886  
FXUS21 KWNC 142137  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST FEBRUARY 14 2018  
 
SYNOPSIS: AN ACTIVE WEATHER PATTERN IS PREDICTED ACROSS THE CONTIGUOUS U.S. AND  
ALASKA DURING THE NEXT TWO WEEKS. DURING THE 3-7 DAY AND WEEK-2 FORECAST  
PERIODS, ON AVERAGE, A FRONTAL ZONE IS EXPECTED TO STRETCH FROM THE SOUTHERN  
GREAT PLAINS NORTHEASTWARD ACROSS THE OHIO VALLEY INTO NEW ENGLAND. MIXED  
PRECIPITATION TYPES, AND THUNDERSTORMS, ARE ANTICIPATED ACROSS PORTIONS OF THIS  
REGION. IN GENERAL, WARMER THAN NORMAL TEMPERATURES ARE EXPECTED EAST OF THIS  
FRONTAL ZONE, AND COLDER THAN NORMAL TEMPERATURES ARE PREDICTED WEST OF THIS  
FRONTAL ZONE.  
 
HAZARDS  
 
HEAVY PRECIPITATION ACROSS PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY, THE  
NORTHEAST, THE GREAT LAKES, THE OHIO VALLEY, AND THE UPPER MISSISSIPPI VALLEY,  
WED, FEB 21.  
 
HEAVY PRECIPITATION ACROSS PORTIONS OF THE MID-ATLANTIC, THE NORTHEAST, AND THE  
CENTRAL APPALACHIANS, SAT-SUN, FEB 17-FEB 18.  
 
HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE TENNESSEE  
VALLEY, THE SOUTHERN PLAINS, THE MIDDLE MISSISSIPPI VALLEY, THE GREAT LAKES,  
AND THE OHIO VALLEY, MON-TUE, FEB 19-FEB 20.  
 
HEAVY RAIN ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN  
APPALACHIANS, THE OHIO VALLEY, AND THE TENNESSEE VALLEY, SAT-SUN, FEB 17-FEB 18.  
 
HEAVY SNOW ACROSS PORTIONS OF THE PACIFIC NORTHWEST, THE NORTHERN ROCKIES, AND  
THE NORTHERN GREAT BASIN, SAT-SUN, FEB 17-FEB 18.  
 
FLOODING OCCURRING OR IMMINENT ACROSS PORTIONS OF THE SOUTHEAST, THE LOWER  
MISSISSIPPI VALLEY, THE OHIO VALLEY, AND THE TENNESSEE VALLEY.  
 
FLOODING LIKELY ACROSS PORTIONS OF THE LOWER MISSISSIPPI VALLEY.  
 
HIGH WINDS ACROSS PORTIONS OF CALIFORNIA, MON-TUE, FEB 19-FEB 20.  
 
HIGH WINDS ACROSS PORTIONS OF THE CENTRAL PLAINS, THE NORTHERN PLAINS, AND THE  
NORTHERN ROCKIES, SUN-MON, FEB 18-FEB 19.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF THE CENTRAL PLAINS, THE  
NORTHERN PLAINS, AND THE NORTHERN ROCKIES, MON-WED, FEB 19-FEB 21.  
 
MUCH ABOVE NORMAL TEMPERATURES ACROSS PORTIONS OF MAINLAND ALASKA, SUN-WED, FEB  
18-FEB 21.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE CENTRAL  
PLAINS, THE CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE SOUTHERN PLAINS, THE  
NORTHERN ROCKIES, THE CENTRAL ROCKIES, THE MIDDLE MISSISSIPPI VALLEY,  
CALIFORNIA, THE NORTHERN GREAT BASIN, THE UPPER MISSISSIPPI VALLEY, THE ALASKA  
PANHANDLE, THE PACIFIC NORTHWEST, AND THE SOUTHWEST, THU-WED, FEB 22-FEB 28.  
 
