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SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Jul 18 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC STATES... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the Mid-Atlantic on Saturday. ...Synopsis... The upper pattern is forecast to be characterized by western CONUS ridging and central/eastern CONUS troughing throughout the period with only a slight westward shift in these features anticipated. A low-amplitude, convectively augmented shortwave trough will likely be moving across the central Plains early Saturday morning, embedded within the northwesterly flow aloft between the western ridge and eastern trough. This shortwave trough is expected to continue southeastward through OK and into TX. Farther west, a pair of shortwave troughs is expected to move through the northwest periphery of the upper ridge. The southernmost shortwave will likely move along the central CA coast throughout the period while the northernmost shortwave approaches the northern CA/Pacific Northwest coast early Sunday. At the surface, high pressure is expected to remain over the OH Valley, with a weak stationary front along the southern periphery of this high across the Southeast. Lee troughing is also anticipated through the period as well, with moderate low-level moisture east of this troughing across the majority of the Plains. Outflow from showers and thunderstorms associated with the central Plains shortwave trough may exist as well, but low predictability limits confidence in its presence and location. Thunderstorms appear probable along the stationary front from the Southeast into the Mid-Atlantic, as well as beneath the upper ridging across much of the western CONUS and in the vicinity of the central/southern Plains shortwave trough. In each of these areas, limited vertical shear is expected to limit overall storm strength, tempering the severe potential. The only exception is across the Mid-Atlantic, where enhanced mid-level flow between the eastern CONUS troughing and subtropical ridge over the western Atlantic may support stronger shear and better storm organization. Damaging gusts are possible within any of the stronger storms over this area. ..Mosier.. 07/18/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Jul 18 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC STATES... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the Mid-Atlantic on Saturday. ...Synopsis... The upper pattern is forecast to be characterized by western CONUS ridging and central/eastern CONUS troughing throughout the period with only a slight westward shift in these features anticipated. A low-amplitude, convectively augmented shortwave trough will likely be moving across the central Plains early Saturday morning, embedded within the northwesterly flow aloft between the western ridge and eastern trough. This shortwave trough is expected to continue southeastward through OK and into TX. Farther west, a pair of shortwave troughs is expected to move through the northwest periphery of the upper ridge. The southernmost shortwave will likely move along the central CA coast throughout the period while the northernmost shortwave approaches the northern CA/Pacific Northwest coast early Sunday. At the surface, high pressure is expected to remain over the OH Valley, with a weak stationary front along the southern periphery of this high across the Southeast. Lee troughing is also anticipated through the period as well, with moderate low-level moisture east of this troughing across the majority of the Plains. Outflow from showers and thunderstorms associated with the central Plains shortwave trough may exist as well, but low predictability limits confidence in its presence and location. Thunderstorms appear probable along the stationary front from the Southeast into the Mid-Atlantic, as well as beneath the upper ridging across much of the western CONUS and in the vicinity of the central/southern Plains shortwave trough. In each of these areas, limited vertical shear is expected to limit overall storm strength, tempering the severe potential. The only exception is across the Mid-Atlantic, where enhanced mid-level flow between the eastern CONUS troughing and subtropical ridge over the western Atlantic may support stronger shear and better storm organization. Damaging gusts are possible within any of the stronger storms over this area. ..Mosier.. 07/18/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Jul 18 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC STATES... