Aggregator

SPC Day 3-8 Fire Weather Outlook
Day 3-8 Fire Weather Outlook NWS Storm Prediction Center Norman OK 0421 PM CDT Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...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 Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...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 Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...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 Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...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 Tue Aug 26 2025 Valid 281200Z - 031200Z Weak upper lows will drift north out of the northwestern US Day 3/Thursday - Day 4/Friday with remnants of monsoonal moisture surge lingering across portions of Washington and Montana. Drier air will filter in behind this surge as upper-level ridging begins to build slowly over the Intermountain West. Thunderstorm coverage decreases across the Sierra and western Great Basin and northern Rockies Day 4/Friday through the weekend. Another upper low will approach the Northwest coast Day 4/Friday and is likely to move into Washington over the weekend. The track of this upper low remains uncertain, especially from late Day 6/Sunday and beyond. ...Day 3/Thursday - Day 4/Friday... Isolated mixed wet/dry thunderstorms are possible in portions northern Washington into northwest Montana on Day 3/Thursday, with chances potentially lingering in the Idaho Panhandle/northwest Montana on Day 4/Friday. However, there is too much uncertainty regarding actual lightning production and not just high-based showers to introduce probabilities at this time. ...Day 4/Friday - Day 6/Sunday... Dry/breezy conditions are likely in portions of northern California into the Inland Northwest and northwest Great Basin as the upper low approaches and eventually moves into the Northwest. Given the recent lightning and dry fuels, holdovers will be a concern, and any ongoing active large wildfires in these areas are likely to see increased growth. Showers are likely in portions of western Washington associated with the upper low. ..Nauslar.. 08/26/2025 ...Please see www.spc.noaa.gov/fire for graphic product... Read more

5-Day Uncertainty Track last updated Tue, 26 Aug 2025 20:37:05 GMT


Wind Speed Probabilities last updated Tue, 26 Aug 2025 21:26:15 GMT

5-Day Uncertainty Track last updated Tue, 26 Aug 2025 20:37:05 GMT


Wind Speed Probabilities last updated Tue, 26 Aug 2025 20:37:05 GMT

Issued at 200 PM PDT Tue Aug 26 2025 000 WTPZ45 KNHC 262034 TCDEP5 Tropical Storm Juliette Discussion Number 9 NWS National Hurricane Center Miami FL EP102025 200 PM PDT Tue Aug 26 2025 The center of Juliette appears to be near the northern edge of the central convective area, as there could still be some moderate northeasterly shear affecting the cyclone. Overall, the structure appears similar to, but slightly degraded compared to, the system's appearance on satellite imagery 6 h ago. The latest objective intensity estimates have been running in the 45-50 kt range, and the latest Final-T numbers from TAFB and SAB are both 3.5 (55 kt). The initial intensity is set at 55 kt for this advisory. Although vertical wind shear over Juliette is forecast to be very low for the next 24-30 h, the cyclone is expected to cross the 26C sea-surface temperature (SST) isotherm by hour 12, and water temperatures will continue to decrease with time along its path. Juliette will also be moving into a progressively drier and more stable airmass. Little change in strength is expected over the next 12-24 h, but steady weakening is expected when the cyclone moves over colder water and through drier air. The NHC intensity forecast is near the higher end of the guidance through 24 h, but lies in the middle of the guidance envelope thereafter. Beyond 36 h, southwesterly wind shear will increase as Juliette moves closer to an upper-level trough located well to its northwest. The increasing shear, along with the cold SSTs and dry air, should cause the cyclone to lose its convection and become post-tropical in about 2 days. Global models show the remnant low gradually spinning down and dissipating in 3 to 4 days. Juliette's initial motion is estimated to be northwest, or 325/9 kt. This general motion should continue over the next couple of days as Juliette moves in between two strong mid-level ridges, one located over northwestern Mexico and the other located well to the west-northwest of the cyclone. Juliette should slow down some on Wednesday as the steering currents weaken on the west side of the mid-level ridge over northwestern Mexico. There has been a large northeastward shift to the guidance this cycle. The latest official forecast is in best agreement with the Google DeepMind ensemble mean, but not nearly as far to the right as some of the other consensus models like the TCVE and HCCA. FORECAST POSITIONS AND MAX WINDS INIT 26/2100Z 19.9N 117.2W 55 KT 65 MPH 12H 27/0600Z 21.0N 118.4W 55 KT 65 MPH 24H 27/1800Z 22.7N 119.8W 50 KT 60 MPH 36H 28/0600Z 24.2N 120.7W 40 KT 45 MPH 48H 28/1800Z 25.2N 121.2W 30 KT 35 MPH...POST-TROP/REMNT LOW 60H 29/0600Z 26.0N 121.6W 25 KT 30 MPH...POST-TROP/REMNT LOW 72H 29/1800Z 26.5N 121.9W 20 KT 25 MPH...POST-TROP/REMNT LOW 96H 30/1800Z...DISSIPATED $$ Forecaster Hagen

