Aggregator

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0210 AM CDT Thu Apr 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Great Lakes... Poleward low-level moisture return from the western Gulf will become more pervasive across the central states on Saturday as a surface anticyclone drifts east near the northeast Gulf coast. This will occur beneath a broad elevated mixed layer. By Saturday night, low-level warm theta-e advection should yield at least isolated, highly elevated convection in parts of the Upper Great Lakes vicinity. Favorable west-northwesterly speed shear should be present, conditionally favoring a threat for hail. But scant buoyancy to the northeast of the elevated mixed layer will probably curtail appreciable hail growth. Some signal exists early morning Sunday for isolated convection to develop in the south Lower MI to northwest OH vicinity, where elevated buoyancy will be greater. This area will be monitored in later outlooks for a possible hail-driven level 1-MRGL risk. ...West... The amplified mid/upper low just off the central CA coast will dampen as it gradually wobbles inland. The initially meridional and intense mid-level jet east-southeast of the low will weaken as it flattens to a southwesterly orientation across south CA into the south Great Basin. Mid-level flow will become more backed and weaker across the Northwest relative to Friday, lowering confidence in highlighting any appreciable severe threat. Low-topped, isolated thunderstorms will be possible across parts of central CA, with additional isolated thunderstorms possible from north CA to the northern Rockies. ..Grams.. 04/11/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0210 AM CDT Thu Apr 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Great Lakes... Poleward low-level moisture return from the western Gulf will become more pervasive across the central states on Saturday as a surface anticyclone drifts east near the northeast Gulf coast. This will occur beneath a broad elevated mixed layer. By Saturday night, low-level warm theta-e advection should yield at least isolated, highly elevated convection in parts of the Upper Great Lakes vicinity. Favorable west-northwesterly speed shear should be present, conditionally favoring a threat for hail. But scant buoyancy to the northeast of the elevated mixed layer will probably curtail appreciable hail growth. Some signal exists early morning Sunday for isolated convection to develop in the south Lower MI to northwest OH vicinity, where elevated buoyancy will be greater. This area will be monitored in later outlooks for a possible hail-driven level 1-MRGL risk. ...West... The amplified mid/upper low just off the central CA coast will dampen as it gradually wobbles inland. The initially meridional and intense mid-level jet east-southeast of the low will weaken as it flattens to a southwesterly orientation across south CA into the south Great Basin. Mid-level flow will become more backed and weaker across the Northwest relative to Friday, lowering confidence in highlighting any appreciable severe threat. Low-topped, isolated thunderstorms will be possible across parts of central CA, with additional isolated thunderstorms possible from north CA to the northern Rockies. ..Grams.. 04/11/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0210 AM CDT Thu Apr 11 2024 Valid 131200Z - 141200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe thunderstorms are not forecast on Saturday. ...Great Lakes... Poleward low-level moisture return from the western Gulf will become more pervasive across the central states on Saturday as a surface anticyclone drifts east near the northeast Gulf coast. This will occur beneath a broad elevated mixed layer. By Saturday night, low-level warm theta-e advection should yield at least isolated, highly elevated convection in parts of the Upper Great Lakes vicinity. Favorable west-northwesterly speed shear should be present, conditionally favoring a threat for hail. But scant buoyancy to the northeast of the elevated mixed layer will probably curtail appreciable hail growth. Some signal exists early morning Sunday for isolated convection to develop in the south Lower MI to northwest OH vicinity, where elevated buoyancy will be greater. This area will be monitored in later outlooks for a possible hail-driven level 1-MRGL risk. ...West... The amplified mid/upper low just off the central CA coast will dampen as it gradually wobbles inland. The initially meridional and intense mid-level jet east-southeast of the low will weaken as it flattens to a southwesterly orientation across south CA into the south Great Basin. Mid-level flow will become more backed and weaker across the Northwest relative to Friday, lowering confidence in highlighting any appreciable severe threat. Low-topped, isolated thunderstorms will be possible across parts of central CA, with additional isolated thunderstorms possible from north CA to the northern Rockies. ..Grams.. 04/11/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 0143 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...Synopsis... Elevated fire weather conditions are anticipated across a large swath of the central Plains this afternoon. ...northern Oklahoma to southern South Dakota... 06 UTC surface observations show strengthening northwesterly winds behind a cold front across the northern Plains. This cold advection regime will persist into the afternoon, and despite an influx of cooler temperatures, diurnal heating of a dry air mass will support RH reductions into the 20-30% range. Sustained winds between 15-25 mph (gusting to 30-40 mph) should support widespread, sustained elevated conditions with localized areas of critical fire weather conditions - especially across eastern NE/KS where winds in the 850-700 mb layer are forecast to be strongest. Recent fuel reports and precipitation analyses continue to suggest that fine fuels are sufficiently dry to support the fire weather concern. ...Eastern New Mexico to Southwest Texas... Localized elevated conditions are possible this afternoon on the lee side of more prominent terrain features across eastern NM into Southwest TX. A modest westerly flow regime will promote areas of downslope warming/drying with pockets of afternoon RH minimums in the 15-20% range and 15-20 mph winds. These conditions are expected to remain sufficiently localized to preclude highlights. ..Moore.. 04/11/2024 ...