031  
FXUS06 KWBC 262041  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST MON FEBRUARY 26 2018  
 
6-10 DAY OUTLOOK FOR MAR 04 - 08 2018  
 
TODAY'S MODEL SOLUTIONS FEATURE STRONG POSITIVE 500-HPA ANOMALIES AT HIGH  
LATITUDES CONSISTENT WITH A NEGATIVE AO PATTERN. RIDGES ARE PREDICTED SOUTH OF  
THE ALEUTIANS AS WELL AS OVER EASTERN CANADA CENTERED OVER OR JUST TO THE NORTH  
OF NORTHERN QUEBEC. FARTHER TO THE SOUTH, NEAR TO BELOW NORMAL HEIGHTS ARE  
EXPECTED FOR MUCH OF THE CONUS AS A TROUGH OVER THE WESTERN CONUS EARLY IN THE  
PERIOD PROGRESSES TOWARD THE EASTERN CONUS LATER IN THE PERIOD. SLIGHTLY  
POSITIVE HEIGHTS ARE INDICATED FOR PARTS OF THE SOUTHWESTERN CONUS AS HEIGHTS  
RISE IN ADVANCE OF A TROUGH OVER THE EASTERN PACIFIC LATE IN THE PERIOD.  
POSITIVE HEIGHT ANOMALIES ARE ALSO EXPECTED FOR PARTS OF THE GREAT LAKES AND  
NORTHEAST IN ASSOCIATION WITH THE MEAN RIDGE OVER EASTERN CANADA. ENSEMBLE  
SPREAD IS VERY HIGH OVER MUCH OF THE FORECAST DOMAIN, LEADING TO LOWER THAN  
NORMAL CONFIDENCE. DUE TO HIGH MODEL SPREAD, TODAY'S MANUAL 500-HPA HEIGHT  
BLEND IS BASED PRIMARILY ON THE ENSEMBLE MEAN SOLUTIONS.  
 
TROUGHING AND BELOW NORMAL HEIGHTS LEAD TO ENHANCED PROBABILITIES OF BELOW  
NORMAL TEMPERATURES ACROSS THE WESTERN CONUS, PARTICULARLY EARLY IN THE PERIOD.  
ABOVE NORMAL HEIGHTS ASSOCIATED WITH THE RIDGE OVER EASTERN CANADA FAVOR ABOVE  
NORMAL TEMPERATURES FOR THE GREAT LAKES AND NORTHEAST. THERE ARE ENHANCED  
PROBABILITIES OF BELOW NORMAL TEMPERATURES FOR PARTS OF THE SOUTHEAST AND  
MID-ATLANTIC DUE TO BELOW NORMAL HEIGHTS AND ANOMALOUS NORTHERLY 500-HPA FLOW.  
RIDGING AND ABOVE NORMAL SSTS LEAD TO FAVORED ABOVE NORMAL TEMPERATURES ACROSS  
MUCH OF THE ALEUTIANS AND WESTERN MAINLAND ALASKA. WEAK TROUGHING DOWNSTREAM  
FAVORS BELOW NORMAL TEMPERATURES FOR PARTS OF SOUTHEASTERN MAINLAND ALASKA AND  
THE PANHANDLE.  
 
AS A TROUGH PROGRESSES FROM WEST TO EAST ACROSS THE CONUS, ABOVE NORMAL  
PRECIPITATION IS FAVORED FOR MUCH OF THE EAST-CENTRAL CONUS. WEAK RIDGING LEADS  
TO SLIGHTLY ENHANCED PROBABILITIES OF BELOW NORMAL PRECIPITATION FOR PARTS OF  
THE SOUTHWESTERN AND NORTHWESTERN CONUS. MOIST FLOW AHEAD OF A TROUGH IN THE  
EASTERN PACIFIC LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION  
FOR MUCH OF CALIFORNIA. CONVERSELY, NEAR TO BELOW NORMAL PRECIPITATION IS  
FAVORED FOR THE EASTERN SEABOARD UNDERNEATH ANOMALOUS NORTHERLY MID-LEVEL FLOW.  
ENHANCED WESTERLY 500-HPA FLOW LEADS TO INCREASED PROBABILITIES OF ABOVE NORMAL  
PRECIPITATION FOR WESTERN MAINLAND ALASKA AND THE ALEUTIANS. OFFSHORE FLOW IS  
ANTICIPATED FOR THE ALASKA PANHANDLE, FAVORING BELOW NORMAL PRECIPITATION  
THERE.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 25% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 20% OF TODAY'S 0Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF YESTERDAY'S 12Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 7, 5% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON  
DAY 8, 15% 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: BELOW AVERAGE, 2 OUT OF 5, DUE TO  
HIGHER THAN NORMAL SPREAD OVER MUCH OF THE FORECAST DOMAIN.  
 
8-14 DAY OUTLOOK FOR MAR 06 - 12 2018  
 
DURING THE WEEK-2 PERIOD POSITIVE 500-HPA HEIGHT ANOMALIES CONTINUE OVER MUCH  
OF THE HIGH LATITUDES DUE TO RIDGES SOUTH OF THE ALEUTIANS AND OVER EASTERN  
CANADA. HOWEVER, THE RIDGE OVER EASTERN CANADA IS FORECAST TO WEAKEN RELATIVE  
TO THE PRECEDING 6 TO 10 DAY PERIOD. BETWEEN THESE TWO FEATURES, HEIGHTS ARE  
EXPECTED TO LOWER OVER MAINLAND ALASKA IN ASSOCIATION WITH A DEVELOPING TROUGH.  
FARTHER TO THE SOUTH, NEAR TO BELOW NORMAL HEIGHTS ARE DEPICTED OVER MOST OF  
THE CONUS. GENERALLY, CYCLONIC FLOW IS EXPECTED OVER THE EASTERN CONUS WHILE  
WEAK RIDGING IS FORECAST OVER PARTS OF THE WESTERN CONUS. MODERATE TO HIGH  
SPREAD CONTINUES OVER MUCH OF THE FORECAST DOMAIN. THE ENSEMBLE MEAN SOLUTIONS  
FORM THE BASIS FOR THE WEEK-2 500-HPA BLEND DUE, IN PART, TO LARGE  
DISAGREEMENTS AMONG THE DETERMINISTIC MODELS.  
 
BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE CONUS UNDERNEATH NEAR TO  
BELOW NORMAL HEIGHTS. HOWEVER, ABOVE NORMAL TEMPERATURES ARE SLIGHTLY FAVORED  
FOR PARTS OF THE NORTHEASTERN CONUS IN ASSOCIATION WITH THE RIDGE OVER EASTERN  
CANADA. NEAR TO ABOVE NORMAL HEIGHTS LEAD TO SLIGHTLY ELEVATED CHANCES FOR  
ABOVE NORMAL TEMPERATURES FOR PARTS OF THE SOUTHWEST. TROUGH DEVELOPMENT OVER  
MAINLAND ALASKA LEADS TO ENHANCED PROBABILITIES OF BELOW NORMAL TEMPERATURES  
ACROSS MUCH OF THE STATE. HOWEVER, ABOVE NORMAL SSTS AND BELOW NORMAL SEA ICE  
EXTENT FAVOR ABOVE NORMAL TEMPERATURES FOR THE ALEUTIANS AND PARTS OF WESTERN  
MAINLAND ALASKA.  
 
THERE ARE LARGE DISAGREEMENTS AMONG RAW AND CALIBRATED DYNAMICAL MODEL  
PRECIPITATION GUIDANCE LEADING TO LOWER THAN NORMAL CONFIDENCE. THERE ARE  
SLIGHTLY ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR PARTS OF THE  
LOWER MISSISSIPPI VALLEY AND SOUTHEAST CONUS DUE, IN PART, TO TELECONNECTIONS  
FROM THE EXPECTED POSITIVE HEIGHT ANOMALY CENTER OVER EASTERN CANADA.  
CALIBRATED DYNAMICAL MODEL GUIDANCE, AS WELL AS ANALOGS FROM THE MANUAL BLEND  
FAVOR BELOW NORMAL PRECIPITATION FOR PARTS OF THE GREAT LAKES EXTENDING  
NORTHEAST TO PARTS OF NORTHERN NEW ENGLAND. WEAK RIDGING SLIGHTLY FAVORS BELOW  
NORMAL PRECIPITATION ACROSS THE WEST-CENTRAL CONUS. THERE ARE ENHANCED  
PROBABILITIES FOR ABOVE NORMAL PRECIPITATION FOR THE WEST COAST OF THE CONUS  
AHEAD OF A TROUGH OVER THE EASTERN PACIFIC. ENHANCED WESTERLY 500-HPA FLOW  
LEADS TO INCREASED PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR MUCH OF  
WESTERN ALASKA.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 10% OF TODAY'S OPERATIONAL 6Z GFS 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, 10% 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  
FAIRLY HIGH MODEL SPREAD AND POOR AGREEMENT AMONG THE PRECIPITATION TOOLS.  
 
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  
MARCH 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:  
19900213 - 19850303 - 19640308 - 19630312 - 19570207  
 
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:  
19510205 - 19520205 - 19530205 - 19540205 - 19550205  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 04 - 08 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B B OREGON B N NRN CALIF B A  
SRN CALIF B B IDAHO B N NEVADA B N  
W MONTANA B B E MONTANA B N WYOMING B N  
UTAH B N ARIZONA B B COLORADO B B  
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 A W TEXAS N B  
MINNESOTA N A IOWA N A MISSOURI N A  
ARKANSAS N A LOUISIANA N A WISCONSIN A A  
ILLINOIS A A MISSISSIPPI N A MICHIGAN A N  
INDIANA A A OHIO A N KENTUCKY N N  
TENNESSEE N N ALABAMA N N NEW YORK A B  
VERMONT A B NEW HAMP A B MAINE A B  
MASS A B CONN A B RHODE IS A N  
PENN A B NEW JERSEY N B W VIRGINIA N N  
MARYLAND N B DELAWARE N B VIRGINIA B N  
N CAROLINA B N S CAROLINA B N GEORGIA B N  
FL PNHDL N N FL PENIN B B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN N A  
AK S INT B A AK SO COAST B N AK PNHDL B B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 06 - 12 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 N NEVADA B A  
W MONTANA B N E MONTANA B B WYOMING B B  
UTAH B N ARIZONA N B COLORADO B B  
NEW MEXICO N B N DAKOTA B N S DAKOTA B N  
NEBRASKA B N KANSAS B B OKLAHOMA B B  
N TEXAS B N S TEXAS B N W TEXAS B B  
MINNESOTA B N IOWA B N MISSOURI B N  
ARKANSAS B N LOUISIANA B A WISCONSIN N N  
ILLINOIS B N MISSISSIPPI B A MICHIGAN N N  
INDIANA N N OHIO N N KENTUCKY B N  
TENNESSEE B A ALABAMA B A NEW YORK A N  
VERMONT A N NEW HAMP A N MAINE A N  
MASS A N CONN N N RHODE IS A N  
PENN N N NEW JERSEY N N W VIRGINIA B N  
MARYLAND N N DELAWARE B N VIRGINIA B N  
N CAROLINA B N S CAROLINA B A GEORGIA B A  
FL PNHDL B A FL PENIN B N AK N SLOPE N A  
AK ALEUTIAN N A AK WESTERN N A AK INT BSN B A  
AK S INT B A 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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