488  
FXUS21 KWNC 012107  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 01 2018  
 
SYNOPSIS: MID-LEVEL LOW PRESSURE IS LIKELY TO AFFECT THE EASTERN TWO-THIRDS OF  
THE CONTIGUOUS U.S. OVER THE NEXT TWO WEEKS, WHILE MID-LEVEL HIGH PRESSURE IS  
ANTICIPATED NEAR THE WEST COAST. SEVERAL SURFACE LOW PRESSURE SYSTEMS ARE  
EXPECTED TO BRING FRONTAL ACTIVITY TO THE PACIFIC NORTHWEST AND ROCKIES, WHILE  
TWO STORM SYSTEMS COULD AFFECT THE EASTERN LOWER 48 STATES DURING THE 3-7 DAY  
PERIOD. WEEK-2 IS LIKELY TO FEATURE A MOSTLY DRY PATTERN WITH SURFACE HIGH  
PRESSURE SYSTEMS MOVING SOUTH OUT OF CANADA OVER THE CENTRAL AND EASTERN CONUS.  
THE FORECAST CIRCULATION OVER ALASKA IS FORECAST TO BE SIMILARLY STATIONARY  
DURING THIS PERIOD, WITH A SERIES OF LOW PRESSURE SYSTEMS OVER THE ALEUTIAN  
ISLANDS AND MID-LEVEL HIGH PRESSURE OVER THE NORTHERN PART OF THE STATE, AS  
WELL AS THE PANHANDLE.  
 
HAZARDS  
 
MUCH BELOW NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE AND ADJACENT PARTS OF  
THE SOUTHEASTERN MAINLAND, SUN, FEB 4.  
 
HEAVY RAIN FOR LOWER-ELEVATION PORTIONS OF THE PACIFIC NORTHWEST, SUN-MON, FEB  
4-5.  
 
HEAVY SNOW FOR MOUNTAINOUS REGIONS OF THE PACIFIC NORTHWEST, SUN-MON, FEB 4-5.  
 
HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN AND CENTRAL ROCKIES AND ADJACENT  
PARTS OF THE HIGH PLAINS, SUN-MON, FEB 4-5.  
 
HEAVY SNOW FROM THE UPPER OHIO VALLEY AND NORTHERN MID-ATLANTIC THROUGH MUCH OF  
NEW ENGLAND, SUN-MON, FEB 4-5.  
 
HEAVY RAIN FOR MUCH OF ALABAMA AND GEORGIA, SUN-MON, FEB 4-5.  
 
HEAVY SNOW FROM EASTERN MISSOURI NORTHEASTWARD ACROSS MUCH OF THE OHIO VALLEY  
AND NORTHEAST, TUE-WED, FEB 6-7.  
 
HEAVY RAIN FOR NORTHERN PORTIONS OF MISSISSIPPI AND ALABAMA, TUE-WED, FEB 6-7.  
 
MUCH BELOW NORMAL TEMPERATURES FROM EASTERN MONTANA AND THE DAKOTAS TO THE  
UPPER PENINSULA OF MICHIGAN, SUN-WED, FEB 4-7.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR MOST OF THE EASTERN HALF OF  
THE CONUS, FRI-MON, FEB 9-12.  
 
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 SUNDAY FEBRUARY 04 - THURSDAY FEBRUARY 08: BACK-TO-BACK SURFACE HIGH  
PRESSURE SYSTEMS ARE FORECAST TO MOVE SOUTH AND EAST OUT OF CANADA, ACROSS THE  
CENTRAL AND EASTERN CONUS DURING THIS PERIOD. NEAR THE LEADING EDGE OF THESE  
CONTINENTAL AIR MASSES, STORM SYSTEMS ARE PREDICTED TO FORM, AND BRING  
PRECIPITATION TO EASTERN PORTIONS OF THE CONUS. THE FIRST OF THESE TWO STORM  
SYSTEMS IS EXPECTED TO BRING HEAVY SNOW (4-8 INCHES) FROM THE UPPER OHIO VALLEY  
AND NORTHERN MID-ATLANTIC THROUGH MUCH OF NEW ENGLAND, AND HEAVY RAIN (1-3  
INCHES) TO ALABAMA AND GEORGIA, ON FEB 4-5. THE SUBSEQUENT STORM SYSTEM IS  
FORECAST TO BRING A SWATH OF SNOW (PERHAPS 4-8 INCHES) FROM EASTERN MISSOURI  
NORTHEASTWARD ACROSS MUCH OF THE OHIO VALLEY AND NORTHEAST, AND HEAVY RAIN (1-3  
INCHES) TO NORTHERN PORTIONS OF MISSISSIPPI AND ALABAMA, ON FEB 6-7. THIS  
PATTERN FAVORS MUCH BELOW NORMAL TEMPERATURES (12 TO 24 DEGREES F BELOW NORMAL)  
FROM EASTERN MONTANA AND THE DAKOTAS TO THE UPPER PENINSULA OF MICHIGAN.  
 
