Aggregator

...JULIETTE STRENGTHENS... ...EXPECTED TO BECOME A HURRICANE LATER TODAY... As of 3:00 AM MDT Mon Sep 2 the center of Juliette was located near 16.2, -111.8 with movement WNW at 14 mph. The minimum central pressure was 997 mb with maximum sustained winds of about 65 mph.

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 02 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE IMMEDIATE CAROLINA COAST AND FOR PORTIONS OF NEW ENGLAND... ...SUMMARY... A couple of tornadoes are possible near the immediate Carolina coast mainly Wednesday afternoon through Wednesday night. Isolated damaging gusts are possible Wednesday in New England. ...Synopsis... A broad, progressive mid-level trough will move across southeastern Canada and New England on Wednesday while a mid-level anticyclone moves little over the south-central U.S. Hurricane Dorian is forecast to approach the southeastern U.S. coastline according to the latest National Hurricane Center forecast. ...Carolina coast... Confidence is gradually increasing that the outer spiral convective bands will move ashore the Carolina coast on Wednesday and especially Wednesday night into early Thursday morning. If this scenario unfolds, increasing low-level shear within a maritime tropical airmass yielding weak buoyancy, may promote mini supercell development and a risk for tornadoes. Please monitor National Hurricane Center forecasts for the latest forecast movement of Hurricane Dorian as it approaches the Southeast U.S. ...New England... A surface low over central Quebec is forecast to develop northeast during the day as a cold front over the lower Great Lakes pushes east into New England. During the morning, showers/thunderstorms are forecast initially over the Adirondacks into the St. Lawrence Valley. This activity or outflow will gradually move east with heating contributing to a weakly unstable airmass. Strong deep-layer shear could act to organize the scattered thunderstorms into a band moving east across Maine and into portions of southern New England. Damaging gusts are the primary severe risk. ..Smith.. 09/02/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 02 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE IMMEDIATE CAROLINA COAST AND FOR PORTIONS OF NEW ENGLAND... ...SUMMARY... A couple of tornadoes are possible near the immediate Carolina coast mainly Wednesday afternoon through Wednesday night. Isolated damaging gusts are possible Wednesday in New England. ...Synopsis... A broad, progressive mid-level trough will move across southeastern Canada and New England on Wednesday while a mid-level anticyclone moves little over the south-central U.S. Hurricane Dorian is forecast to approach the southeastern U.S. coastline according to the latest National Hurricane Center forecast. ...Carolina coast... Confidence is gradually increasing that the outer spiral convective bands will move ashore the Carolina coast on Wednesday and especially Wednesday night into early Thursday morning. If this scenario unfolds, increasing low-level shear within a maritime tropical airmass yielding weak buoyancy, may promote mini supercell development and a risk for tornadoes. Please monitor National Hurricane Center forecasts for the latest forecast movement of Hurricane Dorian as it approaches the Southeast U.S. ...New England... A surface low over central Quebec is forecast to develop northeast during the day as a cold front over the lower Great Lakes pushes east into New England. During the morning, showers/thunderstorms are forecast initially over the Adirondacks into the St. Lawrence Valley. This activity or outflow will gradually move east with heating contributing to a weakly unstable airmass. Strong deep-layer shear could act to organize the scattered thunderstorms into a band moving east across Maine and into portions of southern New England. Damaging gusts are the primary severe risk. ..Smith.. 09/02/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 02 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE IMMEDIATE CAROLINA COAST AND FOR PORTIONS OF NEW ENGLAND... ...SUMMARY... A couple of tornadoes are possible near the immediate Carolina coast mainly Wednesday afternoon through Wednesday night. Isolated damaging gusts are possible Wednesday in New England. ...Synopsis... A broad, progressive mid-level trough will move across southeastern Canada and New England on Wednesday while a mid-level anticyclone moves little over the south-central U.S. Hurricane Dorian is forecast to approach the southeastern U.S. coastline according to the latest National Hurricane Center forecast. ...Carolina coast... Confidence is gradually increasing that the outer spiral convective bands will move ashore the Carolina coast on Wednesday and especially Wednesday night into early Thursday morning. If this scenario unfolds, increasing low-level shear within a maritime tropical airmass yielding weak buoyancy, may promote mini supercell development and a risk for tornadoes. Please monitor National Hurricane Center forecasts for the latest forecast movement of Hurricane Dorian as it approaches the Southeast U.S. ...New England... A surface low over central Quebec is forecast to develop northeast during the day as a cold front over the lower Great Lakes pushes east into New England. During the morning, showers/thunderstorms are forecast initially over the Adirondacks into the St. Lawrence Valley. This activity or outflow will gradually move east with heating contributing to a weakly unstable airmass. Strong deep-layer shear could act to organize the scattered thunderstorms into a band moving east across Maine and into portions of southern New England. Damaging gusts are the primary severe risk. ..Smith.. 