Severe Storms

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0121 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...Synopsis... Dry thunderstorms will remain the primary fire weather concern on Sunday across parts of the Great Basin and Pacific Northwest. An upper-level low is evident in early-morning water-vapor imagery off the northern CA coast. This feature is expected to begin moving onshore Sunday afternoon into the overnight hours. Broadscale ascent ahead of this feature will overspread northern CA/southern OR and the northern Great Basin, resulting in slightly stronger surface winds compared to previous days (though generally at or below 15 mph) and isolated thunderstorm chances. Forecast soundings from across the region suggest buoyancy will be adequate for convection on the northern fringe of a modest monsoonal moisture plume, but mixed-layer LCLs between 3 to 3.5 km (indicative of a deep, dry boundary-layer) will promote little rain accumulation. As such, dry lightning appears likely and will pose a fire weather threat given regional ERC values between the 80th to 90th percentiles. Stronger forcing for ascent may result in higher thunderstorm coverage across the Great Basin compared to previous days, and recent CAM solutions hint that central to northeast NV may see the greatest potential for dry lightning strikes. ..Moore.. 08/31/2024 ...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 Sat Aug 31 2024 Valid 011200Z - 021200Z ...Synopsis... Dry thunderstorms will remain the primary fire weather concern on Sunday across parts of the Great Basin and Pacific Northwest. An upper-level low is evident in early-morning water-vapor imagery off the northern CA coast. This feature is expected to begin moving onshore Sunday afternoon into the overnight hours. Broadscale ascent ahead of this feature will overspread northern CA/southern OR and the northern Great Basin, resulting in slightly stronger surface winds compared to previous days (though generally at or below 15 mph) and isolated thunderstorm chances. Forecast soundings from across the region suggest buoyancy will be adequate for convection on the northern fringe of a modest monsoonal moisture plume, but mixed-layer LCLs between 3 to 3.5 km (indicative of a deep, dry boundary-layer) will promote little rain accumulation. As such, dry lightning appears likely and will pose a fire weather threat given regional ERC values between the 80th to 90th percentiles. Stronger forcing for ascent may result in higher thunderstorm coverage across the Great Basin compared to previous days, and recent CAM solutions hint that central to northeast NV may see the greatest potential for dry lightning strikes. ..Moore.. 08/31/2024 ...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 1258 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND MID-ATLANTIC REGIONS...AND SOUTHWESTWARD TO THE SOUTHERN APPALACHIANS... ...SUMMARY... Strong/isolated severe storms capable of producing gusty/damaging winds will be possible from the Mid-Atlantic region to the central and southern Appalachians, and possibly parts of New England on Sunday. ...Synopsis... An upper trough advancing initially across Ontario and the Upper Great Lakes region will progress steadily eastward eastern Canada and the northeastern U.S. through the period. Upstream, ridging will prevail over the West, though an eastern Pacific upper low will approach the Oregon/northern California Coasts late in the period. At the surface, an initial/weakening cold front lingering across New England and the Atlantic Coast states during the first half of the period will be gradually overtaken by a second/stronger front shifting across the Great Lakes/Midwest early in the period. By Monday morning, the front will likely have reached/moved off the New England and Mid-Atlantic Coasts, trailing southwestward across the southeast and Gulf Coast regions. ...Parts of New England to the Mid-Atlantic region, and into the central/southern Appalachians... The remnant surface cold front -- gradually being overtaken by the stronger/reinforcing front -- will serve as a focus for convective activity Sunday. As the upper trough steadily advances, increasingly strong flow aloft will overspread the Northeast/New England. With that said however, substantial questions persist across the Northeast -- particularly into New England -- given likelihood for ongoing convection/cloud cover in the vicinity of the initial/weakening front. Thus, despite increasingly favorable deep-layer shear that would otherwise support well-organized convection, afternoon destabilization potential may be sufficiently hampered so as to substantially limit severe potential. Farther to the south -- across portions of the Mid-Atlantic region and west-southwestward across the Appalachians, somewhat greater destabilization potential is expected, but with weaker flow aloft as compared to areas farther north. Still, shear may prove sufficient when combined with the anticipated/modest afternoon destabilization to support stronger storms locally, and associated risk for gusty outflow winds and local/minor wind damage during the afternoon and early evening hours. ..Goss.. 08/31/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND MID-ATLANTIC REGIONS...AND SOUTHWESTWARD