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the Mid-Atlantic on Saturday. ...Synopsis... The upper pattern is forecast to be characterized by western CONUS ridging and central/eastern CONUS troughing throughout the period with only a slight westward shift in these features anticipated. A low-amplitude, convectively augmented shortwave trough will likely be moving across the central Plains early Saturday morning, embedded within the northwesterly flow aloft between the western ridge and eastern trough. This shortwave trough is expected to continue southeastward through OK and into TX. Farther west, a pair of shortwave troughs is expected to move through the northwest periphery of the upper ridge. The southernmost shortwave will likely move along the central CA coast throughout the period while the northernmost shortwave approaches the northern CA/Pacific Northwest coast early Sunday. At the surface, high pressure is expected to remain over the OH Valley, with a weak stationary front along the southern periphery of this high across the Southeast. Lee troughing is also anticipated through the period as well, with moderate low-level moisture east of this troughing across the majority of the Plains. Outflow from showers and thunderstorms associated with the central Plains shortwave trough may exist as well, but low predictability limits confidence in its presence and location. Thunderstorms appear probable along the stationary front from the Southeast into the Mid-Atlantic, as well as beneath the upper ridging across much of the western CONUS and in the vicinity of the central/southern Plains shortwave trough. In each of these areas, limited vertical shear is expected to limit overall storm strength, tempering the severe potential. The only exception is across the Mid-Atlantic, where enhanced mid-level flow between the eastern CONUS troughing and subtropical ridge over the western Atlantic may support stronger shear and better storm organization. Damaging gusts are possible within any of the stronger storms over this area. ..Mosier.. 07/18/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0229 AM CDT Thu Jul 18 2024 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE MID-ATLANTIC STATES... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the Mid-Atlantic on Saturday. ...Synopsis... The upper pattern is forecast to be characterized by western CONUS ridging and central/eastern CONUS troughing throughout the period with only a slight westward shift in these features anticipated. A low-amplitude, convectively augmented shortwave trough will likely be moving across the central Plains early Saturday morning, embedded within the northwesterly flow aloft between the western ridge and eastern trough. This shortwave trough is expected to continue southeastward through OK and into TX. Farther west, a pair of shortwave troughs is expected to move through the northwest periphery of the upper ridge. The southernmost shortwave will likely move along the central CA coast throughout the period while the northernmost shortwave approaches the northern CA/Pacific Northwest coast early Sunday. At the surface, high pressure is expected to remain over the OH Valley, with a weak stationary front along the southern periphery of this high across the Southeast. Lee troughing is also anticipated through the period as well, with moderate low-level moisture east of this troughing across the majority of the Plains. Outflow from showers and thunderstorms associated with the central Plains shortwave trough may exist as well, but low predictability limits confidence in its presence and location. Thunderstorms appear probable along the stationary front from the Southeast into the Mid-Atlantic, as well as beneath the upper ridging across much of the western CONUS and in the vicinity of the central/southern Plains shortwave trough. In each of these areas, limited vertical shear is expected to limit overall storm strength, tempering the severe potential. The only exception is across the Mid-Atlantic, where enhanced mid-level flow between the eastern CONUS troughing and subtropical ridge over the western Atlantic may support stronger shear and better storm organization. Damaging gusts are possible within any of the stronger storms over this area. ..Mosier.. 07/18/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0121 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...Synopsis... An upper-level ridge will continue to slowly expand west and north over the western CONUS Friday. Hot and mostly dry conditions will persist under the influence of this feature, where only very localized wetting rains have occurred through the past week or so. Shallow mid to upper-level monsoonal moisture is still expected over the Great Basin atop a well-mixed boundary layer, where PWAT values will be even lower than the previous day's. Isolated dry thunderstorms are expected to develop above increasingly receptive fuels Friday afternoon, via orographic ascent, and continue into the early evening. Very little wetting rainfall is expected to accompany this elevated convection. ..Barnes.. 07/18/2024 ...