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ABPZ20 KNHC 091113
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
500 AM PDT Mon Sep 9 2024

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

Offshore of Southwestern Mexico:
An area of low pressure is forecast to form during the middle part
of the week, near or just to the south of the coast of southwestern
Mexico. Environmental conditions are forecast to be conducive for
some gradual development of this system, and a tropical depression
could form during the middle to latter part of this week while it
moves generally north-northwestward, near the coast of southwestern
Mexico.
* Formation chance through 48 hours...low...near 0 percent.
* Formation chance through 7 days...medium...60 percent.

$$
Forecaster Roberts

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Mon Sep 09 2024 Valid 121200Z - 171200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... A tropical cyclone is forecast to move slowly northward through the lower to mid Mississippi Valley from Thursday to Saturday. A tornado threat will be possible to the east of the center across much of the central Gulf Coast region on Thursday. Model forecasts suggest that the tornado threat could shift northward into the Tennessee Valley on Friday. On Saturday, uncertainty is considerable concerning the location of any tropical cyclone remnants. If current solutions are reasonably close, then a tornado threat would be possible in the Southeast, potentially from the southern Appalachians into the Carolinas. ...Sunday/Day 7 and Monday/Day 8... Mid-level flow is forecast to be relatively weak across the central and eastern U.S. on Sunday and Monday. The diffuse pattern and weak deep-layer shear across most of the U.S. suggests that the severe potential will remain low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Mon Sep 09 2024 Valid 121200Z - 171200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... A tropical cyclone is forecast to move slowly northward through the lower to mid Mississippi Valley from Thursday to Saturday. A tornado threat will be possible to the east of the center across much of the central Gulf Coast region on Thursday. Model forecasts suggest that the tornado threat could shift northward into the Tennessee Valley on Friday. On Saturday, uncertainty is considerable concerning the location of any tropical cyclone remnants. If current solutions are reasonably close, then a tornado threat would be possible in the Southeast, potentially from the southern Appalachians into the Carolinas. ...Sunday/Day 7 and Monday/Day 8... Mid-level flow is forecast to be relatively weak across the central and eastern U.S. on Sunday and Monday. The diffuse pattern and weak deep-layer shear across most of the U.S. suggests that the severe potential will remain low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Mon Sep 09 2024 Valid 121200Z - 171200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... A tropical cyclone is forecast to move slowly northward through the lower to mid Mississippi Valley from Thursday to Saturday. A tornado threat will be possible to the east of the center across much of the central Gulf Coast region on Thursday. Model forecasts suggest that the tornado threat could shift northward into the Tennessee Valley on Friday. On Saturday, uncertainty is considerable concerning the location of any tropical cyclone remnants. If current solutions are reasonably close, then a tornado threat would be possible in the Southeast, potentially from the southern Appalachians into the Carolinas. ...Sunday/Day 7 and Monday/Day 8... Mid-level flow is forecast to be relatively weak across the central and eastern U.S. on Sunday and Monday. The diffuse pattern and weak deep-layer shear across most of the U.S. suggests that the severe potential will remain low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Mon Sep 09 2024 Valid 121200Z - 171200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... A tropical cyclone is forecast to move slowly northward through the lower to mid Mississippi Valley from Thursday to Saturday. A tornado threat will be possible to the east of the center across much of the central Gulf Coast region on Thursday. Model forecasts suggest that the tornado threat could shift northward into the Tennessee Valley on Friday. On Saturday, uncertainty is considerable concerning the location of any tropical cyclone remnants. If current solutions are reasonably close, then a tornado threat would be possible in the Southeast, potentially from the southern Appalachians into the Carolinas. ...Sunday/Day 7 and Monday/Day 8... Mid-level flow is forecast to be relatively weak across the central and eastern U.S. on Sunday and Monday. The diffuse pattern and weak deep-layer shear across most of the U.S. suggests that the severe potential will remain low. Read more

Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0351 AM CDT Mon Sep 09 2024 Valid 121200Z - 171200Z ...DISCUSSION... ...Thursday/Day 4 to Saturday/Day 6... A tropical cyclone is forecast to move slowly northward through the lower to mid Mississippi Valley from Thursday to Saturday. A tornado threat will be possible to the east of the center across much of the central Gulf Coast region on Thursday. Model forecasts suggest that the tornado threat could shift northward into the Tennessee Valley on Friday. On Saturday, uncertainty is considerable concerning the location of any tropical cyclone remnants. If current solutions are reasonably close, then a tornado threat would be possible in the Southeast, potentially from the southern Appalachians into the Carolinas. ...Sunday/Day 7 and Monday/Day 8... Mid-level flow is forecast to be relatively weak across the central and eastern U.S. on Sunday and Monday. The diffuse pattern and weak deep-layer shear across most of the U.S. suggests that the severe potential will remain low. Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 09 2024 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST REGION.... ...SUMMARY... An isolated tornado threat is expected to develop across the central Gulf Coast Wednesday and Wednesday night. ...Central Gulf Coast... A tropical storm is forecast by the National Hurricane Center to develop across the western Gulf of Mexico today, and move north-northeastward toward the coast of Louisiana on Tuesday and Wednesday. Although uncertainty is substantial concerning landfall and intensity, the system is forecast to become a hurricane and move onshore into southwestern Louisiana early Wednesday evening. If this were to happen, an isolated tornado threat would be expected across much of the central Gulf Coast from Wednesday afternoon into the overnight period. Forecast soundings near the location of expected landfall have 0-3 km storm-relative helicity in the 300 to 500 m2/s2 range, with strong low-level shear extending eastward across much of the central Gulf Coast region. If the current scenario plays out as expected, an isolated tornado threat would develop, from near the landfall location eastward across southern Mississippi, southern Alabama into the western Florida Panhandle. The threat would continue throughout the central Gulf Coast region through late in the period, as the system moves inland into the lower Mississippi Valley. ..Broyles.. 09/09/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 09 2024 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST REGION.... ...SUMMARY... An isolated tornado threat is expected to develop across the central Gulf Coast Wednesday and Wednesday night. ...Central Gulf Coast... A tropical storm is forecast by the National Hurricane Center to develop across the western Gulf of Mexico today, and move north-northeastward toward the coast of Louisiana on Tuesday and Wednesday. Although uncertainty is substantial concerning landfall and intensity, the system is forecast to become a hurricane and move onshore into southwestern Louisiana early Wednesday evening. If this were to happen, an isolated tornado threat would be expected across much of the central Gulf Coast from Wednesday afternoon into the overnight period. Forecast soundings near the location of expected landfall have 0-3 km storm-relative helicity in the 300 to 500 m2/s2 range, with strong low-level shear extending eastward across much of the central Gulf Coast region. If the current scenario plays out as expected, an isolated tornado threat would develop, from near the landfall location eastward across southern Mississippi, southern Alabama into the western Florida Panhandle. The threat would continue throughout the central Gulf Coast region through late in the period, as the system moves inland into the lower Mississippi Valley. ..Broyles.. 09/09/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 09 2024 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST REGION.... ...SUMMARY... An isolated tornado threat is expected to develop across the central Gulf Coast Wednesday and Wednesday night. ...Central Gulf Coast... A tropical storm is forecast by the National Hurricane Center to develop across the western Gulf of Mexico today, and move north-northeastward toward the coast of Louisiana on Tuesday and Wednesday. Although uncertainty is substantial concerning landfall and intensity, the system is forecast to become a hurricane and move onshore into southwestern Louisiana early Wednesday evening. If this were to happen, an isolated tornado threat would be expected across much of the central Gulf Coast from Wednesday afternoon into the overnight period. Forecast soundings near the location of expected landfall have 0-3 km storm-relative helicity in the 300 to 500 m2/s2 range, with strong low-level shear extending eastward across much of the central Gulf Coast region. If the current scenario plays out as expected, an isolated tornado threat would develop, from near the landfall location eastward across southern Mississippi, southern Alabama into the western Florida Panhandle. The threat would continue throughout the central Gulf Coast region through late in the period, as the system moves inland into the lower Mississippi Valley. ..Broyles.. 