PARTS OF THE PACIFIC NORTHWEST AND NORTHERN ROCKIES ARE EXPECTED TO EXPERIENCE  
HEAVY SNOW ACROSS HIGHER ELEVATIONS, AND RAIN AT LOWER ELEVATIONS, ON FEB 4-5.  
PREDICTED LIQUID EQUIVALENT AMOUNTS RANGE FROM ABOUT 3-4 INCHES IN THE  
CASCADES, ABOUT 3 INCHES IN THE BITTERROOT MOUNTAINS, AND 2 INCHES NEAR  
YELLOWSTONE NATIONAL PARK IN NORTHWESTERN WYOMING.  
 
FOR ALASKA, A FEW SURFACE LOW PRESSURE SYSTEMS ARE FORECAST TO MOVE OVER THE  
ALEUTIANS AND THE GULF OF ALASKA, PERIODICALLY AFFECTING THE SOUTHERN PART OF  
THE STATE. A SURFACE HIGH IS LIKELY TO REMAIN ENTRENCHED OVER THE NORTHERN AND  
EASTERN SECTIONS OF ALASKA THROUGH THE PERIOD. MUCH BELOW NORMAL TEMPERATURES,  
LIKELY 20-30 DEGREES F NEGATIVE ANOMALIES, ARE EXPECTED ACROSS PARTS OF THE  
PANHANDLE AND NEARBY SOUTHEASTERN MAINLAND ON FEB 4. ADDITIONALLY, WITH THIS  
STRONG SURFACE HIGH, CONDITIONS APPEAR FAVORABLE FOR STRONG, LOCALIZED GAP  
WINDS OVER THE PANHANDLE REGION.  
 
FOR FRIDAY FEBRUARY 09 - THURSDAY FEBRUARY 15: MID-LEVEL CIRCULATION PATTERNS  
PRESENT IN DAYS 3-7 ARE LIKELY TO PERSIST THROUGH WEEK-2. THE GFS AND ECMWF  
ENSEMBLE MEAN SOLUTIONS CONTINUE TO DIVERGE IN WEEK-2, HOWEVER, WITH THE ECMWF  
BEING MORE PROGRESSIVE OVERALL, AND THUS MILDER OVER THE EASTERN CONUS. A  
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES IS DEPICTED FOR MOST OF THE  
EASTERN HALF OF THE CONUS (BY THE GEFS), WHERE ENHANCED ODDS (20 PERCENT) OF  
MINIMUM TEMPERATURES BELOW THE 15TH CLIMATOLOGICAL PERCENTILE ARE FORECAST FOR  
TWO OR MORE DAYS (IN THIS CASE, FOUR DAYS). IT IS THOUGHT THAT THE ECMWF  
ENSEMBLE MEAN SOLUTION MAY BE WARMING UP THE EASTERN CONUS TOO QUICKLY.  
 
ANOMALOUS RIDGING IS FORECAST TO REMAIN INTACT OVER THE WESTERN CONUS, WITH  
MUCH ABOVE NORMAL TEMPERATURES EXPECTED DURING THE WEEK-2 PERIOD OVER THE AREA.  
WHILE THIS IS NOT DEPICTED ON THE MAP DUE TO THE COOL CLIMATOLOGY, THERE  
APPEARS TO BE DRAMATICALLY INCREASED ODDS OF RECORD HIGH TEMPERATURES,  
ESPECIALLY EARLY IN WEEK-2 AND CENTERED OVER CALIFORNIA AND THE SOUTHWEST.  
WARMER TEMPERATURES COUPLED WITH ANOMALOUSLY LOW SOIL MOISTURE VALUES AND  
ANOMALOUS OFFSHORE FLOW, FAVOR AN ELEVATED FIRE WEATHER RISK DURING WEEK-2.  
 
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: ANTHONY ARTUSA  
 

 
 
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