09/02/2019 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 02 2019 Valid 041200Z - 051200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR THE IMMEDIATE CAROLINA COAST AND FOR PORTIONS OF NEW ENGLAND... ...SUMMARY... A couple of tornadoes are possible near the immediate Carolina coast mainly Wednesday afternoon through Wednesday night. Isolated damaging gusts are possible Wednesday in New England. ...Synopsis... A broad, progressive mid-level trough will move across southeastern Canada and New England on Wednesday while a mid-level anticyclone moves little over the south-central U.S. Hurricane Dorian is forecast to approach the southeastern U.S. coastline according to the latest National Hurricane Center forecast. ...Carolina coast... Confidence is gradually increasing that the outer spiral convective bands will move ashore the Carolina coast on Wednesday and especially Wednesday night into early Thursday morning. If this scenario unfolds, increasing low-level shear within a maritime tropical airmass yielding weak buoyancy, may promote mini supercell development and a risk for tornadoes. Please monitor National Hurricane Center forecasts for the latest forecast movement of Hurricane Dorian as it approaches the Southeast U.S. ...New England... A surface low over central Quebec is forecast to develop northeast during the day as a cold front over the lower Great Lakes pushes east into New England. During the morning, showers/thunderstorms are forecast initially over the Adirondacks into the St. Lawrence Valley. This activity or outflow will gradually move east with heating contributing to a weakly unstable airmass. Strong deep-layer shear could act to organize the scattered thunderstorms into a band moving east across Maine and into portions of southern New England. Damaging gusts are the primary severe risk. ..Smith.. 09/02/2019 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0150 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level ridge will remain fortified across the western CONUS, with another mid-level shortwave trough cresting the ridge and traversing the Pacific Northwest during the Day 2/Tuesday period. As such, mildly breezy and dry conditions may be observed east of the Cascades. Deep-layer ascent and marginal instability accompanying the aforementioned shortwave may yield very isolated thunderstorm development across parts of the Pacific Northwest. ...Pacific Northwest... Downslope flow along the lee of the Cascades, particularly in Oregon, may support up to 15 mph sustained westerly winds and 15-20% RH by afternoon peak heating. Currently, the latest model guidance differs in the placement and timing of elevated conditions, precluding a delineation. In addition, enhanced lift may also foster the development of a couple thunderstorms, especially along the lee of the northern Cascades in Washington. Given precipitable water values in the 0.50-0.75 inch range, a dry strike or two cannot be ruled out. ..Squitieri.. 09/02/2019 ...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 0150 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level ridge will remain fortified across the western CONUS, with another mid-level shortwave trough cresting the ridge and traversing the Pacific Northwest during the Day 2/Tuesday period. As such, mildly breezy and dry conditions may be observed east of the Cascades. Deep-layer ascent and marginal instability accompanying the aforementioned shortwave may yield very isolated thunderstorm development across parts of the Pacific Northwest. ...Pacific Northwest... Downslope flow along the lee of the Cascades, particularly in Oregon, may support up to 15 mph sustained westerly winds and 15-20% RH by afternoon peak heating. Currently, the latest model guidance differs in the placement and timing of elevated conditions, precluding a delineation. In addition, enhanced lift may also foster the development of a couple thunderstorms, especially along the lee of the northern Cascades in Washington. Given precipitable water values in the 0.50-0.75 inch range, a dry strike or two cannot be ruled out. ..Squitieri.. 09/02/2019 ...