Issued at 2100 UTC TUE AUG 26 2025 508 FOPZ15 KNHC 262033 PWSEP5 TROPICAL STORM JULIETTE WIND SPEED PROBABILITIES NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102025 2100 UTC TUE AUG 26 2025 AT 2100Z THE CENTER OF TROPICAL STORM JULIETTE WAS LOCATED NEAR LATITUDE 19.9 NORTH...LONGITUDE 117.2 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 55 KTS...65 MPH...100 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) PACIFIC DAYLIGHT TIME (PDT)...SUBTRACT 7 HOURS FROM Z TIME HAWAIIAN STANDARD TIME (HST)...SUBTRACT 10 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 18Z TUE AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 18Z TUE 06Z WED 18Z WED 06Z THU 18Z THU 18Z FRI 18Z SAT PERIODS TO TO TO TO TO TO TO 06Z WED 18Z WED 06Z THU 18Z THU 18Z FRI 18Z SAT 18Z SUN FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT 20N 120W 34 1 2( 3) X( 3) X( 3) X( 3) X( 3) X( 3) 25N 120W 34 X 2( 2) 19(21) 4(25) 1(26) X(26) X(26) 25N 120W 50 X X( X) 2( 2) 1( 3) X( 3) X( 3) X( 3) $$ FORECASTER HAGEN

Issued at 200 PM PDT Tue Aug 26 2025 457 WTPZ35 KNHC 262033 TCPEP5 BULLETIN Tropical Storm Juliette Advisory Number 9 NWS National Hurricane Center Miami FL EP102025 200 PM PDT Tue Aug 26 2025 ...JULIETTE FORECAST TO WEAKEN OVER THE NEXT COUPLE DAYS... SUMMARY OF 200 PM PDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...19.9N 117.2W ABOUT 410 MI...660 KM WNW OF SOCORRO ISLAND ABOUT 515 MI...825 KM WSW OF THE SOUTHERN TIP OF BAJA CALIFORNIA MAXIMUM SUSTAINED WINDS...65 MPH...100 KM/H PRESENT MOVEMENT...NW OR 325 DEGREES AT 10 MPH...17 KM/H MINIMUM CENTRAL PRESSURE...996 MB...29.42 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 200 PM PDT (2100 UTC), the center of Tropical Storm Juliette was located near latitude 19.9 North, longitude 117.2 West. Juliette is moving toward the northwest near 10 mph (17 km/h). A slower motion toward the north-northwest is expected by late Wednesday. Maximum sustained winds are near 65 mph (100 km/h) with higher gusts. Little change in strength is expected through today. A weakening trend is forecast to begin by early Wednesday, and Juliette is expected to become a remnant low on Thursday. Tropical-storm-force winds extend outward up to 70 miles (110 km) from the center. The estimated minimum central pressure is 996 mb (29.42 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 800 PM PDT. $$ Forecaster Hagen

...JULIETTE FORECAST TO WEAKEN OVER THE NEXT COUPLE DAYS... As of 2:00 PM PDT Tue Aug 26 the center of Juliette was located near 19.9, -117.2 with movement NW at 10 mph. The minimum central pressure was 996 mb with maximum sustained winds of about 65 mph.

Issued at 2100 UTC TUE AUG 26 2025 294 WTPZ25 KNHC 262032 TCMEP5 TROPICAL STORM JULIETTE FORECAST/ADVISORY NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL EP102025 2100 UTC TUE AUG 26 2025 TROPICAL STORM CENTER LOCATED NEAR 19.9N 117.2W AT 26/2100Z POSITION ACCURATE WITHIN 20 NM PRESENT MOVEMENT TOWARD THE NORTHWEST OR 325 DEGREES AT 9 KT ESTIMATED MINIMUM CENTRAL PRESSURE 996 MB MAX SUSTAINED WINDS 55 KT WITH GUSTS TO 65 KT. 50 KT....... 20NE 30SE 0SW 0NW. 34 KT....... 50NE 60SE 40SW 40NW. 4 M SEAS....120NE 90SE 60SW 90NW. WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT. REPEAT...CENTER LOCATED NEAR 19.9N 117.2W AT 26/2100Z AT 26/1800Z CENTER WAS LOCATED NEAR 19.5N 116.8W FORECAST VALID 27/0600Z 21.0N 118.4W MAX WIND 55 KT...GUSTS 65 KT. 50 KT... 20NE 20SE 0SW 0NW. 34 KT... 50NE 50SE 40SW 40NW. FORECAST VALID 27/1800Z 22.7N 119.8W MAX WIND 50 KT...GUSTS 60 KT. 50 KT... 20NE 0SE 0SW 0NW. 34 KT... 40NE 40SE 30SW 40NW. FORECAST VALID 28/0600Z 24.2N 120.7W MAX WIND 40 KT...GUSTS 50 KT. 34 KT... 40NE 40SE 20SW 30NW. FORECAST VALID 28/1800Z 25.2N 121.2W...POST-TROP/REMNT LOW MAX WIND 30 KT...GUSTS 40 KT. FORECAST VALID 29/0600Z 26.0N 121.6W...POST-TROP/REMNT LOW MAX WIND 25 KT...GUSTS 35 KT. FORECAST VALID 29/1800Z 26.5N 121.9W...POST-TROP/REMNT LOW MAX WIND 20 KT...GUSTS 30 KT. EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 100 NM ON DAY 4 AND 125 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY OUTLOOK VALID 30/1800Z...DISSIPATED REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.9N 117.2W NEXT ADVISORY AT 27/0300Z $$ FORECASTER HAGEN

