020  
FXUS21 KWNC 082036  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 08 2018  
 
SYNOPSIS: A MID-LEVEL TROUGH AND SURFACE HIGH PRESSURE ARE ANTICIPATED TO  
INFLUENCE THE FORECAST FOR THE CONTINENTAL U.S. OVER THE NEXT TWO WEEKS. A  
SERIES OF WEAK SURFACE LOW PRESSURE SYSTEMS IS LIKELY TO CAUSE SOME ACTIVE  
FRONTAL ZONES FOR THE EASTERN HALF OF THE CONUS. MID-LEVEL RIDGING IS FORECAST  
TO REMAIN STATIONARY THROUGHOUT THE PERIOD OFF THE WESTERN COAST OF THE U.S.,  
LEAVING THE REGION VOID OF ANY FRONTAL ACTIVITY. ALASKA IS EXPECTED TO  
EXPERIENCE CONTINUOUS MID-LEVEL HIGH PRESSURE ACROSS MUCH OF THE MAINLAND, WITH  
A FEW SURFACE LOW PRESSURE SYSTEMS MOVING ALONG THE ALEUTIANS AND COAST.  
 
HAZARDS  
 
HEAVY RAIN ACROSS PORTIONS OF THE MID-ATLANTIC, THE LOWER MISSISSIPPI VALLEY,  
THE SOUTHEAST, AND THE OHIO VALLEY, SUN-MON, FEB 11-FEB 12.  
 
FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE CENTRAL PLAINS AND THE  
PACIFIC NORTHWEST.  
 
HIGH WINDS ACROSS PORTIONS OF CALIFORNIA, SUN-TUE, FEB 11-FEB 13.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL PLAINS, THE  
NORTHERN PLAINS, THE ROCKIES, THE MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS,  
SUN-TUE, FEB 11-FEB 13.  
 
HIGH WINDS ACROSS PORTIONS OF MAINLAND ALASKA AND THE ALEUTIANS, TUE-WED, FEB  
13-FEB 14.  
 
HIGH SIGNIFICANT WAVE HEIGHTS FOR COASTAL PORTIONS OF MAINLAND ALASKA AND THE  
ALEUTIANS, TUE-WED, FEB 13-FEB 14.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE CENTRAL  
PLAINS, THE NORTHERN PLAINS, THE GREAT LAKES, THE NORTHERN ROCKIES, THE  
MISSISSIPPI VALLEY, THE SOUTHERN PLAINS, AND THE OHIO VALLEY, FRI-THU, FEB  
16-FEB 22.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE GREAT  
LAKES, THE UPPER MISSISSIPPI VALLEY, AND THE NORTHERN PLAINS, FRI-SUN, FEB  
16-FEB 18.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE CENTRAL PLAINS, THE  
MISSISSIPPI VALLEY, AND THE SOUTHERN PLAINS, FRI-SUN, FEB 16-FEB 18.  
 
SEVERE DROUGHT ACROSS THE CENTRAL PLAINS, THE CENTRAL ROCKIES, THE LOWER  
MISSISSIPPI VALLEY, THE CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE TENNESSEE  
VALLEY, THE SOUTHERN ROCKIES, THE MIDDLE MISSISSIPPI VALLEY, THE MID-ATLANTIC,  
CALIFORNIA, THE SOUTHEAST, THE SOUTHERN APPALACHIANS, THE SOUTHERN PLAINS, AND  
THE SOUTHWEST.  
 
DETAILED SUMMARY  
 
FOR SUNDAY FEBRUARY 11 - THURSDAY FEBRUARY 15: A FRONTAL ZONE FROM THE SOUTHERN  
PLAINS ALONG THE OHIO VALLEY AND EAST COAST IS LIKELY TO BE ACTIVE DURING THE  
3-7 DAY PERIOD, WITH A SERIES OF LOW PRESSURE SYSTEMS MOVING THROUGH THE AREA.  
A COLD FRONT IS EXPECTED TO PASS OVER THE EASTERN SEABOARD ON FEB 11-12,  
BRINGING HEAVY RAIN (EXCEEDING 1 INCH IN 24 HOURS) TO THE SOUTHEAST AND  
MID-ATLANTIC REGIONS.  
 
