTHEAST SOUTH CAROLINA COAST THROUGH COASTAL NORTH CAROLINA... ...SUMMARY... Isolated tornadoes will be possible Thursday in association with Hurricane Dorian from northern coastal South Carolina through coastal North Carolina. Isolated downburst winds will be possible over a portion of western and central Oregon Thursday afternoon. ...Eastern Carolinas... Hurricane Dorian is forecast by the National Hurricane Center (NHC) to be located just off the central South Carolina coast Thursday morning and off southeast North Carolina coast Thursday evening. Based on this forecast, increasingly large low-level hodographs north of the center will evolve across northeast South Carolina and eastern North Carolina where very moist onshore winds will result in modest buoyancy. Mini supercells developing north of the center over the Gulf Stream and moving onshore will be capable of producing isolated tornadoes, especially along and inland of the North Carolina coast. ...Western and central Oregon... Steep mid-level lapse rates will spread across Oregon downstream from a shortwave trough that will move inland later Thursday afternoon and evening. Dewpoints will mix down into the 40s F during the day with inverted-V boundary layers and MLCAPE of 500 J/kg. Destabilization and increasing forcing for ascent downstream from the shortwave trough will support at least isolated high-based storms developing later during the afternoon and evening. Effective bulk shear will increase to 35-40 kt with approach of the trough supporting potential for a few storms to develop mid-level rotation. Isolated downburst winds and possibly hail may occur with the stronger storms. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 5% - Marginal Hail: 5% - Marginal ..Dial.. 09/04/2019 Read more