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 0150 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level ridge will remain fortified across the western CONUS, with another mid-level shortwave trough cresting the ridge and traversing the Pacific Northwest during the Day 2/Tuesday period. As such, mildly breezy and dry conditions may be observed east of the Cascades. Deep-layer ascent and marginal instability accompanying the aforementioned shortwave may yield very isolated thunderstorm development across parts of the Pacific Northwest. ...Pacific Northwest... Downslope flow along the lee of the Cascades, particularly in Oregon, may support up to 15 mph sustained westerly winds and 15-20% RH by afternoon peak heating. Currently, the latest model guidance differs in the placement and timing of elevated conditions, precluding a delineation. In addition, enhanced lift may also foster the development of a couple thunderstorms, especially along the lee of the northern Cascades in Washington. Given precipitable water values in the 0.50-0.75 inch range, a dry strike or two cannot be ruled out. ..Squitieri.. 09/02/2019 ...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 0150 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...NO CRITICAL AREAS... ...Synopsis... An upper-level ridge will remain fortified across the western CONUS, with another mid-level shortwave trough cresting the ridge and traversing the Pacific Northwest during the Day 2/Tuesday period. As such, mildly breezy and dry conditions may be observed east of the Cascades. Deep-layer ascent and marginal instability accompanying the aforementioned shortwave may yield very isolated thunderstorm development across parts of the Pacific Northwest. ...Pacific Northwest... Downslope flow along the lee of the Cascades, particularly in Oregon, may support up to 15 mph sustained westerly winds and 15-20% RH by afternoon peak heating. Currently, the latest model guidance differs in the placement and timing of elevated conditions, precluding a delineation. In addition, enhanced lift may also foster the development of a couple thunderstorms, especially along the lee of the northern Cascades in Washington. Given precipitable water values in the 0.50-0.75 inch range, a dry strike or two cannot be ruled out. ..Squitieri.. 09/02/2019 ...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 1230 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE NORTHERN HALF OF ILLINOIS...NORTHERN INDIANA...SOUTHEAST WISCONSIN...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible over the middle Mississippi Valley into the central Great Lakes on Tuesday and Tuesday evening. ...Synopsis... A mid-level trough will move from the Upper Midwest into the central Great Lakes by late afternoon and subsequently into the lower Great Lakes and southeastern Canada late Tuesday night. Farther west, a mid-level anticyclone will be stationary and be centered near Raton Mesa. Hurricane Dorian is forecast to slowly approach the Southeast United States. In the low levels, a cold front is forecast to move southeast across the Midwest and into the lower Great Lakes. ...Great Lakes... Models are in good agreement in a scenario with morning storms over the western Great Lakes in association with a strong southwesterly LLJ. A lingering severe risk may accompany this activity mainly in the form of isolated damaging gusts before dissipating by the late morning. A plume of steep 700-500mb lapse rates will advect northeast into the southern Great Lakes during the day. Despite a capping inversion, convergence near the boundary and strong heating will likely lead to local erosion of the cap and isolated to scattered storm development by late afternoon from northern IL east into southern Lower MI. A moderate to very unstable airmass is progged by guidance with 3000+ J/kg MLCAPE possible across IL and decreasing to 1500 J/kg into Lower MI. Hodographs are forecast to enlarge during the late afternoon/evening across the southern Great Lakes concurrent with diurnal storm development. A mix mode of supercells and multicells capable of all severe hazards are possible primarily during the 21z-03z period. Farther southwest over MO into western IL, lower storm coverage is forecast but large CAPE and a wind profile supportive of organized storms would lend a conditional risk for severe with the stronger storms. ...East Coast of the FL Peninsula (Hurricane Dorian)... Uncertainty remains regarding the eventual track of Hurricane Dorian as it moves into the Gulf Stream waters east of the FL Peninsula Monday night into Tuesday morning. If the northeast quadrant were to overspread the FL Peninsula on Tuesday and/or Tuesday night, then a risk for potential tornadoes would include those areas. At this time, uncertainty is too high to include low-severe probabilities. Please refer to the National Hurricane Center for the latest guidance regarding the forecast track of Hurricane Dorian. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% SIG - Slight Hail: 15% SIG - Slight ..Smith.. 09/02/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE NORTHERN HALF OF ILLINOIS...NORTHERN INDIANA...SOUTHEAST WISCONSIN...