215  
FXUS01 KWBC 031955  
PMDSPD  
 
SHORT RANGE FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
254 PM EST SAT FEB 03 2018  
 
VALID 00Z SUN FEB 04 2018 - 00Z TUE FEB 06 2018  
 
...HEAVY SNOW TO BLANKET THE INTERIOR NORTHEASTERN U.S. WITH  
ACCUMULATING ICE ALONG THE SPINE OF THE SOUTHERN/CENTRAL  
APPALACHIANS...  
 
...ABUNDANT PRECIPITATION TO FALL OVER THE OLYMPICS, WASHINGTON  
CASCADES, AND BITTERROOTS...  
 
...AMPLE WARMTH OVER THE WESTERN STATES MAY BREAK DAILY  
TEMPERATURE RECORDS THROUGH SUNDAY...  
 
WITH MODIFIED ARCTIC AIR IN PLACE EAST OF THE ROCKIES, A WINTRY  
PRECIPITATION THREAT WILL EXIST WITH AN EVOLVING SYSTEM ACROSS THE  
EASTERN U.S. A STRONG UPPER TROUGH SWEEPING THROUGH THE GREAT  
LAKES ON SUNDAY AFTERNOON WILL BE A FOCUS FOR MODERATE TO POSSIBLY  
LOCALLY HEAVY SNOW FROM THE GREAT LAKES INTO INTERIOR NEW ENGLAND.  
A WIDESPREAD SWATH OF 4 TO 8 INCHES OF SNOW IS POSSIBLE WITH  
FORECAST AMOUNTS SOMEWHAT LIMITED BY THE PROGRESSIVE NATURE OF THE  
FEATURE. MEANWHILE, A SEPARATE THREAT FOR ACCUMULATING ICE SHOULD  
BE AN ISSUE FOR LOCATIONS JUST WEST OF I-95 BACK TOWARD THE SPINE  
OF THE SOUTHERN/CENTRAL APPALACHIAN CHAIN. ARCTIC AIR WHICH HAS  
SETTLED AT THE SURFACE WILL LIKELY BE STUBBORN TO BE COMPLETELY  
SCOURED OUT ON SUNDAY. ALL THE WHILE, A PLUME OF MILDER AIR WILL  
OVERRIDE THIS AIR MASS LEADING TO A FREEZING RAIN SETUP FROM  
EXTREME NORTHEASTERN GEORGIA ALONG ALONG THE APPALACHIANS INTO  
NORTH-CENTRAL PENNSYLVANIA. FARTHER SOUTH FROM THE LOWER  
MISSISSIPPI VALLEY INTO THE SOUTHEASTERN U.S., WET CONDITIONS WILL  
PREVAIL AS A FRONTAL ZONE SLIDES THROUGH THE REGION.  
 
AS A STRONG UPPER RIDGE SITS OVER THE COASTAL EASTERN PACIFIC  
WATERS, A SERIES OF IMPULSES WILL TRAVERSE THE NORTHERN EXTENT OF  
THIS ANTICYCLONE ACROSS THE PACIFIC NORTHWEST AND INTO THE UPPER  
INTERMOUNTAIN WEST. VIGOROUS LIFT FROM THESE IMPULSES IN  
CONJUNCTION WITH CONVERGENCE ALONG THE STALLED ARCTIC FRONT WILL  
SPREAD ABUNDANT PRECIPITATION FROM THE OLYMPICS AND WASHINGTON  
CASCADES EASTWARD INTO THE BITTERROOTS, SAWTOOTH, AND TETONS. THE  
HEAVIEST AMOUNTS ARE FORECAST OVER THE WASHINGTON CASCADES WITH  
AROUND 3 TO 5 INCHES OF PRECIPITATION EXPECTED THROUGH MONDAY.  
THIS IS WHERE SOME OF THE STRONGER UPSLOPE FLOW AND BETTER  
MOISTURE PROFILES WILL RESIDE. THE AIR MASS SHOULD BE PLENTY COLD  
ENOUGH TO SUPPORT WIDESPREAD WINTRY PRECIPITATION OVER THE REGION  
WITH 1 TO 2 FEET LIKELY ACROSS WESTERN MONTANA DOWN INTO  
NORTHWESTERN WYOMING.  
 
GIVEN THE HIGHLY AMPLIFIED UPPER-LEVEL PATTERN, TEMPERATURES  
SHOULD RESIDE WELL AWAY FROM CLIMATOLOGY THROUGH THE WEEKEND. THE  
COLDEST READINGS WILL REMAIN FIXED OVER THE NORTHERN ROCKIES  
EASTWARD THROUGH THE DAKOTAS AND INTO THE UPPER MIDWEST/GREAT  
LAKES. WHILE HIGHS STRUGGLE TO GET OUT OF THE SINGLE DIGITS, THE  
OVERNIGHT LOW TEMPERATURES WILL PLUNGE INTO THE NEGATIVE TEENS  
WITH A BREEZE MAKING WIND CHILLS DANGEROUSLY COLD, POSSIBLY IN THE  
-20 TO -40 FAHRENHEIT RANGE. AS SUCH, THE LOCAL OFFICES OVER THIS  
REGION HAVE A WIND CHILL ADVISORY IN EFFECT THROUGH ROUGHLY NOON  
ON SUNDAY. WHILE THIS SECTOR OF THE COUNTRY IS FRIGID, IT WILL BE  
QUITE THE OPPOSITE OVER THE WESTERN STATES. PERSISTENT UPPER  
RIDGING WILL RAISE THE MERCURY EACH DAY AS HIGHS SURGE INTO THE  
50S ACROSS THE PACIFIC NORTHWEST, 50S AND 60S OVER THE CENTRAL  
GREAT BASIN, AND EVEN SOME 80S INTO THE DESERT SOUTHWEST. AS A  
RESULT, THERE MAY BE SOME DAILY TEMPERATURE RECORDS BROKEN THIS  
WEEKEND, PARTICULARLY FOR THE WARM OVERNIGHT LOWS.  
 
RUBIN-OSTER  
 
GRAPHICS AVAILABLE AT  
WWW.WPC.NCEP.NOAA.GOV/BASICWX/BASICWX_NDFD.PHP  

 
 
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