09/09/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0223 AM CDT Mon Sep 09 2024 Valid 111200Z - 121200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CENTRAL GULF COAST REGION.... ...SUMMARY... An isolated tornado threat is expected to develop across the central Gulf Coast Wednesday and Wednesday night. ...Central Gulf Coast... A tropical storm is forecast by the National Hurricane Center to develop across the western Gulf of Mexico today, and move north-northeastward toward the coast of Louisiana on Tuesday and Wednesday. Although uncertainty is substantial concerning landfall and intensity, the system is forecast to become a hurricane and move onshore into southwestern Louisiana early Wednesday evening. If this were to happen, an isolated tornado threat would be expected across much of the central Gulf Coast from Wednesday afternoon into the overnight period. Forecast soundings near the location of expected landfall have 0-3 km storm-relative helicity in the 300 to 500 m2/s2 range, with strong low-level shear extending eastward across much of the central Gulf Coast region. If the current scenario plays out as expected, an isolated tornado threat would develop, from near the landfall location eastward across southern Mississippi, southern Alabama into the western Florida Panhandle. The threat would continue throughout the central Gulf Coast region through late in the period, as the system moves inland into the lower Mississippi Valley. ..Broyles.. 09/09/2024 Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0151 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...Synopsis... Broad troughing over the Northwest is forecast to gradually intensify Tuesday as a stronger shortwave and mid-level jet approach from the eastern Pacific. Falling heights and increasing flow aloft will move inland, supporting the potential for strong surface winds and low humidity over parts of the Northwest and Great Basin. ..Great Basin... Fire weather concerns will increase on Tuesday with the approach of the strong trough/mid-level jet. Initially weak surface winds will intensify over northwest and southern Nevada to 15-25 mph as flow aloft increases. Several hours of elevated to locally critical fire-weather conditions are likely as the stronger surface winds develop with a dry air mass with RH values below 20%. Fuels are driest across parts of the northern Great Basin and ID where rainfall has been sparse. However, fuels farther south in NV and CA remain sufficiently dry, and with stronger winds, elevated to near critical conditions are likely. ...Cascades and Columbia Gorge... Increasing mid-level winds will combine with a strong onshore pressure gradient to drive 15-20 mph winds through the Gorge and the western Columbia Basin along with RH potentially near 15%. The duration of breezy and somewhat dry conditions may be somewhat limited, but elevated to briefly critical fire weather may occur on Tuesday. ..Lyons.. 09/09/2024 ...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 0151 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...Synopsis... Broad troughing over the Northwest is forecast to gradually intensify Tuesday as a stronger shortwave and mid-level jet approach from the eastern Pacific. Falling heights and increasing flow aloft will move inland, supporting the potential for strong surface winds and low humidity over parts of the Northwest and Great Basin. ..Great Basin... Fire weather concerns will increase on Tuesday with the approach of the strong trough/mid-level jet. Initially weak surface winds will intensify over northwest and southern Nevada to 15-25 mph as flow aloft increases. Several hours of elevated to locally critical fire-weather conditions are likely as the stronger surface winds develop with a dry air mass with RH values below 20%. Fuels are driest across parts of the northern Great Basin and ID where rainfall has been sparse. However, fuels farther south in NV and CA remain sufficiently dry, and with stronger winds, elevated to near critical conditions are likely. ...Cascades and Columbia Gorge... Increasing mid-level winds will combine with a strong onshore pressure gradient to drive 15-20 mph winds through the Gorge and the western Columbia Basin along with RH potentially near 15%. The duration of breezy and somewhat dry conditions may be somewhat limited, but elevated to briefly critical fire weather may occur on Tuesday. ..Lyons.. 09/09/2024 ...