012
FXUS01 KWBC 090801
PMDSPD
SHORT RANGE FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EST SAT NOV 09 2024
VALID 12Z SAT NOV 09 2024 - 12Z MON NOV 11 2024
...WIDESPREAD, POTENTIALLY SIGNIFICANT FLASH FLOODING FOR POSSIBLE
IN CENTRAL AND SOUTHWESTERN LOUISIANA TODAY...
...SHOWERS AND THUNDERSTORMS WILL BRING HEAVY RAIN AND THE RISK
FOR FLASH FLOODING FOR 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
OVER THE GULF OF MEXICO 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 FOR THE POTENTIAL OF LOCALLY SIGNIFICANT HEAVY
RAINFALL TOTALS OF 6-8" 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 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 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 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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