399  
FXUS06 KWBC 162001  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST TUE JANUARY 16 2018  
 
6-10 DAY OUTLOOK FOR JAN 22 - 26 2018  
 
TODAYS NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED 500-HPA  
FLOW PATTERN OVER THE FORECAST DOMAIN. ALL OF TODAY'S MODEL SOLUTIONS FORECAST  
A TROUGH OVER MUCH OF MAINLAND ALASKA. WEAK RIDGING IS EXPECTED FARTHER TO THE  
EAST NEAR THE ALASKA PANHANDLE. A BROAD TROUGH IS PREDICTED OVER MOST OF THE  
WEST-CENTRAL CONUS WHILE RIDGING IS LIKELY NEAR THE SOUTHEASTERN CONUS.  
ENSEMBLE SPREAD IS RELATIVELY LOW OVER MUCH OF THE FORECAST DOMAIN AND 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 MAINLAND ALASKA, THE ALASKA PANHANDLE, AND MOST OF  
THE WESTERN TWO-THIRDS OF THE CONUS. ABOVE NORMAL HEIGHTS ARE EXPECTED FOR MUCH  
OF THE EASTERN THIRD OF THE CONUS AS WELL AS THE ALEUTIANS.  
 
THE TROUGH OVER MAINLAND ALASKA LEADS TO ENHANCED PROBABILITIES FOR BELOW  
NORMAL TEMPERATURES ACROSS ALASKA. BELOW NORMAL TEMPERATURES ARE ALSO FAVORED  
ACROSS THE WESTERN CONUS AND THE NORTHERN PLAINS UNDERNEATH CYCLONIC FLOW AND  
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 FOR ABOVE NORMAL PRECIPITATION ACROSS  
MUCH OF THE NORTHWESTERN CONUS EXTENDING EASTWARD TO THE GREAT BASIN AND  
CENTRAL ROCKIES. MOIST FLOW AHEAD OF THE LONGWAVE TROUGH OVER THE WEST-CENTAL  
CONUS FAVORS ABOVE NORMAL PRECIPITATION FOR MUCH OF THE EASTERN CONUS. BELOW  
NORMAL PRECIPITATION IS LIKELY FOR MUCH OF ALASKA UNDERNEATH EASTERLY LOW LEVEL  
FLOW.  
 
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, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF  
YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, 30% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO  
GOOD AGREEMENT AMONG THE MODEL SOLUTIONS.  
 
8-14 DAY OUTLOOK FOR JAN 24 - 30 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 MEAN TROUGH IS FORECAST TO PERSIST  
OVER MUCH OF MAINLAND ALASKA WITH RIDGES PREDICTED ON EITHER SIDE OF THIS  
FEATURE OVER THE ALEUTIANS AND THE ALASKA PANHANDLE, RESPECTIVELY. FARTHER TO  
THE SOUTH, TROUGHS ARE FORECAST NEAR THE GREAT LAKES AND OVER THE SOUTHWESTERN  
CONUS WHILE A RIDGE IS EXPECTED OVER THE CARIBBEAN EXPENDING TO PARTS OF THE  
SOUTHEASTERN CONUS. ENSEMBLE SPREAD IS RELATIVELY HIGH OVER THE WESTERN CONUS  
DUE, IN PART, TO MODEL UNCERTAINTY ON THE DEGREE OF PHASING BETWEEN A NORTHERN  
STREAM TROUGH FORECAST NEAR THE GREAT LAKES AND A SOUTHERN STREAM TROUGH  
EXPECTED OVER THE SOUTHWESTERN CONUS. DUE TO THESE UNCERTAINTIES, THE MANUAL  
500-HPA HEIGHT BLEND IS BASED ENTIRELY ON THE ENSEMBLE MEAN SOLUTIONS. ABOVE  
NORMAL HEIGHTS ARE EXPECTED FOR THE EASTERN THIRD OF THE CONUS AND THE  
ALEUTIANS WHILE BELOW NORMAL HEIGHTS ARE FORECAST FOR MAINLAND ALASKA, THE  
ALASKA PANHANDLE, AND MUCH OF THE WESTERN CONUS. HOWEVER, THE MAGNITUDE OF THE  
500-HPA HEIGHT ANOMALIES ARE REDUCED FOR WEEK-2, PARTICULARLY OVER THE WESTERN  
CONUS DUE TO INCREASED MODEL SPREAD AND UNCERTAINTY DURING THIS TIME PERIOD.  
 