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible over the middle Mississippi Valley into the central Great Lakes on Tuesday and Tuesday evening. ...Synopsis... A mid-level trough will move from the Upper Midwest into the central Great Lakes by late afternoon and subsequently into the lower Great Lakes and southeastern Canada late Tuesday night. Farther west, a mid-level anticyclone will be stationary and be centered near Raton Mesa. Hurricane Dorian is forecast to slowly approach the Southeast United States. In the low levels, a cold front is forecast to move southeast across the Midwest and into the lower Great Lakes. ...Great Lakes... Models are in good agreement in a scenario with morning storms over the western Great Lakes in association with a strong southwesterly LLJ. A lingering severe risk may accompany this activity mainly in the form of isolated damaging gusts before dissipating by the late morning. A plume of steep 700-500mb lapse rates will advect northeast into the southern Great Lakes during the day. Despite a capping inversion, convergence near the boundary and strong heating will likely lead to local erosion of the cap and isolated to scattered storm development by late afternoon from northern IL east into southern Lower MI. A moderate to very unstable airmass is progged by guidance with 3000+ J/kg MLCAPE possible across IL and decreasing to 1500 J/kg into Lower MI. Hodographs are forecast to enlarge during the late afternoon/evening across the southern Great Lakes concurrent with diurnal storm development. A mix mode of supercells and multicells capable of all severe hazards are possible primarily during the 21z-03z period. Farther southwest over MO into western IL, lower storm coverage is forecast but large CAPE and a wind profile supportive of organized storms would lend a conditional risk for severe with the stronger storms. ...East Coast of the FL Peninsula (Hurricane Dorian)... Uncertainty remains regarding the eventual track of Hurricane Dorian as it moves into the Gulf Stream waters east of the FL Peninsula Monday night into Tuesday morning. If the northeast quadrant were to overspread the FL Peninsula on Tuesday and/or Tuesday night, then a risk for potential tornadoes would include those areas. At this time, uncertainty is too high to include low-severe probabilities. Please refer to the National Hurricane Center for the latest guidance regarding the forecast track of Hurricane Dorian. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% SIG - Slight Hail: 15% SIG - Slight ..Smith.. 09/02/2019 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1230 AM CDT Mon Sep 02 2019 Valid 031200Z - 041200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR THE NORTHERN HALF OF ILLINOIS...NORTHERN INDIANA...SOUTHEAST WISCONSIN...AND SOUTHERN LOWER MICHIGAN... ...SUMMARY... Severe thunderstorms are possible over the middle Mississippi Valley into the central Great Lakes on Tuesday and Tuesday evening. ...Synopsis... A mid-level trough will move from the Upper Midwest into the central Great Lakes by late afternoon and subsequently into the lower Great Lakes and southeastern Canada late Tuesday night. Farther west, a mid-level anticyclone will be stationary and be centered near Raton Mesa. Hurricane Dorian is forecast to slowly approach the Southeast United States. In the low levels, a cold front is forecast to move southeast across the Midwest and into the lower Great Lakes. ...Great Lakes... Models are in good agreement in a scenario with morning storms over the western Great Lakes in association with a strong southwesterly LLJ. A lingering severe risk may accompany this activity mainly in the form of isolated damaging gusts before dissipating by the late morning. A plume of steep 700-500mb lapse rates will advect northeast into the southern Great Lakes during the day. Despite a capping inversion, convergence near the boundary and strong heating will likely lead to local erosion of the cap and isolated to scattered storm development by late afternoon from northern IL east into southern Lower MI. A moderate to very unstable airmass is progged by guidance with 3000+ J/kg MLCAPE possible across IL and decreasing to 1500 J/kg into Lower MI. Hodographs are forecast to enlarge during the late afternoon/evening across the southern Great Lakes concurrent with diurnal storm development. A mix mode of supercells and multicells capable of all severe hazards are possible primarily during the 21z-03z period. Farther southwest over MO into western IL, lower storm coverage is forecast but large CAPE and a wind profile supportive of organized storms would lend a conditional risk for severe with the stronger storms. ...East Coast of the FL Peninsula (Hurricane Dorian)... Uncertainty remains regarding the eventual track of Hurricane Dorian as it moves into the Gulf Stream waters east of the FL Peninsula Monday night into Tuesday morning. If the northeast quadrant were to overspread the FL Peninsula on Tuesday and/or Tuesday night, then a risk for potential tornadoes would include those areas. At this time, uncertainty is too high to include low-severe probabilities. Please refer to the National Hurricane Center for the latest guidance regarding the forecast track of Hurricane Dorian. ...MAXIMUM RISK BY HAZARD... Tornado: 5% - Slight Wind: 15% SIG - Slight Hail: 15% SIG - Slight ..Smith.. 