Severe Storms

WW 523 SEVERE TSTM MT 180250Z - 180800Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 523 NWS Storm Prediction Center Norman OK 850 PM MDT Thu Jul 17 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Southeast Montana * Effective this Thursday night and Friday morning from 850 PM until 200 AM MDT. * Primary threats include... Scattered damaging wind gusts to 70 mph likely Scattered large hail and isolated very large hail events to 2 inches in diameter possible SUMMARY...Two intense supercells continue to track southeastward into the watch area. Large hail and damaging wind gusts will remain possible for a few more hours with these storms. The severe thunderstorm watch area is approximately along and 40 statute miles north and south of a line from 90 miles west of Miles City MT to 15 miles southeast of Baker MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU3). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 522... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 60 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 29030. ...Hart Read more

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 NNE BIL TO 65 SW GGW TO 65 NNW GGW. ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC033-055-105-180440- MT . MONTANA COUNTIES INCLUDED ARE GARFIELD MCCONE VALLEY 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

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 NNE BIL TO 65 SW GGW TO 65 NNW GGW. ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC033-055-105-180440- MT . MONTANA COUNTIES INCLUDED ARE GARFIELD MCCONE VALLEY 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

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 NNE BIL TO 65 SW GGW TO 65 NNW GGW. ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC033-055-105-180440- MT . MONTANA COUNTIES INCLUDED ARE GARFIELD MCCONE VALLEY 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

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 50 NNE BIL TO 65 SW GGW TO 65 NNW GGW. ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC033-055-105-180440- MT . MONTANA COUNTIES INCLUDED ARE GARFIELD MCCONE VALLEY 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

WW 522 SEVERE TSTM MT 172130Z - 180400Z
URGENT - IMMEDIATE BROADCAST REQUESTED Severe Thunderstorm Watch Number 522 NWS Storm Prediction Center Norman OK 330 PM MDT Thu Jul 17 2025 The NWS Storm Prediction Center has issued a * Severe Thunderstorm Watch for portions of Northern Montana * Effective this Thursday afternoon and evening from 330 PM until 1000 PM MDT. * Primary threats include... Scattered large hail and isolated very large hail events to 2 inches in diameter possible Scattered damaging wind gusts to 65 mph possible SUMMARY...Thunderstorms will continue to develop and intensify across north-central Montana this afternoon and track southeastward across the watch area. A few supercells are expected, capable of large hail and damaging wind gusts. The severe thunderstorm watch area is approximately along and 60 statute miles north and south of a line from 60 miles north northwest of Great Falls MT to 50 miles southeast of Glasgow MT. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU2). PRECAUTIONARY/PREPAREDNESS ACTIONS... REMEMBER...A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area. Persons in these areas should be on the lookout for threatening weather conditions and listen for later statements and possible warnings. Severe thunderstorms can and occasionally do produce tornadoes. && OTHER WATCH INFORMATION...CONTINUE...WW 521... AVIATION...A few severe thunderstorms with hail surface and aloft to 2 inches. Extreme turbulence and surface wind gusts to 55 knots. A few cumulonimbi with maximum tops to 500. Mean storm motion vector 28030. ...Hart Read more

WW 0523 Status Updates
STATUS REPORT ON WW 523 THE SEVERE WEATHER THREAT CONTINUES ACROSS THE ENTIRE WATCH AREA. ..DEAN..07/18/25 ATTN...WFO...BYZ...GGW... STATUS REPORT FOR WS 523 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC017-025-079-087-103-180440- MT . MONTANA COUNTIES INCLUDED ARE CUSTER FALLON PRAIRIE ROSEBUD TREASURE 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

