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SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0238 PM CDT Sun Aug 04 2024 Valid 042000Z - 051200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR A FEW TORNADOES OVER PART OF FLORIDA AND EXTREME SOUTHERN GEORGIA...AND FOR DAMAGING GUSTS ACROSS SOUTHEAST MONTANA THIS EVENING... ...SUMMARY... Tropical Storm Debby may produce a few tornadoes over parts of Florida and extreme southern Georgia through early tomorrow morning as it intensifies. Scattered thunderstorms may produce damaging wind gusts across parts of Montana this evening. ...20Z Update... Overall forecast outlined in the previous discussion (appended below) remains valid, with no changes needed. TS Debby continues to strengthen off the west coast of FL, while numerous convective rain bands progress across FL Peninsula. Brief tornadoes will remain possible within these bands through the afternoon and evening, with a lower, but still non-zero chances overnight. Thunderstorms capable of strong gusts are still anticipated this evening from eastern ID into southern MT and northern WY. Strong gusts are possible this evening from eastern SD into southern MN and northern IA, with some isolated hail possible as well. Isolated severe threat across the Northeast was discussed in recently issued MCD #1814, which mentioned that short-lived, strong storm cores capable of marginally severe hail will be the primary risk over the next few hours as they travel east/southeast across the narrow instability zone. ..Mosier.. 08/04/2024 .PREV DISCUSSION... /ISSUED 1123 AM CDT Sun Aug 04 2024/ ...FL/South GA... Tropical Storm Debby continues to intensify off the west coast of the FL. Low-level wind fields are enlarging, resulting in strengthening shear profiles across much of peninsula. Dewpoints in the mid-upper 70s and pockets of heating, combined with deep tropical moisture, will result in scattered to widespread afternoon thunderstorms. Given the favorable wind fields, a few tornadoes are possible. ...MT/WY... Water vapor loop shows a well-defined mid-level shortwave trough moving eastward across ID. This feature and an associated mid-level speed max will cross the northern Rockies and into southern MT/northern WY this afternoon/evening. A consensus of 12z model guidance shows clusters of thunderstorms forming in this region, tracking eastward across southern MT through the evening. CAMs have a consistent signal for a more organized damaging wind threat, so have added a small SLGT to account for this scenario. ...SD/MN/IA... A strengthening low-level jet will enhance warm advection and lift over eastern SD/western MN this evening/tonight. Isolated thunderstorm development is possible in this regime, perhaps not until after midnight. This region will be beneath the southern fringe of stronger west-northwest flow aloft, and in a region of relatively steep mid-level lapse rates. Elevated storms capable of hail and perhaps gusty winds are possible. ...Northeast States... Scattered thunderstorms are expected today across much of New England and eastern NY/PA into NJ. Surface conditions are considerably cooler than recent days, which should weaken low-level lapse rates and temper the overall severe threat. Nevertheless, a few strong storms are possible - capable of gusty wind and small hail. Read more

MD 1815 CONCERNING TORNADO WATCH 594... FOR MUCH OF THE FLORIDA PENINSULA AND FAR SOUTHERN GEORGIA
Mesoscale Discussion 1815 NWS Storm Prediction Center Norman OK 1247 PM CDT Sun Aug 04 2024 Areas affected...much of the Florida Peninsula and far southern Georgia Concerning...Tornado Watch 594... Valid 041747Z - 041945Z The severe weather threat for Tornado Watch 594 continues. SUMMARY...Mini supercells within the outer bands of intensifying TC Debby will remain capable of tornadoes this afternoon. DISCUSSION...As of 1745 UTC, the latest NHC Aircraft recon fixed the low-level center of TS Debby near 27.0 N, 84.3 W. As the TC continues to deepen, low-level hodograph expansion has been noted at most of the radar sites east/northeast of the center. A few tornadoes are possible with miniature supercells embedded within the spiral rain bands as they move ashore into moderate low-level SRH. Stronger low-level mesocyclones within the most westward band have moved offshore over the past few hours, but a new band developing to the east has shown some stronger convective development recently. As low-level shear continues to intensify, tornado potential should increase, especially where low-level flow is more backed. Warmer surface temperatures to the north of the main cloud shield may also support more intense convection and a locally greater tornado or damaging gust risk this afternoon. ..Lyons.. 08/04/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MFL...MLB...TBW...JAX...TAE... LAT...LON 26378186 26958227 27618259 28778267 29468327 30138435 30688414 30788356 30848219 30778159 30168131 29288102 28358068 27928072 27318071 26408115 26278154 26378186 Read more

000
ABPZ20 KNHC 041751
TWOEP

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
1100 AM PDT Sun Aug 4 2024

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

Active Systems:
The National Hurricane Center is issuing advisories on Tropical
Storm Carlotta, on Tropical Storm Daniel, and on newly formed
Tropical Depression Five-E, all located well offshore of the coast
of Mexico.

