Severe Storms

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0500 PM CDT Tue Aug 20 2024 Valid 221200Z - 281200Z An upper low over the West Coast is forecast to move south and linger over parts of the Northwest through the weekend. Stronger southwesterly flow east of the low will overspread a modestly dry air mass across parts of the Great Basin and Northwest through the weekend. This should support elevated to critical fire-weather potential and some risk for isolated dry thunderstorms. ...Northwest and Great Basin... As the aforementioned upper low approaches from the northwest D3/Thursday and D4/Friday, stronger flow on the eastern side will gradually overspread a warm and fairly dry air mass across parts of OR/ID and into the Great Basin. Several days of dry and breezy conditions are expected with the potential for elevated to near-critical fire-weather concerns. Winds are expected to be strongest D4/Friday over parts of southern NV and western UT with gusts to 35 mph possible. Area fuels should continue to dry and be at least partially receptive to fire spread heading into the weekend. Fire-weather concerns should continue through the weekend as stronger flow aloft begins to extend into the northern/central Rockies. Confidence in more widespread elevated fire-weather potential is highest for D5/Saturday, though some risk may continue across parts of WY/CO/MT into early next week. ...Southern Plains... Periodic dry return flow is possible over parts of the southern Plains late this week into the weekend. Gusty southerly flow ahead of the upper low to the west may support occasional 10-15 mph winds and RH below 20% over parts of west TX and eastern NM. Confidence remains low in the coverage and duration of elevated to critical fire-weather potential. ...Dry thunderstorm potential... Mid-level moisture should increase ahead of the low over much of the Western US beginning D3/Thursday. Medium-range guidance shows a plume of 0.6 to 0.8 inch PWATs moving into the Pacific Northwest ahead of the upper low into OR and WA. Some dry lightning will be possible Thursday, though the best storm coverage may remain away from the driest fuels. Confidence in dry thunderstorm and lightning potential over dry fuels is higher in southeast OR and western ID beginning D4/Friday as the upper low continues south and moisture depth increases. At least some risk for occasional dry storms will continue through the weekend, though the increase in moisture should gradually limit fuels as temperatures cool and chances for wetting rains increase beneath the upper low. ..Lyons.. 08/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0500 PM CDT Tue Aug 20 2024 Valid 221200Z - 281200Z An upper low over the West Coast is forecast to move south and linger over parts of the Northwest through the weekend. Stronger southwesterly flow east of the low will overspread a modestly dry air mass across parts of the Great Basin and Northwest through the weekend. This should support elevated to critical fire-weather potential and some risk for isolated dry thunderstorms. ...Northwest and Great Basin... As the aforementioned upper low approaches from the northwest D3/Thursday and D4/Friday, stronger flow on the eastern side will gradually overspread a warm and fairly dry air mass across parts of OR/ID and into the Great Basin. Several days of dry and breezy conditions are expected with the potential for elevated to near-critical fire-weather concerns. Winds are expected to be strongest D4/Friday over parts of southern NV and western UT with gusts to 35 mph possible. Area fuels should continue to dry and be at least partially receptive to fire spread heading into the weekend. Fire-weather concerns should continue through the weekend as stronger flow aloft begins to extend into the northern/central Rockies. Confidence in more widespread elevated fire-weather potential is highest for D5/Saturday, though some risk may continue across parts of WY/CO/MT into early next week. ...Southern Plains... Periodic dry return flow is possible over parts of the southern Plains late this week into the weekend. Gusty southerly flow ahead of the upper low to the west may support occasional 10-15 mph winds and RH below 20% over parts of west TX and eastern NM. Confidence remains low in the coverage and duration of elevated to critical fire-weather potential. ...Dry thunderstorm potential... Mid-level moisture should increase ahead of the low over much of the Western US beginning D3/Thursday. Medium-range guidance shows a plume of 0.6 to 0.8 inch PWATs moving into the Pacific Northwest ahead of the upper low into OR and WA. Some dry lightning will be possible Thursday, though the best storm coverage may remain away from the driest fuels. Confidence in dry thunderstorm and lightning potential over dry fuels is higher in southeast OR and western ID beginning D4/Friday as the upper low continues south and moisture depth increases. At least some risk for occasional dry storms will continue through the weekend, though the increase in moisture should gradually limit fuels as temperatures cool and chances for wetting rains increase beneath the upper low. ..Lyons.. 08/20/2024 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

