865  
FXUS06 KWBC 232001  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST THU NOVEMBER 23 2017  
 
6-10 DAY OUTLOOK FOR NOV 29 - DEC 03, 2017  
 
TODAY'S DYNAMICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA  
CIRCULATION PATTERN FOR THE 6-10 DAY PERIOD OVER NORTH AMERICA. A RIDGE IS  
FORECAST OVER ALASKA, WHILE A TROUGH IS PREDICTED OVER THE BERING SEA,  
EXTENDING INTO THE NORTHEAST PACIFIC. ANOTHER TROUGH IS FORECAST OVER THE  
NORTHEASTERN AND THE ATLANTIC. ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER  
MUCH OF MAINLAND ALASKA, THE ALASKA PANHANDLE, AND ACROSS MUCH OF THE CONUS.  
 
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR ALASKA, AS WELL AS MOST OF THE CONUS  
UNDER PREDICTED ABOVE NORMAL 500-HPA HEIGHTS.  
 
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH OF MAINLAND ALASKA, AND THE  
ALEUTIANS, DUE TO THE FORECAST TROUGH UPSTREAM AND ONSHORE FLOW. BELOW NORMAL  
PRECIPITATION IS MOST LIKELY FOR NORTHEASTERN MAINLAND ALASKA, AHEAD OF A  
PREDICTED RIDGE AND DUE TO OFFSHORE FLOW. ABOVE NORMAL PRECIPITATION IS MOST  
LIKELY FOR PART OF THE CENTRAL PLAINS AHEAD OF THE PREDICTED TROUGH OVER THE  
NORTH PACIFIC. PROBABILITIES OF BELOW NORMAL PRECIPITATION ARE ELEVATED FOR  
REST OF THE CONUS.  
 
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  
GOOD MODEL AGREEMENT ON THE EXPECTED CIRCULATION PATTERN  
 
8-14 DAY OUTLOOK FOR DEC 01 - 07 2017  
 
DURING THE 8-14 DAY PERIOD, MODELS AGREE IN PREDICTING THE 500-HPA CIRCULATION  
PATTERN ACROSS NORTH AMERICA. A RIDGE IS FORECAST OVER ALASKA, WHILE A TROUGH  
IS PREDICTED OVER THE WESTERN CONUS. ANOTHER TROUGH IS FORECAST OVER THE  
NORTHEASTERN AND THE ATLANTIC. ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER  
ALASKA, AND ACROSS THE CENTRAL AND EASTERN CONUS, WHILE BELOW NORMAL 500-HPA  
HEIGHTS ARE EXPECTED OVER THE WESTERN CONUS. THE ENSEMBLE SPAGHETTI DIAGRAMS  
INDICATE MODERATE TO LARGE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN.  
 
ABOVE NORMAL HEIGHTS TILT THE ODDS TO ABOVE NORMAL TEMPERATURES FOR ALASKA AND  
THE CENTRAL AND EASTERN CONUS. PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE  
FAVORED FOR THE WESTERN CONUS UNDERNEATH THE TROUGH AND DUE TO NORTHWESTERLY  
FLOW.  
 
ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE SOUTHWESTERN AND CENTRAL CONUS,  
THE GREAT LAKES, AND THE OHIO VALLEY AND THE TENNESSEE VALLEY, CONSISTENT WITH  
ESTIMATES FROM THE ECMWF AND GEFS REFORECAST TOOLS. BELOW NORMAL PRECIPITATION  
IS LIKELY FOR THE NORTHWESTERN, PART OF THE SOUTHEASTERN CONUS AND THE ATLANTIC  
COAST STATES. ABOVE NORMAL PRECIPITATION IS LIKELY FOR MAINLAND ALASKA AND THE  
ALEUTIANS, UNDER PREDICTED ONSHORE AND CYCLONIC FLOW.  
 
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, 20% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 20% OF  
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, 20% OF YESTERDAY'S 12Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10, AND 10% OF TODAY'S 0Z CANADIAN  
ENSEMBLE MEAN CENTERED ON DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5, DUE  
TO FAIR AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS ON THE 500-HPA CIRCULATION  
PATTERN, OFFSET BY MODERATE TO LARGE SPREAD AMONG THE ENSEMBLE MEMBERS.  
 
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  
DECEMBER 21  
 
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:  
19701122 - 19711108 - 19991127 - 19541203 - 19901111  
 
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:  
19711107 - 19701120 - 19901113 - 19971121 - 19601127  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR NOV 29 - DEC 03, 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON N N OREGON N B NRN CALIF A B  
SRN CALIF A B IDAHO A B NEVADA A B  
W MONTANA A N E MONTANA A B WYOMING A N  
UTAH A A ARIZONA A N COLORADO A N  
NEW MEXICO A N N DAKOTA A B S DAKOTA A B  
NEBRASKA A B KANSAS A B OKLAHOMA A B  
N TEXAS A B S TEXAS A B W TEXAS A B  
MINNESOTA A B IOWA A B MISSOURI A B  
ARKANSAS A B LOUISIANA A B WISCONSIN A B  
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B  
INDIANA A B OHIO A B KENTUCKY A B  
TENNESSEE A B ALABAMA A B NEW YORK A B  
VERMONT A B NEW HAMP A B MAINE A N  
MASS A B CONN A B RHODE IS A B  
PENN A B NEW JERSEY A B W VIRGINIA A B  
MARYLAND A B DELAWARE A B VIRGINIA A B  
N CAROLINA A B S CAROLINA A B GEORGIA A B  
FL PNHDL A B 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 A A AK SO COAST A A AK PNHDL A N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR DEC 01 - 07 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B B OREGON B N NRN CALIF B B  
SRN CALIF B A IDAHO B N NEVADA B A  
W MONTANA B N E MONTANA N N WYOMING N A  
UTAH N A ARIZONA A A COLORADO A A  
NEW MEXICO A A N DAKOTA A A S DAKOTA A A  
NEBRASKA A A KANSAS A A OKLAHOMA A A  
N TEXAS A A S TEXAS A A W TEXAS A A  
MINNESOTA A A IOWA A A MISSOURI A A  
ARKANSAS A A LOUISIANA A B WISCONSIN A A  
ILLINOIS A A MISSISSIPPI A B MICHIGAN A A  
INDIANA A A OHIO A A KENTUCKY A A  
TENNESSEE A B ALABAMA A B NEW YORK A B  
VERMONT A B NEW HAMP A B MAINE A N  
MASS A B CONN A B RHODE IS A B  
PENN A B NEW JERSEY A B W VIRGINIA A B  
MARYLAND A B DELAWARE A B VIRGINIA A B  
N CAROLINA A B S CAROLINA A B GEORGIA A B  
FL PNHDL A B 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 A A AK SO COAST A A AK PNHDL N 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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