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 0151 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...Synopsis... Broad troughing over the Northwest is forecast to gradually intensify Tuesday as a stronger shortwave and mid-level jet approach from the eastern Pacific. Falling heights and increasing flow aloft will move inland, supporting the potential for strong surface winds and low humidity over parts of the Northwest and Great Basin. ..Great Basin... Fire weather concerns will increase on Tuesday with the approach of the strong trough/mid-level jet. Initially weak surface winds will intensify over northwest and southern Nevada to 15-25 mph as flow aloft increases. Several hours of elevated to locally critical fire-weather conditions are likely as the stronger surface winds develop with a dry air mass with RH values below 20%. Fuels are driest across parts of the northern Great Basin and ID where rainfall has been sparse. However, fuels farther south in NV and CA remain sufficiently dry, and with stronger winds, elevated to near critical conditions are likely. ...Cascades and Columbia Gorge... Increasing mid-level winds will combine with a strong onshore pressure gradient to drive 15-20 mph winds through the Gorge and the western Columbia Basin along with RH potentially near 15%. The duration of breezy and somewhat dry conditions may be somewhat limited, but elevated to briefly critical fire weather may occur on Tuesday. ..Lyons.. 09/09/2024 ...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 0151 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...Synopsis... Broad troughing over the Northwest is forecast to gradually intensify Tuesday as a stronger shortwave and mid-level jet approach from the eastern Pacific. Falling heights and increasing flow aloft will move inland, supporting the potential for strong surface winds and low humidity over parts of the Northwest and Great Basin. ..Great Basin... Fire weather concerns will increase on Tuesday with the approach of the strong trough/mid-level jet. Initially weak surface winds will intensify over northwest and southern Nevada to 15-25 mph as flow aloft increases. Several hours of elevated to locally critical fire-weather conditions are likely as the stronger surface winds develop with a dry air mass with RH values below 20%. Fuels are driest across parts of the northern Great Basin and ID where rainfall has been sparse. However, fuels farther south in NV and CA remain sufficiently dry, and with stronger winds, elevated to near critical conditions are likely. ...Cascades and Columbia Gorge... Increasing mid-level winds will combine with a strong onshore pressure gradient to drive 15-20 mph winds through the Gorge and the western Columbia Basin along with RH potentially near 15%. The duration of breezy and somewhat dry conditions may be somewhat limited, but elevated to briefly critical fire weather may occur on Tuesday. ..Lyons.. 09/09/2024 ...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 0150 AM CDT Mon Sep 09 2024 Valid 091200Z - 101200Z ...Synopsis... Broad trouhging over the Northwest should continue today as an embedded perturbation moves eastward over the northern Rockies. Southwesterly flow aloft is forecast to increase over much of the West as the broad trough slowly shifts east. At the surface, a cold front will move into the Rockies, bringing a cooler air mass to parts of the Northwest, but gusty winds to parts of the Cascades. A lee trough developing east of the Rockies will help support isolated dry thunderstorms over parts of WY and MT. Periods of stronger surface winds and low RH will support elevated to near-critical fire-weather conditions. ...Northwest and Great Basin.... Stronger flow aloft is expected to persist today over much of the Northwest and northern Great Basin. Surface winds should increase to 15-25 mph as momentum from aloft mixes down. Downsloping and mid-level drying should keep the air mass quite dry with diurnal RH minimums below 15% likely. Several hours of widespread elevated to near-critical fire-weather conditions are likely across the northern Sierra and Great Basin. Farther north, more moderate RH of 25-30% is expected beneath the upper trough and behind the cold front. Despite the arrival of a cooler Pacific air mass, downslope winds of 15-25 mph should overlap with dry fuels and pockets of lower RH during the day. Overlapping with recent lightning and fire activity, a few hours of elevated to near-critical conditions are possible in the lee of the Cascades as winds increase. ...Northern Rockies... Stronger westerly flow head of the embedded shortwave will aid in deepening a lee trough east of the Rockies. Westerly surface winds should strengthen in turn, supporting pockets of downslope winds of 15-25 mph across parts of MT and WY. With hot temperatures and little recent rainfall, afternoon RH values should remain quite low, generally below 20%. Increasing winds, receptive fuels, and persistent dry conditions should support several hours of elevated to near critical fire-weather conditions over parts of the northern Rockies. ...Dry Thunder... Isolated, high-based thunderstorms appear likely over parts of the Rockies (mainly WY and MT) today ahead of the shortwave trough. Weak buoyancy, and PWATs of 0.5 to 0.7 inches, atop dry and well-mixed low levels will support poor precipitation efficiency and the potential for strong outflow winds. At least isolated storms are expected over areas of receptive fuels. Thus, dry lightning ignitions are possible, especially across parts of north-central WY, where storm coverage appears greatest. ..Lyons.. 