327  
FXUS01 KWBC 122012  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 PM EST TUE NOV 12 2024  
 
VALID 00Z WED NOV 13 2024 - 00Z FRI NOV 15 2024  
 
...HEAVY COASTAL RAIN AND HIGH-ELEVATION MOUNTAIN SNOW EXPECTED TO  
REACH THE PACIFIC NORTHWEST AND NORTHERN CALIFORNIA THIS EVENING...  
 
...SHOWERS AND THUNDERSTORMS WILL BRING LOCALLY HEAVY RAINFALL,  
SOME STRONG THUNDERSTORMS AND ISOLATED FLASH FLOODING CONCERNS TO  
THE TENNESSEE AND MISSISSIPPI AS WELL AS THE LOWER OHIO VALLEYS ON  
WEDNESDAY...  
 
...ABOVE AVERAGE TEMPERATURES CONTINUE FOR MUCH OF THE CENTRAL  
U.S. AND GULF COAST STATES WHILE COLDER AIR MOVES INTO THE  
NORTHEAST AND THE WEST...  
 
A LOW PRESSURE SYSTEM DEVELOPING OVER THE CENTRAL HIGH PLAINS WILL  
QUICKLY MOVE ACROSS THE NORTH-CENTRAL U.S. TONIGHT. LIGHT TO  
MODERATE LOWER-ELEVATION WINTRY MIX AND HIGHER-ELEVATION SNOW  
ASSOCIATED WITH THE LOW PRESSURE SYSTEM ACROSS THE NORTHERN  
ROCKIES AND GREAT BASIN WILL MOVE INTO THE CENTRAL ROCKIES THIS  
EVENING AND THEN GRADUALLY TAPER OFF TONIGHT. MEANWHILE, ANOTHER  
PACIFIC FRONTAL SYSTEM AND ACCOMPANYING ATMOSPHERIC RIVER WILL  
APPROACH THE WEST, BRINGING A WAVE OF PACIFIC MOISTURE AND  
TRIGGERING INCREASINGLY HEAVIER LOWER ELEVATION/COASTAL RAIN AND  
HIGHER ELEVATION MOUNTAIN SNOW BY THIS EVENING. THE SYSTEM WILL  
MOVE SWIFTLY INLAND, BRINGING AN EXPANDING AREA OF LOWER  
ELEVATION/COASTAL RAIN AND HIGH ELEVATION MOUNTAIN SNOW TO  
NORTHERN CALIFORNIA AND A WINTRY MIX INTO THE NORTHERN ROCKIES AND  
GREAT BASIN THROUGH WEDNESDAY. FAVORABLE UPSLOPE REGIONS ALONG THE  
COASTAL RANGES AND CASCADES WILL SEE LOCALLY HEAVY RAINFALL AND  
THE THREAT OF SOME ISOLATED FLOODING TODAY, EXPANDING SOUTHWARD  
INTO COASTAL NORTHERN CALIFORNIA ON WEDNESDAY. BY WEDNESDAY NIGHT  
INTO THURSDAY, THE PRECIPITATION COVERAGE ACROSS THE WEST WILL  
GRADUALLY DECREASE WITH TIME AS THE MAIN ENERGY OF THE SYSTEM  
CONTINUES TO PROGRESS EAST INTO A DRY RIDGE OF HIGH PRESSURE IN  
THE ROCKIES. THE RAIN WILL CONTINUE TO LINGER INTO THURSDAY  
AFTERNOON NEAR THE COAST OF THE PACIFIC NORTHWEST ALONG WITH SOME  
HIGH-ELEVATION SNOW OVER NORTHERN IDAHO.  
 
