797
FXUS01 KWBC 130746
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 AM EDT THU AUG 13 2026
VALID 12Z THU AUG 13 2026 - 12Z SAT AUG 15 2026
...DANGEROUS HEAT CONTINUES FROM THE CENTRAL/SOUTHERN PLAINS INTO
THE SOUTHEAST...
...AN ACTIVE PATTERN WILL KEEP THE THREAT OF HEAVY RAINFALL/FLASH
FLOODING IN THE FORECAST THROUGHOUT MUCH OF THE MIDWEST AND
WESTERN U.S...
A HEATWAVE HAS SETTLED IN ACROSS THE CENTRAL/SOUTHERN PLAINS AND
THE SOUTHEAST AS AN UPPER-HIGH STRENGTHENS OVERHEAD. FORECAST
HIGHS IN THE UPPER 90S TO LOW 100S COMBINED WITH HIGH HUMIDITY
WILL LEAD TO HEAT INDICES IN THE 105-115 DEGREE RANGE. SOME
POTENTIAL RECORD-TYING/BREAKING TEMPERATURES ARE POSSIBLE WITH
MANY AREAS FORECAST TO SEE THEIR HOTTEST TEMPERATURES SO FAR THIS
YEAR OR EVEN IN THE PAST FEW YEARS. MORNING LOWS ONLY DROPPING
INTO THE MID-70S TO LOW 80S WILL PROVIDE LITTLE RELIEF FROM THE
HEAT OVERNIGHT. WIDESPREAD MAJOR TO EXTREME HEATRISK (LEVELS 3 AND
4 OUT OF 4) IS EXPECTED INDICATING OPPRESSIVE HEAT DANGEROUS TO
ANYONE WITHOUT ACCESS TO ADEQUATE COOLING OR HYDRATION.
UNFORTUNATELY, THE HEATWAVE IS FORECAST TO CONTINUE WELL BEYOND
THE CURRENT FORECAST PERIOD THROUGH AT LEAST MID-AUGUST.
ALONG THE NORTHERN PERIPHERY OF THE UPPER-HIGH, A WAVY STATIONARY
FRONT WILL MAINTAIN THE FOCUS FOR DAILY THUNDERSTORMS FROM THE
HIGH PLAINS TO THE OHIO VALLEY. WIDELY SCATTERED FLASH FLOODING
(SOME OF WHICH COULD BE SIGNIFICANT) IS POSSIBLE ACROSS THIS BROAD
AREA AS TRAINING THUNDERSTORMS OVERLAP WITH AREAS OF INCREASINGLY
SATURATED SOILS FROM RECENT HEAVY RAINFALL. THE SEVERE WEATHER
THREAT WITH THIS ACTIVITY IS SLIGHTLY LOWER, ALTHOUGH ISOLATED TO
SCATTERED DAMAGING WIND GUSTS WILL BE POSSIBLE EACH DAY. THE
UNSETTLED WEATHER WILL ALSO CONTINUE ALONG AND WEST OF THE ROCKIES
AS BROAD UPPER-TROUGHING SIPHONS PACIFIC MOISTURE TOWARDS THE
INTERMOUNTAIN WEST. AS SUCH, THE GREATEST COVERAGE OF SHOWERS AND
THUNDERSTORMS ACROSS THE WEST IS EXPECTED OVER THE NEXT TWO DAYS
WITH AN ATTENDANT THREAT OF ISOLATED TO SCATTERED FLASH FLASH
FLOODING ACROSS THE SOUTHWEST, GREAT BASIN, AND INTERMOUNTAIN
WEST. ONE BENEFIT OF THE PRECIPITATION, HOWEVER, IS THAT DAYTIME
TEMPERATURES WEST OF THE CONTINENTAL DIVIDE WILL BE NOTABLY COOLER
THAN NORMAL FOR THIS TIME OF YEAR TO PROVIDE SOME RELIEF FROM THE
RECENT HEAT.
ASHERMAN/PUTNAM
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