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 0121 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...Synopsis... An upper-level ridge will continue to slowly expand west and north over the western CONUS Friday. Hot and mostly dry conditions will persist under the influence of this feature, where only very localized wetting rains have occurred through the past week or so. Shallow mid to upper-level monsoonal moisture is still expected over the Great Basin atop a well-mixed boundary layer, where PWAT values will be even lower than the previous day's. Isolated dry thunderstorms are expected to develop above increasingly receptive fuels Friday afternoon, via orographic ascent, and continue into the early evening. Very little wetting rainfall is expected to accompany this elevated convection. ..Barnes.. 07/18/2024 ...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 0121 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...Synopsis... An upper-level ridge will continue to slowly expand west and north over the western CONUS Friday. Hot and mostly dry conditions will persist under the influence of this feature, where only very localized wetting rains have occurred through the past week or so. Shallow mid to upper-level monsoonal moisture is still expected over the Great Basin atop a well-mixed boundary layer, where PWAT values will be even lower than the previous day's. Isolated dry thunderstorms are expected to develop above increasingly receptive fuels Friday afternoon, via orographic ascent, and continue into the early evening. Very little wetting rainfall is expected to accompany this elevated convection. ..Barnes.. 07/18/2024 ...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 0121 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...Synopsis... An upper-level ridge will continue to slowly expand west and north over the western CONUS Friday. Hot and mostly dry conditions will persist under the influence of this feature, where only very localized wetting rains have occurred through the past week or so. Shallow mid to upper-level monsoonal moisture is still expected over the Great Basin atop a well-mixed boundary layer, where PWAT values will be even lower than the previous day's. Isolated dry thunderstorms are expected to develop above increasingly receptive fuels Friday afternoon, via orographic ascent, and continue into the early evening. Very little wetting rainfall is expected to accompany this elevated convection. ..Barnes.. 07/18/2024 ...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 1257 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF THE NORTHERN/CENTRAL HIGH PLAINS INTO THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the northern/central High Plains into the northern/central Plains on Friday. ...Synopsis... Expansive upper ridging is expected to be in place from the Southwest into western Canada early Friday morning, with upper troughing anticipated east of this ridging across the central/ eastern CONUS and much of eastern Canada. A shortwave trough embedded within this eastern troughing is forecast to progress eastward across Ontario and adjacent portions of the St. Lawrence Valley and northern New England. Another shortwave trough is forecast to progress through the northeastern periphery of the western ridge, moving from eastern MT southeastward across the northern High Plains and reaching the central Plains by early Saturday. Surface pattern early Friday will be dominated by a strong high over the OH Valley, with a weak stationary front along its southern periphery stretching from SC into the TX Hill Country. Warm and moist conditions are expected along this boundary, helping to support afternoon thunderstorms amid modest low-level convergence along the front as well as in the vicinity of a convectively generated vorticity maximum expected to move across the Lower MS Valley and MS/AL. Storm severity should be mitigated by weak shear and largely disorganized storm mode. ...Northern/Central High Plains into the northern/central Plains... Surface lee troughing is anticipated across the High Plains, with moderate low-level moisture east of this lee troughing across the majority of the Plains. Afternoon thunderstorm development appears probable along the lee trough as well as farther east into more of SD and NE as the previously mentioned shortwave trough moves into the region. Moderate northwesterly flow aloft will support a southeasterly storm motion, taking any development into areas with more favorable low-level moisture and stronger buoyancy. Additionally, this moderate northwesterly flow aloft atop low-level southerlies will help support moderate deep-layer vertical shear. This shear could help organize initially high-based, outflow-dominant storms into one or more coherent bowing segments capable of damaging gusts. While this overall convective evolution appears probable, where it occurs is less certain. Furthermore, there is uncertainty regarding just how strong the gusts with this line (or lines) will be. Uncertainties merit delaying the inclusion of higher probabilities to later outlooks when these more mesoscale details become predictable. ..Mosier.. 