MD 1964 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHWEST INTO CENTRAL MT
Mesoscale Discussion 1964 NWS Storm Prediction Center Norman OK 0311 PM CDT Tue Aug 20 2024 Areas affected...southwest into central MT Concerning...Severe potential...Watch possible Valid 202011Z - 202215Z Probability of Watch Issuance...60 percent SUMMARY...Isolated to widely scattered thunderstorms could produce strong/damaging gusts and isolated hail into early evening across parts of southeast into central Montana. Area is being monitored for possible severe thunderstorm watch issuance. DISCUSSION...Isolated thunderstorms have developed this afternoon over the higher terrain of southwest Montana. This area has quickly warmed into the 80s F as earlier cloud cover has shifted northeast. Additional convection is expected to develop further east near the Beartooth/Absarokas over the next couple of hours. Collectively this convection will spread northeast into this evening. Modest instability, mainly supported by steep midlevel lapse rates/cool temps aloft, and effective shear magnitudes greater than 35 kt will support organized/robust updrafts. Forecast hodographs along with regional VWP data also indicate shear favorable for supercells. Given high-based storms and steepening low-level lapse rates, strong/damaging gusts are possible with this activity as it becomes better organized with time and northeastward extent into the high Plains. A few instances of hail up to 1.25 inch diameter is also possible. A severe thunderstorm watch may be needed this afternoon. ..Leitman/Hart.. 08/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...GGW...TFX...MSO... LAT...LON 45531289 46451251 46751218 47121145 47421034 47500949 47450855 47020732 46200683 45770694 45210755 45210863 44971202 45041265 45231284 45531289 Read more

WW 0641 Status Updates
STATUS REPORT ON WW 641 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..HALBERT..08/20/24 ATTN...WFO...TFX...BYZ...GGW... STATUS REPORT FOR WS 641 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC001-003-005-007-009-013-015-027-031-033-037-041-043-045-049- 057-059-065-067-069-071-087-095-097-103-105-107-111-202240- MT . MONTANA COUNTIES INCLUDED ARE BEAVERHEAD BIG HORN BLAINE BROADWATER CARBON CASCADE CHOUTEAU FERGUS GALLATIN GARFIELD GOLDEN VALLEY HILL JEFFERSON JUDITH BASIN LEWIS AND CLARK MADISON MEAGHER MUSSELSHELL PARK PETROLEUM PHILLIPS ROSEBUD STILLWATER SWEET GRASS TREASURE VALLEY WHEATLAND YELLOWSTONE THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES. Read more

MD 1963 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR SOUTHEASTERN COLORADO...NORTHEASTERN NEW MEXICO
Mesoscale Discussion 1963 NWS Storm Prediction Center Norman OK 0221 PM CDT Tue Aug 20 2024 Areas affected...southeastern Colorado...northeastern New Mexico Concerning...Severe potential...Watch unlikely Valid 201921Z - 202115Z Probability of Watch Issuance...5 percent SUMMARY...Marginal risk for hail and strong to severe gusts. DISCUSSION...Thunderstorm coverage is increasing across southeastern Colorado and northern New Mexico. Temperatures in this region have warmed into the upper 80s to 90s with dew points in the upper 40s to 50s along the higher terrain, increasing to the mid 60s across the lower plains. Steep low to mid-level lapse rates and large dew point depressions may support a few instances of strong to severe wind with any stronger cores. Across southeastern Colorado, a MLCAPE gradient of 1000-2500 J/kg will support a few instances of hail and gusty winds. Given lack of deep layer shear for organization and strong ridging aloft, this threat should remain localized and a watch is not likely to be needed. ..Thornton/Hart.. 08/20/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DDC...GLD...AMA...PUB...BOU...ABQ... LAT...LON 37050196 36310308 36170510 37430611 38630580 39350385 39340303 38600219 38240200 37050196 Read more

WW 0641 Status Updates
STATUS FOR WATCH 0641 HAS NOT BEEN ISSUED YET Read more

No watches are valid as of Tue Aug 20 20:14:02 UTC 2024.

