414  
FXUS06 KWBC 192001  
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 19 2018  
 
6-10 DAY OUTLOOK FOR JAN 25 - 29 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED  
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. ALL OF TODAY'S MODEL SOLUTIONS  
FORECAST A RIDGE OVER THE WESTERN ALEUTIANS AND TROUGH OVER MUCH OF MAINLAND  
ALASKA. WEAK RIDGING IS EXPECTED FARTHER TO THE EAST OVER WESTERN CANADA AND TO  
THE SOUTH OFF THE COAST OF CALIFORNIA. A BROAD TROUGH IS PREDICTED OVER THE  
WEST-CENTRAL CONUS. TODAY'S MANUAL 500-HPA BLEND IS BASED PRIMARILY ON THE  
ENSEMBLE MEANS FROM THE CANADIAN, EUROPEAN, AND GEFS MODEL SUITES. THE  
RESULTANT MANUAL BLEND DEPICTS BELOW NORMAL HEIGHTS OVER SOUTHERN MAINLAND  
ALASKA, THE ALASKA PANHANDLE, AND MOST OF THE WESTERN CONUS. ABOVE NORMAL  
HEIGHTS ARE EXPECTED FOR MUCH OF THE EASTERN CONUS, CALIFORNIA, AS WELL AS  
NORTHERN ALASKA AND THE ALEUTIANS.  
 
THE TROUGH OVER MAINLAND ALASKA LEADS TO ENHANCED PROBABILITIES OF BELOW NORMAL  
TEMPERATURES ACROSS ALASKA. BELOW NORMAL TEMPERATURES ARE ALSO FAVORED ACROSS  
THE WESTERN CONUS UNDERNEATH CYCLONIC FLOW AND NEAR TO BELOW NORMAL HEIGHTS.  
RIDGING AND ABOVE NORMAL HEIGHTS TO THE EAST OF THIS TROUGH FAVOR ABOVE NORMAL  
TEMPERATURES FOR MUCH OF THE EASTERN CONUS.  
 
THE POTENTIAL FOR SHORTWAVE TROUGHS TO MOVE INTO THE WESTERN CONUS FROM THE  
PACIFIC LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION ACROSS  
MUCH OF THE NORTHWESTERN CONUS EXTENDING EASTWARD TO THE NORTHERN AND CENTRAL  
PLAINS. MOIST FLOW AHEAD OF THE LONGWAVE TROUGH OVER THE WEST-CENTRAL CONUS  
FAVORS ABOVE NORMAL PRECIPITATION FOR MUCH OF THE EASTERN CONUS. BELOW NORMAL  
PRECIPITATION IS LIKELY FOR MUCH OF ALASKA UNDERNEATH NORTHEASTERLY LOW LEVEL  
FLOW. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE SOUTHWESTERN CONUS  
CONSISTENT WITH DYNAMICAL MODEL GUIDANCE FROM THE GEFS AND ECMWF ENSEMBLES AS  
WELL AS ANALOGS FROM THE MANUAL BLEND.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 5% OF TODAY'S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 25% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 7, 10% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED  
ON DAY 8, 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 5% OF  
YESTERDAY'S 12Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 7  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY  
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFFSET BY POOR AGREEMENT AMONG  
THE SURFACE TOOLS.  
 
8-14 DAY OUTLOOK FOR JAN 27 - FEB 02, 2018  
 
THE MEAN 500-HPA PATTERN EXPECTED FOR THE WEEK-2 PERIOD IS SIMILAR TO THAT  
DEPICTED FOR THE 6 TO 10 DAY TIME FRAME. A TROUGH IS FORECAST OVER MAINLAND  
ALASKA WITH RIDGE PREDICTED TO THE WEST THIS FEATURE NEAR THE ALEUTIANS.  
FARTHER TO THE SOUTH, RIDGING IS FORECAST OFF THE WEST COAST OF THE CONUS WHILE  
A TROUGH IS FORECAST OVER PARTS OF THE CENTRAL CONUS. A RIDGE IS EXPECTED OVER  
THE CARIBBEAN EXTENDING TO PARTS OF THE SOUTHEASTERN CONUS.  
 
THE TEMPERATURE PROBABILITY FORECAST FOR THE WEEK-2 PERIOD IS SIMILAR TO THE  
6-10 DAY PERIOD. THE TROUGH OVER ALASKA LEADS TO ENHANCED PROBABILITIES FOR  
BELOW NORMAL TEMPERATURES ACROSS MOST OF THE STATE. ABOVE NORMAL HEIGHTS  
ENHANCE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ACROSS MUCH OF THE EASTERN  
CONUS. NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN  
AND CENTRAL CONUS. HOWEVER, PROBABILITIES ARE REDUCED RELATIVE TO THE 6 TO 10  
DAY TIME PERIOD DUE TO INCREASED MODEL UNCERTAINTY DURING WEEK-2.  
 
THE PRECIPITATION PROBABILITY FORECAST FOR THE WEEK-2PERIOD IS ALSO SIMILAR TO  
THE 6-10 DAY PERIOD. A STRONGER LOW LEVEL FLOW FROM THE GULF OF MEXICO  
INCREASES PROBABILITIES OF ABOVE NORMAL PRECIPITATION IN PARTS OF THE EASTERN  
CONUS.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 30% OF TODAY'S  
0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 5% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 10, 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN  
CENTERED ON DAY 11, AND 5% OF YESTERDAY'S 12Z CANADIAN ENSEMBLE MEAN CENTERED  
ON DAY 10  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO  
RELATIVELY HIGH MODEL SPREAD AND POOR AGREEMENT AMONG THE SURFACE TOOLS.  
 
FORECASTER: LUKE H  
 
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  
FEBRUARY 15.  
 
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:  
20060104 - 20010121 - 19950112 - 20000130 - 19860115  
 
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:  
20060104 - 19860116 - 19950112 - 20010121 - 20060109  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 25 - 29 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON B A NRN CALIF B N  
SRN CALIF B B IDAHO B A NEVADA B N  
W MONTANA B A E MONTANA B A WYOMING B A  
UTAH B N ARIZONA B B COLORADO B A  
NEW MEXICO B B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA N A  
N TEXAS N A S TEXAS N N W TEXAS N 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 A GEORGIA A A  
FL PNHDL A A FL PENIN A A AK N SLOPE B B  
AK ALEUTIAN B B AK WESTERN B B AK INT BSN B B  
AK S INT B B AK SO COAST B B AK PNHDL B N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 27 - FEB 02, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON N A OREGON N A NRN CALIF N B  
SRN CALIF N B IDAHO N A NEVADA N N  
W MONTANA N A E MONTANA B A WYOMING B A  
UTAH N N ARIZONA N B COLORADO B N  
NEW MEXICO N B N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA N A  
N TEXAS N A S TEXAS N N W TEXAS N N  
MINNESOTA N A IOWA N 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 A GEORGIA A A  
FL PNHDL A A FL PENIN A A AK N SLOPE B B  
AK ALEUTIAN N N AK WESTERN B N AK INT BSN B B  
AK S INT B B AK SO COAST B N AK PNHDL B A  
 
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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