07/18/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF THE NORTHERN/CENTRAL HIGH PLAINS INTO THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the northern/central High Plains into the northern/central Plains on Friday. ...Synopsis... Expansive upper ridging is expected to be in place from the Southwest into western Canada early Friday morning, with upper troughing anticipated east of this ridging across the central/ eastern CONUS and much of eastern Canada. A shortwave trough embedded within this eastern troughing is forecast to progress eastward across Ontario and adjacent portions of the St. Lawrence Valley and northern New England. Another shortwave trough is forecast to progress through the northeastern periphery of the western ridge, moving from eastern MT southeastward across the northern High Plains and reaching the central Plains by early Saturday. Surface pattern early Friday will be dominated by a strong high over the OH Valley, with a weak stationary front along its southern periphery stretching from SC into the TX Hill Country. Warm and moist conditions are expected along this boundary, helping to support afternoon thunderstorms amid modest low-level convergence along the front as well as in the vicinity of a convectively generated vorticity maximum expected to move across the Lower MS Valley and MS/AL. Storm severity should be mitigated by weak shear and largely disorganized storm mode. ...Northern/Central High Plains into the northern/central Plains... Surface lee troughing is anticipated across the High Plains, with moderate low-level moisture east of this lee troughing across the majority of the Plains. Afternoon thunderstorm development appears probable along the lee trough as well as farther east into more of SD and NE as the previously mentioned shortwave trough moves into the region. Moderate northwesterly flow aloft will support a southeasterly storm motion, taking any development into areas with more favorable low-level moisture and stronger buoyancy. Additionally, this moderate northwesterly flow aloft atop low-level southerlies will help support moderate deep-layer vertical shear. This shear could help organize initially high-based, outflow-dominant storms into one or more coherent bowing segments capable of damaging gusts. While this overall convective evolution appears probable, where it occurs is less certain. Furthermore, there is uncertainty regarding just how strong the gusts with this line (or lines) will be. Uncertainties merit delaying the inclusion of higher probabilities to later outlooks when these more mesoscale details become predictable. ..Mosier.. 07/18/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF THE NORTHERN/CENTRAL HIGH PLAINS INTO THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the northern/central High Plains into the northern/central Plains on Friday. ...Synopsis... Expansive upper ridging is expected to be in place from the Southwest into western Canada early Friday morning, with upper troughing anticipated east of this ridging across the central/ eastern CONUS and much of eastern Canada. A shortwave trough embedded within this eastern troughing is forecast to progress eastward across Ontario and adjacent portions of the St. Lawrence Valley and northern New England. Another shortwave trough is forecast to progress through the northeastern periphery of the western ridge, moving from eastern MT southeastward across the northern High Plains and reaching the central Plains by early Saturday. Surface pattern early Friday will be dominated by a strong high over the OH Valley, with a weak stationary front along its southern periphery stretching from SC into the TX Hill Country. Warm and moist conditions are expected along this boundary, helping to support afternoon thunderstorms amid modest low-level convergence along the front as well as in the vicinity of a convectively generated vorticity maximum expected to move across the Lower MS Valley and MS/AL. Storm severity should be mitigated by weak shear and largely disorganized storm mode. ...Northern/Central High Plains into the northern/central Plains... Surface lee troughing is anticipated across the High Plains, with moderate low-level moisture east of this lee troughing across the majority of the Plains. Afternoon thunderstorm development appears probable along the lee trough as well as farther east into more of SD and NE as the previously mentioned shortwave trough moves into the region. Moderate northwesterly flow aloft will support a southeasterly storm motion, taking any development into areas with more favorable low-level moisture and stronger buoyancy. Additionally, this moderate northwesterly flow aloft atop low-level southerlies will help support moderate deep-layer vertical shear. This shear could help organize initially high-based, outflow-dominant storms into one or more coherent bowing segments capable of damaging gusts. While this overall convective evolution appears probable, where it occurs is less certain. Furthermore, there is uncertainty regarding just how strong the gusts with this line (or lines) will be. Uncertainties merit delaying the inclusion of higher probabilities to later outlooks when these more mesoscale details become predictable. ..Mosier.. 