TO THE SOUTHERN APPALACHIANS... ...SUMMARY... Strong/isolated severe storms capable of producing gusty/damaging winds will be possible from the Mid-Atlantic region to the central and southern Appalachians, and possibly parts of New England on Sunday. ...Synopsis... An upper trough advancing initially across Ontario and the Upper Great Lakes region will progress steadily eastward eastern Canada and the northeastern U.S. through the period. Upstream, ridging will prevail over the West, though an eastern Pacific upper low will approach the Oregon/northern California Coasts late in the period. At the surface, an initial/weakening cold front lingering across New England and the Atlantic Coast states during the first half of the period will be gradually overtaken by a second/stronger front shifting across the Great Lakes/Midwest early in the period. By Monday morning, the front will likely have reached/moved off the New England and Mid-Atlantic Coasts, trailing southwestward across the southeast and Gulf Coast regions. ...Parts of New England to the Mid-Atlantic region, and into the central/southern Appalachians... The remnant surface cold front -- gradually being overtaken by the stronger/reinforcing front -- will serve as a focus for convective activity Sunday. As the upper trough steadily advances, increasingly strong flow aloft will overspread the Northeast/New England. With that said however, substantial questions persist across the Northeast -- particularly into New England -- given likelihood for ongoing convection/cloud cover in the vicinity of the initial/weakening front. Thus, despite increasingly favorable deep-layer shear that would otherwise support well-organized convection, afternoon destabilization potential may be sufficiently hampered so as to substantially limit severe potential. Farther to the south -- across portions of the Mid-Atlantic region and west-southwestward across the Appalachians, somewhat greater destabilization potential is expected, but with weaker flow aloft as compared to areas farther north. Still, shear may prove sufficient when combined with the anticipated/modest afternoon destabilization to support stronger storms locally, and associated risk for gusty outflow winds and local/minor wind damage during the afternoon and early evening hours. ..Goss.. 08/31/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND MID-ATLANTIC REGIONS...AND SOUTHWESTWARD TO THE SOUTHERN APPALACHIANS... ...SUMMARY... Strong/isolated severe storms capable of producing gusty/damaging winds will be possible from the Mid-Atlantic region to the central and southern Appalachians, and possibly parts of New England on Sunday. ...Synopsis... An upper trough advancing initially across Ontario and the Upper Great Lakes region will progress steadily eastward eastern Canada and the northeastern U.S. through the period. Upstream, ridging will prevail over the West, though an eastern Pacific upper low will approach the Oregon/northern California Coasts late in the period. At the surface, an initial/weakening cold front lingering across New England and the Atlantic Coast states during the first half of the period will be gradually overtaken by a second/stronger front shifting across the Great Lakes/Midwest early in the period. By Monday morning, the front will likely have reached/moved off the New England and Mid-Atlantic Coasts, trailing southwestward across the southeast and Gulf Coast regions. ...Parts of New England to the Mid-Atlantic region, and into the central/southern Appalachians... The remnant surface cold front -- gradually being overtaken by the stronger/reinforcing front -- will serve as a focus for convective activity Sunday. As the upper trough steadily advances, increasingly strong flow aloft will overspread the Northeast/New England. With that said however, substantial questions persist across the Northeast -- particularly into New England -- given likelihood for ongoing convection/cloud cover in the vicinity of the initial/weakening front. Thus, despite increasingly favorable deep-layer shear that would otherwise support well-organized convection, afternoon destabilization potential may be sufficiently hampered so as to substantially limit severe potential. Farther to the south -- across portions of the Mid-Atlantic region and west-southwestward across the Appalachians, somewhat greater destabilization potential is expected, but with weaker flow aloft as compared to areas farther north. Still, shear may prove sufficient when combined with the anticipated/modest afternoon destabilization to support stronger storms locally, and associated risk for gusty outflow winds and local/minor wind damage during the afternoon and early evening hours. ..Goss.. 08/31/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND MID-ATLANTIC REGIONS...AND SOUTHWESTWARD TO THE SOUTHERN APPALACHIANS... ...SUMMARY... Strong/isolated severe storms capable of producing gusty/damaging winds will be possible from the Mid-Atlantic region to the central and southern Appalachians, and possibly parts of New England on Sunday. ...Synopsis... An upper trough advancing initially across Ontario and the Upper Great Lakes region will progress steadily eastward eastern Canada and the northeastern U.S. through the period. Upstream, ridging will