Severe Storms

No Mesoscale Discussions are in effect as of Mon Aug 18 22:15:13 UTC 2025.

MD 1988 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR SOUTHEAST IOWA...FAR NORTHEAST MISSOURI...AND NORTHWEST ILLINOIS
Mesoscale Discussion 1988 NWS Storm Prediction Center Norman OK 0351 PM CDT Mon Aug 18 2025 Areas affected...southeast Iowa...far northeast Missouri...and northwest Illinois Concerning...Severe potential...Watch possible Valid 182051Z - 182215Z Probability of Watch Issuance...40 percent SUMMARY...Storm coverage is increasing across southeast Iowa and vicinity. A watch is possible late this afternoon into the early evening. DISCUSSION...Several storms have developed across southeast Iowa where 3000+ J/kg MLCAPE is present amid mid to upper 70s dewpoints and temperatures in the 90s. The DVN VWP shows around 30-40 knots of mid-level flow (the upper bounds which are significantly stronger than most of the guidance). If this is representative of the environment, more organized storms may be possible this afternoon into the early afternoon. Trends will be monitored across this region and a severe thunderstorm watch may need to be issued if a more organized severe weather threat appears imminent. ..Bentley/Mosier.. 08/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...LSX...DVN...DMX...EAX... LAT...LON 40849372 41569260 42059154 41989039 42038957 41638918 40928987 40199104 39929224 40849372 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

MD 1987 CONCERNING SEVERE THUNDERSTORM WATCH 599... FOR NORTHERN ILLINOIS AND SOUTHEAST WISCONSIN
Mesoscale Discussion 1987 NWS Storm Prediction Center Norman OK 0338 PM CDT Mon Aug 18 2025 Areas affected...northern Illinois and southeast Wisconsin Concerning...Severe Thunderstorm Watch 599... Valid 182038Z - 182215Z The severe weather threat for Severe Thunderstorm Watch 599 continues. SUMMARY...The damaging wind threat is increasing across northeast Illinois and southeast Wisconsin. DISCUSSION...The earlier line of storms mostly weakened/broke apart as it moved across southern Wisconsin and northern Illinois. However, additional storms have started to develop along the remnant outflow in north-central Illinois. This will likely bring a renewed severe weather focus this afternoon, especially if storms congeal into a eastward moving cluster. Strong instability amid upper 70s dewpoints will provide a thermodynamic environment favorable for damaging wind gusts. In addition, mid-level flow has started to strengthen somewhat on the LOT VWP (~30 knots) which may aid in storm maintenance and this more organized threat. ..Bentley.. 08/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LOT...ILX...MKX...DVN... LAT...LON 41568968 42278893 42778847 43278785 43268726 42808701 42218696 41758711 41358766 41128833 41118914 41218980 41568968 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH Read more

MD 1985 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR WESTERN SOUTH DAKOTA
Mesoscale Discussion 1985 NWS Storm Prediction Center Norman OK 0315 PM CDT Mon Aug 18 2025 Areas affected...Western South Dakota Concerning...Severe potential...Watch possible Valid 182015Z - 182215Z Probability of Watch Issuance...40 percent SUMMARY...Storms may produce large hail and severe winds this afternoon. Storm coverage remains uncertain, but a watch is possible depending on convective trends. DISCUSSION...A supercell has developed and intensified in the Black Hills and is currently progressing southeastward. With 7.8 C/km mid-level lapse rate sampled by the observed 18Z RAP sounding and the storm moving into modestly greater shear, it is probable this storm will continue into the afternoon. Additional cumulus are deepening along a surface boundary in northern South Dakota. Additional storms may form within the next couple of hours. The main uncertainty will be the coverage of storms. This region is in the wake of a shortwave trough now in eastern North Dakota per water vapor imagery. That, along with rising mid-level heights, may mean storms remain isolated. Those that do develop will be capable of large hail and severe winds, especially with southern extent. ..Wendt/Mosier.. 08/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...UNR... LAT...LON 44020373 44520381 45590280 45460115 44790075 43730145 43520272 43720371 44020373 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