09/09/2024 ...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 0150 AM CDT Mon Sep 09 2024 Valid 091200Z - 101200Z ...Synopsis... Broad trouhging over the Northwest should continue today as an embedded perturbation moves eastward over the northern Rockies. Southwesterly flow aloft is forecast to increase over much of the West as the broad trough slowly shifts east. At the surface, a cold front will move into the Rockies, bringing a cooler air mass to parts of the Northwest, but gusty winds to parts of the Cascades. A lee trough developing east of the Rockies will help support isolated dry thunderstorms over parts of WY and MT. Periods of stronger surface winds and low RH will support elevated to near-critical fire-weather conditions. ...Northwest and Great Basin.... Stronger flow aloft is expected to persist today over much of the Northwest and northern Great Basin. Surface winds should increase to 15-25 mph as momentum from aloft mixes down. Downsloping and mid-level drying should keep the air mass quite dry with diurnal RH minimums below 15% likely. Several hours of widespread elevated to near-critical fire-weather conditions are likely across the northern Sierra and Great Basin. Farther north, more moderate RH of 25-30% is expected beneath the upper trough and behind the cold front. Despite the arrival of a cooler Pacific air mass, downslope winds of 15-25 mph should overlap with dry fuels and pockets of lower RH during the day. Overlapping with recent lightning and fire activity, a few hours of elevated to near-critical conditions are possible in the lee of the Cascades as winds increase. ...Northern Rockies... Stronger westerly flow head of the embedded shortwave will aid in deepening a lee trough east of the Rockies. Westerly surface winds should strengthen in turn, supporting pockets of downslope winds of 15-25 mph across parts of MT and WY. With hot temperatures and little recent rainfall, afternoon RH values should remain quite low, generally below 20%. Increasing winds, receptive fuels, and persistent dry conditions should support several hours of elevated to near critical fire-weather conditions over parts of the northern Rockies. ...Dry Thunder... Isolated, high-based thunderstorms appear likely over parts of the Rockies (mainly WY and MT) today ahead of the shortwave trough. Weak buoyancy, and PWATs of 0.5 to 0.7 inches, atop dry and well-mixed low levels will support poor precipitation efficiency and the potential for strong outflow winds. At least isolated storms are expected over areas of receptive fuels. Thus, dry lightning ignitions are possible, especially across parts of north-central WY, where storm coverage appears greatest. ..Lyons.. 09/09/2024 ...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 0150 AM CDT Mon Sep 09 2024 Valid 091200Z - 101200Z ...Synopsis... Broad trouhging over the Northwest should continue today as an embedded perturbation moves eastward over the northern Rockies. Southwesterly flow aloft is forecast to increase over much of the West as the broad trough slowly shifts east. At the surface, a cold front will move into the Rockies, bringing a cooler air mass to parts of the Northwest, but gusty winds to parts of the Cascades. A lee trough developing east of the Rockies will help support isolated dry thunderstorms over parts of WY and MT. Periods of stronger surface winds and low RH will support elevated to near-critical fire-weather conditions. ...Northwest and Great Basin.... Stronger flow aloft is expected to persist today over much of the Northwest and northern Great Basin. Surface winds should increase to 15-25 mph as momentum from aloft mixes down. Downsloping and mid-level drying should keep the air mass quite dry with diurnal RH minimums below 15% likely. Several hours of widespread elevated to near-critical fire-weather conditions are likely across the northern Sierra and Great Basin. Farther north, more moderate RH of 25-30% is expected beneath the upper trough and behind the cold front. Despite the arrival of a cooler Pacific air mass, downslope winds of 15-25 mph should overlap with dry fuels and pockets of lower RH during the day. Overlapping with recent lightning and fire activity, a few hours of elevated to near-critical conditions are possible in the lee of the Cascades as winds increase. ...Northern Rockies... Stronger westerly flow head of the embedded shortwave will aid in deepening a lee trough east of the Rockies. Westerly surface winds should strengthen in turn, supporting pockets of downslope winds of 15-25 mph across parts of MT and WY. With hot temperatures and little recent rainfall, afternoon RH values should remain quite low, generally below 20%. Increasing winds, receptive fuels, and persistent dry conditions should support several hours of elevated to near critical fire-weather conditions over parts of the northern Rockies. ...Dry Thunder... Isolated, high-based thunderstorms appear likely over parts of the Rockies (mainly WY and MT) today ahead of the shortwave trough. Weak buoyancy, and PWATs of 0.5 to 0.7 inches, atop dry and well-mixed low levels will support poor precipitation efficiency and the potential for strong outflow winds. At least isolated storms are expected over areas of receptive fuels. Thus, dry lightning ignitions are possible, especially across parts of north-central WY, where storm coverage appears greatest. ..Lyons.. 