439  
FXUS21 KWNC 071907  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 07 2018  
 
SYNOPSIS: WEAK AREAS OF SURFACE LOW PRESSURE ARE FORECAST TO PROPAGATE ALONG A  
COLD FRONT MOVING SOUTHEAST ACROSS THE EASTERN U.S. FEB 10-11. LOW PRESSURE  
OVER THE SOUTHERN PLAINS ON FEB 10 MOVES EASTWARD TO THE LOWER MISSISSIPPI  
VALLEY FEB 11. AREAS OF SURFACE HIGH PRESSURE ARE FORECAST TO MOVE ACROSS THE  
GREAT BASIN AND CENTRAL U.S. FEB 10-14. A STRONG AREA OF SURFACE LOW PRESSURE  
IS EXPECTED TO MOVE FROM THE ALEUTIANS TO THE ALASKA PENINSULA FEB 10-11.  
DURING WEEK-2 AN AREA OF MID-LEVEL LOW PRESSURE IS FORECAST OVER THE CENTRAL  
PART OF THE NATION WHILE ANOTHER AREA OF MID-LEVEL LOW PRESSURE IS ANTICIPATED  
OVER THE ALEUTIANS.  
 
HAZARDS  
 
MUCH BELOW-NORMAL TEMPERATURES FOR PARTS OF THE GREAT PLAINS, UPPER AND MIDDLE  
MISSISSIPPI VALLEYS, AND GREAT LAKES, SAT-MON, FEB 10-12.  
 
HEAVY SNOW FOR PARTS OF THE CENTRAL ROCKIES, SAT, FEB 10.  
 
HEAVY RAIN FOR PARTS OF THE LOWER MISSISSIPPI VALLEY, TENNESSEE VALLEY, CENTRAL  
AND SOUTHERN APPALACHIANS, SOUTHEAST, MID-ATLANTIC, AND NORTHEAST, SAT-SUN, FEB  
10-11.  
 
HEAVY SNOW FOR PARTS OF THE CENTRAL PLAINS AND MIDDLE MISSISSIPPI VALLEY,  
SAT-SUN, FEB 10-11.  
 
PERIODS OF HIGH WINDS FOR COASTAL SECTIONS OF SOUTHWESTERN OREGON AND NORTHERN  
AND CENTRAL CALIFORNIA, SAT-WED, FEB 10-14.  
 
HIGH WINDS ACROSS PORTIONS OF SOUTHWEST MAINLAND ALASKA AND THE ALASKA  
PENINSULA, SAT, FEB 10.  
 
FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE PACIFIC NORTHWEST.  
 
SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN AND  
CENTRAL GREAT PLAINS, UPPER AND MIDDLE MISSISSIPPI VALLEYS, OHIO VALLEY, AND  
GREAT LAKES, THU-WED, FEB 15-21.  
 
SEVERE DROUGHT ACROSS PARTS OF CALIFORNIA, THE CENTRAL AND SOUTHERN  
INTERMOUNTAIN REGION, THE CENTRAL AND SOUTHERN ROCKIES, THE GREAT PLAINS, THE  
MIDDLE AND LOWER MISSISSIPPI VALLEY, THE SOUTHEAST, AND THE MID-ATLANTIC.  
 
DETAILED SUMMARY  
 
FOR SATURDAY FEBRUARY 10 - WEDNESDAY FEBRUARY 14: A FRONTAL SYSTEM IS EXPECTED  
TO STRETCH FROM NEW ENGLAND SOUTHWESTWARD ACROSS THE OHIO VALLEY, LOWER  
MISSISSIPPI VALLEY TO THE SOUTHERN PLAINS FEB 10. AREAS OF LOW PRESSURE WILL  
PROPAGATE ALONG THE FRONT LEADING TO HEAVY RAIN (AMOUNTS IN EXCESS OF 1 INCH IN  
24 HOURS) FOR PARTS OF THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS, CENTRAL AND  
SOUTHERN APPALACHIANS, SOUTHEAST, MID-ATLANTIC, AND NORTHEAST FEB 10-11. HEAVY  
SNOW (AMOUNTS IN EXCESS OF 4 INCHES IN 24 HOURS) IS ANTICIPATED FOR PORTIONS OF  
THE CENTRAL PLAINS AND MIDDLE MISSISSIPPI VALLEY FEB 10-11.  
 
AREAS OF ARCTIC HIGH PRESSURE ARE PREDICTED TO MOVE ACROSS THE GREAT BASIN,  
ROCKIES, AND CENTRAL CONUS FEB 10-14. UPSLOPE FLOW LEADS TO HEAVY SNOW (AMOUNTS  
IN EXCESS OF 6 INCHES IN 24 HOURS) FOR PARTS OF THE CENTRAL ROCKIES FEB 10.  
OFFSHORE FLOW IS EXPECTED TO CAUSE PERIODS OF HIGH WINDS FOR COASTAL SECTIONS  
OF SOUTHWESTERN OREGON AND NORTHERN AND CENTRAL CALIFORNIA FEB 10-14. MUCH  
BELOW NORMAL TEMPERATURES (NEGATIVE ANOMALIES OF UP TO 20-25 DEGREES F) ARE  
FORECAST FOR PARTS OF THE GREAT PLAINS, UPPER AND MIDDLE MISSISSIPPI VALLEYS,  
AND GREAT LAKES FEB 10-12.  
 
A DEEP SURFACE LOW NEAR THE ALEUTIANS ON FEB 10 IS FORECAST TO MOVE OVER THE  
ALASKA PENINSULA AND SOUTHWESTERN MAINLAND ALASKA FEB 11. A TIGHT PRESSURE  
GRADIENT BETWEEN THE AREA OF LOW PRESSURE AND SURFACE HIGH PRESSURE EXPECTED  
OVER EASTERN ALASKA IS LIKELY TO PROMOTE HIGH WINDS (SPEEDS OF 40 KNOTS OR  
HIGHER) ACROSS THE ALASKA PENINSULA, KODIAK ISLAND, AND SOUTHWEST MAINLAND  
ALASKA ON FEB 10. WAVE HEIGHTS ARE EXPECTED TO REMAIN BELOW THE HAZARDOUS  
THRESHOLD.  
 
ANTECEDENT PRECIPITATION AND SNOW MELT LEAD TO FLOODING OCCURRING OR IMMINENT  
FOR PORTIONS OF WEST-CENTRAL WASHINGTON.  
 
FOR THURSDAY FEBRUARY 15 - WEDNESDAY FEBRUARY 21: AN MID-LEVEL TROUGH FORECAST  
OVER CENTRAL CANADA AND THE NORTH-CENTRAL CONUS IN COMBINATION WITH ARCTIC  
SURFACE HIGH PRESSURE LEAD TO A SLIGHT RISK OF MUCH BELOW-NORMAL TEMPERATURES  
FOR PARTS OF THE NORTHERN AND CENTRAL GREAT PLAINS, UPPER AND MIDDLE  
MISSISSIPPI VALLEYS, OHIO VALLEY, AND GREAT LAKES FEB 15-21.  
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 30, 2018 INDICATES A SUBSTANTIAL  
INCREASE IN THE COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 13.60%  
LAST WEEK TO 17.21% THIS WEEK. DRYNESS AND DROUGHT HAVE INCREASED IN SPATIAL  
COVERAGE AND/OR INTENSIFIED OVER PORTIONS OF CALIFORNIA AND THE SOUTHWEST THIS  
WEEK. SOME DETERIORATION IN CONDITIONS IS ALSO NOTED OVER THE SOUTHERN PLAINS.  
 
FORECASTER: RANDY SCHECHTER  
 

 
 
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