009  
FXUS01 KWBC 191951  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
250 PM EST WED DEC 19 2018  
 
VALID 00Z THU DEC 20 2018 - 00Z SAT DEC 22 2018  
 
...WIDESPREAD RAIN AND THUNDERSTORMS WILL SPREAD FROM THE LOWER  
MISSISSIPPI VALLEY EAST AND NORTH THROUGH FRIDAY...  
 
...ANOTHER LOW APPROACHES THE NORTHWEST, BRINGING MORE RAIN AND  
SNOW...  
 
...RECORD WARMTH POSSIBLE BY FRIDAY IN THE MID-ATLANTIC REGION AND  
NORTHEAST...  
 
A DEEP UPPER-LEVEL TROUGH WILL CONTINUE MOVING EASTWARD THROUGH  
THE PLAINS, MISSISSIPPI VALLEY, AND OHIO VALLEY THROUGH THE END OF  
THE WORKWEEK. THIS WILL PUSH A SURFACE LOW PRESSURE SYSTEM  
EASTWARD ACROSS THE GULF COAST ON THURSDAY AND NORTHWARD ACROSS  
THE EASTERN SEABOARD BY FRIDAY. GULF OF MEXICO AND ATLANTIC  
MOISTURE ARE EXPECTED TO COMBINE TO CREATE A HEAVY RAINFALL EVENT  
FOR THE EASTERN U.S. WIDESPREAD RAINFALL TOTALS ARE FORECAST TO BE  
1 TO 2 INCHES ACROSS THE SOUTHEAST AND THE APPALACHIANS EASTWARD,  
WITH HIGHER WIDESPREAD TOTALS OF 3 INCHES IN THE FLORIDA  
PENINSULA, EASTERN NORTH CAROLINA, AND SOUTHERN NEW ENGLAND. PLUS,  
LOCALLY HIGHER RAINFALL AMOUNTS ARE EXPECTED IN THUNDERSTORMS AND  
WHERE RAIN TRAINS OVER THE SAME LOCATION. SLIGHT RISKS OF  
EXCESSIVE RAINFALL/FLASH FLOODING ARE IN EFFECT ON THURSDAY.  
ADDITIONALLY, SEVERE WEATHER IS POSSIBLE ALONG THE ATLANTIC COAST.  
ON THURSDAY, THERE IS AN ENHANCED RISK OF SEVERE WEATHER IN PLACE  
ACROSS EASTERN FLORIDA FROM THE STORM PREDICTION CENTER. BEHIND A  
SECONDARY COLD FRONT ON FRIDAY, SNOW COULD MIX IN ON THE BACK EDGE  
OF THE PRECIPITATION ACROSS THE OHIO VALLEY AND INTO THE  
APPALACHIANS.  
 
AFTER A BRIEF LIGHTENING OF THE PRECIPITATION IN THE NORTHWESTERN  
U.S., A SURFACE LOW APPROACHES ON WEDNESDAY NIGHT AND THURSDAY,  
INCREASING PRECIPITATION CHANCES AGAIN AS A COLD FRONT MOVES  
QUICKLY THROUGH THE REGION. THE HIGHER ELEVATIONS OF THE CASCADES  
COULD SEE 12 TO 18 INCHES OF SNOW, AND THE NORTHERN ROCKIES ARE  
EXPECTING 6 TO 10 INCHES OF SNOW. PRECIPITATION WILL REMAIN RAIN  
AT LOWER ELEVATIONS OF THE PACIFIC NORTHWEST. FARTHER EAST, STRONG  
WINDS ARE EXPECTED FOR THE NORTHERN/CENTRAL ROCKIES AND PLAINS  
THROUGH WEDNESDAY NIGHT, AND HIGH WIND WARNINGS AND WIND  
ADVISORIES ARE IN EFFECT.  
 
TEMPERATURE-WISE, THE WIDESPREAD RAIN WILL KEEP HIGH TEMPERATURES  
BELOW AVERAGE FOR THE LOWER MISSISSIPPI VALLEY AND THE SOUTHEAST.  
THE PACIFIC NORTHWEST IS EXPECTED TO COOL DOWN TO AT OR BELOW  
AVERAGE ON FRIDAY AFTER THE COLD FRONT. CONVERSELY, THE  
MID-ATLANTIC REGION AND NORTHEAST WILL WARM CONSIDERABLY THROUGH  
THE END OF THE WORKWEEK. BY FRIDAY, TEMPERATURES OF 20 DEGREES  
ABOVE AVERAGE ARE FORECAST, AND RECORD HIGH MINIMUM AND MAXIMUM  
TEMPERATURES ARE LIKELY. IN NEW ENGLAND, THE LOW TEMPERATURES  
COULD BE ABOVE THE AVERAGE HIGH FOR THE DATE. THE SOUTHWEST,  
PLAINS, AND MIDWEST ARE EXPECTING ABOVE NORMAL TEMPERATURES AS  
WELL.  
 
TATE  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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