125  
FXUS21 KWNC 091955  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 09 2018  
 
SYNOPSIS: AREAS OF ARCTIC HIGH PRESSURE ARE FORECAST TO MOVE FROM THE GREAT  
BASIN TO THE CENTRAL, AND THEN EASTERN PART OF THE NATION FEB 12-14. A SERIES  
OF FRONTAL SYSTEMS ASSOCIATED WITH AREAS OF SURFACE LOW PRESSURE ARE  
ANTICIPATED TO CROSS THE ALEUTIANS AND ALASKA PENINSULA FEB 12-16. A BROAD AREA  
OF MID-LEVEL LOW PRESSURE IS PREDICTED TO DOMINATE MUCH OF THE LOWER 48 STATES  
DURING THE WEEK-2 PERIOD, WHILE MID-LEVEL HIGH PRESSURE IS FORECAST OVER  
MAINLAND ALASKA.  
 
HAZARDS  
 
HIGH WINDS ACROSS COASTAL PORTIONS OF CALIFORNIA AND SOUTHERN OREGON, MON-TUE,  
FEB 12-FEB 13.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE PLAINS, THE UPPER AND  
MIDDLE MISSISSIPPI VALLEYS, AND THE GREAT LAKES, MON-TUE, FEB 12-FEB 13.  
 
PERIODS OF HIGH WINDS ACROSS PORTIONS OF THE ALASKA PENINSULA AND THE  
ALEUTIANS, MON-WED, FEB 12-FEB 14.  
 
PERIODS OF HIGH SIGNIFICANT WAVE HEIGHTS FOR COASTAL PORTIONS OF THE ALASKA  
PENINSULA AND THE ALEUTIANS, MON-WED, FEB 12-FEB 14.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN  
ROCKIES, NORTHERN AND CENTRAL PLAINS, UPPER AND MIDDLE MISSISSIPPI VALLEYS, AND  
THE GREAT LAKES, SAT-FRI, FEB 17-FEB 23.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN  
PLAINS, AND UPPER AND MIDDLE MISSISSIPPI VALLEYS, SAT-SUN, FEB 17-FEB 18.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI,  
TENNESSEE, AND OHIO VALLEYS, SAT-WED, FEB 17-FEB 21.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF THE SOUTHERN PLAINS, WED-FRI,  
FEB 21-23.  
 
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 MONDAY FEBRUARY 12 - FRIDAY FEBRUARY 16: ARCTIC SURFACE HIGH PRESSURE IS  
EXPECTED TO MOVE ACROSS THE GREAT BASIN TO THE CENTRAL AND THEN EASTERN CONUS.  
OFF-SHORE FLOW IS FORECAST TO CAUSE HIGH WINDS (SPEEDS IN EXCESS OF 30 KNOTS)  
FOR COASTAL SECTIONS OF SOUTHWESTERN OREGON AND NORTHERN AND CENTRAL CALIFORNIA  
FEB 12-13. MUCH BELOW NORMAL TEMPERATURES (NEGATIVE ANOMALIES AS MUCH AS 20-25  
DEGREES F) ARE ANTICIPATED ACROSS PORTIONS OF THE PLAINS, THE UPPER AND MIDDLE  
MISSISSIPPI VALLEYS, AND THE GREAT LAKES FEB 12-13.  
 
A SERIES OF FRONTAL SYSTEMS ASSOCIATED WITH AREAS OF SURFACE LOW PRESSURE ARE  
ANTICIPATED TO CROSS THE ALEUTIANS AND ALASKA PENINSULA LEADING TO PERIODS OF  
HIGH WINDS (SPEEDS IN EXCESS OF 40 KNOTS) AND PERIODS OF HIGH SIGNIFICANT WAVE  
HEIGHTS (OVER 30 FEET) FOR COASTAL PORTIONS OF THE ALASKA PENINSULA AND THE  
ALEUTIANS FEB 12-14.  
 
LATE IN THE PERIOD, MID-LEVEL LOW PRESSURE MOVING ACROSS THE SOUTHWEST CONUS IN  
COMBINATION WITH MOIST INFLOW FROM THE GULF OF MEXICO IS EXPECTED TO CAUSE A  
LARGE PRECIPITATION SHIELD TO DEVELOP OVER THE SOUTHWESTERN AND CENTRAL CONUS.  
FROZEN PRECIPITATION IS LIKELY ON THE NORTHERN AND NORTHWESTERN PORTIONS OF THE  
PRECIPITATION SHIELD BUT MODEL UNCERTAINTY REGARDING TIMING AND LOCATION  
PRECLUDES THE SPECIFICATION OF HAZARD SHAPES AT THE CURRENT TIME.  
 
FOR SATURDAY FEBRUARY 17 - FRIDAY FEBRUARY 23: DURING WEEK-2, A BROAD MID-LEVEL  
TROUGH IS EXPECTED TO DOMINATE MOST OF THE CONUS. THIS LEADS TO A SLIGHT RISK  
OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN ROCKIES,  
NORTHERN AND CENTRAL PLAINS, UPPER AND MIDDLE MISSISSIPPI VALLEYS, AND THE  
GREAT LAKES FEB 17-23, AND A MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES  
FOR PORTIONS OF THE NORTHERN PLAINS, AND UPPER AND MIDDLE MISSISSIPPI VALLEYS  
FEB 17-18.  
 
THE BROAD TROUGH AND MOIST INFLOW FROM THE GULF OF MEXICO LEAD TO A SLIGHT RISK  
OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI, TENNESSEE AND  
OHIO VALLEYS FEB 17-21, AND A SLIGHT RISK OF HEAVY PRECIPITATION FOR PARTS OF  
THE SOUTHERN PLAINS FEB 21-23.  
 
ALASKA IS FORECAST TO EXPERIENCE MID-LEVEL RIDGING AND ANOMALOUS SOUTHEASTERLY  
SURFACE FLOW RESULTING IN A WARMER AND WETTER THAN NORMAL PATTERN. NO HAZARDS  
ARE EXPECTED AT THIS TIME.  
 
THE U.S. DROUGHT MONITOR, VALID ON FEB 6 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: RANDY SCHECHTER  
 

 
 
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