215
FXUS01 KWBC 300800
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
359 AM EDT TUE SEP 30 2025
VALID 12Z TUE SEP 30 2025 - 12Z THU OCT 02 2025
...MOISTURE ASSOCIATED WITH IMELDA WILL CONTINUE TO SUPPORT
SHOWERS AND THUNDERSTORMS ALONG THE SOUTHEAST U.S. COASTLINE TODAY
INTO TONIGHT...
...A SERIES OF PACIFIC FRONTS WILL BRING PERIODIC WAVES OF SHOWERS
AND THUNDERSTORMS TO PARTS OF THE GREAT BASIN AND PACIFIC
NORTHWEST THE NEXT FEW DAYS...
...UNSEASONABLY HOT TEMPERATURES CONTINUE FOR MUCH OF THE PLAINS
AND MIDWEST THROUGH THE REMAINDER OF THE WEEK...
AS IMELDA BEGINS ITS SHARP TURN TO THE NORTHEAST TODAY, MOISTURE
ASSOCIATED WITH THE TROPICAL SYSTEM WILL CONTINUE TO POOL ALONG A
STATIONARY BOUNDARY DRAPED ALONG THE SOUTHEAST U.S. COASTLINE. THE
INTERACTION BETWEEN THE FRONT AND IMELDA'S TROPICAL MOISTURE WILL
RESULT IN ADDITIONAL SHOWERS AND THUNDERSTORMS TODAY INTO TONIGHT,
ESPECIALLY FOR COASTAL LOCATIONS OF THE CAROLINAS. SOME SHOWERS
AND STORMS WILL LIKELY CONTAIN PERIODS OF HEAVIER RAINFALL WHICH
COULD LEAD TO LOCALIZED PONDING ON ROADWAYS AND IN THE MOST
VULNERABLE LOW-LYING AND POOR DRAINAGE AREAS. IMELDA WILL QUICKLY
ACCELERATE FARTHER OUT TO SEA TONIGHT INTO WEDNESDAY, TAKING MOST
SHOWER AND STORM CHANCES WITH IT. HOWEVER, STRONG HIGH PRESSURE IS
FORECAST TO BUILD SOUTHWARD FROM CANADA BEFORE SETTLING OVER THE
NORTHEAST AND MID-ATLANTIC MID TO LATE WEEK. IN ADDITION TO
BRINGING A MUCH MORE FALL-LIKE AIR MASS TO THE EAST COAST, STRONG
EASTERLY WINDS ON THE SOUTHERN PERIPHERY OF THIS DOME OF HIGH
PRESSURE WILL SET UP AN EXTENDED PERIOD OF ONSHORE FLOW ACROSS
MUCH OF THE SOUTHEAST U.S. COAST. THE MOIST ONSHORE FLOW WILL LEAD
TO NUMEROUS ROUNDS OF SHOWERS AND THUNDERSTORMS, PARTICULARLY
ALONG THE EAST COAST OF THE FLORIDA BEGINNING WEDNESDAY INTO
THURSDAY AND LIKELY LASTING THROUGH AT LEAST THE WEEKEND. THE
REPEATING NATURE OF THIS ACTIVITY COULD LEAD TO ISOLATED FLASH
FLOODING CONCERNS HEADING INTO THE LATTER PART OF THE WEEK. THE
PROLONGED ONSHORE FLOW COUPLED WITH THE INCREASED WAVE ACTION
GENERATED BY BOTH IMELDA AND HUMBERTO WILL ALSO LEAD TO SWELLS,
HIGH SURF, AND DANGEROUS RIP CURRENTS ALONG MUCH OF THE EAST COAST
THE NEXT SEVERAL DAYS.
OUT WEST, A STRETCH OF UNSETTLED AND UNSEASONABLY COOL WEATHER IS
IN STORE FOR PARTS OF THE PACIFIC NORTHWEST, GREAT BASIN, AND
INTERMOUNTAIN WEST THE NEXT FEW DAYS AS A SERIES OF PACIFIC FRONTS
PUSH INLAND. THESE MOISTURE-LADEN FRONTS WILL BRING PERIODIC WAVES
OF SHOWERS AND THUNDERSTORMS, SOME OF WHICH COULD CONTAIN BURSTS
OF HEAVY RAINFALL. WHILE THE OVERALL THREAT IS LOW, LOCALIZED
FLASH FLOODING CONCERNS CAN'T BE RULED OUT ACROSS PARTS OF THE
GREAT BASIN, NORTHERN ROCKIES, AND THE OLYMPIC PENINSULA. THE
INCREASED PRESENCE OF CLOUDS AND PRECIPITATION ASSOCIATED WITH THE
PASSING FRONTS AND PERSISTENT UPPER-LEVEL TROUGHING WILL RESULT IN
HIGH TEMPERATURES ROUGHLY 5 TO 15 DEGREES BELOW SEASONAL AVERAGES
ACROSS MUCH OF THE WESTERN U.S. THROUGH MID TO LATE WEEK.
DOWNSTREAM OF THE DEEP UPPER-LEVEL TROUGHING ALONG THE WEST COASTS
OF THE U.S. AND CANADA IS A HIGHLY AMPLIFIED UPPER-LEVEL RIDGE
LOCATED OVER THE HEART OF NORTH AMERICA. THIS RIDGE OF HIGH
PRESSURE HAS BEEN RESPONSIBLE FOR THE UNSEASONABLY HOT WEATHER
ACROSS A LARGE PORTION OF THE COUNTRY EAST OF THE ROCKIES THE LAST
FEW DAYS. WITH THE RIDGE FORECAST TO GO NOWHERE ANYTIME SOON, THIS
SUMMER-LIKE HEAT WILL CONTINUE THROUGH AT LEAST THE END OF THE
WEEK. THIS WILL ESPECIALLY BE THE CASE FROM THE NORTHERN/CENTRAL
PLAINS TO THE UPPER MIDWEST, WHERE HIGH TEMPERATURES WILL SOAR
WELL INTO THE MID/UPPER 80S AND LOW 90S. THESE TEMPERATURES ARE
ROUGHLY 15 AND 25 DEGREES ABOVE NORMAL, MAKING FOR A TOASTY END OF
SEPTEMBER AND START TO OCTOBER.
MILLER
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