09/09/2024 ...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 0150 AM CDT Mon Sep 09 2024 Valid 091200Z - 101200Z ...Synopsis... Broad trouhging over the Northwest should continue today as an embedded perturbation moves eastward over the northern Rockies. Southwesterly flow aloft is forecast to increase over much of the West as the broad trough slowly shifts east. At the surface, a cold front will move into the Rockies, bringing a cooler air mass to parts of the Northwest, but gusty winds to parts of the Cascades. A lee trough developing east of the Rockies will help support isolated dry thunderstorms over parts of WY and MT. Periods of stronger surface winds and low RH will support elevated to near-critical fire-weather conditions. ...Northwest and Great Basin.... Stronger flow aloft is expected to persist today over much of the Northwest and northern Great Basin. Surface winds should increase to 15-25 mph as momentum from aloft mixes down. Downsloping and mid-level drying should keep the air mass quite dry with diurnal RH minimums below 15% likely. Several hours of widespread elevated to near-critical fire-weather conditions are likely across the northern Sierra and Great Basin. Farther north, more moderate RH of 25-30% is expected beneath the upper trough and behind the cold front. Despite the arrival of a cooler Pacific air mass, downslope winds of 15-25 mph should overlap with dry fuels and pockets of lower RH during the day. Overlapping with recent lightning and fire activity, a few hours of elevated to near-critical conditions are possible in the lee of the Cascades as winds increase. ...Northern Rockies... Stronger westerly flow head of the embedded shortwave will aid in deepening a lee trough east of the Rockies. Westerly surface winds should strengthen in turn, supporting pockets of downslope winds of 15-25 mph across parts of MT and WY. With hot temperatures and little recent rainfall, afternoon RH values should remain quite low, generally below 20%. Increasing winds, receptive fuels, and persistent dry conditions should support several hours of elevated to near critical fire-weather conditions over parts of the northern Rockies. ...Dry Thunder... Isolated, high-based thunderstorms appear likely over parts of the Rockies (mainly WY and MT) today ahead of the shortwave trough. Weak buoyancy, and PWATs of 0.5 to 0.7 inches, atop dry and well-mixed low levels will support poor precipitation efficiency and the potential for strong outflow winds. At least isolated storms are expected over areas of receptive fuels. Thus, dry lightning ignitions are possible, especially across parts of north-central WY, where storm coverage appears greatest. ..Lyons.. 09/09/2024 ...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 1242 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected to develop on Tuesday across the Gulf Coast region and from the Four Corners northward into the north-central U.S. No severe threat is expected across the U.S. Tuesday or Tuesday night. ...DISCUSSION... A shortwave ridge will move eastward across the Great Lakes region on Tuesday, as an upper-level trough develops near the West Coast. Southwesterly mid-level flow will be in place from the Intermountain West into the central and northern Rockies. Isolated to scattered thunderstorms will be possible on Tuesday in the higher terrain from the vicinity of the Four Corners northward into the northern Rockies and northeastward into the upper Mississippi Valley. Additional storms will be possible along the Gulf Coast, near the northern edge of a moist airmass. No severe threat is expected across the U.S. on Tuesday and Tuesday night. ..Broyles.. 09/09/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1242 AM CDT Mon Sep 09 2024 Valid 101200Z - 111200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Thunderstorms are expected to develop on Tuesday across the Gulf Coast region and from the Four Corners northward into the north-central U.S. No severe threat is expected across the U.S. Tuesday or Tuesday night. ...DISCUSSION... A shortwave ridge will move eastward across the Great Lakes region on Tuesday, as an upper-level trough develops near the West Coast. Southwesterly mid-level flow will be in place from the Intermountain West into the central and northern Rockies. Isolated to scattered thunderstorms will be possible on Tuesday in the higher terrain from the vicinity of the Four Corners northward into the northern Rockies and northeastward into the upper Mississippi Valley. Additional storms will be possible along the Gulf Coast, near the northern edge of a moist airmass. No severe threat is expected across the U.S. on Tuesday and Tuesday night. ..Broyles.. 09/09/2024 Read more