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SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1036 AM CST Wed Nov 13 2024 Valid 131700Z - 141200Z ...Mid-Atlantic/New England The previous forecast remains on track with only minor adjustments made across the New England region. Surface and VWP observations show low-level winds are gradually weakening across the broader Mid-Atlantic/New England region, and this trend should continue as a surface high migrates east through the day. However, given recent fire starts over the past 24 hours and very dry conditions (RH values are already falling into the low 30s and upper 20s per 16 UTC observations), the fire weather highlight is maintained/expanded into areas with recent fire activity. ...West Virginia... Dry conditions remain likely on the northern/northwestern slopes of the southern to central Appalachians today as winds gradually become more southeasterly. Some high-res solutions hint that areas of elevated to critical conditions are possible within the higher terrain of the southern Allegheny Mountains and the Potomac Highlands, and appear most likely through the Monongahela National Forest where a few stations are already reporting elevated conditions. However, the presence of the synoptic surface high suggests that while very dry conditions are likely, winds should remain benign away from the terrain. Gradient winds should increase near/after sunset in response to an approaching surface low from the southwest, but this should be temporally displaced from afternoon RH minimums. 12z guidance generally supports this idea, casting uncertainty onto the spatial extent of elevated/critical conditions. While the fire weather potential is noted, highlights are withheld due to coverage concerns. ..Moore.. 11/13/2024 .PREV DISCUSSION... /ISSUED 1246 AM CST Wed Nov 13 2024/ ...Synopsis... ...Northeast/New England... Gusty post-frontal offshore flow will continue across the northeastern US today, with potential for relative humidity reductions to around 30-40 percent and northwesterly winds around 10 mph gusting 20-25 mph. An Elevated delineation was maintained with this outlook to cover this threat. Winds should gradually weaken through the afternoon as high pressure builds in across the region. ...Appalachians Tennessee/North Carolina border through the West Virginia-Virginia Border... Strong southeast winds further enhanced by downslope flow will bring areas of locally Elevated fire weather concerns to portions of the Appalachians near the TN/NC border through the WV/VA border. Relative humidity reductions to around 20-25 percent may overlap with enhanced flow in favored north facing slopes. Wetting rainfall will overspread this region Wednesday night into Thursday. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1630Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1033 AM CST Wed Nov 13 2024 Valid 131630Z - 141200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN PORTIONS OF LOUISIANA/MISSISSIPPI... ...SUMMARY... Isolated severe thunderstorms may occur today across the Lower Mississippi Valley, posing a risk for isolated severe wind gusts and potentially a couple of tornadoes. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Have upgraded portions of southeast Louisiana and far southern Mississippi for the possibility of a couple of tornadoes and localized wind damage. While multi-layer cloud cover has generally persisted, small pockets of clearing/scattering have occurred within the warm sector with several surface observations with temperatures near/just above 80 F. Rich low-level moisture will continue to stream northward today, while an upper trough over the Plains continues eastward towards the Ohio Valley. Primary surface low and better forcing associated with this upper trough will initially be well north of the inland-advancing warm sector. However, scattered surface-based thunderstorms should develop and become more common this afternoon as the remnant/weak surface low off the Louisiana Coast moves slowly inland. Low-level shear (through 1-3km AGL) should increase through late afternoon into this evening, particularly in vicinity of the surface low/triple point. A few supercells/clusters will pose potential for damaging winds and possibly a couple of tornadoes. ...Coastal Pacific Northwest... Associated with an eastward-moving upper-level trough, cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates will yield weak instability today across parts of the coastal Pacific Northwest (see 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Guyer/Lyons.