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0248 PM CDT Tue Aug 20 2024 Valid 202000Z - 211200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF CENTRAL MONTANA... ...SUMMARY... Severe thunderstorm winds and large hail are possible today, mainly over parts of Montana. ...Montana and the High Plains... The previous forecast remains on track with only minor modifications made to the Marginal risk/wind probabilities across southwest MT to account for developing convection within a deeply-mixed environment. See the previous discussion for additional details regarding the severe risk across Montana, and MCD #1963 for recent convective trends regarding CO/NM. ...South Carolina Coast... A targeted Marginal risk was considered for the immediate SC coast where convection is developing along a sea breeze boundary. The thermodynamic and kinematic environment along the coast appears conducive for a few strong, to perhaps severe, storms. However, longevity of initial cells appears limited based on regional radar imagery, and recent high-res guidance suggests any threat will remain very localized to mainly coastal counties. Given these concerns, risk highlights were withheld. ..Moore.. 08/20/2024 .PREV DISCUSSION... /ISSUED 1108 AM CDT Tue Aug 20 2024/ ...MT... Morning water vapor imagery shows a progressive shortwave trough and associated mid/upper level speed max rotating across NV/ID. Lift associated with this system will overspread the mountains of ID/southwest MT this afternoon, where increasing mid-level moisture and strong heating will lead to scattered thunderstorm development. As these storms move off the higher terrain, they will encounter a deeply mixed and marginally unstable air mass. Steep low-level lapse rates and favorably strong westerly mid-level winds will favor damaging wind gusts or perhaps hail with the more intense clusters of storms. Activity will spread into eastern MT during the evening and slowly weaken as diurnal cooling ensues. ...CO/NM... A persistent upper ridge remains over NM, with several weak perturbations rotating around the top of the ridge across UT/CO. Widely scattered high-based thunderstorms are expected to develop across central/southern CO later this afternoon and spread slowly eastward into the Plains. A few of the storms may produce gusty winds or hail. Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Tue Aug 20 2024 Valid 211200Z - 221200Z ...20z update... A few hours of elevated fire-weather conditions are possible over parts of northern and central WY D2/Wed. Strong flow aloft will overlap with deep mixing supporting gusty winds of 15-20 mph and RH minimums of 10-15%. Fuels are at least partially receptive to spread with pockets of ERC values above the 80th percentile. Thus, an Elevated area was introduced over the best overlap of dry fuels and elevated fire-weather potential. Farther south across NV, the Great Basin, and eastern Snake River Valley, a corridor of elevated to near-critical fire-weather conditions remains apparent. Southwest surface winds of 20-25 mph and RH below 15% will allow for elevated to near-critical meteorological conditions to develop. However, this area currently overlaps with fuels that are not overly receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles from recent rainfall. With dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and at least some potential for elevated fire-weather concerns persists despite uncertainties with fuel availability. See the prior discussion for more information. ..Lyons.. 08/20/2024 .PREV DISCUSSION... /ISSUED 0143 AM CDT Tue Aug 20 2024/ ...Synopsis... Broad southwesterly mid-level flow, and a progressive shortwave trough moving through the northern Great Basin/Northwest U.S., will bring sustained dry/windy conditions to portions of Nevada, Utah, and Idaho on Wednesday. ...Dry/Windy... Deep boundary-layer mixing beneath broad southwesterly mid-level flow, and a progressive shortwave trough moving from northern Nevada/southern Oregon into Idaho and Montana, will be responsible for elevated fire-weather conditions across the Great Basin on Wednesday. High-resolution ensemble guidance suggests there may be a narrow corridor of critical fire-weather conditions across Nevada, where relative humidity values will drop into the single digits and winds could get as high as 20-25 MPH. This area currently overlaps with fuels that are not expected to be receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles. However, with dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and critical highlights could be needed in subsequent updates. ...Dry Thunderstorms... A mix of wet and dry thunderstorms will be possible across southwestern Montana, with additional dry thunderstorm development likely across southern Colorado and northern New Mexico. However, current fuels guidance suggests that both of these regions are unlikely to be receptive to new ignitions and wildfire spread, with ERC values below the 60th annual percentile for both regions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more

SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0230 PM CDT Tue Aug 20 2024 Valid 211200Z - 221200Z ...20z update... A few hours of elevated fire-weather conditions are possible over parts of northern and central WY D2/Wed. Strong flow aloft will overlap with deep mixing supporting gusty winds of 15-20 mph and RH minimums of 10-15%. Fuels are at least partially receptive to spread with pockets of ERC values above the 80th percentile. Thus, an Elevated area was introduced over the best overlap of dry fuels and elevated fire-weather potential. Farther south across NV, the Great Basin, and eastern Snake River Valley, a corridor of elevated to near-critical fire-weather conditions remains apparent. Southwest surface winds of 20-25 mph and RH below 15% will allow for elevated to near-critical meteorological conditions to develop. However, this area currently overlaps with fuels that are not overly receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles from recent rainfall. With dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and at least some potential for elevated fire-weather concerns persists despite uncertainties with fuel availability. See the prior discussion for more information. ..Lyons.. 08/20/2024 .PREV DISCUSSION... /ISSUED 0143 AM CDT Tue Aug 20 2024/ ...Synopsis... Broad southwesterly mid-level flow, and a progressive shortwave trough moving through the northern Great Basin/Northwest U.S., will bring sustained dry/windy conditions to portions of Nevada, Utah, and Idaho on Wednesday. ...Dry/Windy... Deep boundary-layer mixing beneath broad southwesterly mid-level flow, and a progressive shortwave trough moving from northern Nevada/southern Oregon into Idaho and Montana, will be responsible for elevated fire-weather conditions across the Great Basin on Wednesday. High-resolution ensemble guidance suggests there may be a narrow corridor of critical fire-weather conditions across Nevada, where relative humidity values will drop into the single digits and winds could get as high as 20-25 MPH. This area currently overlaps with fuels that are not expected to be receptive to wildfire spread, with ERC values around the 60th-65th annual percentiles. However, with dry/windy conditions expected the preceding day, some additional curing of fuels can be expected, and critical highlights could be needed in subsequent updates. ...Dry Thunderstorms... A mix of wet and dry thunderstorms will be possible across southwestern Montana, with additional dry thunderstorm development likely across southern Colorado and northern New Mexico. However, current fuels guidance suggests that both of these regions are unlikely to be receptive to new ignitions and wildfire spread, with ERC values below the 60th annual percentile for both regions. ...Please see www.spc.noaa.gov/fire for graphic product... Read more