09/02/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO CENTRAL MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms are expected over parts of the northern Plains and upper Mississippi Valley this afternoon through early Tuesday morning. Damaging winds and large hail are likely. Isolated severe storms are possible across parts of southern New England and extending southward into northern Virginia. ...Northern Plains through upper Mississippi Valley... A shortwave trough will amplify as it moves east southeast through southern Alberta and Saskatchewan, reaching the northern Plains by early this evening and the upper MS Valley late tonight. Downstream from this feature, a warm front will advance northeast, and will be situated from a weak surface low in northwest ND through northeast SD and central IA by early evening. A cold front will extend southward from the low through the western Dakotas and advance east during the evening. A moist warm sector will reside south of the warm front. Surface dewpoints will range from the mid 60s to upper 70s F beneath a plume of steep mid-level lapse rates associated with the eastward expansion of an elevated mixed layer (EML). Warm air at the base of the EML will result in a substantial cap in warm sector during the day. Theta-e advection along a southerly low-level jet will contribute to northeastward destabilization through the Dakotas and into the upper MS Valley this afternoon and evening with MUCAPE increasing from 2000-3000 J/kg north of the warm front. Isolated storms with a marginal hail threat may be ongoing from SD into NE within zone of warm advection. However, primary severe threat is expected during the afternoon into the evening when forcing for ascent associated with approaching shortwave trough and attendant strengthening low-level jet will result in development of storms north of the warm front over northern ND. These storms will be elevated, but effective bulk shear from 40-50 kt and a favorable thermodynamic environment will support a few supercells with large hail the initial primary threat. Storms may eventually evolve into an MCS with primary threat transitioning to damaging wind during the evening and overnight as activity continues southeast through MN into WI along instability gradient. Given favorable low-level hodographs, a conditional threat will exist for a couple of tornadoes with any surface-based storms that can develop on the warm front. However, current indications are that the warm sector will probably remain capped to parcels originating in the boundary layer. ...Southern New England through northern Virginia... Band of convection associated with a progressive shortwave trough currently from western NY through southeast OH will continue east through the early morning. Destabilization of the boundary layer may occur downstream from this activity, resulting in modest instability and storm intensification. Similar to Sunday, wind profiles with 30-35 kt effective bulk shear will support multicell and some marginal supercell structures with isolated damaging wind and perhaps a brief tornado possible through early evening. ...Southeast Florida... Hurricane Dorian is forecast by the National Hurricane center to gradually turn to the northwest, but should remain far enough offshore to limit the tornado threat this period. However, storms developing in the outer rainbands will reach the eastern FL coastal areas, and low-level hodographs might become at least marginally supportive of a brief tornado by late this afternoon into the evening. ..Dial/Squitieri.. 09/02/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO CENTRAL MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms are expected over parts of the northern Plains and upper Mississippi Valley this afternoon through early Tuesday morning. Damaging winds and large hail are likely. Isolated severe storms are possible across parts of southern New England and extending southward into northern Virginia. ...Northern Plains through upper Mississippi Valley... A shortwave trough will amplify as it moves east southeast through southern Alberta and Saskatchewan, reaching the northern Plains by early this evening and the upper MS Valley late tonight. Downstream from this feature, a warm front will advance northeast, and will be situated from a weak surface low in northwest ND through northeast SD and central IA by early evening. A cold front will extend southward from the low through the western Dakotas and advance east during the evening. A moist warm sector will reside south of the warm front. Surface dewpoints will range from the mid 60s to upper 70s F beneath a plume of steep mid-level lapse rates associated with the eastward expansion of an elevated mixed layer (EML). Warm air at the base of the EML will result in a substantial cap in warm sector during the