486  
FXUS21 KWNC 222141  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST JANUARY 22 2018  
 
SYNOPSIS: AT THE BEGINNING OF THE HAZARDS OUTLOOK PERIOD, A FRONTAL SYSTEM IS  
PREDICTED ACROSS THE WESTERN HALF OF THE CONTIGUOUS U.S., WITH SURFACE HIGH  
PRESSURE OVER THE EASTERN HALF. DURING THE ENSUING FEW DAYS, THE SURFACE HIGH  
IS EXPECTED TO MOVE EASTWARD OFF THE UPPER MID-ATLANTIC COAST, WHILE THE  
FRONTAL SYSTEM ADVANCES EASTWARD INTO THE EASTERN HALF OF THE CONUS. A MORE  
COMPACT FRONTAL SYSTEM IS ANTICIPATED TO REACH THE PACIFIC NORTHWEST COAST. BY  
THE END OF THE 3-7 DAY PERIOD, THE FIRST FRONTAL SYSTEM IS PREDICTED TO BE NEAR  
THE ATLANTIC COAST, WITH SURFACE HIGH PRESSURE IN ITS WAKE ACROSS MOST OF THE  
EASTERN HALF OF THE CONUS. IN THE ALASKA DOMAIN, PERSISTENT SURFACE LOW  
PRESSURE IS FORECAST OVER THE NORTHERN GULF OF ALASKA AND APPROXIMATELY THE  
SOUTHERN THIRD OF THE 49TH STATE, WITH SURFACE HIGH PRESSURE EXPECTED OVER THE  
CENTRAL AND NORTHERN THIRDS OF ALASKA. DURING THE WEEK-2 PERIOD, COLD  
TEMPERATURE HAZARDS ARE FORECAST FOR THE ALASKA PANHANDLE AND THE NORTHERN  
GREAT PLAINS, AND A HEAVY PRECIPITATION HAZARD IS FORECAST FOR PORTIONS OF THE  
LOWER MISSISSIPPI VALLEY AND SOUTHEAST.  
 
HAZARDS  
 
HEAVY RAIN FOR A SIGNIFICANT PORTION OF THE SOUTHEASTERN QUARTER OF THE CONUS,  
AND PORTIONS OF THE UPPER MID-ATLANTIC AND NORTHEAST, SAT-SUN, JAN 27-28.  
 
PERIODS OF HEAVY PRECIPITATION (MOUNTAIN SNOW AND VALLEY RAIN) FOR THE PACIFIC  
NORTHWEST, THU-SUN, JAN 25-28.  
 
FLOODING POSSIBLE IN LOWER MICHIGAN.  
 
MUCH BELOW NORMAL TEMPERATURES FOR SOUTHWESTERN MAINLAND ALASKA AND ADJACENT  
PARTS OF THE ALASKA PENINSULA, THU-FRI, JAN 25-26.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE NORTHERN GREAT PLAINS,  
SAT-MON, FEB 3-5.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE,  
SAT-MON, FEB 3-5.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR THE LOWER MISSISSIPPI VALLEY AND  
SOUTHEAST, THU-SAT, FEB 1-3.  
 
SEVERE DROUGHT FOR PARTS OF THE GREAT PLAINS, SOUTHWEST, MIDDLE AND LOWER  
MISSISSIPPI VALLEY, AND SOUTHEAST.  
 