MD 1986 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR FRONT RANGE INTO SOUTHEAST WYOMING AND NEBRASKA PANHANDLE
Mesoscale Discussion 1986 NWS Storm Prediction Center Norman OK 0320 PM CDT Mon Aug 18 2025 Areas affected...Front Range into southeast Wyoming and Nebraska Panhandle Concerning...Severe potential...Watch possible Valid 182020Z - 182215Z Probability of Watch Issuance...40 percent SUMMARY...Large hail and severe winds will be possible as storms gradually intensify and move eastward this afternoon into evening. A watch may be needed later this afternoon. Convective trends will need to be monitored. DISCUSSION...Thunderstorms are increasing in coverage from the Palmer Divide into southeast Wyoming. Persistent weak warm advection has sustained elevated thunderstorms in southwest Nebraska. With weak mid-level ascent and the slowly building upper ridge, an increase in storms intensity will likely be gradual over the next few hours. Steep mid-level lapse rates along with 45 kts of effective shear were noted on the observed 18Z LBF sounding. As MLCIN erodes away from the terrain, some storms will intensify/organized and be capable of severe wind gusts and isolated large hail. Guidance continues to suggest that storms will eventually congeal/cluster by early evening. Where and when this occurs is not entirely certain. With the persistent elevated convection, there may be a preference for clustering to occur south of that activity. That said, a watch is not anticipated in the short term, but one may become necessary for parts of the central High Plains as confidence in a greater corridor of severe risk increases later today. ..Wendt/Mosier.. 08/18/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LBF...GLD...PUB...BOU...CYS... LAT...LON 38830455 39270495 40930488 41760474 42220426 42220417 42020301 41660266 41170249 39940260 39070273 38540316 38830455 MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more

WW 0600 Status Updates
STATUS FOR WATCH 0600 HAS NOT BEEN ISSUED YET Read more

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...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 0421 PM CDT Mon Aug 18 2025 Valid 201200Z - 261200Z An upper-level ridge centered near the Four Corners will break down over the Northern Rockies Day 3/Wednesday - Day 4/Thursday. A dry cold front will stall in the northern Great Basin and across northern Wyoming by Day 4/Thursday with a cold front likely pushing south down the Plains and into the Southeast late this week and this weekend. The upper-level ridge is forecast to shift west and build through the Northwest and northern Rockies late this week and through the weekend. Monsoonal moisture will move north and west into the Great Basin, central Rockies, and southern California, increasing chances of thunderstorms following. ...Day 3/Wednesday: central Great Basin into northern Rockies... Isolated dry thunderstorms are possible from eastern Nevada into far southwest Montana and northwest Wyoming on Day 3/Wednesday, including possibly overnight in eastern Idaho and northwest Wyoming. Mid-level moisture will increase ahead of the upper-level trough on the western/northern periphery of the upper high, but uncertainty remains regarding the coverage and location of high-based thunderstorms in a corridor from eastern Nevada/western Utah into southwest Montana and western Wyoming. Hot, dry, and breezy conditions are also likely across the northern Great Basin with elevated fire weather conditions possible. ...Day 4/Thursday - Day 8/Monday... As the ridge builds over much of the West, monsoonal moisture will continue to push west and north increasing thunderstorm chances across portions of southern California, the Sierra, Great Basin, and the Rocky Mountains of Colorado and Wyoming. Forecast uncertainty remains regarding the magnitude of the monsoonal moisture, especially regarding the arrival of deeper monsoonal moisture in portions of the southern/central Intermountain West. High-based, drier thunderstorms are likely along the periphery and leading edge of this monsoonal moisture, but too much uncertainty on timing and location precludes introducing probabilities at this time. Well above normal temperatures are expected across much of the West, with low RH ahead of the monsoonal moisture. ..Nauslar.. 08/18/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

