800  
FXUS21 KWNC 182032  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST JANUARY 18 2018  
 
SYNOPSIS: SURFACE LOW PRESSURE OVER THE CENTRAL PLAINS ON JAN 21 IS FORECAST TO  
DEEPEN AND MOVE TO THE UPPER MISSISSIPPI VALLEY JAN 22, AND THEN INTO EASTERN  
CANADA LATE ON JAN 23. A SERIES OF AREAS OF LOW PRESSURE AT THE SURFACE AND  
MID-LEVELS IS FORECAST TO CROSS THE NORTHWEST U.S. JAN 21-24. AREAS OF SURFACE  
LOW PRESSURE ARE ANTICIPATED OVER THE GULF OF ALASKA WHILE SURFACE HIGH  
PRESSURE BUILDS OVER WESTERN PORTIONS OF THE STATE. DURING WEEK-2, MID-LEVEL  
LOW PRESSURE IS ANTICIPATED OVER THE CENTRAL U.S. AND MAINLAND ALASKA.  
 
HAZARDS  
 
PERIODS OF HEAVY PRECIPITATION ACROSS PORTIONS OF THE GREAT BASIN, THE NORTHERN  
ROCKIES, CALIFORNIA, AND THE PACIFIC NORTHWEST, SUN-TUE, JAN 21-JAN 23.  
 
HEAVY SNOW FOR PARTS OF THE CASCADES AND BITTERROOTS, WED, JAN 24.  
 
PERIODS OF HIGH WINDS ACROSS COASTAL PORTIONS OF THE PACIFIC NORTHWEST AND  
NORTHERN CALIFORNIA, SUN-TUE, JAN 21-23.  
 
HIGH SIGNIFICANT WAVE HEIGHTS FOR COASTAL PORTIONS OF NORTHERN CALIFORNIA AND  
THE PACIFIC NORTHWEST, SUN, JAN 21.  
 
HIGH WINDS ACROSS PORTIONS OF THE CENTRAL AND SOUTHERN PLAINS, THE CENTRAL AND  
SOUTHERN ROCKIES, AND THE SOUTHWEST, SUN, JAN 21.  
 
HEAVY SNOW ACROSS PORTIONS OF THE NORTHERN AND CENTRAL PLAINS, THE UPPER AND  
MIDDLE MISSISSIPPI VALLEYS, AND THE GREAT LAKES, SUN-MON, JAN 21-22.  
 
HEAVY PRECIPITATION ACROSS PORTIONS OF THE NORTHEAST AND THE GREAT LAKES,  
MON-TUE, JAN 22-JAN 23.  
 
HIGH WINDS ACROSS COASTAL PORTIONS OF THE MID-ATLANTIC AND THE NORTHEAST,  
TUE-WED, JAN 23-JAN 24.  
 
PERIODS OF HIGH WINDS ACROSS PORTIONS OF THE SOUTH COAST OF ALASKA, THE ALASKA  
PENINSULA, AND KODIAK ISLAND, SUN-THU, JAN 21-JAN 25.  
 
MUCH BELOW NORMAL TEMPERATURES ACROSS PORTIONS OF MAINLAND ALASKA AND THE  
ALASKA PENINSULA, SUN-THU, JAN 21-JAN 25.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PORTIONS OF SOUTHERN MAINLAND  
ALASKA, THE ALASKA PENINSULA, AND THE EASTERN ALEUTIANS, FRI-MON, JAN 26-29.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHWESTERN  
MAINLAND ALASKA AND THE ALASKA PENINSULA, FRI-MON, JAN 26-29.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE NORTHEAST, SAT-SUN, JAN  
27-JAN 28.  
 
MODERATE RISK OF HEAVY PRECIPITATION FOR COASTAL PORTIONS OF THE NORTHEAST,  
SAT-SUN, JAN 27-28.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE LOWER MISSISSIPPI AND  
TENNESSEE VALLEYS, SOUTHEAST, SOUTHERN APPALACHIANS, AND MID-ATLANTIC, FRI-TUE,  
JAN 26-30.  
 
SEVERE DROUGHT FOR PARTS OF THE GREAT PLAINS, THE SOUTHWEST, THE CENTRAL AND  
SOUTHERN MISSISSIPPI VALLEY, THE SOUTHEAST, AND HAWAII.  
 