day. Theta-e advection along a southerly low-level jet will contribute to northeastward destabilization through the Dakotas and into the upper MS Valley this afternoon and evening with MUCAPE increasing from 2000-3000 J/kg north of the warm front. Isolated storms with a marginal hail threat may be ongoing from SD into NE within zone of warm advection. However, primary severe threat is expected during the afternoon into the evening when forcing for ascent associated with approaching shortwave trough and attendant strengthening low-level jet will result in development of storms north of the warm front over northern ND. These storms will be elevated, but effective bulk shear from 40-50 kt and a favorable thermodynamic environment will support a few supercells with large hail the initial primary threat. Storms may eventually evolve into an MCS with primary threat transitioning to damaging wind during the evening and overnight as activity continues southeast through MN into WI along instability gradient. Given favorable low-level hodographs, a conditional threat will exist for a couple of tornadoes with any surface-based storms that can develop on the warm front. However, current indications are that the warm sector will probably remain capped to parcels originating in the boundary layer. ...Southern New England through northern Virginia... Band of convection associated with a progressive shortwave trough currently from western NY through southeast OH will continue east through the early morning. Destabilization of the boundary layer may occur downstream from this activity, resulting in modest instability and storm intensification. Similar to Sunday, wind profiles with 30-35 kt effective bulk shear will support multicell and some marginal supercell structures with isolated damaging wind and perhaps a brief tornado possible through early evening. ...Southeast Florida... Hurricane Dorian is forecast by the National Hurricane center to gradually turn to the northwest, but should remain far enough offshore to limit the tornado threat this period. However, storms developing in the outer rainbands will reach the eastern FL coastal areas, and low-level hodographs might become at least marginally supportive of a brief tornado by late this afternoon into the evening. ..Dial/Squitieri.. 09/02/2019 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM EASTERN NORTH DAKOTA INTO CENTRAL MINNESOTA AND WESTERN WISCONSIN... ...SUMMARY... Severe thunderstorms are expected over parts of the northern Plains and upper Mississippi Valley this afternoon through early Tuesday morning. Damaging winds and large hail are likely. Isolated severe storms are possible across parts of southern New England and extending southward into northern Virginia. ...Northern Plains through upper Mississippi Valley... A shortwave trough will amplify as it moves east southeast through southern Alberta and Saskatchewan, reaching the northern Plains by early this evening and the upper MS Valley late tonight. Downstream from this feature, a warm front will advance northeast, and will be situated from a weak surface low in northwest ND through northeast SD and central IA by early evening. A cold front will extend southward from the low through the western Dakotas and advance east during the evening. A moist warm sector will reside south of the warm front. Surface dewpoints will range from the mid 60s to upper 70s F beneath a plume of steep mid-level lapse rates associated with the eastward expansion of an elevated mixed layer (EML). Warm air at the base of the EML will result in a substantial cap in warm sector during the day. Theta-e advection along a southerly low-level jet will contribute to northeastward destabilization through the Dakotas and into the upper MS Valley this afternoon and evening with MUCAPE increasing from 2000-3000 J/kg north of the warm front. Isolated storms with a marginal hail threat may be ongoing from SD into NE within zone of warm advection. However, primary severe threat is expected during the afternoon into the evening when forcing for ascent associated with approaching shortwave trough and attendant strengthening low-level jet will result in development of storms north of the warm front over northern ND. These storms will be elevated, but effective bulk shear from 40-50 kt and a favorable thermodynamic environment will support a few supercells with large hail the initial primary threat. Storms may eventually evolve into an MCS with primary threat transitioning to damaging wind during the evening and overnight as activity continues southeast through MN into WI along instability gradient. Given favorable low-level hodographs, a conditional threat will exist for a couple of tornadoes with any surface-based storms that can develop on the warm front. However, current indications are that the warm sector will probably remain capped to parcels originating in the boundary layer. ...Southern New England through northern Virginia... Band of convection associated with a progressive shortwave trough currently from western