07/18/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1257 AM CDT Thu Jul 18 2024 Valid 191200Z - 201200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM PORTIONS OF THE NORTHERN/CENTRAL HIGH PLAINS INTO THE NORTHERN/CENTRAL PLAINS... ...SUMMARY... Isolated strong to severe thunderstorms are possible across portions of the northern/central High Plains into the northern/central Plains on Friday. ...Synopsis... Expansive upper ridging is expected to be in place from the Southwest into western Canada early Friday morning, with upper troughing anticipated east of this ridging across the central/ eastern CONUS and much of eastern Canada. A shortwave trough embedded within this eastern troughing is forecast to progress eastward across Ontario and adjacent portions of the St. Lawrence Valley and northern New England. Another shortwave trough is forecast to progress through the northeastern periphery of the western ridge, moving from eastern MT southeastward across the northern High Plains and reaching the central Plains by early Saturday. Surface pattern early Friday will be dominated by a strong high over the OH Valley, with a weak stationary front along its southern periphery stretching from SC into the TX Hill Country. Warm and moist conditions are expected along this boundary, helping to support afternoon thunderstorms amid modest low-level convergence along the front as well as in the vicinity of a convectively generated vorticity maximum expected to move across the Lower MS Valley and MS/AL. Storm severity should be mitigated by weak shear and largely disorganized storm mode. ...Northern/Central High Plains into the northern/central Plains... Surface lee troughing is anticipated across the High Plains, with moderate low-level moisture east of this lee troughing across the majority of the Plains. Afternoon thunderstorm development appears probable along the lee trough as well as farther east into more of SD and NE as the previously mentioned shortwave trough moves into the region. Moderate northwesterly flow aloft will support a southeasterly storm motion, taking any development into areas with more favorable low-level moisture and stronger buoyancy. Additionally, this moderate northwesterly flow aloft atop low-level southerlies will help support moderate deep-layer vertical shear. This shear could help organize initially high-based, outflow-dominant storms into one or more coherent bowing segments capable of damaging gusts. While this overall convective evolution appears probable, where it occurs is less certain. Furthermore, there is uncertainty regarding just how strong the gusts with this line (or lines) will be. Uncertainties merit delaying the inclusion of higher probabilities to later outlooks when these more mesoscale details become predictable. ..Mosier.. 07/18/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1256 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...Synopsis... Isolated dry thunderstorms are expected over most of the Great Basin and portions of the Upper Colorado River Basin Thursday afternoon and evening. A shallow plume of mid to upper-level moisture will remain in place Thursday within a broad ridge extending over most of the western CONUS. Orographic ascent juxtaposed with this moisture, combined with relatively low PWAT values and a very well-mixed boundary layer up to or exceeding 3 km, will support isolated dry lightning. Some locations within the Isolated Dry Thunderstorm area across UT may receive wetting rains, but these areas were too confined to exclude them given fairly widespread ERC percentiles above 85. In addition to dry thunderstorms, westerly downslope gusty winds and low relative humidity may support very localized elevated fire weather conditions in the southern lee of the Cascades. ..Barnes.. 07/18/2024 ...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 1256 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...Synopsis... Isolated dry thunderstorms are expected over most of the Great Basin and portions of the Upper Colorado River Basin Thursday afternoon and evening. A shallow plume of mid to upper-level moisture will remain in place Thursday within a broad ridge extending over most of the western CONUS. Orographic ascent juxtaposed with this moisture, combined with relatively low PWAT values and a very well-mixed boundary layer up to or exceeding 3 km, will support isolated dry lightning. Some locations within the Isolated Dry Thunderstorm area across UT may receive wetting rains, but these areas were too confined to exclude them given fairly widespread ERC percentiles above 85. In addition to dry thunderstorms, westerly downslope gusty winds and low relative humidity may support very localized elevated fire weather conditions in the southern lee of the Cascades. ..Barnes.. 07/18/2024 ...