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SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0156 AM CDT Mon Jul 22 2024 Valid 231200Z - 241200Z ...Synopsis... The upper trough over the Northwest is forecast to remain mostly stationary as the adjacent ridge over the Rockies begins to weaken and shift to the east. Stronger flow aloft will gradually overspread the Northwest and northern Rockies through the week. Isolated dry thunderstorms and gusty downslope winds will promote elevated fire-weather potential D2/Tuesday. ...Northwest and Northern Rockies... With the upper trough over the Northwest expected to remain fairly stationary, lingering mid-level moisture and weak ascent will continue to support mid-level destabilization and thunderstorms D2/Tuesday afternoon. Very warm surface temperatures and fast storm speeds will again favor mostly dry storms with the potential for lightning ignitions in dry fuels. Forcing for ascent should be slightly less than previous days, casting some uncertainty on storm coverage. However, at least isolated dry thunderstorms are possible over parts of eastern WA/OR and into western ID. West/southwest flow aloft is forecast to increase over the northern Rockies and Cascade Gaps ahead of the trough. This may promote several hours of gusty downslope winds across parts of eastern ID and western MT. Model guidance shows surface winds of 15-25 mph overlapping with RH values below 20%. This, along with the increase in lightning, will support the potential for elevated fire-weather conditions D2/Tuesday afternoon. ..Lyons.. 07/22/2024 ...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 0154 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...Synopsis... An upper ridge centered over the Rockies will begin to weaken today under the influence of a broad mid-level trough moving onshore over the Pacific Northwest. Weak ascent, increasingly strong southwesterly flow aloft and inland moisture advection will support thunderstorms and gusty winds across the higher terrain of the Northwest and northern Rockies. Dry lightning and locally dry and breezy conditions are possible. ...Northwest, and Northern Rockies... Isolated, mostly dry, thunderstorms are expected to be ongoing at the start of the period as convection from overnight lifts north with the advancing upper trough. Additional storm development is possible later this afternoon, as peak diurnal heating and lingering mid-level moisture will support the development of weak elevated buoyancy. Deep and well-mixed sub-cloud layers, along with moderate storm speeds, will favor low precipitation efficiency and the potential for dry lightning strikes with any storm that develops. Scattered thunderstorms are also possible farther south across parts of the Great Basin, but higher PWATs and multiple days of prior storms suggest a wetter mode is more probable. Coverage of dry storms appears highest across parts of south-central OR, extending northeastward across central ID into western MT. With receptive fuels in place over much of the Northwest and northern Rockies, the risk for lightning ignitions is high. In addition to the risk for lightning, gusty downslope winds are possible across parts of the Cascades and western Columbia Basin this afternoon. Increasing mid-level flow atop a hot and well-mixed boundary layer may support occasional gusts to 15-25 mph through the Cascade Gaps. However, coverage and duration of the gusty winds is expected to be limited. ..Lyons.. 07/22/2024 ...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 0154 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...Synopsis... An upper ridge centered over the Rockies will begin to weaken today under the influence of a broad mid-level trough moving onshore over the Pacific Northwest. Weak ascent, increasingly strong southwesterly flow aloft and inland moisture advection will support thunderstorms and gusty winds across the higher terrain of the Northwest and northern Rockies. Dry lightning and locally dry and breezy conditions are possible. ...Northwest, and Northern Rockies... Isolated, mostly dry, thunderstorms are expected to be ongoing at the start of the period as convection from overnight lifts north with the advancing upper trough. Additional storm development is possible later this afternoon, as peak diurnal heating and lingering mid-level moisture will support the development of weak elevated buoyancy. Deep and well-mixed sub-cloud layers, along with moderate storm speeds, will favor low precipitation efficiency and the potential for dry lightning strikes with any storm that develops. Scattered thunderstorms are also possible farther south across parts of the Great Basin, but higher PWATs and multiple days of prior storms suggest a wetter mode is more probable. Coverage of dry storms appears highest across parts of south-central OR, extending northeastward across central ID into western MT. With receptive fuels in place over much of the Northwest and northern Rockies, the risk for lightning ignitions is high. In addition to the risk for lightning, gusty downslope winds are possible across parts of the Cascades and western Columbia Basin this afternoon. Increasing mid-level flow atop a hot and well-mixed boundary layer may support occasional gusts to 15-25 mph through the Cascade Gaps. However, coverage and duration of the gusty winds is expected to be limited. ..Lyons.. 07/22/2024 ...