prevail over the West, though an eastern Pacific upper low will approach the Oregon/northern California Coasts late in the period. At the surface, an initial/weakening cold front lingering across New England and the Atlantic Coast states during the first half of the period will be gradually overtaken by a second/stronger front shifting across the Great Lakes/Midwest early in the period. By Monday morning, the front will likely have reached/moved off the New England and Mid-Atlantic Coasts, trailing southwestward across the southeast and Gulf Coast regions. ...Parts of New England to the Mid-Atlantic region, and into the central/southern Appalachians... The remnant surface cold front -- gradually being overtaken by the stronger/reinforcing front -- will serve as a focus for convective activity Sunday. As the upper trough steadily advances, increasingly strong flow aloft will overspread the Northeast/New England. With that said however, substantial questions persist across the Northeast -- particularly into New England -- given likelihood for ongoing convection/cloud cover in the vicinity of the initial/weakening front. Thus, despite increasingly favorable deep-layer shear that would otherwise support well-organized convection, afternoon destabilization potential may be sufficiently hampered so as to substantially limit severe potential. Farther to the south -- across portions of the Mid-Atlantic region and west-southwestward across the Appalachians, somewhat greater destabilization potential is expected, but with weaker flow aloft as compared to areas farther north. Still, shear may prove sufficient when combined with the anticipated/modest afternoon destabilization to support stronger storms locally, and associated risk for gusty outflow winds and local/minor wind damage during the afternoon and early evening hours. ..Goss.. 08/31/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1258 AM CDT Sat Aug 31 2024 Valid 011200Z - 021200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE NORTHEAST AND MID-ATLANTIC REGIONS...AND SOUTHWESTWARD TO THE SOUTHERN APPALACHIANS... ...SUMMARY... Strong/isolated severe storms capable of producing gusty/damaging winds will be possible from the Mid-Atlantic region to the central and southern Appalachians, and possibly parts of New England on Sunday. ...Synopsis... An upper trough advancing initially across Ontario and the Upper Great Lakes region will progress steadily eastward eastern Canada and the northeastern U.S. through the period. Upstream, ridging will prevail over the West, though an eastern Pacific upper low will approach the Oregon/northern California Coasts late in the period. At the surface, an initial/weakening cold front lingering across New England and the Atlantic Coast states during the first half of the period will be gradually overtaken by a second/stronger front shifting across the Great Lakes/Midwest early in the period. By Monday morning, the front will likely have reached/moved off the New England and Mid-Atlantic Coasts, trailing southwestward across the southeast and Gulf Coast regions. ...Parts of New England to the Mid-Atlantic region, and into the central/southern Appalachians... The remnant surface cold front -- gradually being overtaken by the stronger/reinforcing front -- will serve as a focus for convective activity Sunday. As the upper trough steadily advances, increasingly strong flow aloft will overspread the Northeast/New England. With that said however, substantial questions persist across the Northeast -- particularly into New England -- given likelihood for ongoing convection/cloud cover in the vicinity of the initial/weakening front. Thus, despite increasingly favorable deep-layer shear that would otherwise support well-organized convection, afternoon destabilization potential may be sufficiently hampered so as to substantially limit severe potential. Farther to the south -- across portions of the Mid-Atlantic region and west-southwestward across the Appalachians, somewhat greater destabilization potential is expected, but with weaker flow aloft as compared to areas farther north. Still, shear may prove sufficient when combined with the anticipated/modest afternoon destabilization to support stronger storms locally, and associated risk for gusty outflow winds and local/minor wind damage during the afternoon and early evening hours. ..Goss.. 08/31/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms, associated with severe wind gusts and hail, will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts will be possible in parts of the northern Great Lakes. ...Central Appalachians/Ohio and Tennessee Valleys... An upper-level trough will move through the Great Lakes region, with the southern end of the trough located in the mid Mississippi Valley. An associated cold front will advance southeastward through the mid Mississippi Valley and southern Great Lakes. Ahead of the front, a moist airmass will be in place with surface dewpoints in the upper 60s and lower 70s F. Moderate instability is expected to develop by midday ahead of much of the front. Further to the east, a pre-frontal trough will be located from western New York and western Pennsylvania southwestward into eastern Kentucky. Scattered thunderstorms will form from near the front