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 1256 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...Synopsis... Isolated dry thunderstorms are expected over most of the Great Basin and portions of the Upper Colorado River Basin Thursday afternoon and evening. A shallow plume of mid to upper-level moisture will remain in place Thursday within a broad ridge extending over most of the western CONUS. Orographic ascent juxtaposed with this moisture, combined with relatively low PWAT values and a very well-mixed boundary layer up to or exceeding 3 km, will support isolated dry lightning. Some locations within the Isolated Dry Thunderstorm area across UT may receive wetting rains, but these areas were too confined to exclude them given fairly widespread ERC percentiles above 85. In addition to dry thunderstorms, westerly downslope gusty winds and low relative humidity may support very localized elevated fire weather conditions in the southern lee of the Cascades. ..Barnes.. 07/18/2024 ...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 1256 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...Synopsis... Isolated dry thunderstorms are expected over most of the Great Basin and portions of the Upper Colorado River Basin Thursday afternoon and evening. A shallow plume of mid to upper-level moisture will remain in place Thursday within a broad ridge extending over most of the western CONUS. Orographic ascent juxtaposed with this moisture, combined with relatively low PWAT values and a very well-mixed boundary layer up to or exceeding 3 km, will support isolated dry lightning. Some locations within the Isolated Dry Thunderstorm area across UT may receive wetting rains, but these areas were too confined to exclude them given fairly widespread ERC percentiles above 85. In addition to dry thunderstorms, westerly downslope gusty winds and low relative humidity may support very localized elevated fire weather conditions in the southern lee of the Cascades. ..Barnes.. 07/18/2024 ...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 1256 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...Synopsis... Isolated dry thunderstorms are expected over most of the Great Basin and portions of the Upper Colorado River Basin Thursday afternoon and evening. A shallow plume of mid to upper-level moisture will remain in place Thursday within a broad ridge extending over most of the western CONUS. Orographic ascent juxtaposed with this moisture, combined with relatively low PWAT values and a very well-mixed boundary layer up to or exceeding 3 km, will support isolated dry lightning. Some locations within the Isolated Dry Thunderstorm area across UT may receive wetting rains, but these areas were too confined to exclude them given fairly widespread ERC percentiles above 85. In addition to dry thunderstorms, westerly downslope gusty winds and low relative humidity may support very localized elevated fire weather conditions in the southern lee of the Cascades. ..Barnes.. 07/18/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NORTH CAROLINA INTO FAR SOUTHEAST VIRGINIA... ...SUMMARY... Isolated strong to severe thunderstorms are possible Thursday afternoon across parts of north-central Montana and the central and southern High Plains. Isolated to scattered severe thunderstorms are also expected from the southern Appalachians into eastern North Carolina. ...Synopsis... Early-morning surface observations show a diffuse cold front draped from the Mid-Atlantic region into the southern Plains. This feature is expected to slowly push south over the next 24 hours, as surface high pressure builds over the Plains/Midwest in the wake of an eastward-tracking upper wave. A reservoir of upper 60s to low 70s dewpoints lies to the south of the cold front, and while mid-level lapse rates are fairly modest (based on 00 UTC soundings), diurnal heating into the mid 80s should be sufficient to promote thunderstorm development along the front by early afternoon. Thunderstorm coverage is expected to be somewhat more focused across the southern Appalachians into the Carolinas, as ascent associated with a weak mid-level perturbation (currently over the mid-MS Valley) overspreads the region at peak heating. To the west, isolated to scattered thunderstorms appear likely within an upslope flow regime along the central Rockies and ahead of a shortwave trough over northern Montana. ...Carolinas... The synoptic cold front is currently forecast to be along the VA/NC border by around mid-day. Thunderstorm development along the front appears probable by around 18 UTC, as temperatures warm into the low 80s and ascent from a subtle mid-level impulse overspreads the region. Large hail may be an initial concern depending on storm coverage along the front, but storm motion and deep-layer shear vectors along and/or towards the cool side of the boundary will likely promote upscale growth by mid/late afternoon. As this occurs, the potential for strong to severe winds will increase downstream across eastern NC and far southeast VA. Latest CAM guidance shows reasonably good agreement in the development of a squall line, and while deep-layer shear will not be overly strong (around 25 knots), heating