773  
FXUS01 KWBC 232002  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
301 PM EST SAT DEC 23 2017  
 
VALID 00Z SUN DEC 24 2017 - 00Z TUE DEC 26 2017  
 
...HEAVY SNOW POSSIBLE OVER PARTS OF THE NORTHEAST AND THE UPPER  
GREAT LAKES...  
 
...SNOW POSSIBLE FOR PART OF THE CASCADES AND THE NORTHERN/CENTRAL  
ROCKIES...  
 
...SNOW, RAIN, AND FREEZING RAIN MIXED OVER PARTS OF THE  
NORTHEAST...  
 
A FRONTAL ZONE DROPPING THROUGH THE INTERMOUNTAIN WEST ALONG WITH  
A WAVE OF LOW PRESSURE APPROACHING FROM THE PACIFIC WILL PROMOTE  
COASTAL RAINS FOR WASHINGTON, OREGON, AND EVENTUALLY NORTHWEST  
CALIFORNIA WITH AREAS OF SNOW ACROSS THE CASCADES AND INTERIOR  
NORTHWEST, AS WELL AS, THE NORTHERN/CENTRAL ROCKIES OVER THE NEXT  
COUPLE OF DAYS. NUMEROUS WINTER WEATHER ADVISORIES AND A HANDFUL  
OF WINTER STORM WARNINGS ARE IN EFFECT FROM OREGON TO WESTERN  
NEBRASKA. HEAVY SNOW IS EXPECTED FOR PORTIONS OF THE CASCADES,  
FROM THE WASATCH RANGE TO SOUTH OF THE BEARTOOTHS AND FOR THE  
FRONT RANGE AND SURROUNDING AREA.  
 
A CLIPPER SYSTEM WILL DROP THROUGH THE NORTHERN AND CENTRAL  
PLAINS; WHICH WILL REINFORCE COLD AIR OVER THE CENTRAL U.S. AND  
THE GREAT LAKES REGION. THIS DOES NOT BODE WELL FOR TRAVEL OVER  
THE NEXT FEW DAYS AS PRECIPITATION WILL LIKELY BE A MIX OF ICE AND  
SNOW FROM THE GREAT LAKES TO NEW ENGLAND. PLEASE SEE WPC'S WINTER  
WEATHER PRODUCTS AND DISCUSSION FOR MORE INFORMATION PERTAINING TO  
THE WINTER WEATHER HAZARDS ASSOCIATED WITH THIS SYSTEM. ARCTIC AIR  
WILL SURGE SOUTHWARD ALONG THE NORTHERN ROCKIES AND INTO THE  
NORTHERN PLAINS IN THE WAKE OF THE COLD FRONT MOVING THROUGH THE  
SOUTHEAST AND A SECONDARY BOUNDARY DROPPING INTO THE NORTHERN  
PLAINS ON SUNDAY. TEMPERATURES ACROSS THIS SECTOR WILL PLUMMET  
INTO THE TEENS ABOVE ZERO, WHICH ON AVERAGE WILL BE 20 DEGREES  
BELOW NORMAL FOR LATE DECEMBER, THOUGH NO RECORD LOWS OR RECORD  
COLD HIGH TEMPERATURES ARE ANTICIPATED UNTIL AT LEAST MONDAY.  
 
WIDESPREAD SHOWERS AND THUNDERSTORMS FROM THE SOUTHERN PLAINS TO  
LOWER/MIDDLE MISSISSIPPI VALLEY AND TENNESSEE VALLEY ARE DUE TO  
WARM, MOIST GULF AIR ADVECTING NORTH AHEAD OF A COLD FRONT. AIR  
WITHIN THE WARM SECTOR IS HIGH ENOUGH TO THREATEN RECORD HIGH  
TEMPERATURES ACROSS PORTIONS OF LOUISIANA AND MISSISSIPPI THIS  
AFTERNOON. WITH AN EXPECTED SLOW EASTERN PROGRESSION WITH THIS  
SYSTEM, AN AXIS OF HIGHER RAINFALL AMOUNTS IS FORECAST TO SPAN  
FROM SOUTHERN ARKANSAS TO CENTRAL KENTUCKY. CONCERNS FOR FLOODING  
ARE ALREADY ELEVATED ACROSS THIS REGION - NUMEROUS COUNTIES ARE IN  
A FLASH FLOOD WATCH, WITH A HANDFUL OF COUNTIES NEAR THE BOOT HILL  
OF MISSOURI IN FLOOD/FLASH FLOOD WARNINGS. LATER TODAY, THE AREA  
OF CONCERN WILL SHIFT TO THE EASTERN TENNESSEE VALLEY/CENTRAL  
APPALACHIANS AS THE COLD FRONT SHIFTS TO THE EAST.  
 
ZIEGENFELDER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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