280  
FXUS06 KWBC 122050  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST FRI JANUARY 12 2018  
 
6-10 DAY OUTLOOK FOR JAN 18 - 22 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA  
FLOW PATTERN OVER THE FORECAST DOMAIN. A TROUGH IS EXPECTED OVER THE GULF OF  
ALASKA AND A RIDGE IS FORECAST OVER THE WESTERN NORTH AMERICA. A TROUGH IS  
FORECAST TO EXIT THE EASTERN CONUS DURING THE PERIOD. ABOVE NORMAL 500-HPA  
HEIGHTS ARE PREDICTED OVER THE EASTERN CONUS, WHILE BELOW NORMAL 500-HPA  
HEIGHTS ARE FORECAST FOR MUCH OF THE CENTRAL AND WESTERN CONUS.  
 
ABOVE NORMAL HEIGHTS FORECAST OVER MUCH OF MAINLAND ALASKA, AND RIDGING OVER  
NORTHWESTERN NORTH AMERICA, LEADS TO INCREASED CHANCES OF ABOVE NORMAL  
TEMPERATURES FOR MUCH OF THE CENTRAL CONUS AS WELL AS THE MAINLAND ALASKA.  
BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE WEST COAST DUE TO THE PACIFIC  
TROUGH CLOSER. BELOW NORMAL TEMPERATURES ARE ALSO FAVORED FOR THE SOUTHERN  
ATLANTIC COAST STATES, BEHIND A TROUGH MOVING OUT EARLY IN THE PERIOD.  
 
OFFSHORE FLOW AT THE SURFACE INCREASES CHANCES OF BELOW NORMAL PRECIPITATION  
OVER SOUTHERN ALASKA AND THE ALASKA PANHANDLE, WHILE ABOVE NORMAL PRECIPITATION  
IS FORECAST OVER NORTHWESTERN ALASKA. ABOVE NORMAL PRECIPITATION IS FAVORED FOR  
THE WESTERN CONUS, THE MISSISSIPPI VALLEY, THE GREAT LAKES REGION, OHIO AND  
TENNESSEE VALLEYS, AND THE NORTHEAST, DUE TO PREDICTED FRONTAL ACTIVITY AND  
SOUTHWESTERLY SURFACE FLOW. ENHANCED PROBABILITIES OF BELOW NORMAL  
PRECIPITATION ACROSS THE SOUTHERN PLAINS, AND THE SOUTHERN ATLANTIC COAST  
STATES ARE CONSISTENT WITH PREDICTIONS FROM THE ECMWF AND GEFS CALIBRATED  
REFORECAST TOOLS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 20% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 20% OF TODAY'S 0Z  
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
REASONABLY GOOD AGREEMENT AMONG MOST MODELS AND TOOLS.  
 
8-14 DAY OUTLOOK FOR JAN 20 - 26 2018  
 
DURING WEEK-2, MODELS ARE IN FAIRLY GOOD AGREEMENT, AND THEY PREDICT THAT THE  
TROUGH OVER THE EAST PACIFIC IS LIKELY TO MOVE CLOSER TO THE WEST COAST. THE  
TROUGH PREDICTED OVER THE EASTERN CONUS IS FORECAST TO MOVE OFFSHORE OF THE  
EAST COAST DURING WEEK-2, WITH RAPIDLY RISING MID-TROPOSPHERIC HEIGHTS AND  
POSITIVE ANOMALOUS HEIGHTS OVER THIS REGION, WHILE NEGATIVE ANOMALOUS HEIGHTS  
MOVE INTO THE CENTRAL AND WESTERN CONUS.  
 
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE CENTRAL AND EASTERN CONUS  
DURING THE WEEK-2 PERIOD, ASSOCIATED WITH POSITIVE ANOMALOUS HEIGHTS. BELOW  
NORMAL TEMPERATURES ARE FAVORED FOR THE WESTERN CONUS, SOUTHERN ALASKA, AND THE  
ALASKA PANHANDLE, DUE TO THE NEGATIVE ANOMALOUS HEIGHTS FORECAST OVER THE  
WESTERN CONUS.  
 
FOR THE WEEK-2 PRECIPITATION OUTLOOK, BELOW NORMAL PRECIPITATION IS FAVORED  
OVER ALASKA, AS THE ANOMALOUS TROUGH PROGRESSES TO THE WESTERN COAST OF NORTH  
AMERICA. TROUGHING OVER THE WEST COAST AND ENHANCED PACIFIC FLOW SUPPORT STORM  
ACTIVITY FROM THE WESTERN CONUS TO THE GREAT LAKES, THE MISSISSIPPI VALLEY, THE  
OHIO AND THE TENNESSEE VALLEYS AND NORTHEAST, WHERE NEAR TO ABOVE NORMAL  
PRECIPITATION IS FAVORED. BELOW NORMAL PRECIPITATION IS LIKELY FOR PARTS OF THE  
SOUTHERN PLAINS, AND THE SOUTHERN ATLANTIC COAST, CONSISTENT WITH PREDICTION  
FROM THE ECMWF AND GEFS REFORECAST TOOLS.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 20% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 20% OF TODAY'S 0Z  
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR AVERAGE, 3 OUT OF 5, DUE TO  
REASONABLE OVERALL MODEL AND TOOL AGREEMENT, BUT OFFSET BY THE UNCERTAINTY  
INHERENT IN A TRANSITIONING CIRCULATION PATTERN.  
 