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 0154 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...Synopsis... An upper ridge centered over the Rockies will begin to weaken today under the influence of a broad mid-level trough moving onshore over the Pacific Northwest. Weak ascent, increasingly strong southwesterly flow aloft and inland moisture advection will support thunderstorms and gusty winds across the higher terrain of the Northwest and northern Rockies. Dry lightning and locally dry and breezy conditions are possible. ...Northwest, and Northern Rockies... Isolated, mostly dry, thunderstorms are expected to be ongoing at the start of the period as convection from overnight lifts north with the advancing upper trough. Additional storm development is possible later this afternoon, as peak diurnal heating and lingering mid-level moisture will support the development of weak elevated buoyancy. Deep and well-mixed sub-cloud layers, along with moderate storm speeds, will favor low precipitation efficiency and the potential for dry lightning strikes with any storm that develops. Scattered thunderstorms are also possible farther south across parts of the Great Basin, but higher PWATs and multiple days of prior storms suggest a wetter mode is more probable. Coverage of dry storms appears highest across parts of south-central OR, extending northeastward across central ID into western MT. With receptive fuels in place over much of the Northwest and northern Rockies, the risk for lightning ignitions is high. In addition to the risk for lightning, gusty downslope winds are possible across parts of the Cascades and western Columbia Basin this afternoon. Increasing mid-level flow atop a hot and well-mixed boundary layer may support occasional gusts to 15-25 mph through the Cascade Gaps. However, coverage and duration of the gusty winds is expected to be limited. ..Lyons.. 07/22/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Mon Jul 22 2024 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe-thunderstorm potential appears low on Wednesday. ...Synopsis... The upper trough over the upper Great Lakes vicinity will slowly begin to migrate east toward the lower Great Lakes and the OH Valley on Wednesday into early Thursday. This will result in modestly increasing mid/upper southwesterly flow across parts of the Mid-Atlantic and Northeast, especially the second half of the forecast period. At the surface, a cold front will sag south/southeast across the Mid-MS and OH Valleys. Meanwhile, a surface trough is expected to extend south/southwest across eastern/central VA/NC. Weak vertical shear and poor convergence along the Midwest cold front will preclude organized severe thunderstorm chances. Further east, some severe potential could develop across the Mid-Atlantic vicinity where a very moist airmass will persist. However, forecast guidance depicts varying amounts of cloud cover and possibly early convection across the region. Furthermore, poor lapse rates and marginal vertical shear (around 30 kt effective shear magnitudes) may further limit severe potential across parts of NC/VA into the Chesapeake Bay vicinity. ..Leitman.. 07/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Mon Jul 22 2024 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe-thunderstorm potential appears low on Wednesday. ...Synopsis... The upper trough over the upper Great Lakes vicinity will slowly begin to migrate east toward the lower Great Lakes and the OH Valley on Wednesday into early Thursday. This will result in modestly increasing mid/upper southwesterly flow across parts of the Mid-Atlantic and Northeast, especially the second half of the forecast period. At the surface, a cold front will sag south/southeast across the Mid-MS and OH Valleys. Meanwhile, a surface trough is expected to extend south/southwest across eastern/central VA/NC. Weak vertical shear and poor convergence along the Midwest cold front will preclude organized severe thunderstorm chances. Further east, some severe potential could develop across the Mid-Atlantic vicinity where a very moist airmass will persist. However, forecast guidance depicts varying amounts of cloud cover and possibly early convection across the region. Furthermore, poor lapse rates and marginal vertical shear (around 30 kt effective shear magnitudes) may further limit severe potential across parts of NC/VA into the Chesapeake Bay vicinity. ..Leitman.. 07/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Mon Jul 22 2024 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe-thunderstorm potential appears low on Wednesday. ...Synopsis... The upper trough over the upper Great Lakes vicinity will slowly begin to migrate east toward the lower Great Lakes and the OH Valley on Wednesday into early Thursday. This will result in modestly increasing mid/upper southwesterly flow across parts of the Mid-Atlantic and Northeast, especially the second half of the forecast period. At the surface, a cold front will sag south/southeast across the Mid-MS and OH Valleys. Meanwhile, a surface trough is expected to extend south/southwest across eastern/central VA/NC. Weak vertical shear and poor convergence along the Midwest cold front will preclude organized severe thunderstorm chances. Further east, some severe potential could develop across the Mid-Atlantic vicinity where a very moist airmass will persist. However, forecast guidance depicts varying amounts of cloud cover and possibly early convection across the region. Furthermore, poor lapse rates and marginal vertical shear (around 30 kt effective shear magnitudes) may further limit severe potential across parts of NC/VA into the Chesapeake Bay vicinity. ..Leitman.. 07/22/2024 Read more