eastward to near the pre-frontal trough. By early to mid afternoon, RAP forecast soundings have MLCAPE peaking in the 1500 to 2000 J/kg range from western New York southwestward into West Virginia. Along this portion of the instability corridor, 0-6 km shear is forecast to be in the 20 to 30 knot range. This, along with 0-3 km lapse rates near 7.5 C/km will support severe wind gusts with the more organized bowing line segments. Hail will also be possible. Further to the southwest into parts of the lower Ohio and Tennessee Valleys, the models suggest that deep-layer shear will generally be below 20 knots. Although steep low-level lapse rates could be enough for a marginal wind-damage threat, the weakness in shear should keep any threat isolated. ...Northern Great Lakes... A cyclonic mid-level flow pattern will be in place today across much of southern Canada and over the Great Lakes. Within this flow, a shortwave trough and an associated cold front is forecast to move southeastward toward the northern Great Lakes. Ahead of the front, surface dewpoints in the 50s F will contribute to weak destabilization by afternoon. Thunderstorms are expected to form along and ahead of the front as instability peaks during the mid to late afternoon. In spite of the weak instability, large-scale ascent and strong deep-layer shear, associated with the shortwave trough, could be enough for isolated severe wind gusts. ..Broyles/Moore.. 08/31/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms, associated with severe wind gusts and hail, will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts will be possible in parts of the northern Great Lakes. ...Central Appalachians/Ohio and Tennessee Valleys... An upper-level trough will move through the Great Lakes region, with the southern end of the trough located in the mid Mississippi Valley. An associated cold front will advance southeastward through the mid Mississippi Valley and southern Great Lakes. Ahead of the front, a moist airmass will be in place with surface dewpoints in the upper 60s and lower 70s F. Moderate instability is expected to develop by midday ahead of much of the front. Further to the east, a pre-frontal trough will be located from western New York and western Pennsylvania southwestward into eastern Kentucky. Scattered thunderstorms will form from near the front eastward to near the pre-frontal trough. By early to mid afternoon, RAP forecast soundings have MLCAPE peaking in the 1500 to 2000 J/kg range from western New York southwestward into West Virginia. Along this portion of the instability corridor, 0-6 km shear is forecast to be in the 20 to 30 knot range. This, along with 0-3 km lapse rates near 7.5 C/km will support severe wind gusts with the more organized bowing line segments. Hail will also be possible. Further to the southwest into parts of the lower Ohio and Tennessee Valleys, the models suggest that deep-layer shear will generally be below 20 knots. Although steep low-level lapse rates could be enough for a marginal wind-damage threat, the weakness in shear should keep any threat isolated. ...Northern Great Lakes... A cyclonic mid-level flow pattern will be in place today across much of southern Canada and over the Great Lakes. Within this flow, a shortwave trough and an associated cold front is forecast to move southeastward toward the northern Great Lakes. Ahead of the front, surface dewpoints in the 50s F will contribute to weak destabilization by afternoon. Thunderstorms are expected to form along and ahead of the front as instability peaks during the mid to late afternoon. In spite of the weak instability, large-scale ascent and strong deep-layer shear, associated with the shortwave trough, could be enough for isolated severe wind gusts. ..Broyles/Moore.. 08/31/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms, associated with severe wind gusts and hail, will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts will be possible in parts of the northern Great Lakes. ...Central Appalachians/Ohio and Tennessee Valleys... An upper-level trough will move through the Great Lakes region, with the southern end of the trough located in the mid Mississippi Valley. An associated cold front will advance southeastward through the mid Mississippi Valley and southern Great Lakes. Ahead of the front, a moist airmass will be in place with surface dewpoints in the upper 60s and lower 70s F. Moderate instability is expected to develop by midday ahead of much of the front. Further to the east, a pre-frontal trough will be located from western New York and western Pennsylvania southwestward into eastern Kentucky. Scattered thunderstorms will form from near the front eastward to near the pre-frontal trough. By early to mid afternoon, RAP forecast soundings have MLCAPE peaking in the 1500 to 2000 J/kg range from western New York southwestward into West Virginia. Along this portion of the instability corridor, 0-6 km shear is forecast to be in the 20 to 30 knot range. This, along with 0-3 km lapse rates near 7.5 C/km will support severe wind gusts with the more organized bowing line segments. Hail will also be possible. Further to the southwest into parts of the lower Ohio and Tennessee Valleys, the models suggest that deep-layer shear will generally be below 20 