DETAILED SUMMARY  
 
FOR THURSDAY JANUARY 25 - MONDAY JANUARY 29: SURFACE HIGH PRESSURE OVER THE  
EASTERN HALF OF THE CONUS EARLY IN THIS PERIOD IS FORECAST TO SHIFT EASTWARD  
TOWARDS THE ATLANTIC COAST, MOVING OFFSHORE BY THE END OF THE 3-7 DAY PERIOD. A  
FRONTAL SYSTEM INITIALLY OVER THE WESTERN HALF OF THE CONUS IS PREDICTED TO  
ADVANCE EASTWARD TO THE EASTERN CONUS DURING THIS SAME PERIOD. MOIST, SOUTHERLY  
FLOW STREAMING UP AHEAD OF THIS FRONTAL SYSTEM IS ANTICIPATED TO RESULT IN A  
BROAD AREA OF MARGINALLY HEAVY RAIN (2 INCHES, JAN 27-28) TO A SIGNIFICANT  
PORTION OF THE SOUTHEASTERN QUARTER OF THE CONUS, AND INTO PORTIONS OF THE  
UPPER MID-ATLANTIC AND NORTHEAST.  
 
IN THE PACIFIC NORTHWEST, PERIODS OF HEAVY PRECIPITATION (MOUNTAIN SNOW AND  
VALLEY RAIN) ARE ANTICIPATED FROM JAN 25-28. ABOUT 2 INCHES (LIQUID EQUIVALENT)  
IS PREDICTED DURING JAN 25-26, WITH 5-7 INCHES POSSIBLE DURING JAN 27-28, WITH  
THE EXPECTED APPROACH OF A COMPACT FRONTAL SYSTEM.  
 
FLOODING IS POSSIBLE IN PARTS OF LOWER MICHIGAN, ALONG THE GRAND RIVER WHICH IS  
RISING QUICKLY. ADDITIONAL RAINFALL ON FROZEN GROUND MAY RESULT IN MODERATE  
FLOODING.  
 
IN SOUTHWESTERN MAINLAND ALASKA AND ADJACENT PORTIONS OF THE ALASKA PENINSULA,  
DAILY TEMPERATURES ARE EXPECTED TO BE 20 DEGREES F (OR GREATER) BELOW NORMAL  
FOR THIS TIME OF YEAR (JAN 25-26).  
 
FOR TUESDAY JANUARY 30 - MONDAY FEBRUARY 05: DURING WEEK-2, THERE IS A SLIGHT  
RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI VALLEY AND  
SOUTHEAST (FEB 1-3). THERE ARE DIFFERENCES BETWEEN THE ECMWF AND GEFS SOLUTIONS  
IN THE PREDICTED LOCATIONS OF THE HEAVY RAIN AREA. THE ECMWF ENSEMBLE FAVORS  
THE MORE EASTERN PORTIONS OF THIS GENERAL REGION, AND THE GEFS FAVORS MORE  
WESTERN LOCATIONS. TELECONNECTIONS USING THE CURRENT ENHANCED PHASE OF THE MJO  
ALSO LEND SUPPORT FOR THE PREDICTION OF A POTENTIAL HEAVY PRECIPITATION HAZARD  
TWO WEEKS LATER, IN THE GENERAL REGION OF THE LOWER MISSISSIPPI VALLEY AND  
SOUTHEAST.  
 
TOWARDS THE END OF THE WEEK-2 PERIOD, ANOMALOUSLY COLD AIR IS PREDICTED TO  
OVERSPREAD THE NORTHERN GREAT PLAINS AND THE ALASKA PANHANDLE, AS INDICATED BY  
THE PROBABILISTIC EXTREMES OUTLOOK (PEO) TOOL, AND THE GEFS REFORECAST  
TEMPERATURE TOOL. THEREFORE, SLIGHT RISK AREAS OF MUCH BELOW NORMAL  
TEMPERATURES HAVE BEEN DESIGNATED FOR THESE TWO REGIONS.  
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 16, 2018 INDICATES AN INCREASE IN  
THE COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 8.70% LAST WEEK TO  
10.03% THIS WEEK. SEVERE DROUGHT CONTINUED TO EXPAND ACROSS THE SOUTHERN GREAT  
PLAINS WITH NEARLY HALF OF OKLAHOMA DESIGNATED WITH SEVERE DROUGHT.  
 
FORECASTER: ANTHONY ARTUSA  
 

 
 
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