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0256 PM CDT Tue Aug 26 2025 Valid 262000Z - 271200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... Organized severe thunderstorms appear unlikely across the contiguous United States through tonight. ...20Z Update... Isolated strong storms remain possible in the Four Corners vicinity this afternoon. Observed 18Z soundings from Tucson and Flagstaff indicate relatively poor mid-level lapse rates and marginal effective shear. Areas of stronger surface heating could promote stronger outflow winds, but organized severe storms are still unlikely. Only minor modifications were made to the general thunder area based on current observations. Additional forecast details are in the previous discussion below. ..Wendt.. 08/26/2025 .PREV DISCUSSION... /ISSUED 1120 AM CDT Tue Aug 26 2025/ ...Synopsis and Discussion... Large-scale upper troughing will remain over the eastern CONUS today, with surface high pressure dominating much of the central/eastern CONUS. Isolated thunderstorms may occur this afternoon and evening along/south of a surface cold front across parts of the FL Peninsula and central/south TX. However, weak flow aloft and related deep-layer shear should preclude an organized severe threat across these regions with this activity. Scattered to numerous thunderstorms are expected to develop today across much of the interior western CONUS, as upper ridging weakens over the Southwest and multiple weak mid-level perturbations move north-northeastward across the Sierras and Great Basin. Ongoing thunderstorms this morning across the Central Valley in CA will be in a relatively more favorable thermodynamic environment, with modestly steepened mid-level lapse rates compared to locations farther east over the Great Basin potentially supporting small hail with the stronger cores. Still, shear is expected to remain modest at best with westward extent, which should limit updraft organization and overall severe potential. Isolated strong/gusty winds may also occur with any convection that can develop over parts of interior southern CA into the lower CO River Valley, particularly where steepened low-level lapse rates can develop with daytime heating/mixing of the boundary layer away from ongoing cloud cover. The potential for a more concentrated corridor of severe winds still appears low across this area, as it will be in a generally subsident regime behind a weak mid-level shortwave trough advancing northward from southern NV across the Great Basin this afternoon. Finally, an occasional/very isolated strong to severe gust cannot be ruled out across the Four Corners region this afternoon, as convection develops along the Mogollon Rim in northern AZ and subsequently spreads north-northeastward in tandem with a weak mid-level shortwave trough. Even so, deep-layer shear appears too marginal to include low severe wind probabilities with this update. Read more

SPC 1930Z Day 3 Outlook
Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0214 PM CDT Tue Aug 26 2025 Valid 281200Z - 291200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few strong thunderstorms are possible across parts of the southern Plains Thursday afternoon and evening. ...Southern Plains... An MCS is likely to be ongoing Thursday morning across portions of KS/OK/AR. This activity will likely diminish as it develops southeast toward the ArkLaTex during the afternoon. A composite outflow/surface cold front will then spread south/southwest across OK/the Panhandles/eastern NM by mid-afternoon, though forecast guidance varies on the exact location of the surface boundary. Near the boundary, a corridor of 60s F dewpoints will be in place. While midlevel lapse rates are expected to be relatively weak, rich boundary layer moisture should support a corridor of 1000-2000 J/kg MLCAPE in the vicinity of the Red River. Low-level winds are expected to remain light, but vertically veering profiles will support around 20-30 kt effective shear magnitude. Where strong heating can occur ahead of the boundary, isolated strong storms could develop during the afternoon/evening. Locally strong gusts are possible with this activity. At this time, uncertainty in the evolution of the surface boundary and coverage of thunderstorms precludes severe probabilities. ..Leitman.. 08/26/2025 Read more