knots. Although steep low-level lapse rates could be enough for a marginal wind-damage threat, the weakness in shear should keep any threat isolated. ...Northern Great Lakes... A cyclonic mid-level flow pattern will be in place today across much of southern Canada and over the Great Lakes. Within this flow, a shortwave trough and an associated cold front is forecast to move southeastward toward the northern Great Lakes. Ahead of the front, surface dewpoints in the 50s F will contribute to weak destabilization by afternoon. Thunderstorms are expected to form along and ahead of the front as instability peaks during the mid to late afternoon. In spite of the weak instability, large-scale ascent and strong deep-layer shear, associated with the shortwave trough, could be enough for isolated severe wind gusts. ..Broyles/Moore.. 08/31/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms, associated with severe wind gusts and hail, will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts will be possible in parts of the northern Great Lakes. ...Central Appalachians/Ohio and Tennessee Valleys... An upper-level trough will move through the Great Lakes region, with the southern end of the trough located in the mid Mississippi Valley. An associated cold front will advance southeastward through the mid Mississippi Valley and southern Great Lakes. Ahead of the front, a moist airmass will be in place with surface dewpoints in the upper 60s and lower 70s F. Moderate instability is expected to develop by midday ahead of much of the front. Further to the east, a pre-frontal trough will be located from western New York and western Pennsylvania southwestward into eastern Kentucky. Scattered thunderstorms will form from near the front eastward to near the pre-frontal trough. By early to mid afternoon, RAP forecast soundings have MLCAPE peaking in the 1500 to 2000 J/kg range from western New York southwestward into West Virginia. Along this portion of the instability corridor, 0-6 km shear is forecast to be in the 20 to 30 knot range. This, along with 0-3 km lapse rates near 7.5 C/km will support severe wind gusts with the more organized bowing line segments. Hail will also be possible. Further to the southwest into parts of the lower Ohio and Tennessee Valleys, the models suggest that deep-layer shear will generally be below 20 knots. Although steep low-level lapse rates could be enough for a marginal wind-damage threat, the weakness in shear should keep any threat isolated. ...Northern Great Lakes... A cyclonic mid-level flow pattern will be in place today across much of southern Canada and over the Great Lakes. Within this flow, a shortwave trough and an associated cold front is forecast to move southeastward toward the northern Great Lakes. Ahead of the front, surface dewpoints in the 50s F will contribute to weak destabilization by afternoon. Thunderstorms are expected to form along and ahead of the front as instability peaks during the mid to late afternoon. In spite of the weak instability, large-scale ascent and strong deep-layer shear, associated with the shortwave trough, could be enough for isolated severe wind gusts. ..Broyles/Moore.. 08/31/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0101 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL APPALACHIANS AND UPPER OHIO VALLEY... ...SUMMARY... Severe thunderstorms, associated with severe wind gusts and hail, will be possible today from parts of the central Appalachians into the Ohio and Tennessee Valleys. Isolated severe wind gusts will be possible in parts of the northern Great Lakes. ...Central Appalachians/Ohio and Tennessee Valleys... An upper-level trough will move through the Great Lakes region, with the southern end of the trough located in the mid Mississippi Valley. An associated cold front will advance southeastward through the mid Mississippi Valley and southern Great Lakes. Ahead of the front, a moist airmass will be in place with surface dewpoints in the upper 60s and lower 70s F. Moderate instability is expected to develop by midday ahead of much of the front. Further to the east, a pre-frontal trough will be located from western New York and western Pennsylvania southwestward into eastern Kentucky. Scattered thunderstorms will form from near the front eastward to near the pre-frontal trough. By early to mid afternoon, RAP forecast soundings have MLCAPE peaking in the 1500 to 2000 J/kg range from western New York southwestward into West Virginia. Along this portion of the instability corridor, 0-6 km shear is forecast to be in the 20 to 30 knot range. This, along with 0-3 km lapse rates near 7.5 C/km will support severe wind gusts with the more organized bowing line segments. Hail will also be possible. Further to the southwest into parts of the lower Ohio and Tennessee Valleys, the models suggest that deep-layer shear will generally be below 20 knots. Although steep low-level lapse rates could be enough for a marginal wind-damage threat, the weakness in shear should keep any threat isolated. ...Northern Great Lakes... A cyclonic mid-level flow pattern will be in place today across much of southern Canada and over the Great Lakes. Within this flow, a shortwave trough and an associated cold front is forecast to move southeastward toward the northern Great Lakes. Ahead of the front, surface dewpoints in the 50s F will contribute to weak destabilization by afternoon. Thunderstorms are expected to form along and ahead of the front as instability peaks during the mid to late afternoon. In spite of the weak instability, large-scale ascent and strong deep-layer shear, associated with the shortwave trough, could be enough for isolated severe wind gusts. ..Broyles/Moore.. 