581
FXUS01 KWBC 200818
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
400 AM EDT FRI SEP 20 2024
VALID 12Z FRI SEP 20 2024 - 12Z SUN SEP 22 2024
...SEVERE THUNDERSTORM THREAT WILL SHIFT FROM THE UPPER MIDWEST
THIS MORNING TO THE SOUTHERN HIGH PLAINS BY SATURDAY NIGHT/EARLY
SUNDAY...
..RAINY WEATHER LINGERS OVER SOUTHEASTERN NEW ENGLAND
...A MODERATE TO HEAVY RAIN EVENT DEVELOPING THIS WEEKEND FROM THE
CENTRAL HIGH PLAINS EASTWARD TOWARD THE MID-MISSISSIPPI VALLEY...
...MUCH ABOVE AVERAGE TEMPERATURES THROUGH THE MID-SECTION OF THE
COUNTRY AND INTO OHIO VALLEY AND GREAT LAKES...
A COLD/OCCLUDED FRONTAL SYSTEM CLASHING WITH A WEAK WARM FRONT
WILL CONTINUE TO SUPPORT FORMATION OF STRONG TO SEVERE
THUNDERSTORMS ACROSS THE UPPER MIDWEST EARLY THIS MORNING. THESE
THUNDERSTORMS WILL GENERALLY LOSE INTENSITY AS THEY MOVE INTO THE
GREAT LAKES THROUGH THE REST OF TODAY. THE RELATIVELY FAST MOTION
OF THE FRONT WILL LIMIT RAINFALL AMOUNTS. HOWEVER, THERE IS STILL
THE POTENTIAL FOR ISOLATED HEAVY TOTALS, THAT COULD RESULT IN
LOCALIZED FLOODING, ESPECIALLY OVER URBANIZED REGIONS.
THE DEEP LOW PRESSURE SYSTEM ASSOCIATED WITH THE FRONTS ARE MOVING
FARTHER AWAY INTO CENTRAL CANADA. THERE WILL NOT BE MUCH
TEMPERATURE RELIEF IN THE WAKE OF THE FRONTS FROM THE MUCH ABOVE
AVERAGE TEMPERATURES CURRENTLY STRETCHING ACROSS THE PLAINS INTO
THE MID- TO UPPER MISSISSIPPI VALLEY AND GREAT LAKES. THESE
REGIONS WILL CONTINUE TO SEE SOME LATE SUMMER HEAT OVER THE NEXT
TWO DAYS. AN ALBERTA CLIPPER WILL TAKE SHAPE AND WILL THEN USHER
IN A FRESH DOSE OF COOL AIR FROM WESTERN CANADA THROUGH THE
NORTHERN ROCKIES FOLLOWED BY NORTHERN PLAINS THIS WEEKEND.
THERE IS NOT EXPECTED TO BE LARGE AREAS OF HEAVY RAINS ACROSS THE
LOWER 48 OVER THE NEXT TWO DAYS. EXCEPTIONS WILL BE ACROSS
SOUTHEASTERN NEW ENGLAND WHERE A SLOW-MOVING LOW OFF THE SOUTHEAST
NEW ENGLAND COAST WILL KEEP CONDITIONS WET FRIDAY AND SATURDAY.
SHOWERY WEATHER WILL ALSO LIKELY TO PERSIST ACROSS SOUTH FLORIDA
WHERE TROPICAL MOISTURE WILL BRING THE POTENTIAL FOR LOCALIZED
HEAVY RAINS AND ISOLATED URBAN FLASH FLOODING FROM DAILY
THUNDERSTORMS.
A STRONG MID TO UPPER LEVEL LOW MOVING ONSHORE INTO THE CENTRAL TO
SOUTHERN CALIFORNIA COAST WILL BE PRESSING EASTWARD FOR THE NEXT
COUPLE OF DAYS ACROSS THE SOUTHWEST AND INTO THE FOUR CORNERS
REGION. THERE IS NOT EXPECTED TO BE ANY LARGE AREAS OF
PRECIPIATION ASSOCIATED WITH THIS STRONG MID TO UPPER LEVEL LOW
ACROSS CENTRAL TO SOUTHERN CALIFORNIA INTO THE SOUTHWEST.
HOWEVER, DURING SATURDAY, HIGHER LEVELS OF MOISTURE ARE EXPECTED
TO BE TRANSPORTED NORTHWARD AHEAD OF THE MID TO UPPER LEVEL LOW
INTO THE CENTRAL TO SOUTHERN ROCKIES AND SOUTHERN HIGH PLAINS AS
THE MOISTURE BEGINS TO INTERACT WITH A SURGE OF COOL AIR FROM THE
NORTH. THIS INTERACTION WILL INITIATE AN INCREASINGLY LARGE
PRECIPITATION EVENT, FIRST ACROSS PORTIONS OF THE CENTRAL TO
SOUTHERN ROCKIES ON SATURDAY, THEN EXPANDING EASTWARD SATURDAY
EVENING/NIGHT INTO THE CENTRAL PLAINS AND LOWER MISSOURI VALLEY,
AND THEN TOWARD THE MID-MISSISSIPPI VALLEY EARLY ON SUNDAY. IN
ADDITION, THE POTENTIAL OF SEVERE THUNDERSTORMS WILL INCREASE
LATER ON SATURDAY INTO EARLY SUNDAY OVER THE SOUTHERN HIGH PLAINS
AHEAD OF A COLD FRONT AND A DRY LINE. IN ADDITION, COLD AIR
BEHIND THE FRONT WILL CHANGE THE RAIN TO WET SNOW OVER THE
COLORADO ROCKIES EARLY ON SUNDAY.
KONG/ORAVEC
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