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 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1249 AM CDT Thu Apr 11 2024 Valid 121200Z - 131200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS IN EAST OR...SOUTHWEST ID...AND FAR NORTH NV... ...SUMMARY... Isolated marginally severe wind gusts and hail are possible across parts of the northwest Great Basin vicinity during the late afternoon to early evening Friday. ...Northwest Great Basin... An amplified shortwave trough will approach but remain west of the central CA coast through 12Z Saturday. While the bulk of PW increase will remain over parts of CA and the OR Pacific Coast, modest moistening should occur within the 700-mb baroclinic zone farther east across northwest NV and east OR into southwest ID. Isolated to scattered high-based thunderstorms should develop just after peak heating. Moderate southwesterly flow should exist within the meager buoyancy layer between the offshore trough and the mid-level ridge that will become centered over the High Plains. Strong to localized severe wind gusts will be the main threat. Marginally severe hail may occur in a portion of east OR/southwest ID where brief supercell structures are possible, before convection wanes after dusk. ...East... Deep surface cyclone near the Georgian Bay of Lake Huron at 12Z Friday should occlude and slowly weaken as it continues northeastward into western Quebec. The arcing occluded front across parts of the Northeast may be a focus for low-topped convection during the late morning to early afternoon. Low-level hodograph curvature should be largest at the beginning of the period, and weaken through the day. Surface-based destabilization appears to be very limited, and the severe threat in the east NY vicinity appears too low to warrant an areal delineation. As the northern-stream shortwave impulse translates through the basal portion of the amplified upper trough over the East, cold mid-level temperatures will support isolated to scattered low-topped convection spreading from west to east across parts of the central OH Valley/Cumberland Plateau into VA/NC. Surface-based buoyancy should be scant at most amid decidedly westerly wind profiles. Still, moderate to strong low-level flow may be mixed to the surface and yield locally gusty winds during the afternoon. ..Grams.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Thu Apr 11 2024 Valid 111200Z - 121200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO RIVER VALLEY... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE OHIO RIVER VALLEY AND NORTHERN FLORIDA TO SOUTHERN GEORGIA... ...SUMMARY... Severe thunderstorms with a few tornadoes, scattered damaging winds, and isolated large hail are possible across the upper Ohio River Valley and parts of the Appalachians this afternoon. Scattered damaging winds and a couple tornadoes will also be possible across southeast Georgia into northern Florida, mainly this morning through early afternoon. ...Synopsis... 04 UTC surface observations depict a diffuse surface low over the lower MS River Valley. This low is forecast to deepen over the next 24 hours as it lifts northward into the OH Valley/Great Lakes region in tandem with the phasing of an amplified upper-level trough over the MS Valley with an approaching upstream perturbation. A surface cold front currently draped across southeast LA will surge to the east/northeast as the low deepens, and should act to focus thunderstorm development through the late morning and afternoon hours across both the upper OH Valley and Southeast. ...Upper OH River Valley... Recent 925/850 mb analyses and surface observations show a consolidating warm frontal zone draped from the surface low over the lower MS Valley into the upper OH River Valley. The surface low will deepen along this corridor amid a combination of strong height falls and ascent within the left-exit region of a mid-level jet. A plume of low to mid-60s dewpoints will advect northward with the deepening low, establishing a focused warm sector ahead of the approaching cold front by early afternoon across parts of KY, OH, and WV. The current expectation is for sufficient destabilization within the warm sector to support surface-based convection by the 18-21 UTC time frame. A combination of strong synoptic-scale ascent and 40-50 knot deep-layer shear vectors off the cold front should promote a mix of discrete cells and semi-discrete clusters - including the potential for a few supercells. Increasing southeasterly winds through the lowest 1-2 km should yield effective SRH values between 150-300 m2/s2, which will support a tornado threat with the more robust/organized cells as well as a wind threat with more organized clusters. This threat appears greatest across southeast OH into western WV where latest guidance continues to show a focused convective signal. Further to the east into parts of northwest VA, a somewhat weaker convective signal is noted in most CAM guidance, but 50-knot flow in the lowest 2 km will likely pose a substantial wind threat with any storms that can mature. Risk probabilities have been expanded into this region to account for this potential. That said, this scenario appears to be conditional on achieving sufficient low-level warming within the warm sector. While an extensive dry slot is noted in water-vapor imagery across the Mid-South into central IN, the low/mid-level warm advection regime is maintaining mid-level stratus across the region with most ASOS stations reporting overcast skies and ceilings near 6 kft. It is unclear how much clearing will occur through early afternoon given persistent ascent, and a 10 F spread in afternoon high temperatures is noted across OH/WV in recent ensemble guidance. Based on forecast soundings, surface temperatures in the upper 60s may be required to realize 500+ J/kg SBCAPE with minimal inhibition. The median of the temperature distribution appears to reside in the upper 60s, but SBCAPE may still only reach 500-1000 J/kg per ensemble distributions. ...Florida/Georgia... Lingering thunderstorms associated with overnight convection will likely be ongoing across the FL Panhandle at 12 UTC. This activity should become consolidated into a more organized line as the cold front pushes east through the morning across southern GA and northern FL. Poor lapse rates sampled by 00 UTC soundings across central/northern FL will limit buoyancy despite mid/upper 60s dewpoints. However, strong kinematic fields should be in place as a mid-level jet max passes overhead. Forecast hodographs suggest effective bulk shear values around 50-55 knots will be common, and low-level SRH may approach 150 m2/s2 along/ahead of the line. The severe risk will likely be modulated by the degree of diurnal destabilization that can occur ahead of the line, but stronger cells/segments may pose a severe wind/tornado risk given the favorable wind profiles. This risk may peak by late morning before the line begins to move offshore and forcing for ascent gradually abates by late afternoon as the synoptic low lifts well to the north. ..Moore/Darrow.. 04/11/2024 Read more