ahead of the line should yield moderate buoyancy with MLCAPE reaching up to 2500 J/kg that will promote robust convection capable of damaging gusts. The coverage of this threat appears sufficient to warrant higher (15%) wind risk probabilities. ...Central to southern High Plains... Another day of easterly upslope winds along the southern to central Rockies is anticipated as a surface high to the east builds. Latest upper-air analyses show the east slopes of the Rockies lie on the periphery of a plume of relatively steep (7+ C/km) lapse rates. This should support isolated to scattered thunderstorm development by mid to late afternoon. Adequate deep-layer shear will be in place to promote storm organization, including the potential for a supercell or two if more discrete storm modes can be realized. However, weak low-level storm-relative winds and steep low-level lapse rates will likely favor cold-pool driven storm propagation and the development of multiple convective clusters with an attendant severe-wind risk. ...Montana... A shortwave impulse is evident in early-morning water-vapor imagery across the Pacific Northwest. This feature is expected to crest the apex of a stout upper ridge over the next 24 hours. Advected precipitable water imagery shows a diluted plume of monsoonal moisture ahead of this wave, which should provide adequate mid-level moisture for thunderstorm development by late afternoon. While buoyancy will be very modest (around 500 J/kg SBCAPE), 30 knot mid-level flow atop easterly low-level winds should provide adequate deep-layer wind shear for some storm organization, most likely into somewhat cohesive clusters given deep-boundary layer mixing that will favor strong cold pool production. Such clusters may be capable of strong to severe winds as they push east across north-central MT. ..Moore.. 07/18/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NORTH CAROLINA INTO FAR SOUTHEAST VIRGINIA... ...SUMMARY... Isolated strong to severe thunderstorms are possible Thursday afternoon across parts of north-central Montana and the central and southern High Plains. Isolated to scattered severe thunderstorms are also expected from the southern Appalachians into eastern North Carolina. ...Synopsis... Early-morning surface observations show a diffuse cold front draped from the Mid-Atlantic region into the southern Plains. This feature is expected to slowly push south over the next 24 hours, as surface high pressure builds over the Plains/Midwest in the wake of an eastward-tracking upper wave. A reservoir of upper 60s to low 70s dewpoints lies to the south of the cold front, and while mid-level lapse rates are fairly modest (based on 00 UTC soundings), diurnal heating into the mid 80s should be sufficient to promote thunderstorm development along the front by early afternoon. Thunderstorm coverage is expected to be somewhat more focused across the southern Appalachians into the Carolinas, as ascent associated with a weak mid-level perturbation (currently over the mid-MS Valley) overspreads the region at peak heating. To the west, isolated to scattered thunderstorms appear likely within an upslope flow regime along the central Rockies and ahead of a shortwave trough over northern Montana. ...Carolinas... The synoptic cold front is currently forecast to be along the VA/NC border by around mid-day. Thunderstorm development along the front appears probable by around 18 UTC, as temperatures warm into the low 80s and ascent from a subtle mid-level impulse overspreads the region. Large hail may be an initial concern depending on storm coverage along the front, but storm motion and deep-layer shear vectors along and/or towards the cool side of the boundary will likely promote upscale growth by mid/late afternoon. As this occurs, the potential for strong to severe winds will increase downstream across eastern NC and far southeast VA. Latest CAM guidance shows reasonably good agreement in the development of a squall line, and while deep-layer shear will not be overly strong (around 25 knots), heating ahead of the line should yield moderate buoyancy with MLCAPE reaching up to 2500 J/kg that will promote robust convection capable of damaging gusts. The coverage of this threat appears sufficient to warrant higher (15%) wind risk probabilities. ...Central to southern High Plains... Another day of easterly upslope winds along the southern to central Rockies is anticipated as a surface high to the east builds. Latest upper-air analyses show the east slopes of the Rockies lie on the periphery of a plume of relatively steep (7+ C/km) lapse rates. This should support isolated to scattered thunderstorm development by mid to late afternoon. Adequate deep-layer shear will be in place to promote storm organization, including the potential for a supercell or two if more discrete storm modes can be realized. However, weak low-level storm-relative winds and steep low-level lapse rates will likely favor cold-pool driven storm propagation and the development of multiple convective