385
FXUS01 KWBC 090848
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
347 AM EST SAT NOV 09 2024
VALID 12Z SAT NOV 09 2024 - 12Z MON NOV 11 2024
...WIDESPREAD, POTENTIALLY SIGNIFICANT FLASH FLOODING POSSIBLE IN
CENTRAL AND SOUTHWESTERN LOUISIANA TODAY...
...SHOWERS AND THUNDERSTORMS WILL BRING HEAVY RAIN AND THE RISK
FOR FLASH FLOODING TO THE LOWER MISSISSIPPI AND TENNESSEE/OHIO
VALLEYS THIS WEEKEND...
...ATMOSPHERIC RIVER TO ARRIVE ACROSS THE PACIFIC NORTHWEST ON
SUNDAY WITH HEAVY COASTAL RAINS AND HIGH ELEVATION SNOWFALL...
...ABOVE AVERAGE TEMPERATURES CONTINUE FOR MUCH OF THE COUNTRY
THIS WEEKEND...
A SIGNIFICANT FLASH FLOODING EVENT IS ANTICIPATED TODAY AHEAD OF A
LOW PRESSURE SYSTEM/COLD FRONT MOVING EASTWARD TOWARDS THE
MISSISSIPPI VALLEY THIS MORNING THAT WILL SLOW AND EVENTUALLY
STALL AS RIDGING BUILDS NORTHWARD OVER THE EASTERN U.S. STRONG
SOUTHERLY FLOW AHEAD OF THE FRONT WILL CONTINUE TO BRING A FETCH
OF DEEP, VERY MOIST AIR ASSOCIATED WITH TROPICAL STORM RAFAEL
NORTHWARD OVER THE REGION. NUMEROUS SHOWERS AND THUNDERSTORMS
PRODUCING VERY HEAVY DOWNPOURS (RAIN RATES 1-2"+ PER HOUR) ARE
EXPECTED ALONG AND AHEAD OF THE FRONT FROM THE LOWER TENNESSEE
VALLEY/MID-SOUTH SOUTHWESTWARD INTO THE LOWER MISSISSIPPI VALLEY
AND THE WESTERN GULF COAST. A CONCENTRATED RISK OF LOCALLY
SIGNIFICANT HEAVY RAINFALL TOTALS OF 3-6", LOCALLY 10", AND
WIDESPREAD INSTANCES OF FLASH FLOODING IS EXPECTED AHEAD OF THE
FRONT CLOSER TO THE GULF OVER CENTRAL/SOUTHWESTERN LOUISIANA,
WHERE A HIGH RISK OF EXCESSIVE RAINFALL (LEVEL 4/4) IS IN EFFECT.
A BROADER SLIGHT RISK (LEVEL 2/4) COVERS THE REST OF THE REGION
FOR MORE SCATTERED INSTANCES OF FLASH FLOODING. THE FRONT WILL
MAKE SOME PROGRESS EASTWARD SUNDAY, ESPECIALLY WITH NORTHERN
EXTENT, BRINGING THE HEAVY RAINFALL THREAT FURTHER EASTWARD ACROSS
THE OHIO AND TENNESSEE VALLEYS WHILE LINGERING THROUGH THE LOWER
MISSISSIPPI VALLEY. HOWEVER, THE MORE PROGRESSIVE NATURE OF THE
FRONT/STORM MOVEMENT AS WELL AS A DECREASING FETCH OF MOISTURE
SHOULD LIMIT THE FLASH FLOOD THREAT TO A FEW ISOLATED INSTANCES.
WHILE THIS MOISTURE STREAMING NORTHWARD FROM RAFAEL WILL INFLUENCE
THE THREAT FOR HEAVY RAIN, THE STORM IS LOCATED FAR OFFSHORE OVER
THE GULF OF MEXICO AND FORECAST BY THE NATIONAL HURRICANE CENTER
TO REMAIN OFFSHORE AND DISSIPATE OVER THE NEXT FEW DAYS.
OUTSIDE OF THIS HEAVY RAINFALL THREAT, AN EXPANDING AREA OF
SHOWERS AND THUNDERSTORMS IS FORECAST AHEAD OF THE LOW PRESSURE
SYSTEM AND AN ARCING OCCLUDED/COLD FRONT LIFTING NORTHEASTWARD
ACROSS THE NORTHERN PLAINS, MIDWEST, AND MISSISSIPPI VALLEY ON
SATURDAY WITH SOME MODERATE AMOUNTS POSSIBLE. SOME MODERATE SNOW
MAY LINGER OVER PORTIONS OF THE CENTRAL ROCKIES IN COLORADO AFTER
A HISTORIC SNOWSTORM THE PAST COUPLE DAYS, THOUGH MOST SNOW WILL
HAVE TAPERED OFF THIS MORNING AS THE LOW MOVES AWAY. THE LOW
PRESSURE SYSTEM/FRONT WILL CONTINUE EASTWARD ON SUNDAY, BRINGING A
BROAD AREA OF BENEFICIAL RAINFALL TO THE NORTHEAST AFTER WEEKS OF
LITTLE TO NO PRECIPITATION. SHOWERS AND THUNDERSTORMS ARE ALSO
EXPECTED IN VICINITY OF A WAVY FRONTAL BOUNDARY ALONG THE COASTAL
SOUTHEAST/FLORIDA THIS WEEKEND. ELSEWHERE, AN INITIAL SYSTEM
PUSHING INLAND OVER THE PACIFIC NORTHWEST WILL CONTINUE TO BRING
MODERATE TO HEAVY SHOWERS FOR LOWER ELEVATIONS WITH SOME VERY HIGH
ELEVATION SNOW SATURDAY, AND A WINTRY MIX AND HIGHER ELEVATION
SNOW SPREADING INTO THE NORTHERN ROCKIES BY SUNDAY MORNING. THEN,
DURING THE DAY SUNDAY, A STRONGER SYSTEM AND ACCOMPANYING
ATMOSPHERIC RIVER WILL BEGIN TO BRING HEAVIER RAIN WITH AN
ISOLATED CHANCE OF FLOODING TO THE PACIFIC NORTHWEST, EXPECTED TO
LAST OVER THE NEXT SEVERAL DAYS.
MOST OF THE COUNTRY WILL CONTINUE TO SEE ABOVE AVERAGE
TEMPERATURES THIS WEEKEND OUTSIDE OF PORTIONS OF THE
CENTRAL/SOUTHERN ROCKIES AND HIGH PLAINS ON SATURDAY, THOUGH
TEMPERATURES WILL BEGIN TO RECOVER HERE AS WELL BY SUNDAY.
FORECAST HIGHS WILL GENERALLY BE IN THE 50S FROM THE PACIFIC
NORTHWEST EAST THROUGH THE NORTHERN ROCKIES/PLAINS, GREAT LAKES,
AND INTO NEW ENGLAND; THE 50S AND 60S IN THE GREAT BASIN, CENTRAL
PLAINS, MIDWEST, AND MID-ATLANTIC; AND THE 70S AND 80S IN THE
SOUTHWEST, TEXAS, AND THE SOUTHEAST. AFOREMENTIONED COOLER
TEMPERATURES IN THE 40S AND 50S OVER THE CENTRAL/SOUTHERN ROCKIES
AND HIGH PLAINS WILL MODERATE BY 10 DEGREES OR SO FOR MOST
LOCATIONS BY SUNDAY.
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