271  
FXUS06 KWBC 242002  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST FRI NOVEMBER 24 2017  
 
6-10 DAY OUTLOOK FOR NOV 30 - DEC 04, 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 THE NORTHEAST PACIFIC AND EASTERN ALASKA, WHILE A TROUGH IS  
PREDICTED TO PROGRESS INTO CALIFORNIA. ANOTHER RIDGE IS FORECAST OVER THE  
CENTRAL AND EASTERN CONUS. ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER  
ALASKA, AND ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS. BELOW NORMAL 500-HPA  
HEIGHTS ARE PREDICTED OVER THE WESTERN CONUS.  
 
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MAINLAND ALASKA, AS WELL AS MOST OF  
THE CONUS UNDER PREDICTED ABOVE NORMAL 500-HPA HEIGHTS. NEAR TO BELOW NORMAL  
TEMPERATURES ARE FAVORED FOR PARTS OF THE WESTERN CONUS DUE TO TROUGHING ALOFT.  
 
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH OF MAINLAND ALASKA, AND THE  
ALEUTIANS, DUE TO THE FORECAST TROUGH UPSTREAM AND ONSHORE FLOW. ABOVE NORMAL  
PRECIPITATION IS MOST LIKELY FOR THE SOUTHWESTERN CONUS AHEAD OF THE PREDICTED  
TROUGH. PROBABILITIES OF BELOW NORMAL PRECIPITATION ARE ELEVATED FOR THE  
CENTRAL AND EASTERN CONUS, BASED ON A LARGE AREA OF SURFACE HIGH PRESSURE.  
 
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 YESTERDAY'S 12Z  
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7  
 
 
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 02 - 08 2017  
 
ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT TODAY FOR THE WEEK-2 PERIOD OVER  
MOST OF THE FORECAST DOMAIN. THE OVERALL CIRCULATION PATTERN IS QUITE SIMILAR  
TO THE 6-10 DAY PERIOD. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE  
SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN.  
 
ABOVE NORMAL HEIGHTS AT 500-HPA 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, CONSISTENT WITH ESTIMATES FROM THE ECMWF  
AND GEFS REFORECAST TOOLS. BELOW NORMAL PRECIPITATION IS MOST LIKELY FOR THE  
PACIFIC NORTHWEST, PARTS 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: ABOVE AVERAGE, 3 OUT OF 5, DUE  
TO GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS ON THE 500-HPA CIRCULATION  
PATTERN, OFFSET BY MODERATE 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:  
19991127 - 19711108 - 19541204 - 19971122 - 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:  
19901113 - 19711107 - 20031128 - 19971122 - 19991126  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR NOV 30 - DEC 04, 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B N OREGON B N NRN CALIF B A  
SRN CALIF A A IDAHO N A NEVADA B A  
W MONTANA N N E MONTANA A N WYOMING A A  
UTAH A A ARIZONA A A 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 N N  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR DEC 02 - 08 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON B B OREGON B B NRN CALIF B A  
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 N  
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 N  
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 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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