NY through southeast OH will continue east through the early morning. Destabilization of the boundary layer may occur downstream from this activity, resulting in modest instability and storm intensification. Similar to Sunday, wind profiles with 30-35 kt effective bulk shear will support multicell and some marginal supercell structures with isolated damaging wind and perhaps a brief tornado possible through early evening. ...Southeast Florida... Hurricane Dorian is forecast by the National Hurricane center to gradually turn to the northwest, but should remain far enough offshore to limit the tornado threat this period. However, storms developing in the outer rainbands will reach the eastern FL coastal areas, and low-level hodographs might become at least marginally supportive of a brief tornado by late this afternoon into the evening. ..Dial/Squitieri.. 09/02/2019 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN IDAHO... ...Synopsis... A well-defined 500 mb impulse, accompanied by 50+ knot winds, will crest an upper-level ridge across the northern Rockies during the afternoon. A response to the surface mass fields will ensue, with breezy, dry conditions prevailing across parts of the central/northern Rockies and northern Great Basin, promoting conditions favorable for wildfire spread. In addition, monsoonal moisture return across parts of the Great Basin may induce isolated thunderstorm activity over dry fuels. ...Northern/central Rockies into the Great Basin... As the aforementioned impulse glances by to the north, afternoon heating will help transport the stronger flow aloft towards the surface via a deeply mixed boundary layer. 15-20 mph westerly flow and RH under 20% should become commonplace across much of the northern Great Basin into parts of the central/northern Rockies, where an elevated area remains in place. A critical area has also been maintained for portions of the Snake River Plain, where downslope flow along the lee of the southeast Bitterroot Mountains will augment the ambient flow fields to support 20-25 mph sustained westerly surface winds and 10-20% RH. Here, fuels are also critically dry, which would support wildfire-spread potential given the aforementioned wind/RH conditions. Farther southwest into the Great Basin (i.e. Nevada into far western Utah), localized elevated wind/RH may occur during afternoon peak heating, though the brevity of such conditions precludes a delineation at this time. Given the well-mixed boundary layer, any storms that can develop in the Great Basin will be high-based, with at least a few dry strikes possible over critically dry fuels, potentially supporting ignitions. This is especially the case where dry downbursts may occur, where brief but erratic surface winds may worsen the spread of grass fires from recent ignitions. Nonetheless, storm coverage appears too sparse at this time to warrant an isolated dry thunderstorm delineation. ..Squitieri.. 09/02/2019 ...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 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN IDAHO... ...Synopsis... A well-defined 500 mb impulse, accompanied by 50+ knot winds, will crest an upper-level ridge across the northern Rockies during the afternoon. A response to the surface mass fields will ensue, with breezy, dry conditions prevailing across parts of the central/northern Rockies and northern Great Basin, promoting conditions favorable for wildfire spread. In addition, monsoonal moisture return across parts of the Great Basin may induce isolated thunderstorm activity over dry fuels. ...Northern/central Rockies into the Great Basin... As the aforementioned impulse glances by to the north, afternoon heating will help transport the stronger flow aloft towards the surface via a deeply mixed boundary layer. 15-20 mph westerly flow and RH under 20% should become commonplace across much of the northern Great Basin into parts of the central/northern Rockies, where an elevated area remains in place. A critical area has also been maintained for portions of the Snake River Plain, where downslope flow along the lee of the southeast Bitterroot Mountains will augment the ambient flow fields to support 20-25 mph sustained westerly surface winds and 10-20% RH. Here, fuels are also critically dry, which would support wildfire-spread potential given the aforementioned wind/RH conditions. Farther southwest into the Great Basin (i.e. Nevada into far western Utah), localized elevated wind/RH may occur during afternoon peak heating, though the brevity of such conditions precludes a delineation at this time. Given the well-mixed boundary layer, any storms that can develop in the Great Basin will be high-based, with at least a few dry strikes possible over critically dry fuels, potentially supporting ignitions. This is especially the case where dry downbursts may occur, where brief but erratic surface winds may worsen the spread of grass fires from recent ignitions. Nonetheless, storm coverage appears too sparse at this time to warrant an isolated dry thunderstorm delineation. ..Squitieri.. 