DETAILED SUMMARY  
 
FOR SUNDAY JANUARY 21 - THURSDAY JANUARY 25: LOW PRESSURE OVER THE CENTRAL  
PLAINS ON JAN 21 IS EXPECTED TO DEEPEN AND MOVE TOWARDS THE UPPER MISSISSIPPI  
VALLEY BEFORE MOVING INTO EASTERN CANADA LATE ON JAN 23. THIS LEADS TO HIGH  
WINDS (SPEEDS IN EXCESS OF 30 KNOTS) FOR PORTIONS OF THE CENTRAL AND SOUTHERN  
PLAINS, CENTRAL AND SOUTHERN ROCKIES, AND THE SOUTHWEST JAN 21, AND HEAVY SNOW  
(AMOUNTS IN EXCESS OF 6 INCHES IN 24 HOURS) FOR PARTS OF THE NORTHERN AND  
CENTRAL PLAINS, THE UPPER AND MIDDLE MISSISSIPPI VALLEYS, AND THE GREAT LAKES  
JAN 21-22. MARGINALLY ELEVATED FIRE WEATHER CONDITIONS, THOUGH NOT DEPICTED ON  
THE MAP, ARE ALSO FORECAST ACROSS PORTIONS OF WEST-CENTRAL TEXAS ON JAN 21 DUE  
TO THE POTENTIAL FOR DRY AND BREEZY CONDITIONS. AS THE LOW DEEPENS AND MOVES  
NORTHEASTWARD, HEAVY PRECIPITATION (RAINFALL IN EXCESS OF 1 INCH IN 24 HOURS,  
FROZEN PRECIPITATION ON THE NORTHWEST PERIPHERY) IS ANTICIPATED FOR PORTIONS OF  
THE NORTHEAST AND THE GREAT LAKES JAN 22-23, AND HIGH WINDS (SPEEDS IN EXCESS  
OF 30 KNOTS) FOR COASTAL PORTIONS OF THE MID-ATLANTIC AND THE NORTHEAST JAN  
23-24. THE RAINFALL IN COMBINATION WITH SNOW MELT LEADS TO FLOODING CONCERNS  
FOR PARTS OF THE NORTHEAST.  
 
A SERIES OF LOW PRESSURE SYSTEMS ARE FORECAST TO MOVE ACROSS THE NORTHWEST  
CONUS JAN 21-24. PERIODS OF HEAVY PRECIPITATION (LOW ELEVATION RAIN EXCEEDING 2  
INCHES IN 24 HOURS, HIGHER ELEVATION SNOW EXCEEDING 8 INCHES IN 24 HOURS) ARE  
EXPECTED ACROSS PORTIONS OF THE GREAT BASIN, THE NORTHERN ROCKIES, CALIFORNIA,  
AND THE PACIFIC NORTHWEST JAN 21-23. PERIODS OF HIGH WINDS (SPEEDS IN EXCESS OF  
30 KNOTS) ARE ANTICIPATED ACROSS COASTAL PORTIONS OF THE PACIFIC NORTHWEST AND  
NORTHERN CALIFORNIA JAN 21-23. HIGH SIGNIFICANT WAVE HEIGHTS (HEIGHTS IN EXCESS  
OF 20 FEET) ARE FORECAST FOR COASTAL PORTIONS OF NORTHERN CALIFORNIA AND THE  
PACIFIC NORTHWEST JAN 21. HEAVY SNOW (AMOUNTS IN EXCESS OF 6 INCHES IN 24  
HOURS) IS EXPECTED FOR PARTS OF THE CASCADES AND BITTERROOTS JAN 24.  
 
AREAS OF SURFACE LOW PRESSURE LEAD TO PERIODS OF HIGH WINDS (SPEEDS IN EXCESS  
OF 40 KNOTS) ACROSS PORTIONS OF THE SOUTH COAST OF ALASKA, THE ALASKA  
PENINSULA, AND KODIAK ISLAND JAN 21-25. HIGH PRESSURE BUILDING OVER THE WESTERN  
PART OF THE STATE IS EXPECTED TO CAUSE MUCH BELOW NORMAL TEMPERATURES (NEGATIVE  
TEMPERATURE ANOMALIES EXCEEDING 20 DEGREES F) ACROSS PORTIONS OF MAINLAND  
ALASKA AND THE ALASKA PENINSULA JAN 21-25.  
 
FOR FRIDAY JANUARY 26 - THURSDAY FEBRUARY 01: MID-LEVEL TROUGHING OVER THE  
CENTRAL CONUS, AND MOIST INFLOW FROM THE GULF OF MEXICO AND ATLANTIC, LEAD TO A  
SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE NORTHEAST, AND A  
MODERATE RISK OF HEAVY PRECIPITATION FOR COASTAL PORTIONS OF THE NORTHEAST JAN  
27-28. THERE IS ALSO A SLIGHT RISK OF HEAVY PRECIPITATION FOR PORTIONS OF THE  
LOWER MISSISSIPPI AND TENNESSEE VALLEYS, SOUTHEAST, SOUTHERN APPALACHIANS, AND  
MID-ATLANTIC JAN 26-30.  
 
UPPER-LEVEL LOW PRESSURE AND ANOMALOUS NORTHEAST SURFACE FLOW ARE FORECAST OVER  
ALASKA FOR MUCH OF THE PERIOD. THERE IS A SLIGHT RISK OF MUCH BELOW NORMAL  
TEMPERATURES FOR PORTIONS OF SOUTHERN MAINLAND ALASKA, THE ALASKA PENINSULA,  
AND THE EASTERN ALEUTIANS, AND A MODERATE RISK OF MUCH BELOW NORMAL  
TEMPERATURES FOR PARTS OF SOUTHWESTERN MAINLAND ALASKA AND THE ALASKA  
PENINSULA, JAN 26-29.  
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 9, 2018 INDICATES AN INCREASE IN THE  
COVERAGE OF SEVERE TO EXCEPTIONAL DROUGHT (D2-D4) FROM 8.70% LAST WEEK TO  
10.03% THIS WEEK. SEVERE DROUGHT CONTINUED TO EXPAND ACROSS THE SOUTHERN GREAT  
PLAINS WITH NEARLY HALF OF OKLAHOMA DESIGNATED WITH SEVERE DROUGHT.  
 
FORECASTER: RANDY SCHECHTER  
 

 
 
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