FORECASTER: QIN Z  
 
NOTES:  
 
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL  
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES. IN  
THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT ISSUED.  
 
THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS THE SAME AS  
THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW  
 
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER (ORANGE,  
"A"), COLDER (BLUE, "B"), OR CLOSE TO (UNSHADED, "N"). HISTORICAL AVERAGE  
VALUES FOR THE CALENDAR PERIOD OF THE FORECAST (DASHES, "F"). LABELS ON THE  
SHADED LINES GIVE THE PROBABILITY (> 33%) OF THE MORE LIKELY CATEGORY (B OR A).  
PROBABILITY OF N IS ALWAYS < 40%.  
 
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WETTER (GREEN,  
"A"), DRIER (TAN, "B"), OR CLOSE TO (UNSHADED, "N"). HISTORICAL MEDIAN VALUES  
FOR THE CALENDAR PERIOD OF THE FORECAST (DASHES, "INCHES"). LABELS ON THE  
SHADED LINES GIVE THE PROBABILITY (> 33%) OF THE MORE LIKELY CATEGORY (B OR A).  
PROBABILITY OF N IS ALWAYS < 40%.  
 
IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL BE A  
GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY EVEN A NORMAL  
(I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY SEASONS. IN SUCH CASES  
A FORECAST OF NEAR NORMAL IS EFFECTIVELY A FORECAST OF LITTLE OR NO  
PRECIPITATION.  
 
THE CLIMATE PREDICTION CENTER USES 1981-2010 BASE PERIOD MEANS FOR  
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN THE CLIMATE  
OUTLOOKS.  
 
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON  
JANUARY 18.  
 
ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3)  
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE  
INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES:  
19530116 - 19960117 - 19650124 - 19841230 - 19880110  
 
ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4)  
FOR THE REGION FROM 20N TO 70N LATITUDE AND 175E TO 60W LONGITUDE  
INCLUDE THE 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES:  
19530116 - 19650123 - 19821225 - 19841230 - 20071223  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 18 - 22 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON N A OREGON B A NRN CALIF B A  
SRN CALIF N A IDAHO N A NEVADA N A  
W MONTANA N A E MONTANA N A WYOMING N A  
UTAH A A ARIZONA A N COLORADO A A  
NEW MEXICO A B N DAKOTA A A S DAKOTA A A  
NEBRASKA A A KANSAS A N OKLAHOMA A B  
N TEXAS A B S TEXAS A B W TEXAS A B  
MINNESOTA A A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA N N WISCONSIN A A  
ILLINOIS A A MISSISSIPPI N N MICHIGAN A A  
INDIANA A A OHIO N A KENTUCKY N A  
TENNESSEE N A ALABAMA N N NEW YORK A A  
VERMONT A A NEW HAMP A A MAINE A A  
MASS A A CONN N A RHODE IS N A  
PENN N A NEW JERSEY N A W VIRGINIA N A  
MARYLAND N A DELAWARE N N VIRGINIA N A  
N CAROLINA B B S CAROLINA B B GEORGIA B B  
FL PNHDL B B FL PENIN B B AK N SLOPE A N  
AK ALEUTIAN N A AK WESTERN A A AK INT BSN A N  
AK S INT N B AK SO COAST N B AK PNHDL B B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 20 - 26 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON B A NRN CALIF B A  
SRN CALIF B A IDAHO B A NEVADA B A  
W MONTANA B N E MONTANA B N WYOMING B A  
UTAH B A ARIZONA B A COLORADO N A  
NEW MEXICO A A N DAKOTA N A S DAKOTA N A  
NEBRASKA A A KANSAS A A OKLAHOMA A A  
N TEXAS A A S TEXAS A B W TEXAS A B  
MINNESOTA N A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN A A  
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A  
INDIANA A A OHIO A A KENTUCKY A A  
TENNESSEE A A ALABAMA A A NEW YORK A A  
VERMONT A A NEW HAMP A A MAINE A A  
MASS A A CONN A A RHODE IS A A  
PENN A A NEW JERSEY A A W VIRGINIA A A  
MARYLAND A A DELAWARE A A VIRGINIA A A  
N CAROLINA A A S CAROLINA A N GEORGIA A N  
FL PNHDL A B FL PENIN A B AK N SLOPE N N  
AK ALEUTIAN A B AK WESTERN A B AK INT BSN N B  
AK S INT B B AK SO COAST B B AK PNHDL B B  
 
LEGEND  
TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN  
A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN  
B - BELOW B - BELOW  
 
THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL  
VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE  
AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE.  
 
FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS  
PMDMRD.  
 

 
 
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