326  
FXUS06 KWBC 222018  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST THU FEBRUARY 22 2018  
 
6-10 DAY OUTLOOK FOR FEB 28 - MAR 04, 2018  
 
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT ON THE EXPECTED LARGE  
SCALE 500-HPA CIRCULATION PATTERN IN THE 6-10 DAY PERIOD. A HIGH AMPLITUDE  
RIDGE IS PREDICTED OVER THE GULF OF ALASKA. DOWNSTREAM, A STRONG TROUGH IS  
PREDICTED ALONG THE WEST COAST WITH A RIDGE OVER EAST-CENTRAL NORTH AMERICA.  
ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER ALASKA AND THE EAST-CENTRAL  
CONUS. BELOW NORMAL 500-HPA HEIGHTS ARE FORECAST FOR THE WESTERN CONUS.  
 
PERSISTENT TROUGHING IN THE WESTERN CONUS LEADS TO INCREASED CHANCES FOR BELOW  
NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS. A RIDGE  
FORECAST OVER EAST-CENTRAL NORTH AMERICA LEADS TO ENHANCED CHANCES OF ABOVE  
NORMAL TEMPERATURES FOR THE MUCH OF EASTERN CONUS AND THE SOUTHERN PLAINS.  
ANOMALOUS RIDGING OVER ALASKA FAVORS NEAR TO ABOVE NORMAL TEMPERATURES FOR MOST  
OF MAINLAND ALASKA AS WELL AS THE ALEUTIANS. ANOMALOUS NORTHERLY FLOW TILTS THE  
ODDS TO NEAR TO BELOW NORMAL TEMPERATURES FOR THE ALASKA PANHANDLE.  
 
THE DEEP TROUGH FORECAST OVER THE SOUTHWESTERN CONUS AND/OR ANOMALOUS  
SOUTHWESTERLY FLOW ENHANCE PROBABILITIES OF NEAR TO ABOVE NORMAL PRECIPITATION  
OVER MUCH OF THE EAST-CENTRAL AND SOUTHEASTERN CONUS, EXCEPT FOR SOUTHERN  
FLORIDA WHERE BELOW NORMAL PRECIPITATION IS INDICATED DUE TO THE SOUTHEAST  
RIDGE. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE NORTHERN GREAT  
LAKES AND NORTHEAST, WHILE ABOVE NORMAL PRECIPITATION IS FORECAST FOR ALASKA,  
CONSISTENT WITH DYNAMICAL MODEL GUIDANCE FROM THE GFS ENSEMBLE MEAN SOLUTIONS.  
 
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 OPERATIONAL 0Z ECMWF 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  
A RELATIVELY HIGH AMPLIFIED FLOW PATTERN ACROSS MUCH OF THE FORECAST DOMAIN.  
 
8-14 DAY OUTLOOK FOR MAR 02 - 08 2018  
 
THE MEAN 500-HPA FLOW PATTERN EXPECTED FOR THE WEEK-2 PERIOD FEATURES A LESS  
AMPLIFIED CIRCULATION AND THE OVERALL LONG WAVE PATTERN IS SHIFTED WESTWARD.  
BELOW NORMAL HEIGHTS ARE EXPECTED OVER MUCH OF THE WESTERN AND EASTERN CONUS,  
WHILE NEAR TO ABOVE NORMAL HEIGHTS ARE ANTICIPATED OVER ALASKA.  
 
A TROUGH NEAR THE WEST COAST OF THE CONUS LEADS TO INCREASED CHANCES FOR NEAR  
TO BELOW NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND CENTRAL CONUS.  
ENHANCED PROBABILITIES FOR NEAR TO BELOW NORMAL TEMPERATURES ALSO EXTEND TO  
MUCH OF THE EASTERN CONUS DUE TO EXPECTED NEAR TO BELOW NORMAL HEIGHTS AND  
NORTHERLY FLOW. HOWEVER, CALIBRATED DYNAMIC MODEL GUIDANCE PREDICT ENHANCED  
CHANCES OF NEAR TO ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHEAST AND  
FLORIDA. ANOMALOUS RIDGING OVER SOUTHWESTERN ALASKA FAVORS NEAR TO ABOVE NORMAL  
TEMPERATURES FOR NORTHWESTERN MAINLAND ALASKA AS WELL AS THE ALEUTIANS.  
ANOMALOUS NORTHERLY FLOW TILTS THE ODDS TO BELOW NORMAL TEMPERATURES FOR  
SOUTHEASTERN ALASKA AND THE ALASKA PANHANDLE.  
 
THE WEEK-2 PRECIPITATION PROBABILITY FORECAST IS VERY SIMILAR TO THE 6-10 DAY  
FORECAST OVER ALASKA AND THE SOUTHWESTERN CONUS. ENHANCED PROBABILITIES OF NEAR  
TO ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE NORTHERN AND CENTRAL PLAINS,  
WHILE BELOW NORMAL PRECIPITATION IS FORECAST OVER THE SOUTHERN PLAINS AND PARTS  
OF THE EASTERN CONUS ACCORDING TO THE REFORECAST TOOL FROM THE ECMWF ENSEMBLE  
MEAN SOLUTIONS.  
 
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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
FAIRLY GOOD ENSEMBLE MEAN MODEL AGREEEMENT OFFSET BY A TRANSITION TO A LESS  
AMPLIFIED PATTERN DURING WEEK-2.  
 
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  
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:  
19510202 - 19520202 - 19530202 - 19540202 - 19550202  
 
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:  
19510201 - 19520201 - 19530201 - 19540201 - 19550201  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR FEB 28 - MAR 04, 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B A  
SRN CALIF B A IDAHO B N NEVADA B A  
W MONTANA B N E MONTANA B N WYOMING B N  
UTAH B A ARIZONA B A COLORADO B A  
NEW MEXICO B A N DAKOTA B N S DAKOTA B A  
NEBRASKA B A KANSAS N A OKLAHOMA A A  
N TEXAS A A S TEXAS A N W TEXAS N N  
MINNESOTA N B 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 N  
VERMONT A B NEW HAMP A B MAINE A B  
MASS A B CONN A N RHODE IS A N  
PENN A A NEW JERSEY A N 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 N FL PENIN A B AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A  
AK S INT N A AK SO COAST N A AK PNHDL B N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR MAR 02 - 08 2018  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B A  
SRN CALIF B A IDAHO B N NEVADA B A  
W MONTANA B B E MONTANA B B WYOMING B N  
UTAH B A ARIZONA B A COLORADO B B  
NEW MEXICO N N N DAKOTA B A S DAKOTA B A  
NEBRASKA B A KANSAS B N OKLAHOMA B B  
N TEXAS N B S TEXAS N B W TEXAS N B  
MINNESOTA B B IOWA B A MISSOURI B N  
ARKANSAS B N LOUISIANA N B WISCONSIN N B  
ILLINOIS B N MISSISSIPPI N B MICHIGAN N B  
INDIANA B B OHIO B B KENTUCKY B N  
TENNESSEE B N ALABAMA N B NEW YORK N B  
VERMONT A B NEW HAMP A B MAINE A B  
MASS N B CONN N B RHODE IS N B  
PENN N B NEW JERSEY N B W VIRGINIA B B  
MARYLAND B B DELAWARE B B VIRGINIA B B  
N CAROLINA B N S CAROLINA B N GEORGIA B B  
FL PNHDL N B FL PENIN N B AK N SLOPE A A  
AK ALEUTIAN A N AK WESTERN A A AK INT BSN N A  
AK S INT B A AK SO COAST B N 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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