SPC 0730Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0149 AM CDT Mon Jul 22 2024 Valid 241200Z - 251200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe-thunderstorm potential appears low on Wednesday. ...Synopsis... The upper trough over the upper Great Lakes vicinity will slowly begin to migrate east toward the lower Great Lakes and the OH Valley on Wednesday into early Thursday. This will result in modestly increasing mid/upper southwesterly flow across parts of the Mid-Atlantic and Northeast, especially the second half of the forecast period. At the surface, a cold front will sag south/southeast across the Mid-MS and OH Valleys. Meanwhile, a surface trough is expected to extend south/southwest across eastern/central VA/NC. Weak vertical shear and poor convergence along the Midwest cold front will preclude organized severe thunderstorm chances. Further east, some severe potential could develop across the Mid-Atlantic vicinity where a very moist airmass will persist. However, forecast guidance depicts varying amounts of cloud cover and possibly early convection across the region. Furthermore, poor lapse rates and marginal vertical shear (around 30 kt effective shear magnitudes) may further limit severe potential across parts of NC/VA into the Chesapeake Bay vicinity. ..Leitman.. 07/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 AM CDT Mon Jul 22 2024 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe-thunderstorm potential appears low on Tuesday. ...Synopsis... Upper troughing will continue over the Great Lakes into the Mid-South on Tuesday. Some minor increase in mid/upper flow is forecast as the trough deepens over the Great Lakes, while the subtropical high over the western Atlantic pushes closer to the Mid-Atlantic coast. While this will result in some modest increase to mid/upper southwesterly flow over the central Appalachians into southern New England, minor height rises and midlevel warming also will occur. A very moist airmass will exist across the Mid-Atlantic vicinity amid weak to moderate instability, supporting scattered to widespread thunderstorm activity. However, generally unfavorable vertical wind profiles coupled with poor midlevel lapse rates will limit organized severe thunderstorm potential. Nevertheless, high PW values and pockets of steepening low-level lapse rates where stronger heating occurs could still result in sporadic wet microbursts and locally strong gusts. Further east, a weak surface low will shift from the upper MS Valley toward Lower MI and eastern Ontario. As this occurs, a cold front will develop southward across the Upper Midwest into IA, northern IL and Lower MI. A seasonally moist airmass and a band of weak to moderate instability will exist ahead of the front, supporting isolated to scattered thunderstorm development. However, vertical shear will remain very weak, and thunderstorm activity will likely remain pulse-like/disorganized, limiting severe potential. ..Leitman.. 07/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 AM CDT Mon Jul 22 2024 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe-thunderstorm potential appears low on Tuesday. ...Synopsis... Upper troughing will continue over the Great Lakes into the Mid-South on Tuesday. Some minor increase in mid/upper flow is forecast as the trough deepens over the Great Lakes, while the subtropical high over the western Atlantic pushes closer to the Mid-Atlantic coast. While this will result in some modest increase to mid/upper southwesterly flow over the central Appalachians into southern New England, minor height rises and midlevel warming also will occur. A very moist airmass will exist across the Mid-Atlantic vicinity amid weak to moderate instability, supporting scattered to widespread thunderstorm activity. However, generally unfavorable vertical wind profiles coupled with poor midlevel lapse rates will limit organized severe thunderstorm potential. Nevertheless, high PW values and pockets of steepening low-level lapse rates where stronger heating occurs could still result in sporadic wet microbursts and locally strong gusts. Further east, a weak surface low will shift from the upper MS Valley toward Lower MI and eastern Ontario. As this occurs, a cold front will develop southward across the Upper Midwest into IA, northern IL and Lower MI. A seasonally moist airmass and a band of weak to moderate instability will exist ahead of the front, supporting isolated to scattered thunderstorm development. However, vertical shear will remain very weak, and thunderstorm activity will likely remain pulse-like/disorganized, limiting severe potential. ..Leitman.. 07/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 AM CDT Mon Jul 22 2024 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe-thunderstorm potential appears low on Tuesday. ...Synopsis... Upper troughing will continue over the Great Lakes into the Mid-South on Tuesday. Some minor increase in mid/upper flow is forecast as the trough deepens over the Great Lakes, while the subtropical high over the western Atlantic pushes closer to the Mid-Atlantic coast. While this will result in some modest increase to mid/upper southwesterly flow over the central Appalachians into southern New England, minor height rises and midlevel warming also will occur. A very moist airmass will exist across the Mid-Atlantic vicinity amid weak to moderate instability, supporting scattered to widespread thunderstorm activity. However, generally unfavorable vertical wind profiles coupled with poor midlevel lapse rates will limit organized severe thunderstorm potential. Nevertheless, high PW values and pockets of steepening low-level lapse rates where stronger heating occurs could still result in sporadic wet microbursts and locally strong gusts. Further east, a weak surface low will shift from the upper MS Valley toward Lower MI and eastern Ontario. As this occurs, a cold front will develop southward across the Upper Midwest into IA, northern IL and Lower MI. A seasonally moist airmass and a band of weak to moderate instability will exist ahead of the front, supporting isolated to scattered thunderstorm development. However, vertical shear will remain very weak, and thunderstorm activity will likely remain pulse-like/disorganized, limiting severe potential. ..Leitman.. 07/22/2024 Read more

SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1222 AM CDT Mon Jul 22 2024 Valid 231200Z - 241200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Severe-thunderstorm potential appears low on Tuesday. ...Synopsis... Upper troughing will continue over the Great Lakes into the Mid-South on Tuesday. Some minor increase in mid/upper flow is forecast as the trough deepens over the Great Lakes, while the subtropical high over the western Atlantic pushes closer to the Mid-Atlantic coast. While this will result in some modest increase to mid/upper southwesterly flow over the central Appalachians into southern New England, minor height rises and midlevel warming also will occur. A very moist airmass will exist across the Mid-Atlantic vicinity amid weak to moderate instability, supporting scattered to widespread thunderstorm activity. However, generally unfavorable vertical wind profiles coupled with poor midlevel lapse rates will limit organized severe thunderstorm potential. Nevertheless, high PW values and pockets of steepening low-level lapse rates where stronger heating occurs could still result in sporadic wet microbursts and locally strong gusts. Further east, a weak surface low will shift from the upper MS Valley toward Lower MI and eastern Ontario. As this occurs, a cold front will develop southward across the Upper Midwest into IA, northern IL and Lower MI. A seasonally moist airmass and a band of weak to moderate instability will exist ahead of the front, supporting isolated to scattered thunderstorm development. However, vertical shear will remain very weak, and thunderstorm activity will likely remain pulse-like/disorganized, limiting severe potential. ..Leitman.. 07/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE MID-ATLANTIC...AND WESTERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms will be possible over portions of the mid-Atlantic region, and western Arizona on Monday. ...Synopsis... A broad upper-level trough will remain in place from the Great Lakes southwest into northern Texas on Monday, while an embedded impulse within the flow around the trough moves across the mid-Atlantic states. Another impulse will move southeast across the upper Midwest and northern Great Lakes, while an upper-level anticyclone remains anchored in the vicinity of the southern Great Basin. ...Mid-Atlantic... A very moist air mass will be remain in place across the region, characterized by PW values in excess of 2 inches. As the embedded mid-level impulse lifts northeast across the TN Valley and mid-Atlantic region during the day, lower/mid-level wind fields will strengthen and result in 30-40 kts of deep-layer shear by afternoon. Despite poor lapse rates, 70s dew points will contribute to pockets of moderate buoyancy. Thunderstorms should redevelop during the afternoon, aided by ascent with the approaching impulse. NAM/RAP forecast soundings Monday afternoon suggest notable low-level hodograph curvature, suggesting some potential for a tornado or two across northeast NC and eastern VA, especially with any cells that remain relatively discrete. ...Western AZ Vicinity... Thunderstorms are expected to develop across the Mogollon Rim Monday afternoon, with hi-res guidance depicting the greatest coverage across western AZ. Northeast mid-level flow of 15-20 kts should be sufficient for storms to move into lower elevations characterized by a hot/well-mixed boundary layer. Merging outflows should result in clusters of storms with the potential for strong to severe gusts. ...Upper Midwest... Thunderstorms should re-develop along a southward-moving cold front, reinforced by convective outflows, across central/northern MN and northwest WI during the day, with the potential for gusty winds and perhaps small hail. Overall thunderstorm intensity should be tempered by relatively weak shear, precluding severe probabilities with this outlook. ..Bunting/Lyons.. 07/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE MID-ATLANTIC...AND WESTERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms will be possible over portions of the mid-Atlantic region, and western Arizona on Monday. ...Synopsis... A broad upper-level trough will remain in place from the Great Lakes southwest into northern Texas on Monday, while an embedded impulse within the flow around the trough moves across the mid-Atlantic states. Another impulse will move southeast across the upper Midwest and northern Great Lakes, while an upper-level anticyclone remains anchored in the vicinity of the southern Great Basin. ...Mid-Atlantic... A very moist air mass will be remain in place across the region, characterized by PW values in excess of 2 inches. As the embedded mid-level impulse lifts northeast across the TN Valley and mid-Atlantic region during the day, lower/mid-level wind fields will strengthen and result in 30-40 kts of deep-layer shear by afternoon. Despite poor lapse rates, 70s dew points will contribute to pockets of moderate buoyancy. Thunderstorms should redevelop during the afternoon, aided by ascent with the approaching impulse. NAM/RAP forecast soundings Monday afternoon suggest notable low-level hodograph curvature, suggesting some potential for a tornado or two across northeast NC and eastern VA, especially with any cells that remain relatively discrete. ...Western AZ Vicinity... Thunderstorms are expected to develop across the Mogollon Rim Monday afternoon, with hi-res guidance depicting the greatest coverage across western AZ. Northeast mid-level flow of 15-20 kts should be sufficient for storms to move into lower elevations characterized by a hot/well-mixed boundary layer. Merging outflows should result in clusters of storms with the potential for strong to severe gusts. ...Upper Midwest... Thunderstorms should re-develop along a southward-moving cold front, reinforced by convective outflows, across central/northern MN and northwest WI during the day, with the potential for gusty winds and perhaps small hail. Overall thunderstorm intensity should be tempered by relatively weak shear, precluding severe probabilities with this outlook. ..Bunting/Lyons.. 07/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE MID-ATLANTIC...AND WESTERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms will be possible over portions of the mid-Atlantic region, and western Arizona on Monday. ...Synopsis... A broad upper-level trough will remain in place from the Great Lakes southwest into northern Texas on Monday, while an embedded impulse within the flow around the trough moves across the mid-Atlantic states. Another impulse will move southeast across the upper Midwest and northern Great Lakes, while an upper-level anticyclone remains anchored in the vicinity of the southern Great Basin. ...Mid-Atlantic... A very moist air mass will be remain in place across the region, characterized by PW values in excess of 2 inches. As the embedded mid-level impulse lifts northeast across the TN Valley and mid-Atlantic region during the day, lower/mid-level wind fields will strengthen and result in 30-40 kts of deep-layer shear by afternoon. Despite poor lapse rates, 70s dew points will contribute to pockets of moderate buoyancy. Thunderstorms should redevelop during the afternoon, aided by ascent with the approaching impulse. NAM/RAP forecast soundings Monday afternoon suggest notable low-level hodograph curvature, suggesting some potential for a tornado or two across northeast NC and eastern VA, especially with any cells that remain relatively discrete. ...Western AZ Vicinity... Thunderstorms are expected to develop across the Mogollon Rim Monday afternoon, with hi-res guidance depicting the greatest coverage across western AZ. Northeast mid-level flow of 15-20 kts should be sufficient for storms to move into lower elevations characterized by a hot/well-mixed boundary layer. Merging outflows should result in clusters of storms with the potential for strong to severe gusts. ...Upper Midwest... Thunderstorms should re-develop along a southward-moving cold front, reinforced by convective outflows, across central/northern MN and northwest WI during the day, with the potential for gusty winds and perhaps small hail. Overall thunderstorm intensity should be tempered by relatively weak shear, precluding severe probabilities with this outlook. ..Bunting/Lyons.. 07/22/2024 Read more

SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1259 AM CDT Mon Jul 22 2024 Valid 221200Z - 231200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE MID-ATLANTIC...AND WESTERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms will be possible over portions of the mid-Atlantic region, and western Arizona on Monday. ...Synopsis... A broad upper-level trough will remain in place from the Great Lakes southwest into northern Texas on Monday, while an embedded impulse within the flow around the trough moves across the mid-Atlantic states. Another impulse will move southeast across the upper Midwest and northern Great Lakes, while an upper-level anticyclone remains anchored in the vicinity of the southern Great Basin. ...Mid-Atlantic... A very moist air mass will be remain in place across the region, characterized by PW values in excess of 2 inches. As the embedded mid-level impulse lifts northeast across the TN Valley and mid-Atlantic region during the day, lower/mid-level wind fields will strengthen and result in 30-40 kts of deep-layer shear by afternoon. Despite poor lapse rates, 70s dew points will contribute to pockets of moderate buoyancy. Thunderstorms should redevelop during the afternoon, aided by ascent with the approaching impulse. NAM/RAP forecast soundings Monday afternoon suggest notable low-level hodograph curvature, suggesting some potential for a tornado or two across northeast NC and eastern VA, especially with any cells that remain relatively discrete. ...Western AZ Vicinity... Thunderstorms are expected to develop across the Mogollon Rim Monday afternoon, with hi-res guidance depicting the greatest coverage across western AZ. Northeast mid-level flow of 15-20 kts should be sufficient for storms to move into lower elevations characterized by a hot/well-mixed boundary layer. Merging outflows should result in clusters of storms with the potential for strong to severe gusts. ...Upper Midwest... Thunderstorms should re-develop along a southward-moving cold front, reinforced by convective outflows, across central/northern MN and northwest WI during the day, with the potential for gusty winds and perhaps small hail. Overall thunderstorm intensity should be tempered by relatively weak shear, precluding severe probabilities with this outlook. ..Bunting/Lyons.. 07/22/2024 Read more