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0658 AM CST Wed Nov 13 2024 Valid 131300Z - 141200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND COASTAL PACIFIC NORTHWEST... ...SUMMARY... A few strong to severe thunderstorms may occur today across the lower Mississippi Valley, posing a risk for isolated severe gusts and perhaps a tornado or two. Occasional severe winds may also develop along parts of the coastal Pacific Northwest. ...Lower Mississippi Valley... Rich low-level moisture will continue to stream northward today across parts of the lower MS Valley into the Mid-South as an upper trough over the Plains continues eastward towards the OH Valley. Primary surface low and better forcing associated with this upper trough are forecast to remain well north of the inland-advancing warm sector. Even so, scattered surface-based thunderstorms should develop by this afternoon as a remnant/weak surface low off the LA Coast moves slowly inland. Filtered daytime heating of the moist low-level airmass should result in modest instability developing by this afternoon, even though mid-level lapse rates will remain poor (see 12Z JAN/LIX soundings). Low-level southerly flow will not be overly strong across the lower MS Valley, but gradual veering and strengthening of winds with height through mid levels should support sufficient deep-layer shear for modest updraft organization. A few marginal supercells/clusters may pose an isolated threat for strong to damaging winds as they spread eastward across LA/MS this afternoon and evening. Enough low-level shear should also be present to foster some updraft rotation and the threat for a tornado or two, with an isolated severe threat potentially continuing into tonight across parts of southwest AL and vicinity. The warm sector will become increasingly pinched off with northward extent in MS and western TN, with convection generally expected to outpace the low-level moisture return. Given the expected mismatch of stronger forcing/shear farther north and better instability to the south, have opted to maintain the Marginal Risk this update, with some expansion based on latest guidance trends. ...Coastal Pacific Northwest... Cold mid-level temperatures (around -24 to -26C at 500 mb) and modestly steepened mid-level lapse rates associated with an eastward-moving upper trough will help support weak instability today across parts of the coastal Pacific Northwest (reference 12Z UIL sounding). Persistent large-scale ascent across this region will support both low-topped cells and bands of convection moving eastward through this afternoon and early evening. Given the forecast strength of the low-level winds, some of this activity may occasionally produce strong to severe wind gusts, and perhaps small hail. Tornado potential remains unclear, as low-level flow will have a tendency to veer more to southwesterly through the day, which should limit 0-1 km SRH. ..Gleason/Bentley.. 11/13/2024 Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0359 AM CST Wed Nov 13 2024 Valid 161200Z - 211200Z ...DISCUSSION... Some severe potential remains evident across parts of the southern/central Plains (and potentially farther east) early next week, though uncertainty remains regarding the most favored corridor and the magnitude and sufficiency of low-level moisture/instability. ...D5/Sunday - D6/Monday... On Saturday, a shortwave trough and attendant surface low are forecast to move across the northern Great Plains. Low-level southeasterly flow will result in early-stage moisture return into the southern/central Plains, as a surface ridge shifts eastward across the eastern CONUS. Meanwhile, a shortwave mid/upper-level trough initially near the southern CA/Baja coast may evolve into a closed upper-level low as it digs east-southeastward from late Saturday into early Sunday. This trough/low is then forecast to eject northeastward as a negatively tilted trough across parts of the southern/central Plains from late Sunday into Monday, accompanied by significant surface cyclogenesis. The primary uncertainty regarding severe potential for D5/Sunday into D6/Monday is the magnitude of low-level moisture return and destabilization across the warm sector of the developing surface low. While low/mid 60s F dewpoints may return into parts of TX and perhaps OK, with 50s F dewpoints farther north, limited heating and relatively weak lapse rates will limit buoyancy, with the GFS/ECMWF and their related ensembles suggesting MLCAPE of 500 J/kg or greater may be confined to parts of central/south TX, with increasingly limited buoyancy farther north. Some severe potential could evolve on D5/Sunday, especially later in the period when the ejecting shortwave trough may begin to impinge on richer moisture from southwest into central TX. An intensifying low-level jet may support development of widespread convection from late on D5/Sunday into D6/Monday, with a strongly forced band of convection potentially moving east-northeastward across a larger portion of the southern/central Plains. Despite the very limited instability that is currently anticipated across much of the region, the intense wind fields and strong ascent associated with the ejecting shortwave trough (as depicted by the GFS/ECMWF and some ensemble members) could support an organized severe threat within a low-CAPE/high-shear regime. Uncertainty remains regarding the most favorable corridor, with the GFS/ECMWF favoring parts of the southern/central Plains, while some ensemble members favor a zone farther east from the ArkLaTex into the mid MS Valley. ...D7/Tuesday - D8/Wednesday... Some severe potential could continue into D7/Tuesday into parts of the Midwest and Ohio Valley, though there may be a tendency for stronger deep-layer flow and ascent to become increasingly displaced from sufficient moisture and instability. NHC is currently forecasting a high probability of tropical cyclone formation late this week into the weekend across the central/western Caribbean Sea. Predictability remains very low regarding the possibility for this system to influence severe potential across the Southeast toward the middle of next week. Read more