THE TROUGH OVER ALASKA LEADS TO ENHANCED PROBABILITIES FOR BELOW NORMAL  
TEMPERATURES ACROSS THE STATE. ABOVE NORMAL HEIGHTS ENHANCE PROBABILITIES FOR  
ABOVE NORMAL TEMPERATURES ACROSS MUCH OF THE EASTERN CONUS. BELOW NORMAL  
TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS  
UNDERNEATH NEAR TO BELOW NORMAL HEIGHTS. HOWEVER, PROBABILITIES ARE REDUCED  
RELATIVE TO THE 6 TO 10 DAY TIME PERIOD DUE TO INCREASED MODEL UNCERTAINTY  
DURING WEEK-2.  
 
MOIST FLOW AHEAD OF TROUGHS OVER THE NORTH-CENTRAL AND SOUTHWESTERN CONUS  
INCREASES PROBABILITIES FOR ABOVE NORMAL PRECIPITATION OVER MUCH OF THE EASTERN  
HALF OF THE CONUS. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED FOR THE  
NORTHWESTERN CONUS DUE TO THE POTENTIAL FOR SHORTWAVE TROUGHS TO PROGRESS  
THROUGH THE REGION FROM THE PACIFIC. MEAN SURFACE HIGH PRESSURE LEADS TO  
SLIGHTLY ELEVATED PROBABILITIES FOR BELOW NORMAL PRECIPITATION FOR PARTS OF THE  
NORTHERN PLAINS. DYNAMICAL MODEL GUIDANCE FROM THE ECMWF AND GEFS ENSEMBLE  
MEMBERS FAVOR BELOW NORMAL PRECIPITATION FOR PARTS OF THE SOUTHWEST. BELOW  
NORMAL PRECIPITATION IS ALSO FAVORED FOR PARTS OF CENTRAL AND WESTERN MAINLAND  
ALASKA UNDERNEATH MEAN EASTERLY FLOW.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 5% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 5% OF  
YESTERDAY'S 12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, 30% 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD  
AGREEMENT BETWEEN THE GFS AND ECMWF ENSEMBLE MEANS OFFSET BY LARGE SPREAD AMONG  
THEIR ENSEMBLE MEMBERS.  
 
FORECASTER: SCOTT 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  
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:  
20010121 - 19860124 - 20010116 - 19780119 - 19520127  
 
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:  
20010120 - 19941230 - 19860124 - 19580104 - 19780123  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 22 - 26 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON B A NRN CALIF B A  
SRN CALIF B B IDAHO B A NEVADA B A  
W MONTANA B A E MONTANA B N WYOMING B A  
UTAH B A ARIZONA B B COLORADO B A  
NEW MEXICO B B N DAKOTA B N S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA N N  
N TEXAS N N S TEXAS N N W TEXAS N B  
MINNESOTA N A IOWA N A MISSOURI A A  
ARKANSAS A A LOUISIANA A A WISCONSIN N 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 B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR JAN 24 - 30 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B A OREGON B A NRN CALIF B A  
SRN CALIF B N IDAHO B A NEVADA B A  
W MONTANA B A E MONTANA B N WYOMING B A  
UTAH B A ARIZONA N N COLORADO B A  
NEW MEXICO N N N DAKOTA B N S DAKOTA B N  
NEBRASKA B A KANSAS N A OKLAHOMA N A  
N TEXAS N A S TEXAS N N W TEXAS N B  
MINNESOTA N N IOWA N A MISSOURI A A  
ARKANSAS A A LOUISIANA N A WISCONSIN N 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 N AK N SLOPE B N  
AK ALEUTIAN B N AK WESTERN B B AK INT BSN B B  
AK S INT B N AK SO COAST B N AK PNHDL B N  
 
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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