ACROSS MUCH OF THE EASTERN U.S., FINE AND COLDER WEATHER IS  
EXPECTED TO OVERSPREAD THE REGION FOR THE NEXT COUPLE OF DAYS AS  
AN EXPANSIVE HIGH PRESSURE SYSTEM TAKES CONTROL BEHIND AN EXITING  
LOW PRESSURE SYSTEM. MEANWHILE, A COLD FRONT TRAILING SOUTH FROM  
THE DEVELOPING LOW PRESSURE SYSTEM OVER THE NORTH-CENTRAL U.S.  
WILL PUSH EASTWARD AGAINST THE EXPANSIVE HIGH PRESSURE SYSTEM IN  
THE EAST. MOISTURE RETURNING FROM THE GULF OF MEXICO WILL THEN  
INTERACT WITH THE COLD FRONT AND PRODUCE A COUPLE OF EXPANDING  
AREAS OF MODERATE TO HEAVY RAIN WITH EMBEDDED THUNDERSTORMS--ONE  
NEAR THE CENTRAL GULF COAST STATES, AND ANOTHER ACROSS  
NORTH-CENTRAL U.S. AHEAD OF THE COLD FRONT. THE RAIN AND  
THUNDERSTORMS OVER THE CENTRAL GULF COAST IS ASSOCIATED WITH THE  
REMNANTS OF HURRICANE RAFAEL WHICH HAS BEEN MEANDERING OVER THE  
CENTRAL GULF OF MEXICO FOR THE PAST COUPLE OF DAYS. THESE TWO  
AREAS OF EXPANDING RAIN AND THUNDERSTORMS ARE FORECAST TO MERGE  
NEAR THE MID-MISSISSIPPI VALLEY ON WEDNESDAY TO PRODUCE WIDESPREAD  
MODERATE TO LOCALLY HEAVY RAINFALL ACROSS THE LOWER OHIO AND  
TENNESSEE VALLEYS, MID-SOUTH, AND INTO THE LOWER MISSISSIPPI  
VALLEY. SOME ISOLATED FLASH FLOODING IS POSSIBLE ESPECIALLY GIVEN  
WET ANTECEDENT CONDITIONS FROM RECENT RAINFALLS. MORE LIGHT TO  
MODERATE RAINFALL IS LIKELY OVER THE GREAT LAKES WITH LOWER  
INSTABILITY AND AVAILABLE MOISTURE. THE SYSTEM WILL PUSH EASTWARD  
INTO THE APPALACHIANS WEDNESDAY NIGHT INTO THURSDAY MORNING WITH  
MODERATE TO POSSIBLY LOCALLY HEAVY RAIN. BY THURSDAY AFTERNOON,  
THE RAIN WILL REACH INTO THE MID-ATLANTIC AND INTO THE CAROLINAS  
AS A LOW PRESSURE SYSTEM DEVELOPS ALONG A COASTAL FRONT JUST OFF  
THE COASTLINE OF THE CAROLINAS.  
 
MUCH OF THE CENTRAL AND EASTERN U.S. WILL CONTINUE TO SEE ABOVE  
AVERAGE HIGH TEMPERATURES OF 5-15 DEGREES OVER THE NEXT COUPLE OF  
DAYS. FORECAST HIGHS RANGE FROM THE 40S IN THE GREAT LAKES, 50S IN  
THE NORTHERN PLAINS, 60S FOR THE CENTRAL PLAINS, 70S FOR TEXAS AND  
THE SOUTHEAST, AND 80S ALONG THE GULF COAST. COLDER AIR WILL MOVE  
ACROSS THE GREAT LAKES INTO THE NORTHEAST WHILE MORE SEASONABLE  
TEMPERATURES WILL COME TO THE CAROLINAS AND SOUTHEAST ON  
WEDNESDAY, WITH HIGHS DROPPING INTO THE UPPER 50S TO MID-60S. RAIN  
WILL KEEP TEMPERATURES COOLER UP THE EAST COAST ON THURSDAY. THE  
MULTIPLE FRONTAL SYSTEMS WILL KEEP TEMPERATURES COOLER ACROSS MOST  
OF THE WEST AS WELL, WITH HIGHS TUESDAY MOSTLY IN THE 40S AND 50S  
FOR THE PACIFIC NORTHWEST AND INTERIOR LOCATIONS, 60S FOR COASTAL  
CALIFORNIA, AND 60S AND 70S FOR THE DESERT SOUTHWEST. CONDITIONS  
WILL MODERATE BY AROUND 5-10 DEGREES ON WEDNESDAY AND INTO  
THURSDAY.  
 
KONG/PUTNAM  
 
GRAPHICS AVAILABLE AT  
HTTPS://WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  
 
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