SLIGHT RISK OF MUCH ABOVE NORMAL TEMPERATURES FOR PORTIONS OF MAINLAND ALASKA  
AND THE ALEUTIANS, THU-WED, FEB 22-FEB 28.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE CENTRAL  
PLAINS, THE CENTRAL GREAT BASIN, THE NORTHERN PLAINS, THE NORTHERN ROCKIES,  
CALIFORNIA, THE NORTHERN GREAT BASIN, THE PACIFIC NORTHWEST, AND THE SOUTHWEST,  
THU-SAT, FEB 22-FEB 24.  
 
MODERATE RISK OF MUCH ABOVE NORMAL TEMPERATURES FOR PORTIONS OF MAINLAND  
ALASKA, THU-SAT, FEB 22-FEB 24.  
 
HIGH RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF THE PACIFIC  
NORTHWEST, THE NORTHERN ROCKIES, THE NORTHERN GREAT BASIN, AND THE NORTHERN  
PLAINS, THU-SAT, FEB 22-FEB 24.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI  
VALLEY, THE CENTRAL APPALACHIANS, THE TENNESSEE VALLEY, THE MIDDLE MISSISSIPPI  
VALLEY, THE MID-ATLANTIC, THE SOUTHERN APPALACHIANS, THE SOUTHEAST, THE  
SOUTHERN PLAINS, AND THE OHIO VALLEY, THU-SAT, FEB 22-FEB 24.  
 
MODERATE RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE MIDDLE MISSISSIPPI  
VALLEY, THE LOWER MISSISSIPPI VALLEY, THE SOUTHERN PLAINS, THE OHIO VALLEY, AND  
THE TENNESSEE VALLEY, THU-SAT, FEB 22-FEB 24.  
 
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 SATURDAY FEBRUARY 17 - WEDNESDAY FEBRUARY 21: SEVERAL STORM SYSTEMS ARE  
FORECAST TO PRODUCE A VARIETY OF PRECIPITATION TYPES ACROSS PORTIONS OF THE  
CENTRAL AND EASTERN CONUS DURING THIS PERIOD. INITIALLY, AN AREA OF HEAVY RAIN  
(ABOUT 2 INCHES) IS EXPECTED OVER THE TENNESSEE AND SOUTHERN OHIO VALLEYS, FEB  
17-18. AT THE SAME TIME, A BAND OF MIXED PRECIPITATION (SNOW, SLEET AND  
FREEZING RAIN) IS EXPECTED NEAR AND WEST OF THE I-95 CORRIDOR, WITH RAIN  
PRIMARILY FORECAST FOR THE MID-ATLANTIC AND NORTHEAST COASTAL PLAIN. RAIN  
AMOUNTS ARE PREDICTED TO BE BELOW HAZARDOUS THRESHOLDS. ON FEB 19-20, A MUCH  
LARGER PRECIPITATION SHIELD (2-3 INCHES, PRIMARILY RAIN) IS ANTICIPATED TO  
DEVELOP ACROSS THE EAST-CENTRAL CONUS. THIS IS IN RESPONSE TO THE EXPECTED  
AMPLIFICATION OF THE MID-LEVEL TROUGH WEST OF THAT AREA, AND THE DOWNSTREAM  
RIDGE OVER THE SOUTHEAST. WITH INCREASED LOW-LEVEL GULF INFLOW, STRONG  
THUNDERSTORMS ARE ALSO A POSSIBILITY, THOUGH AT THIS TIME, THE STORM PREDICTION  
CENTER DOES NOT DEPICT A SEVERE THREAT FOR THE REGION. AT THE END OF THIS  
PERIOD, FEB 21, AN ELONGATED BAND OF WINTRY PRECIPITATION IS FORECAST FROM THE  
MIDDLE MISSISSIPPI VALLEY NORTHEASTWARD ACROSS THE SOUTHERN GREAT LAKES AND THE  
NORTHEAST. FLOODING IS LIKELY, IMMINENT OR ONGOING FOR PORTIONS OF THE OHIO AND  
TENNESSEE VALLEYS, AND THE LOWER MISSISSIPPI VALLEY, NEAR THE MEAN FRONTAL  
BOUNDARY WHERE RAINFALL IS LIKELY TO BE FOCUSED.  
 
