757  
FXUS21 KWNC 252142  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST JANUARY 25 2018  
 
SYNOPSIS: A COLD FRONT INITIALLY NEAR THE APPALACHIANS IS PREDICTED TO MOVE OFF  
THE EASTERN SEABOARD EARLY IN THE 3-7 DAY PERIOD, FOLLOWED BY SURFACE HIGH  
PRESSURE. SEVERAL LOW PRESSURE SYSTEMS ARE FORECAST TO MOVE ACROSS THE PACIFIC  
NORTHWEST, MAINTAINING AN EXTENDED PERIOD OF STORMY CONDITIONS. ELSEWHERE,  
SEVERAL LOW PRESSURE SYSTEMS ARE ANTICIPATED TO MAINTAIN INCLEMENT WEATHER  
CONDITIONS ACROSS SOUTHERN ALASKA, THOUGH NO HAZARDS ARE EXPECTED AT THIS TIME.  
DURING THE WEEK-2 PERIOD, UNSEASONABLY COLD AIR IS PREDICTED TO OVERSPREAD THE  
ALASKA PANHANDLE, AND MUCH OF THE CONUS, WHILE THE BEST CHANCE FOR HAZARDOUS  
PRECIPITATION IS OVER EASTERN PORTIONS OF THE LOWER 48 STATES.  
 
HAZARDS  
 
HEAVY RAIN FOR THE SOUTHERN ATLANTIC COAST REGION, SUN-MON, JAN 28-29.  
 
HEAVY PRECIPITATION (MOUNTAIN SNOW AND VALLEY RAIN) FOR THE PACIFIC NORTHWEST,  
SUN-MON, JAN 28-29.  
 
HEAVY PRECIPITATION FROM EASTERN MISSOURI TO WESTERN NEW YORK, THU, FEB 1.  
 
MUCH BELOW NORMAL TEMPERATURES FOR THE NORTH-CENTRAL CONUS, THU, FEB 1.  
 
HIGH WINDS FOR THE PACIFIC NORTHWEST COAST, SUN-WED, JAN 28-31.  
 
HIGH SIGNIFICANT WAVE HEIGHTS FOR THE PACIFIC NORTHWEST COAST, SUN-WED, JAN  
28-31.  
 
FLOODING POSSIBLE IN WESTERN WASHINGTON STATE.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE, THE  
NORTHWESTERN CONUS, THE GREAT PLAINS AND MISSISSIPPI VALLEY, THE GREAT LAKES  
REGION, THE OHIO AND TENNESSEE VALLEYS, AND PORTIONS OF THE NORTHEAST, FRI-THU,  
FEB 2-8.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES ALONG THE NORTHERN TIER OF  
STATES FROM WASHINGTON TO MICHIGAN, INCLUDING A LARGE PORTION OF THE PLAINS AND  
MIDWEST, FRI-THU, FEB 2-8.  
 
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES OVER THE NORTH-CENTRAL CONUS,  
SUN-WED, FEB 4-7.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE UPPER OHIO AND TENNESSEE VALLEYS,  
MOST OF THE APPALACHIANS, AND MOST OF THE ATLANTIC COAST STATES, FRI-SAT, FEB  
2-3.  
 
MODERATE RISK OF HEAVY PRECIPITATION FOR THE MID-ATLANTIC AND NORTHEAST,  
FRI-SAT, FEB 2-3.  
 
SEVERE DROUGHT FOR PARTS OF THE GREAT PLAINS, SOUTHWEST, MIDDLE AND LOWER  
MISSISSIPPI VALLEY, AND SOUTHEAST.  
 
DETAILED SUMMARY  
 
FOR SUNDAY JANUARY 28 - THURSDAY FEBRUARY 01: A COLD FRONT APPROACHING THE EAST  
COAST IS EXPECTED TO BRING HEAVY RAIN (SEVERAL INCHES) TO THE SOUTHERN ATLANTIC  
COASTAL REGION ON JAN 28-29.  
 