South of Southwestern Mexico (EP96):
Shower and thunderstorm activity continues to show signs of
organization in association with an area of low pressure located a
few hundred miles south of southwestern Mexico. Environmental
conditions remain conducive for development, and a tropical
depression is likely to form as soon as this afternoon while the
system moves generally west-northwestward at 10 to 15 mph, remaining
well offshore of the coast of Mexico. For more information of this
system, including Gale Warnings, see High Seas Forecasts issued by
the National Weather Service.
* Formation chance through 48 hours...high...80 percent.
* Formation chance through 7 days...high...90 percent.

&&
Public Advisories on Tropical Depression Five-E are issued under
WMO header WTPZ35 KNHC and under AWIPS header MIATCPEP5.
Forecast/Advisories on Tropical Depression Five-E are issued under
WMO header WTPZ25 KNHC and under AWIPS header MIATCMEP5.

High Seas Forecasts issued by the National Weather Service
can be found under AWIPS header NFDHSFEPI, WMO header FZPN02
KWBC, and on the web at ocean.weather.gov/shtml/NFDHSFEPI.php

$$
Forecaster Papin

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC 1730Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1233 PM CDT Sun Aug 04 2024 Valid 051200Z - 061200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHERN FL INTO EASTERN GA AND SOUTHERN SC...ACROSS PORTIONS OF THE UPPER MIDWEST...AND FROM THE UPPER OH VALLEY INTO NEW ENGLAND... ...SUMMARY... A few severe thunderstorms are possible Monday into Monday night from the Upper Ohio Valley into New England, across portions of the Upper Midwest, and from northern Florida into southern Georgia and southeast South Carolina. ...Synopsis... A belt of enhanced westerlies is forecast to extend across the length US/Canada border, from the Pacific Northwest through the northern Plains/Upper Midwest and Northeast. Several shortwave troughs will be embedded within these westerlies, the most prominent of which is a wave that is forecast to progress quickly from central Ontario through southern Quebec and northern ME. Another, low-amplitude shortwave trough is expected to move through the northern Plains, Upper Midwest, and Upper Great Lakes. Expansive upper ridging is expected to remain centered over the Four Corners, extending from the southern Great Basin vicinity through the lower MS Valley. Tropical Cyclone Debby is expected to move between the eastern periphery of the Four Corners ridge and subtropical ridging over the western Atlantic, progressing across northern FL and reaching the southeast GA/southern SC vicinity by early Tuesday morning. Surface pattern early Monday is expected to feature a low over the central SD/NE border vicinity, with a stationary front extending eastward from this low across central IA, northern IL, and southern Lower MI before arcing more northeastward along the St. Lawrence Valley to another low over New Brunswick. Eastern portion of this front is expected to progress southeastward across the Northeast throughout the day, while the portion of the front closer to the SD/NE surface low transitions to a warm front amid southerly low-level flow ahead of the low. A cold front will extend westward from the SD/NE surface low into eastern WY, where it intersects lee troughing extending across the northern and central High Plains. This front is expected to push southward across the central Plains as the low progresses eastward/southeastward through IA. ...Northern FL into southern GA and far southern SC... Tropical cyclone Debby is forecast to progress across northern FL throughout the day, reaching the southeast GA/southern SC vicinity by early Tuesday morning. Strong low-level flow attendant to this system will support the potential for tornadoes within deeper, more persistent updrafts. These updrafts are most likely in the areas where dewpoints exceed 74/75 deg F. This appears most likely across northern FL and southeast GA. However, a more westerly track would allow this more favorable low-level moisture to penetrate inland more of southern GA and perhaps even southern SC. 5-percent tornado probabilities were adjusted northward to account for this possibility. ...Northern OH Valley through the Northeast/New England... Thunderstorm development is anticipated Monday afternoon along the length of the cold front extending from ME into northern IN/OH. Dewpoints ranging from the mid 60s across central ME to the low 70s across IN/OH will support moderate buoyancy, with the strongest buoyancy across the OH Valley where greater low-level moisture exists. Moderate mid-level flow will extend across the region as well, with the stronger flow and greater vertical shear expected across New England. While there is some displacement between the strongest shear and greatest buoyancy, there is still enough overlap to support scattered strong to severe storms, including even some supercells across New England. Damaging gusts will be the primary severe hazard. ...Upper Midwest... Late afternoon/evening thunderstorm development is expected near the surface low and associated warm front moving across IA. The airmass will be very unstable, supported by temperatures in the upper 80s/low 90s and dewpoints in the mid 70s. Even so, there is some question whether true warm sector storms will initiate, given the potential for significant mixing and warm mid-level temperatures. Storms north of the warm front could still pose a severe risk, with large hail and damaging gusts as the primary threats. A surface-based, warm sector storm would have these threat as well, but with an added potential for very large hail and potentially even a tornado or two, given the potential for a supercellular mode. After the initial cellular mode, a quick transition to a more linear/forward-propagating mode is expected. ...Northern Rockies... A low-amplitude shortwave trough is forecast to move through the northern periphery of the ridge across the northern Rockies Monday afternoon. Ascent and increased mid-level moisture attendant to this wave combined with orographic ascent and deep boundary-layer mixing will help support afternoon/evening thunderstorms. Deep-layer vertical shear is strong enough to some organized, more persistent updrafts. High storm bases and steep low-level lapse rates will help support damaging gusts with the strongest storms. ..Mosier.. 08/04/2024 Read more

SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook NWS Storm Prediction Center Norman OK 1154 AM CDT Sun Aug 04 2024 Valid 041700Z - 051200Z ...Update... Latest observational trends in satellite data, combined with recent CAMs and other model output, suggest the most likely area for isolated dry thunderstorm coverage will be shifted southeast from the previous forecast across portions of central UT, southern WY, and western CO, with a small area of additional elevated, dry thunderstorms possible near and east/northeast of the Cascades of OR. These areas will have relatively lower PWATs and drier boundary layer conditions this afternoon. Further north across MT and the rest of WY, wetting thunderstorms are anticipated within an area of stronger mid-level ascent and deeper moisture. In addition, very few thunderstorms are now expected to develop over ID on the backside of an exiting vorticity maximum, and as a result, dry Thunderstorms have been removed from the forecast there. For additional details pertaining to the unchanged Elevated area for windy and dry conditions this afternoon across the High Plains of WY, SD, and NE please see the previous discussion below. ..Barnes.. 08/04/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Sun Aug 04 2024/ ...Synopsis... ...Isolated Dry Thunderstorms... A midlevel disturbance moving across the Great Basin into the northern Rockies will bring isolated dry thunderstorm chances across eastern Oregon into Idaho southward and eastward into Utah and Wyoming this afternoon. In these regions, mid-level moisture will overlap dry surface conditions with faster storm motions. With little to no precipitation expected, dry fuels within these regions will support potential for new ignitions. Gusty and erratic outflow will also be possible. Better potential for wetting rainfall into central/northern Montana precludes the need to include these areas, though fuels in these regions are also sufficiently dry. ...Windy/Dry... A surface low will deepen across eastern MT/WY this afternoon. Surface winds will increase across these regions into western Nebraska and southern South Dakota amid relative humidity reductions to 15-20 percent. Some portions of the Nebraska Panhandle received wetting rainfall in the last 24 hours, though heavier totals were more sparse. Given ERCs near the 95th percentile before this light to moderate rainfall, fuels may still be receptive to fire spread with Elevated fire weather conditions expected. ...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 1154 AM CDT Sun Aug 04 2024 Valid 041700Z - 051200Z ...Update... Latest observational trends in satellite data, combined with recent CAMs and other model output, suggest the most likely area for isolated dry thunderstorm coverage will be shifted southeast from the previous forecast across portions of central UT, southern WY, and western CO, with a small area of additional elevated, dry thunderstorms possible near and east/northeast of the Cascades of OR. These areas will have relatively lower PWATs and drier boundary layer conditions this afternoon. Further north across MT and the rest of WY, wetting thunderstorms are anticipated within an area of stronger mid-level ascent and deeper moisture. In addition, very few thunderstorms are now expected to develop over ID on the backside of an exiting vorticity maximum, and as a result, dry Thunderstorms have been removed from the forecast there. For additional details pertaining to the unchanged Elevated area for windy and dry conditions this afternoon across the High Plains of WY, SD, and NE please see the previous discussion below. ..Barnes.. 08/04/2024 .PREV DISCUSSION... /ISSUED 0202 AM CDT Sun Aug 04 2024/ ...Synopsis... ...Isolated Dry Thunderstorms... A midlevel disturbance moving across the Great Basin into the northern Rockies will bring isolated dry thunderstorm chances across eastern Oregon into Idaho southward and eastward into Utah and Wyoming this afternoon. In these regions, mid-level moisture will overlap dry surface conditions with faster storm motions. With little to no precipitation expected, dry fuels within these regions will support potential for new ignitions. Gusty and erratic outflow will also be possible. Better potential for wetting rainfall into central/northern Montana precludes the need to include these areas, though fuels in these regions are also sufficiently dry. ...Windy/Dry... A surface low will deepen across eastern MT/WY this afternoon. Surface winds will increase across these regions into western Nebraska and southern South Dakota amid relative humidity reductions to 15-20 percent. Some portions of the Nebraska Panhandle received wetting rainfall in the last 24 hours, though heavier totals were more sparse. Given ERCs near the 95th percentile before this light to moderate rainfall, fuels may still be receptive to fire spread with Elevated fire weather conditions expected. ...Please see www.spc.noaa.gov/fire for graphic product... Read more