clusters with an attendant severe-wind risk. ...Montana... A shortwave impulse is evident in early-morning water-vapor imagery across the Pacific Northwest. This feature is expected to crest the apex of a stout upper ridge over the next 24 hours. Advected precipitable water imagery shows a diluted plume of monsoonal moisture ahead of this wave, which should provide adequate mid-level moisture for thunderstorm development by late afternoon. While buoyancy will be very modest (around 500 J/kg SBCAPE), 30 knot mid-level flow atop easterly low-level winds should provide adequate deep-layer wind shear for some storm organization, most likely into somewhat cohesive clusters given deep-boundary layer mixing that will favor strong cold pool production. Such clusters may be capable of strong to severe winds as they push east across north-central MT. ..Moore.. 07/18/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1251 AM CDT Thu Jul 18 2024 Valid 181200Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EASTERN NORTH CAROLINA INTO FAR SOUTHEAST VIRGINIA... ...SUMMARY... Isolated strong to severe thunderstorms are possible Thursday afternoon across parts of north-central Montana and the central and southern High Plains. Isolated to scattered severe thunderstorms are also expected from the southern Appalachians into eastern North Carolina. ...Synopsis... Early-morning surface observations show a diffuse cold front draped from the Mid-Atlantic region into the southern Plains. This feature is expected to slowly push south over the next 24 hours, as surface high pressure builds over the Plains/Midwest in the wake of an eastward-tracking upper wave. A reservoir of upper 60s to low 70s dewpoints lies to the south of the cold front, and while mid-level lapse rates are fairly modest (based on 00 UTC soundings), diurnal heating into the mid 80s should be sufficient to promote thunderstorm development along the front by early afternoon. Thunderstorm coverage is expected to be somewhat more focused across the southern Appalachians into the Carolinas, as ascent associated with a weak mid-level perturbation (currently over the mid-MS Valley) overspreads the region at peak heating. To the west, isolated to scattered thunderstorms appear likely within an upslope flow regime along the central Rockies and ahead of a shortwave trough over northern Montana. ...Carolinas... The synoptic cold front is currently forecast to be along the VA/NC border by around mid-day. Thunderstorm development along the front appears probable by around 18 UTC, as temperatures warm into the low 80s and ascent from a subtle mid-level impulse overspreads the region. Large hail may be an initial concern depending on storm coverage along the front, but storm motion and deep-layer shear vectors along and/or towards the cool side of the boundary will likely promote upscale growth by mid/late afternoon. As this occurs, the potential for strong to severe winds will increase downstream across eastern NC and far southeast VA. Latest CAM guidance shows reasonably good agreement in the development of a squall line, and while deep-layer shear will not be overly strong (around 25 knots), heating ahead of the line should yield moderate buoyancy with MLCAPE reaching up to 2500 J/kg that will promote robust convection capable of damaging gusts. The coverage of this threat appears sufficient to warrant higher (15%) wind risk probabilities. ...Central to southern High Plains... Another day of easterly upslope winds along the southern to central Rockies is anticipated as a surface high to the east builds. Latest upper-air analyses show the east slopes of the Rockies lie on the periphery of a plume of relatively steep (7+ C/km) lapse rates. This should support isolated to scattered thunderstorm development by mid to late afternoon. Adequate deep-layer shear will be in place to promote storm organization, including the potential for a supercell or two if more discrete storm modes can be realized. However, weak low-level storm-relative winds and steep low-level lapse rates will likely favor cold-pool driven storm propagation and the development of multiple convective clusters with an attendant severe-wind risk. ...Montana... A shortwave impulse is evident in early-morning water-vapor imagery across the Pacific Northwest. This feature is expected to crest the apex of a stout upper ridge over the next 24 hours. Advected precipitable water imagery shows a diluted plume of monsoonal moisture ahead of this wave, which should provide adequate mid-level moisture for thunderstorm development by late afternoon. While buoyancy will be very modest (around 500 J/kg SBCAPE), 30 knot mid-level flow atop easterly low-level winds should provide adequate deep-layer wind shear for some storm organization, most likely into somewhat cohesive clusters given deep-boundary layer mixing that will favor strong cold pool production. Such clusters may be capable of strong to severe winds as they push east across north-central MT. ..Moore.. 07/18/2024 Read more