456
FXUS01 KWBC 151350
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
949 AM EDT SUN SEP 15 2024
VALID 12Z SUN SEP 15 2024 - 12Z TUE SEP 17 2024
...HEAVY RAIN/FLASH FLOOD THREAT CONTINUES TODAY FOR PORTIONS OF
THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST...
...A COASTAL STORM WILL BRING WIND AND RAIN TO THE CAROLINAS AND
MID-ATLANTIC OVER THE NEXT FEW DAYS...
...A STRONG LOW PRESSURE SYSTEM WILL BRING UNSETTLED WEATHER AND
WELL BELOW NORMAL TEMPERATURES TO THE WEST WITH HIGH-ELEVATION
SNOW IN THE SIERRA NEVADA...
FRANCINE'S REMNANTS WILL LINGER OVER THE SOUTHEASTERN U.S. EARLY
THIS WEEK AS A NEARLY STATIONARY FRONTAL BOUNDARY SAGS SOUTH TO
THE GULF COAST. CHANCES FOR LOCALLY HEAVY RAIN AND ISOLATED TO
SCATTERED INSTANCES OF FLASH FLOODING WILL CONTINUE TODAY FOR
PORTIONS OF THE LOWER MISSISSIPPI VALLEY AND SOUTHEAST. THERE IS A
SLIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4) FOR PARTS OF
MISSISSIPPI, ALABAMA, AND THE FLORIDA PANHANDLE WHERE FLOODING
WILL BE MOST LIKELY. CHANCES FOR SHOWERS AND STORMS WILL PERSIST
ACROSS THIS REGION OVER THE NEXT FEW DAYS, BUT THE RISK OF
FLOODING WILL GRADUALLY DECREASE, WITH ONLY ISOLATED FLOODING
CONCERNS EXPECTED MONDAY AND TUESDAY.
MEANWHILE, A SEPARATE AREA OF LOW PRESSURE WILL STRENGTHEN OFF THE
SOUTHEAST COAST AND GRADUALLY MOVE NORTH TOWARDS THE CAROLINAS.
THIS SYSTEM IS LIKELY TO BRING GUSTY WINDS, HEAVY RAIN, COASTAL
FLOODING, AND DANGEROUS BEACH CONDITIONS TO THE CAROLINAS AND
PORTIONS OF THE MID-ATLANTIC THROUGH MID-WEEK. STRONG HIGH
PRESSURE OVER THE NORTHEAST WILL SLOW THE FORWARD MOTION OF THIS
SYSTEM, INCREASING THE CHANCE OF HEAVY RAINFALL TOTALS AND FLASH
FLOODING. THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL (LEVEL 2/4)
FOR PORTIONS OF THE EASTERN CAROLINAS AND FAR SOUTHEASTERN
VIRGINIA WHERE THE RISK OF FLASH FLOODING IS EXPECTED TO BE
GREATER. THE NATIONAL HURRICANE CENTER IS ALSO MONITORING THIS
SYSTEM FOR POTENTIAL SUBTROPICAL OR TROPICAL DEVELOPMENT, AND HAS
MARKED THIS AREA WITH A 50% CHANCE OF TROPICAL FORMATION OVER THE
NEXT 48 HOURS. THERE IS STILL QUITE A BIT OF UNCERTAINTY ON THE
TIMING, INTENSITY, AND TRACK OF THIS SYSTEM, SO REGULARLY CHECK
FOR FORECAST UPDATES OVER THE NEXT COUPLE OF DAYS.
IN THE WEST, AN UNSETTLED PATTERN IS BEGINNING TO TAKE ROOT AS
UPPER LEVEL TROUGHING MOVES INTO THE REGION. A DEEP UPPER LOW WILL
MOVE OVER THE WEST COAST TODAY AND MONDAY AND PUSH ACROSS THE
INTERMOUNTAIN WEST TO THE ROCKIES ON TUESDAY. THIS WILL PUSH A
STRONG FRONTAL SYSTEM ACROSS THE WEST THAT WILL BRING WIDESPREAD
PRECIPITATION CHANCES AND MUCH COOLER TEMPERATURES TO THE REGION
OVER THE NEXT FEW DAYS. PRECIPITATION WILL MAINLY FALL AS RAIN,
BUT TEMPERATURES WILL BE COLD ENOUGH IN THE HIGH ELEVATIONS OF THE
SIERRA NEVADA FOR SOME EARLY SEASON SNOW. A WINTER WEATHER
ADVISORY IS IN EFFECT FOR PORTIONS OF THE SIERRA NEVADA ABOVE 8000
FEET WHERE UP TO 4 INCHES OF SNOW MAY FALL TONIGHT AND MONDAY.
PRECIPITATION CHANCES WILL ALSO INCREASE ACROSS THE SOUTHWEST/FOUR
CORNERS REGION TODAY AS TROPICAL MOISTURE STREAMS NORTH FROM
TROPICAL CYCLONE ILEANA, WHICH WILL SUPPORT MONSOON-LIKE SHOWERS
AND THUNDERSTORMS THROUGH TUESDAY.
TEMPERATURES WILL HAVE A LARGE RANGE ACROSS THE UNITED STATES OVER
THE NEXT FEW DAYS. FORECAST PRECIPITATION AND CLOUD COVER WILL
KEEP TEMPERATURES SLIGHTLY BELOW NORMAL ACROSS THE SOUTHEAST AND
MID-ATLANTIC, WITH HIGHS FROM THE MID 70S TO THE MID 80S. WELL
ABOVE AVERAGE TEMPERATURES ARE FORECAST FOR THE CENTRAL U.S. AND
NORTHEAST, WITH THE HIGHEST ANOMALIES FORECAST TO DEVELOP UNDER
HIGH PRESSURE IN THE UPPER MIDWEST/GREAT LAKES REGION. HIGH
TEMPERATURES WILL REACH THE 80S AND 90S, WHICH WILL BE 10-20
DEGREES ABOVE NORMAL FOR SOME AREAS. WELL BELOW AVERAGE
TEMPERATURES ARE FORECAST TO SPREAD ACROSS THE WEST THROUGH
TUESDAY UNDER THE DEEP UPPER LOW/TROUGH, AND HIGH TEMPERATURES
WILL BE AS LOW AS 15-25 DEGREES BELOW NORMAL. THE COLDEST
ANOMALIES WILL BE IN OREGON, NEVADA, AND CALIFORNIA ON MONDAY.
HIGHS IN THE 50S WILL BE COMMON IN THE GREAT BASIN, AND HIGHS WILL
LIKELY ONLY REACH THE 30S AND 40S IN THE SIERRA NEVADA.
DOLAN
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