000
ABPZ20 KNHC 220509
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 PM PDT Sun Jul 21 2024

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

Western East Pacific:
A large area of disorganized showers and thunderstorms located over
the far western portion of the eastern Pacific is associated with a
trough of low pressure. Environmental conditions are forecast to be
marginally conducive for some slow development during the next day
or so. The disturbance is forecast to move westward at 10 to 15 mph
and into the central Pacific basin by early Monday morning. By
midweek, strong upper-level winds are expected to inhibit further
development.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...10 percent.

Central and Western East Pacific:
A tropical wave located hundreds of miles south-southwest of the
southern tip of the Baja California Peninsula is producing
disorganized shower and thunderstorm activity. Environmental
conditions could become a little more conducive for some gradual
development of this system over the next several days while it moves
westward to west-northwestward at 10 to 15 mph across the central
and western portions of the basin.
* Formation chance through 48 hours...low...10 percent.
* Formation chance through 7 days...low...30 percent.

$$
Forecaster Kelly

The city of Havre has banned non-essential water use as the water treatment plant cannot keep up with demand during the hot, dry conditions. Residents are not allowed to water their lawn, fill swimming pools, or wash hard surfaces. Havre Daily Chronicle (Montana), July 22, 2024.

The Attleboro Water Department upgraded its water use ban from Level 1 to Level 3 due to low reservoir levels. The ban includes lawn watering and limits pool filling. Car washing must be done using water purchased outside of Attleboro and well users need to put up a sign for enforcers to see. The Sun Chronicle (MA), July 22, 2024.

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Sun Jul 21 2024 Valid 220100Z - 221200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER SOUTHERN ARIZONA... ...SUMMARY... Isolated severe thunderstorms will remain possible this evening across parts of southern Arizona. ...Southern Arizona... Clusters of thunderstorms continue moving south across central/southern AZ early this evening, with isolated reports of measured severe/near severe gusts, or wind damage, received over the past few hours. Storm-scale outflow has surged southward ahead of the higher reflectivity cores across much of the area, and this has tended to limit more widespread severe potential. The presence of a well-mixed boundary layer persisting for a few more hours, combined with subtle ascent with a southward-moving mid-level shortwave trough, will result in isolated severe potential continuing through the early evening. ...Southeast Colorado/Eastern New Mexico... Isolated thunderstorms continue across southeast CO/northeast NM at 01z, within an environment characterized by MLCAPE of 500-1000 J/kg, and modest effective shear of around 25 kts. Although some potential will remain for a stronger storm over the next couple of hours, the overall trend should be for diminishing intensity with time as boundary-layer cooling commences. ..Bunting.. 07/22/2024 Read more