08/31/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...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 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...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 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...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 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...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 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...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 1242 AM CDT Sat Aug 31 2024 Valid 311200Z - 011200Z ...Synopsis... Dry thunderstorms will be the primary fire weather concern for today across portions of southern/eastern Nevada into far southwest Utah. A modest monsoonal moisture plume has been slowly spreading northwestward from southern/central AZ into southern NV over the past 12 hours per GOES water-vapor and PWAT imagery. Increasing mid-level moisture has also been noted in recent VEF soundings with PWAT values increasing to 0.85 inches as recently as 00 UTC Saturday. This moisture, combined with cool mid-level temperatures, will support isolated thunderstorms by late afternoon as ascent associated with a weak mid-level perturbation overspreads the southern Great Basin. Slow storm motions around 10 knots should promote very narrow swaths of rainfall, but very dry boundary layer conditions (similar in nature to the 00 UTC VEF sounding) will likely be in place by peak heating and should promote limited rain accumulation away from the primary downdraft cores. While thunderstorm coverage is expected to be fairly isolated, dry lightning strikes are likely with any storm that can develop and will pose a fire weather concern considering ERCs are at or above the 80th percentile. Elsewhere, very dry conditions will persist across the remainder of the Great Basin with afternoon RH values in the single digits to teens. Surface gradient winds are forecast to generally remain below 15 mph for most locations, which limits confidence in additional fire weather concerns. The general consensus among recent high-res guidance is that the strongest winds will likely be associated with thunderstorm outflows across southern NV/southwest UT and into central AZ. ..Moore.. 08/31/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Fri Aug 30 2024 Valid 310100Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN GREAT LAKES SOUTHWESTWARD INTO THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe storms, with marginally severe wind gusts and hail will be possible this evening from southeast Lower Michigan southwestward into the mid Mississippi Valley. ...Southern Great Lakes/Mid Mississippi Valley... The latest mosaic water vapor imagery shows an upper-level trough over the western Great Lakes extending southward into the mid Mississippi Valley. An associated cold front is analyzed from southeast Lower Michigan southwestward to near St. Louis, Missouri. Scattered thunderstorms are ongoing along and near the front. Surface dewpoints near and ahead of the front are in the upper 60s and lower 70s F, and the RAP has MLCAPE in the 1200 to 2500 J/k/g range. In addition, regional WSR-88D VWPs near the front have 0-6 km shear ranging from near 20 knot at St. Louis to around 30 knots at Detroit. This environment, combined with steep low-level lapse rates near 7 C/km, should be enough for a marginally severe wind gusts for a couple more hours this evening. Hail could also occur within the cores of the stronger multicells. ..Broyles.. 08/31/2024 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0750 PM CDT Fri Aug 30 2024 Valid 310100Z - 311200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN GREAT LAKES SOUTHWESTWARD INTO THE MID MISSISSIPPI VALLEY... ...SUMMARY... Isolated severe storms, with marginally severe wind gusts and hail will be possible this evening from southeast Lower Michigan southwestward into the mid Mississippi Valley. ...Southern Great Lakes/Mid Mississippi Valley... The latest mosaic water vapor imagery shows an upper-level trough over the western Great Lakes extending southward into the mid Mississippi Valley. An associated cold front is analyzed from southeast Lower Michigan southwestward to near St. Louis, Missouri. Scattered thunderstorms are ongoing along and near the front. Surface dewpoints near and ahead of the front are in the upper 60s and lower 70s F, and the RAP has MLCAPE in the 1200 to 2500 J/k/g range. In addition, regional WSR-88D VWPs near the front have 0-6 km shear ranging from near 20 knot at St. Louis to around 30 knots at Detroit. This environment, combined with steep low-level lapse rates near 7 C/km, should be enough for a marginally severe wind gusts for a couple more hours this evening. Hail could also occur within the cores of the stronger multicells. ..Broyles.. 08/31/2024 Read more