524  
FXUS21 KWNC 232058  
PMDTHR  
US HAZARDS OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
300 PM EST JANUARY 23 2018  
 
SYNOPSIS: AT THE BEGINNING OF THE HAZARDS OUTLOOK PERIOD, A FRONTAL SYSTEM IS  
PREDICTED ACROSS THE CENTRAL CONUS. THIS SYSTEM IS EXPECTED TO REACH THE EAST  
COAST LATE IN THE 3-7 DAY PERIOD, AS ANOTHER FRONTAL SYSTEM MOVES ACROSS THE  
WESTERN CONUS. IN THE ALASKA DOMAIN, PERSISTENT SURFACE LOW PRESSURE IS  
FORECAST OVER THE NORTHERN GULF OF ALASKA AND APPROXIMATELY THE SOUTHERN THIRD  
OF THE 49TH STATE, WITH SURFACE HIGH PRESSURE EXPECTED OVER THE CENTRAL AND  
NORTHERN THIRDS OF ALASKA. DURING THE WEEK-2 PERIOD, UNSEASONABLY COLD AIR IS  
ANTICIPATED TO OVERSPREAD THE ALASKA PANHANDLE AND THE NORTH-CENTRAL CONUS,  
WHILE THE BEST CHANCES FOR HAZARDOUS PRECIPITATION IS OVER MUCH OF THE  
SOUTHEASTERN QUARTER OF THE LOWER 48 STATES.  
 
HAZARDS  
 
HEAVY RAIN FOR THE CENTRAL GULF COAST REGION, FRI-SAT, JAN 26-27.  
 
HEAVY RAIN OVER THE ATLANTIC COAST STATES, SUN-MON, JAN 28-29.  
 
PERIODS OF HEAVY PRECIPITATION (MOUNTAIN SNOW AND VALLEY RAIN) FOR THE PACIFIC  
NORTHWEST, FRI-MON, JAN 26-29.  
 
FLOODING POSSIBLE IN LOWER MICHIGAN AND PARTS OF THE MIDWEST.  
 
MUCH BELOW NORMAL TEMPERATURES FOR SOUTHWESTERN MAINLAND ALASKA AND ADJACENT  
PARTS OF THE ALASKA PENINSULA, FRI, JAN 26.  
 
SLIGHT RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE, AND  
FROM WASHINGTON AND NORTHERN IDAHO EASTWARD ACROSS THE NORTHERN PLAINS TO THE  
UPPER MISSISSIPPI VALLEY, WED-TUE, JAN 31-FEB 6.  
 
MODERATE RISK OF MUCH BELOW NORMAL TEMPERATURES FOR THE SOUTHERN ALASKA  
PANHANDLE, AND ALONG THE NORTHERN TIER OF STATES FROM WASHINGTON TO MINNESOTA  
(INCLUDING SOUTH DAKOTA), SAT-MON, FEB 3-5.  
 
SLIGHT RISK OF HEAVY PRECIPITATION FROM EASTERN KANSAS AND EASTERN OKLAHOMA  
SOUTHEASTWARD ACROSS THE LOWER MISSISSIPPI AND LOWER TENNESSEE VALLEYS TO THE  
CENTRAL AND EASTERN GULF COAST, WED-FRI, JAN 31-FEB 2.  
 
MODERATE RISK OF HEAVY PRECIPITATION FOR MUCH OF ARKANSAS, SOUTHWESTERN  
MISSOURI, EASTERN OKLAHOMA, AND NEARBY PARTS OF KANSAS, WED-FRI, JAN 31-FEB 2.  
 
MODERATE RISK OF HEAVY PRECIPITATION FOR THE EAST-CENTRAL GULF COAST REGION,  
WED-FRI, JAN 31-FEB 2.  
 
SEVERE DROUGHT FOR PARTS OF THE GREAT PLAINS, SOUTHWEST, MIDDLE AND LOWER  
MISSISSIPPI VALLEY, AND SOUTHEAST.  
 
DETAILED SUMMARY  
 
FOR FRIDAY JANUARY 26 - TUESDAY JANUARY 30: SURFACE HIGH PRESSURE INITIALLY  
CENTERED OVER THE ATLANTIC COAST STATES IS PREDICTED TO GRADUALLY GIVE WAY TO A  
FRONTAL SYSTEM APPROACHING FROM THE WEST. INCREASINGLY MOIST SOUTHERLY FLOW  
IN-BETWEEN THESE TWO SYSTEMS IS EXPECTED TO RESULT IN HEAVY RAIN (2.0-3.5  
INCHES) OVER THE CENTRAL GULF COAST AREA, JAN 26-27. OVER THE ENSUING TWO-DAY  
PERIOD, WITH THE EASTWARD ADVANCE OF THE FRONTAL SYSTEM, HEAVY RAIN (1.5-3.0  
INCHES, JAN 28-29) IS PREDICTED TO SPREAD NORTHWARD ACROSS THE EAST COAST  
STATES, WITH THE HEAVIEST RAINFALL AMOUNTS EXPECTED TO BE IN THE NORTHEAST.  
 