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 45 SE LWT TO 75 ESE HVR TO 85 ENE HVR. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1704 ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC033-055-069-071-105-180340- MT . MONTANA COUNTIES INCLUDED ARE GARFIELD MCCONE PETROLEUM PHILLIPS VALLEY 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 1704 CONCERNING SEVERE THUNDERSTORM WATCH 522... FOR NORTH-CENTRAL INTO EASTERN MT
Mesoscale Discussion 1704 NWS Storm Prediction Center Norman OK 0804 PM CDT Thu Jul 17 2025 Areas affected...North-central into eastern MT Concerning...Severe Thunderstorm Watch 522... Valid 180104Z - 180230Z The severe weather threat for Severe Thunderstorm Watch 522 continues. SUMMARY...A threat for hail and localized severe gusts will continue through the evening. DISCUSSION...One supercell is ongoing at 01 UTC across parts of Phillips County in MT, with another supercell east of Great Falls. A compact but vigorous mid/upper-level shortwave trough is moving across southeast AB and northern MT, and ascent attendant to this shortwave will help these isolated to widely scattered cells persist through the evening. With relatively modest low-level moisture and generally weak midlevel lapse rates (as observed in the 00Z GGW sounding), buoyancy is rather modest, with MLCAPE generally in the 500-1000 J/kg range. However, very favorable deep-layer shear (with effective shear of 50-60 kt) and elongated mid/upper-level hodographs will support some hail threat with any sustained supercells, despite the marginal instability. Localized strong to severe gusts may also accompany these cells through the evening, especially if any storm clustering occurs. Farther south, an earlier discrete cell has weakened across southeast MT. While instability is somewhat greater compared to areas farther north, this region is further removed from the primary shortwave trough, and any severe threat in this area is expected to remain isolated in the short term. There is some potential for one or more of the northern MT cells to eventually approach east-central and southeast MT near and after dusk. ..Dean.. 07/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...BYZ...GGW...TFX... LAT...LON 47190961 47730965 48970855 48960620 47830552 47060521 46390559 45910594 45890724 46610885 47190961 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0522 Status Updates
STATUS REPORT ON WW 522 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 40 W LWT TO 30 SSW HVR TO 50 NNE HVR. FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1704 ..DEAN..07/18/25 ATTN...WFO...TFX...GGW... STATUS REPORT FOR WS 522 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS MTC005-027-033-055-069-071-105-180240- MT . MONTANA COUNTIES INCLUDED ARE BLAINE FERGUS GARFIELD MCCONE PETROLEUM PHILLIPS VALLEY 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

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more

SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0747 PM CDT Thu Jul 17 2025 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN EASTERN MT TO FAR SOUTHWEST ND... ...SUMMARY... A couple supercells will remain capable of large hail and severe gusts through about midnight across eastern Montana. ...Northern Great Plains... A couple supercells are ongoing over north-central MT with a history of measured severe gusts and severe hail signatures per MRMS MESH. This activity should persist southeastward through at least late evening amid strong effective bulk shear but weak buoyancy and modest mid-level lapse rates per the 00Z GGW sounding. Most guidance outside of the RRFS suggest that convection will remain as discrete supercells before eventually waning as it impinges on minimal surface-based instability near the MT/ND border. With such a cool and dry boundary layer per surface observations across far eastern MT into ND, the overall severe threat should diminish towards midnight. Elevated convection should develop across parts of the Dakotas overnight, with weak MUCAPE marginalizing severe potential. ...Southern High Plains... A slow-moving, loosely organized cluster is ongoing east-southeast of the Sangre de Cristo Mountains in northeast NM. While the boundary layer is climatologically cool, it is moist and moderately unstable (per the 00Z AMA sounding), amid persistent low-level easterlies. This upslope flow regime should support cluster maintenance through late evening before gradually waning overnight. While heavy rain is the primary hazard (per WPC ERO SLGT risk), a few strong to marginal severe gusts and small hail remain possible. ...Northern ME... Convection has largely waned across New England and should continue to do so over the next hour. With some lingering deep convection across northern ME, a moist boundary layer and still sufficient deep-layer shear (per the CBW VWP) may support a weakly rotating storm or two before convection spreads entirely into NB. ...Eastern OK to the Delmarva... A couple microbursts capable of strong gusts may still occur in yet to be overturned areas across a broad swath from the Ozarks to the Mid-Atlantic Coast. With modest deep-layer shear and nocturnal boundary-layer cooling, severe probabilities appear negligible. ..Grams.. 07/18/2025 Read more