ARCTIC SURFACE HIGH PRESSURE IS LIKELY TO DOMINATE THE CENTRAL PLAINS AND THE  
ROCKIES FOR MUCH OF THE PERIOD. MUCH BELOW NORMAL TEMPERATURES ARE FORECAST FOR  
FEB 11-13 FOR MUCH OF THIS REGION, EXTENDING FROM THE NORTHERN PLAINS INTO  
NORTHERN TEXAS. THE COLD TEMPERATURES (ANOMALIES OF 12-20 DEGF) ARE LIKELY TO  
PENETRATE DOWN INTO NORTHERN TEXAS FROM FEB 11-12 AND THEN RETREAT BACK TO THE  
NORTHERN PLAINS FOR FEB 13. FOR THE WESTERN U.S., OFFSHORE FLOW IS EXPECTED TO  
CAUSE PERIODS OF HIGH WINDS FOR COASTAL SECTIONS OF SOUTHWESTERN OREGON AND  
NORTHERN AND CENTRAL CALIFORNIA FEB 11-13.  
 
MID-LEVEL RIDGING AND SOUTHERLY FLOW ARE EXPECTED TO KEEP TEMPERATURES OVER  
ALASKA MORE MODERATE DURING THE 3-7 DAY PERIOD, THOUGH NOT ANOMALOUSLY WARM  
ENOUGH TO MEET HAZARDOUS CRITERIA. HIGH WINDS (SPEEDS GREATER THAN 40 KNOTS)  
AND SIGNIFICANT WAVE HEIGHTS (OVER 30 FEET) ARE FORECAST FOR THE ALEUTIANS FOR  
FEB 13-14, AS A STRONG SURFACE LOW PRESSURE SYSTEM MOVES INTO THE BERING SEA.  
 
FOR FRIDAY FEBRUARY 16 - THURSDAY FEBRUARY 22: THE WEEK-2 PERIOD IS LIKELY TO  
BE AFFECTED BY A POSITIVELY ALIGNED MID-LEVEL TROUGH FORMING FROM THE  
SOUTHWESTERN US ALONG THE CENTRAL CONUS. A SLIGHT RISK HAS BEEN POSTED FOR MUCH  
BELOW NORMAL TEMPERATURES FOR MOST OF THE CENTRAL US, INCLUDING THE CENTRAL AND  
NORTHERN PLAINS, NORTHERN TEXAS AND PARTS OF THE MIDWEST FOR FEB 16-22. THE  
COLDEST TEMPERATURES ARE LIKELY TO BE IN THE NORTHERN PLAINS AND THE MIDWEST  
FROM FEB 16-18, WHERE A MODERATE RISK IS FORECAST. THE MIDWEST AND PARTS OF THE  
CENTRAL PLAINS ARE ALSO LIKELY TO EXPERIENCE MUCH-BELOW NORMAL TEMPERATURES DUE  
TO LOCAL EFFECTS OF THE SNOWPACK.  
 
A SLIGHT RISK FOR ABOVE AVERAGE PRECIPITATION IS FORECAST FOR OKLAHOMA,  
NORTHERN ARKANSAS AND SOUTHERN MISSOURI FOR FEB 16-18. THIS AREA IS LIKELY TO  
BE A TRANSITION ZONE FROM THE MUCH BELOW NORMAL TEMPERATURES TO WARMER,  
MODERATE TEMPERATURES IN THE SOUTHEAST. THIS DYNAMIC SUPPORTS THE POSSIBILITY  
FOR FREEZING RAIN EVENTS DURING THIS PERIOD ALONG THE TRANSITION ZONE, THOUGH  
MODEL GUIDANCE REMAINS UNCERTAIN AT THIS TIME.  
 
ALASKA IS FORECAST TO REMAIN MODERATE DURING THE WEEK-2 PERIOD WITH CONTINUED  
MID-LEVEL RIDGING AND SOUTHERLY FLOW. NO HAZARDS ARE EXPECTED AT THIS TIME.  
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 30, 2018 INDICATES A SLIGHT INCREASE  
IN THE COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 17.21% LAST WEEK  
TO 18.44% THIS WEEK. DRYNESS AND DROUGHT HAVE INCREASED IN SPATIAL COVERAGE  
AND/OR INTENSIFIED OVER PORTIONS OF NORTHERN TEXAS AND WESTERN OKLAHOMA. SOME  
DETERIORATION IN CONDITIONS IS ALSO NOTED OVER THE SOUTHEAST.  
 
FORECASTER: CHRISTINA FINAN  
 

 
 
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