WW 0599 Status Updates
STATUS REPORT ON WW 599 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW RFD TO 15 SSE JVL TO 25 ENE JVL TO 20 N MKE TO 30 SSW MTW. ..BENTLEY..08/18/25 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 599 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC007-011-031-037-043-063-073-089-093-097-099-103-111-141-155- 195-197-201-182140- IL . ILLINOIS COUNTIES INCLUDED ARE BOONE BUREAU COOK DE KALB DUPAGE GRUNDY HENRY KANE KENDALL LAKE LA SALLE LEE MCHENRY OGLE PUTNAM WHITESIDE WILL WINNEBAGO WIC059-101-127-182140- WI . WISCONSIN COUNTIES INCLUDED ARE KENOSHA RACINE WALWORTH LMZ645-646-671-673-675-740-741-742-777-779-182140- CW Read more

WW 0599 Status Updates
STATUS REPORT ON WW 599 SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 30 WSW RFD TO 15 SSE JVL TO 25 ENE JVL TO 20 N MKE TO 30 SSW MTW. ..BENTLEY..08/18/25 ATTN...WFO...LOT...DVN...MKX... STATUS REPORT FOR WS 599 SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS ILC007-011-031-037-043-063-073-089-093-097-099-103-111-141-155- 195-197-201-182140- IL . ILLINOIS COUNTIES INCLUDED ARE BOONE BUREAU COOK DE KALB DUPAGE GRUNDY HENRY KANE KENDALL LAKE LA SALLE LEE MCHENRY OGLE PUTNAM WHITESIDE WILL WINNEBAGO WIC059-101-127-182140- WI . WISCONSIN COUNTIES INCLUDED ARE KENOSHA RACINE WALWORTH LMZ645-646-671-673-675-740-741-742-777-779-182140- CW Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0259 PM CDT Mon Aug 18 2025 Valid 182000Z - 191200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF NORTHERN ILLINOIS AND PARTS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Strong to severe storms capable of damaging winds are possible in parts of the Midwest today. Widely scattered storms with large hail and severe winds are possible in parts of the central/northern Plains through tonight. ...20Z Update... The primary change to the current Day 1 Outlook was to trim severe probabilities across portions of southern Wisconsin, where the passage of an MCS has resulted in low-level stabilization. Otherwise, only minor changes was made to severe/thunder probabilities to reflect the latest guidance and observations. ..Squitieri.. 08/18/2025 .PREV DISCUSSION... /ISSUED 1129 AM CDT Mon Aug 18 2025/ ...Mid MS Valley... Extensive outflow from last night's MCS currently extends from extreme southwest WI southwestward through eastern IA and north-central MO into eastern KS. This outflow has been moving quickly eastward/southeastward this morning, and this trend is expected to continue, although some slowing of its progression speed is possible over time. The downstream airmass across from southern WI and IL is characterized by dewpoints in the low to mid 70s. Mid-level lapse rates are generally poor across the region, but heating of this very moist airmass will still result in strong to very strong buoyancy (i.e. MLCAPE around 3000 J/kg) by late afternoon. Strong to severe storms are possible along this outflow as it impinges on this moist and buoyant airmass. Current trends suggest the greatest severe potential will exist this afternoon across southern WI and northern IL, where slightly stronger mid-level flow, backed surface winds, and an east-west baroclinic zone exists. Recently issued MCD 1983 addresses the short-term severe potential for this area. ...Central High Plains into the northern/central Plains... Strong heating and ample low/mid level moisture will promote the development of scattered thunderstorms by mid-afternoon over the foothills and plains of central/eastern CO. Additional isolated storms are possible farther north across western NE into the Black Hills region. Much of this area is within a corridor of modest mid-level flow on the northern periphery of the upper ridging covering the southern CONUS. Resulting modest shear may be enough for hail production with the initial development before these high-based storms trend towards outflow-dominant structures with time. These storms may persist into the evening, with an attendant threat for strong to severe gusts progressing into central NE before weakening. ...MO/AR... Clear skies and strong diurnal heating are expected across central/southern MO and much of AR. Temperatures in the upper 90s are expected, with dewpoints remaining in the mid 60s despite strong mixing. These hot and humid conditions will result in strong buoyancy this afternoon, with most guidance suggesting MLCAPE around 2000 J/kg. Shear will be weak, yielding mostly disorganized multicells, but the strongest storms will be capable of locally damaging wind gusts. Read more