515
FXUS01 KWBC 190733
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
332 AM EDT FRI SEP 19 2025
VALID 12Z FRI SEP 19 2025 - 12Z SUN SEP 21 2025
...LINGERING MOISTURE FROM MARIO WILL CONTINUE TO LEAD TO THE RISK
OF FLASH FLOODING IN CALIFORNIA, THE GREAT BASIN, AND THE
SOUTHWEST FRIDAY...
...AN UPPER TROUGH OVER THE CENTRAL U.S. WILL BRING SCATTERED TO
WIDESPREAD STORMS WITH A THREAT FOR ISOLATED FLASH FLOODING THE
NEXT COUPLE OF DAYS...
...MUCH ABOVE AVERAGE, HOT TEMPERATURES FOR THE LAST WEEKEND OF
SUMMER ACROSS MUCH OF THE EASTERN U.S...
LINGERING MOISTURE AND REMNANT ENERGY FROM FORMER TROPICAL STORM
MARIO WILL CONTINUE TO BRING HEAVY RAIN PRODUCING STORMS TO
PORTIONS OF CALIFORNIA, THE GREAT BASIN, AND THE SOUTHWEST TODAY
(FRIDAY). AN ISOLATED THREAT FOR FLASH FLOODING EXISTS BROADLY
ALONG THE HIGHER TERRAIN SURROUNDING THE CENTRAL VALLEYS OF
CALIFORNIA EASTWARD THROUGH THE CENTRAL GREAT BASIN AND INTO THE
SOUTHWEST. A MORE CONCENTRATED THREAT OF FLASH FLOODING IS
EXPECTED ALONG THE CENTRAL SIERRA NEVADA WHERE FAVORABLE UPSLOPE
FLOW WILL HELP FURTHER ENHANCE RAINFALL TOTALS, AND A SLIGHT RISK
OF EXCESSIVE RAINFALL (LEVEL 2/4) IS IN EFFECT. THE HEAVIER
RAINFALL AND THREAT FOR FLASH FLOODING SHOULD SUBSIDE INTO THE
EVENING HOURS. STORM CHANCES ON SATURDAY WILL SHIFT A BIT NORTH
ARCING FROM THE NORTHERN GREAT BASIN EASTWARD INTO THE CENTRAL
ROCKIES WHILE LINGERING FOR THE SOUTHWEST. THESE STORMS ARE
EXPECTED TO REMAIN MORE SCATTERED WITH LIGHTER RAINFALL TOTALS.
TO THE EAST, AN UPPER TROUGH AND ACCOMPANYING SLOWLY PROGRESSING
SURFACE FRONTAL SYSTEM WILL PROVIDE THE FOCUS FOR SCATTERED TO
WIDESPREAD SHOWERS AND THUNDERSTORMS ACROSS MUCH OF THE
MIDWEST/MISSISSIPPI VALLEY AND CENTRAL/SOUTHERN PLAINS THE NEXT
COUPLE OF DAYS. PERIODIC SHORTWAVES ROUNDING THE BROADER UPPER
TROUGH WILL HELP LEAD TO MULTIPLE ROUNDS OF STORMS, WITH MOISTURE
IN PLACE FOR MODERATE TO LOCALLY HEAVY RAINFALL. SOME ISOLATED
FLASH FLOODING IS POSSIBLE, WITH A FOCUS ON THE UPPER MISSISSIPPI
VALLEY SOUTHWEST TO THE CENTRAL PLAINS ON FRIDAY, AND PORTIONS OF
THE CENTRAL/SOUTHERN PLAINS AND ADJACENT OZARKS ON SATURDAY.
ELSEWHERE, SOME SCATTERED STORMS WILL BE POSSIBLE AHEAD OF A
SAGGING COLD FRONT THROUGH THE SOUTHERN MID-ATLANTIC/CENTRAL
APPALACHIANS/UPPER OHIO VALLEY SATURDAY. WIDELY SCATTERED STORMS
WILL ALSO BE POSSIBLE ACROSS THE GULF COAST/SOUTHEAST/FLORIDA AND
INTO THE SOUTHERN APPALACHIANS. A PACIFIC SYSTEM WILL BEGIN TO
BRING MODERATE TO HEAVY RAINFALL TO THE PACIFIC NORTHWEST BY LATE
SATURDAY AND INTO THE DAY SUNDAY.
FORECAST HIGH TEMPERATURES WILL BE ABOVE AVERAGE AND RATHER HOT
ACROSS MUCH OF THE EASTERN U.S. FOR THE LAST WEEKEND OF THE
SUMMER. HIGHS INTO THE UPPER 80S TO MID-90S ARE EXPECTED FROM THE
MID-ATLANTIC/SOUTHEAST WEST THROUGH THE LOWER GREAT LAKES/OHIO
VALLEY, TENNESSEE VALLEY, MISSISSIPPI VALLEY, AND INTO THE
SOUTHERN PLAINS/TEXAS. THESE TEMPERATURES ARE UPWARDS OF 15
DEGREES ABOVE AVERAGE ACROSS THE LOWER GREAT LAKES AND
OHIO/TENNESSEE VALLEYS. SOUTHERN NEW ENGLAND WILL ALSO SEE WELL
ABOVE AVERAGE TEMPERATURES FOR FRIDAY WITH HIGHS INTO THE UPPER
70S TO LOW 80S. TEMPERATURES WILL BE MUCH COOLER AND A BIT BELOW
AVERAGE NORTH OF A COLD FRONT ACROSS THE INTERIOR NORTHEAST/NEW
ENGLAND AND THE UPPER GREAT LAKES, WITH HIGHS MAINLY IN THE 60S.
LOWS SATURDAY AND SUNDAY MORNING ARE EXPECTED TO FALL INTO THE
UPPER 20S TO MID-30S ACROSS THE INTERIOR NORTHEAST/NEW ENGLAND AND
FROST/FREEZE RELATED ADVISORIES/WARNINGS ARE IN PLACE. THE SAGGING
COLD FRONT IS ALSO EXPECTED TO BRING COOLER HIGHS TO SOUTHERN NEW
ENGLAND AND PORTIONS OF THE MID-ATLANTIC SATURDAY AS TEMPERATURES
DROP INTO THE 60S AND 70S. THE NORTHERN/CENTRAL PLAINS WILL BE A
BIT COOL FRIDAY WITH HIGHS IN THE 60S BEFORE TEMPERATURES REBOUND
INTO THE 70S SATURDAY. IN THE WEST, FORECAST HIGHS THE NEXT COUPLE
OF DAYS ARE BELOW AVERAGE ACROSS CALIFORNIA AND PORTIONS OF THE
GREAT BASIN AS A LINGERING UPPER-LOW AND WIDESPREAD PRECIPITATION
KEEP TEMPERATURES MAINLY IN THE 70S. THE FOUR CORNERS REGION AND
SOUTHWEST WILL BE CLOSER TO AVERAGE, AS HIGHS RISE INTO THE 70S
AND 80S, WITH 90S FOR THE DESERT REGIONS. FURTHER NORTH, MUCH
ABOVE AVERAGE HIGHS ARE EXPECTED ACROSS THE PACIFIC NORTHWEST AND
NORTHERN GREAT BASIN/ROCKIES, WITH HIGHS IN THE UPPER 70S TO
MID-80S.
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