165
FXUS01 KWBC 200753
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
353 AM EDT SAT MAY 20 2023
VALID 12Z SAT MAY 20 2023 - 12Z MON MAY 22 2023
...SHOWERS AND THUNDERSTORMS STRETCHING FROM NEW ENGLAND TO THE
SOUTHERN PLAINS SATURDAY...
...WELL ABOVE AVERAGE, RECORD-BREAKING WARMTH CONTINUES FOR
INTERIOR PORTIONS OF THE NORTHWEST THROUGH SATURDAY BEFORE
SHIFTING TOWARDS THE NORTHERN PLAINS SUNDAY...
A COLD FRONT STRETCHING FROM THE GREAT LAKES SOUTHWESTWARD THROUGH
THE OHIO VALLEY, LOWER MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS
SATURDAY MORNING WILL MOVE SOUTHEASTWARD TOWARDS THE ATLANTIC AND
GULF COASTS THROUGH THE WEEKEND. SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO CONTINUE ALONG THE FRONT FROM THE EAST COAST WEST
THROUGH THE SOUTH AND INTO TEXAS. THE HEAVIEST RAINFALL IS MOST
LIKELY OVER NEW ENGLAND AS A LOW PRESSURE SYSTEM OFF THE EAST
COAST HELPS TO FOCUS MOIST, SOUTHERLY ATLANTIC FLOW OVER THE
REGION. ADDITIONAL LOCALLY HEAVY SHOWERS WILL BE POSSIBLE OVER THE
TENNESSEE VALLEY GIVEN FAVORABLE TIMING OF AN UPPER-LEVEL
DISTURBANCE ALOFT TO HELP SUPPORT THUNDERSTORM DEVELOPMENT. THE
FRONT WILL LINGER SUNDAY FROM THE COASTAL CAROLINAS SOUTHWEST INTO
GEORGIA/FLORIDA, AS WELL AS FURTHER WEST ALONG THE RIO GRANDE IN
TEXAS, WITH CONTINUED PRECIPITATION CHANCES. HIGH TEMPERATURES
SATURDAY FOLLOWING THE PASSAGE OF THE FRONT WILL BE BELOW AVERAGE
AND COOL HEADING INTO LATE MAY, WITH 60S AND LOW 70S BROADLY FROM
NEW ENGLAND INTO THE MIDWEST/OHIO VALLEY/TENNESSEE VALLEY AND AS
FAR SOUTH AS THE RIO GRANDE IN WEST TEXAS. TEMPERATURES WILL BE
SEASONABLY WARM AHEAD OF THE FRONT, WITH LOW 80S IN THE
MID-ATLANTIC AND MID-80S TO LOW 90S INTO THE SOUTHEAST. HIGHS WILL
REBOUND SUNDAY BACK INTO THE MID- TO UPPER 70S FOR THE NORTHERN
TIER WHILE THINGS COOL OVER THE SOUTHEAST/CAROLINAS INTO THE
MID-70S TO LOW 80S.
IN THE WEST, AN UPPER-LEVEL RIDGE WILL REMAIN OVER THE REGION WITH
HIGHS FOR MOST LOCATIONS RUNNING ABOVE AVERAGE. ONCE AGAIN, THE
FOCUS FOR THE MOST ANOMALOUS TEMPERATURES 15-25+ DEGREES ABOVE
AVERAGE WILL BE OVER PORTIONS OF THE INTERIOR PACIFIC NORTHWEST,
GREAT BASIN, AND NORTHERN ROCKIES/HIGH PLAINS. HIGHS ON SATURDAY
WILL RANGE FROM THE MID-80S TO LOW 90S, WITH SOME
RECORD-TYING/BREAKING HIGHS POSSIBLE. AN UPPER-LEVEL
LOW/ASSOCIATED SURFACE FRONTAL SYSTEM WILL MOVE EASTWARD THROUGH
THE INTERIOR PACIFIC NORTHWEST SUNDAY, BRINGING COOLER, MORE
SEASONABLE TEMPERATURES IN THE UPPER 70S TO LOW 80S. THE
UPPER-LEVEL RIDGE WILL ALSO MOVE EASTWARD, SHIFTING THE FOCUS OF
ABOVE NORMAL TEMPERATURES OVER THE NORTHERN ROCKIES/GREAT BASIN,
AS WELL AS INTO THE NORTHERN PLAINS, WHERE HIGHS WILL RISE INTO
THE LOW TO MID-80S SUNDAY. ELSEWHERE IN THE WEST, HIGHS WILL STILL
GENERALLY BE ABOVE AVERAGE, WITH 80S AND 90S FOR CALIFORNIA AND
THE DESERT SOUTHWEST. THE ONE COOL SPOT WILL BE PORTIONS OF THE
CENTRAL/SOUTHERN ROCKIES WHERE MONSOON-LIKE SHOWER AND
THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE WEEKEND.
THUNDERSTORM CHANCES WILL ALSO INCREASE FOR PORTIONS OF THE
INTERIOR PACIFIC NORTHWEST/NORTHERN ROCKIES AHEAD OF THE
APPROACHING UPPER-LEVEL TROUGH. ANOMALOUSLY HIGH MOISTURE
LINGERING OVER THESE REGIONS WILL LEAD TO SOME LOCALLY HEAVY
SHOWERS, WITH AN ISOLATED RISK OF FLASH FLOODING IN TERRAIN
SENSITIVE AREAS AND BURN SCARS.
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