09/02/2019 ...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 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN IDAHO... ...Synopsis... A well-defined 500 mb impulse, accompanied by 50+ knot winds, will crest an upper-level ridge across the northern Rockies during the afternoon. A response to the surface mass fields will ensue, with breezy, dry conditions prevailing across parts of the central/northern Rockies and northern Great Basin, promoting conditions favorable for wildfire spread. In addition, monsoonal moisture return across parts of the Great Basin may induce isolated thunderstorm activity over dry fuels. ...Northern/central Rockies into the Great Basin... As the aforementioned impulse glances by to the north, afternoon heating will help transport the stronger flow aloft towards the surface via a deeply mixed boundary layer. 15-20 mph westerly flow and RH under 20% should become commonplace across much of the northern Great Basin into parts of the central/northern Rockies, where an elevated area remains in place. A critical area has also been maintained for portions of the Snake River Plain, where downslope flow along the lee of the southeast Bitterroot Mountains will augment the ambient flow fields to support 20-25 mph sustained westerly surface winds and 10-20% RH. Here, fuels are also critically dry, which would support wildfire-spread potential given the aforementioned wind/RH conditions. Farther southwest into the Great Basin (i.e. Nevada into far western Utah), localized elevated wind/RH may occur during afternoon peak heating, though the brevity of such conditions precludes a delineation at this time. Given the well-mixed boundary layer, any storms that can develop in the Great Basin will be high-based, with at least a few dry strikes possible over critically dry fuels, potentially supporting ignitions. This is especially the case where dry downbursts may occur, where brief but erratic surface winds may worsen the spread of grass fires from recent ignitions. Nonetheless, storm coverage appears too sparse at this time to warrant an isolated dry thunderstorm delineation. ..Squitieri.. 09/02/2019 ...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 0100 AM CDT Mon Sep 02 2019 Valid 021200Z - 031200Z ...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF EASTERN IDAHO... ...Synopsis... A well-defined 500 mb impulse, accompanied by 50+ knot winds, will crest an upper-level ridge across the northern Rockies during the afternoon. A response to the surface mass fields will ensue, with breezy, dry conditions prevailing across parts of the central/northern Rockies and northern Great Basin, promoting conditions favorable for wildfire spread. In addition, monsoonal moisture return across parts of the Great Basin may induce isolated thunderstorm activity over dry fuels. ...Northern/central Rockies into the Great Basin... As the aforementioned impulse glances by to the north, afternoon heating will help transport the stronger flow aloft towards the surface via a deeply mixed boundary layer. 15-20 mph westerly flow and RH under 20% should become commonplace across much of the northern Great Basin into parts of the central/northern Rockies, where an elevated area remains in place. A critical area has also been maintained for portions of the Snake River Plain, where downslope flow along the lee of the southeast Bitterroot Mountains will augment the ambient flow fields to support 20-25 mph sustained westerly surface winds and 10-20% RH. Here, fuels are also critically dry, which would support wildfire-spread potential given the aforementioned wind/RH conditions. Farther southwest into the Great Basin (i.e. Nevada into far western Utah), localized elevated wind/RH may occur during afternoon peak heating, though the brevity of such conditions precludes a delineation at this time. Given the well-mixed boundary layer, any storms that can develop in the Great Basin will be high-based, with at least a few dry strikes possible over critically dry fuels, potentially supporting ignitions. This is especially the case where dry downbursts may occur, where brief but erratic surface winds may worsen the spread of grass fires from recent ignitions. Nonetheless, storm coverage appears too sparse at this time to warrant an isolated dry thunderstorm delineation. ..Squitieri.. 09/02/2019 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

265
ABPZ20 KNHC 020516
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Sep 1 2019

For the eastern North Pacific...east of 140 degrees west longitude:

The National Hurricane Center is issuing advisories on Tropical
Storm Juliette, located several hundred miles south of the southern
tip of the Baja California peninsula.

Tropical cyclone formation is not expected during the next 5 days.

&&

Public Advisories on Juliette are issued under WMO header WTPZ31
KNHC and under AWIPS header MIATCPEP1.
Forecast/Advisories on Juliette are issued under WMO header WTPZ21
KNHC and under AWIPS header MIATCMEP1.

$$
Forecaster Stewart