IN THE PACIFIC NORTHWEST, PERIODS OF HEAVY PRECIPITATION (MOUNTAIN SNOW AND  
VALLEY RAIN) ARE ANTICIPATED FROM JAN 26-29, ASSOCIATED WITH THE PASSAGE OF TWO  
CYCLONIC SYSTEMS. DURING THE FIRST TWO DAYS, LIQUID EQUIVALENT PRECIPITATION  
AMOUNTS ARE FORECAST TO RANGE FROM 2.5-5.5 INCHES, FOLLOWED BY AN ADDITIONAL  
3.0-4.0 INCHES DURING THE SUBSEQUENT TWO-DAY PERIOD.  
 
FLOODING IS POSSIBLE IN PARTS OF LOWER MICHIGAN, SOUTHERN WISCONSIN AND  
ADJACENT PARTS OF NORTHERN ILLINOIS, AND NORTHEASTERN IOWA. THE PRIMARY REASON  
IS DUE TO THE EXPECTATION OF HEAVY RAIN ON FROZEN GROUND. FOR NORTHEASTERN  
IOWA, THERE ARE ADDITIONAL FACTORS TO CONSIDER, SUCH AS SNOW MELT AND ICE JAMS.  
 
IN SOUTHWESTERN MAINLAND ALASKA AND ADJACENT PORTIONS OF THE ALASKA PENINSULA,  
DAILY TEMPERATURES ARE EXPECTED TO BE 20 DEGREES F (OR GREATER) BELOW NORMAL  
FOR THIS TIME OF YEAR (JAN 26).  
 
FOR WEDNESDAY JANUARY 31 - TUESDAY FEBRUARY 06: AS A SURFACE RIDGE OF HIGH  
PRESSURE BREAKS DOWN ACROSS THE GULF COAST REGION, MOIST AND UNSTABLE AIR WILL  
BE ABLE TO MOVE NORTHWARD AND INTERACT WITH A COLD FRONT PREDICTED TO APPROACH  
THE REGION FROM THE WEST. A SLIGHT RISK OF HEAVY PRECIPITATION IS INDICATED  
FROM EASTERN KANSAS AND EASTERN OKLAHOMA SOUTHEASTWARD ACROSS THE LOWER  
MISSISSIPPI AND LOWER TENNESSEE VALLEYS TO THE CENTRAL AND EASTERN GULF COAST,  
JAN 31-FEB 2. EMBEDDED WITHIN THIS RISK AREA ARE TWO AREAS OF MODERATE  
CONFIDENCE FOR HEAVY PRECIPITATION, ONE OVER AND NEAR THE SOUTH-CENTRAL  
MISSISSIPPI VALLEY (BASED ON THE GEFS GUIDANCE), AND ONE OVER THE CENTRAL GULF  
COAST AREA (BASED ON THE EUROPEAN ENSEMBLE GUIDANCE). TELECONNECTIONS USING THE  
CURRENT ENHANCED PHASE OF THE MJO ALSO LEND SUPPORT FOR THE PREDICTION OF A  
POTENTIAL HEAVY PRECIPITATION HAZARD DURING WEEK-2.  
 
ANOMALOUSLY COLD AIR IS FAVORED TO OVERSPREAD THE ALASKA PANHANDLE DURING  
WEEK-2, AND FROM WASHINGTON AND NORTHERN IDAHO EASTWARD ACROSS THE NORTHERN  
PLAINS AND UPPER MISSISSIPPI VALLEY. THEREFORE, A SLIGHT AND MODERATE RISK OF  
MUCH BELOW NORMAL TEMPERATURES WERE INTRODUCED FOR THESE AREAS. THIS PREDICTED  
HAZARD IS BASED PRIMARILY ON THE PROBABILISTIC EXTREMES OUTLOOK (PEO) TOOL AND  
THE GEFS REFORECAST TEMPERATURE TOOL, AND IS CONSISTENT WITH CPC'S PREDICTED  
WEEK-2 500-HPA CIRCULATION PATTERN.  
 
RECENT DETERMINISTIC MODEL RUNS PREDICT AN ARCTIC FRONT WILL SWEEP  
SOUTHEASTWARD ACROSS THE CONUS EAST OF THE ROCKIES, AND INTRODUCE THE POTENTIAL  
FOR WINTRY PRECIPITATION OVER THE EAST-CENTRAL CONUS. IT IS TOO EARLY AT THIS  
TIME TO SPECIFY DETAILS.  
 
 
 
THE U.S. DROUGHT MONITOR, VALID ON JANUARY 16, 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: ANTHONY ARTUSA  
 

 
 
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