A SUBTROPICAL MOISTURE PLUME DIRECTED TOWARDS THE PACIFIC NORTHWEST IS EXPECTED  
TO RESULT IN HEAVY PRECIPITATION (MOUNTAIN SNOW AND VALLEY RAIN) FROM JAN  
28-29. MODEL GUIDANCE DEPICTS A NORTHWARD SHIFT IN THE EXPECTED STORM TRACK  
(FROM YESTERDAY), CONCENTRATING MOST OF THE PRECIPITATION ACROSS WASHINGTON  
STATE AND BRITISH COLUMBIA. FOR WASHINGTON, PRECIPITATION AMOUNTS (LIQUID  
EQUIVALENT) ARE FORECAST TO RANGE FROM 4-7 INCHES. HIGH WIND SPEEDS AND HIGH  
SIGNIFICANT WAVE HEIGHTS ARE OTHER EXPECTED HAZARDS INDICATED FOR THE PACIFIC  
NORTHWEST DURING MOST OF THE 3-7 DAY PERIOD. WINDS OF 40-45 KNOTS, AND  
SIGNIFICANT WAVE HEIGHTS OF AT LEAST 20-25 FEET ARE FORECAST.  
 
ON FEB 1, ARCTIC AIR IS PREDICTED TO MOVE SOUTH OUT OF CANADA ACROSS THE  
NORTH-CENTRAL CONUS, WARRANTING AN AREA OF MUCH BELOW NORMAL TEMPERATURES  
(ABOUT 15-20 DEGREES BELOW NORMAL). AT THE SAME TIME, WINTRY PRECIPITATION MAY  
DEVELOP FROM EASTERN MISSOURI TO WESTERN NEW YORK, NEAR THE LEADING EDGE OF THE  
ARCTIC AIR MASS.  
 
FLOODING IS POSSIBLE IN PARTS OF WESTERN WASHINGTON, RELATED TO HEAVY  
PRECIPITATION THAT HAS ALREADY FALLEN, AND IS PREDICTED TO FALL IN THE NEXT  
WEEK.  
 
SEVERAL LOW PRESSURE SYSTEMS ARE FORECAST TO BRING INCLEMENT (BUT LIKELY  
NON-HAZARDOUS) WEATHER CONDITIONS TO SOUTHERN ALASKA DURING THIS PERIOD, WITH  
HIGH PRESSURE ACROSS THE NORTHERN HALF TO TWO-THIRDS OF THE STATE.  
 
FOR FRIDAY FEBRUARY 02 - THURSDAY FEBRUARY 08: SEVERAL BLASTS OF ARCTIC AIR ARE  
FORECAST TO OVERSPREAD THE ALASKA PANHANDLE, AND PORTIONS OF THE NORTHWESTERN,  
CENTRAL, AND NORTHEASTERN CONUS DURING THIS PERIOD (FEB 2-8), WARRANTING A  
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES. A MODERATE RISK OF MUCH BELOW  
NORMAL TEMPERATURES EXISTS FOR A LARGE PART OF THIS SAME REGION, FOR THE SAME  
PERIOD. A HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES IS SUPPORTED BY VARIOUS  
MODEL GUIDANCE ACROSS THE NORTH-CENTRAL CONUS, FEB 4-7, SUCH AS THE GEFS AND  
ECMWF ENSEMBLE REFORECAST TOOLS, AND THE PROBABILISTIC EXTREMES OUTLOOK (PEO)  
TOOL. IT IS THIS SECOND BLAST OF ARCTIC AIR THAT IS EXPECTED TO BE THE COLDEST  
IN RECENT WEEKS, WITH DEPARTURES OF AT LEAST 20-25 DEGREES F BELOW NORMAL.  
THERE IS A SLIGHT RISK OF HEAVY PRECIPITATION DURING WEEK-2 ACROSS THE EASTERN  
CONUS, FROM ABOUT THE UPPER TENNESSEE AND UPPER OHIO VALLEYS EASTWARD TO THE  
ATLANTIC COAST. A MODERATE RISK AREA IS DEPICTED ACROSS THE MID-ATLANTIC AND  
NORTHEAST REGIONS OF THE LOWER 48 STATES.  
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 23, 2018 INDICATES AN INCREASE IN  
THE COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 10.03% LAST WEEK TO  
13.60% THIS WEEK. SEVERE DROUGHT CONTINUED TO EXPAND ACROSS THE SOUTHERN GREAT  
PLAINS AND SOUTHWEST THIS PAST WEEK.  
 
FORECASTER: ANTHONY ARTUSA  
 

 
 
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