CANADIAN HIGH PRESSURE IS EXPECTED TO SINK SOUTHWARD ACROSS THE NORTHERN AND  
CENTRAL PLAINS, USHERING IN UNSEASONABLY COLD AIR ON BLUSTERY WINDS. WIND  
SPEEDS OF 30 KNOTS ARE PREDICTED ON FEB 18-19, WHILE TEMPERATURES ARE EXPECTED  
TO RANGE FROM 12 TO 30 DEGREES BELOW NORMAL FROM FEB 19-21.  
 
FRONTAL ACTIVITY ACROSS THE NORTHWESTERN CONUS IS EXPECTED TO BRING HEAVY  
SNOWFALL (1.5 INCH LIQUID EQUIVALENT) TO THE CASCADES AND BITTERROOT MOUNTAIN  
RANGES, FEB 17-18. FARTHER SOUTH, STRONG NORTHERLY WIND SPEEDS OF 30 KNOTS ARE  
ANTICIPATED ALONG THE CALIFORNIA COAST, FEB 19-20.  
 
IN NORTHERN ALASKA, TEMPERATURES ARE FORECAST TO RANGE FROM 25-35 DEGREES ABOVE  
NORMAL, FEB 18-21, ASSOCIATED WITH MILD SOUTHERLY FLOW AND DOWNSLOPE WINDS OFF  
THE BROOKS RANGE. MUCH OF THE STATE (WITH THE EXCEPTION OF THE SOUTHEAST  
MAINLAND AND THE PANHANDLE REGION) IS PREDICTED TO EXPERIENCE WARMER THAN  
NORMAL TEMPERATURES DURING THIS PERIOD.  
 
FOR THURSDAY FEBRUARY 22 - WEDNESDAY FEBRUARY 28: A SLIGHT WESTWARD SHIFT IN  
THE MID-LEVEL FLOW PATTERN IS FORECAST DURING WEEK-2 ACROSS NORTH AMERICA. A  
SLIGHT RISK OF MUCH ABOVE NORMAL TEMPERATURES IS INDICATED FOR MUCH OF ALASKA  
(EXCLUDING THE SOUTHEAST MAINLAND AND THE PANHANDLE REGION), FEB 22-28. MUCH OF  
THIS AREA ALSO FALLS UNDER A MODERATE RISK OF MUCH ABOVE NORMAL TEMPERATURES,  
FEB 22-24. IN SHARP CONTRAST, THERE IS A SLIGHT RISK OF MUCH BELOW NORMAL  
TEMPERATURES ACROSS MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS, FEB 22-28,  
ASSOCIATED WITH A MID-LEVEL TROUGH. MODERATE AND HIGH RISK AREAS CONSTITUTE  
SIGNIFICANT SUBSETS OF THIS REGION, FEB 22-24. ACROSS EAST-CENTRAL PORTIONS OF  
THE LOWER 48 STATES, THERE IS A SLIGHT RISK OF HEAVY PRECIPITATION FROM FAR  
EASTERN TEXAS EASTWARD AND NORTHEASTWARD ACROSS THE LOWER AND MIDDLE  
MISSISSIPPI VALLEY, THE SOUTHERN OHIO AND TENNESSEE VALLEYS, AND THE SOUTHERN  
APPALACHIANS, FEB 22-24. AN EMBEDDED MODERATE RISK AREA IS ALSO PREDICTED,  
WHICH COVERS A LARGE FRACTION OF THIS SAME REGION, FEB 22-24. THE GEFS  
REFORECAST SOLUTION FAVORS THE WESTERN PORTIONS OF THIS HEAVY PRECIPITATION  
AREA, WHILE THE ECMWF ENSEMBLE SOLUTION FAVORS THE EASTERN PORTIONS. THIS  
REGION IS ALSO IN ADVANCE OF THE PREDICTED LOCATION OF THE MID-LEVEL TROUGH  
OVER THE WESTERN CONUS.  
 
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: ANTHONY ARTUSA  
 

 
 
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