694  
FXUS06 KWBC 152015  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EST WED NOVEMBER 15 2017  
 
6-10 DAY OUTLOOK FOR NOV 21 - 25 2017  
 
TODAY'S DYNAMICAL MODEL SOLUTIONS ARE IN FAIR AGREEMENT ON THEIR 500-HPA  
CIRCULATION FORECASTS FOR THE 6-10 DAY PERIOD OVER THE NORTH AMERICAN REGION. A  
STRONG RIDGE IS FORECAST OVER THE ALEUTIANS, WHILE A TROUGH IS PREDICTED OVER  
MUCH OF MAINLAND ALASKA, EXTENDING INTO THE NORTH PACIFIC. ANOTHER TROUGH IS  
FORECAST OVER THE EASTERN CONUS WITH A BLOCKING RIDGE OVER THE DAVIS STRAIT.  
ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER EXTREME WESTERN MAINLAND ALASKA  
AND ACROSS THE WESTERN TWO-THIRDS OF THE CONUS. BELOW NORMAL 500-HPA HEIGHTS  
ARE FORECAST OVER THE REMAINDER OF THE CONUS AND CENTRAL EASTERN REGIONS OF  
ALASKA.  
 
BELOW NORMAL TEMPERATURES ARE LIKELY FOR MUCH OF ALASKA, UNDER STRONGLY  
NEGATIVE 500-HPA HEIGHT ANOMALIES AND OFFSHORE FLOW. ABOVE NORMAL TEMPERATURES  
ARE MOST LIKELY FOR THE WESTERN HALF OF THE CONUS UNDER PREDICTED ABOVE NORMAL  
500-HPA HEIGHTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE EASTERN THIRD OF  
THE CONUS FROM THE SOUTHEAST NORTHWARD TO THE OHIO VALLEY, THE EASTERN GREAT  
LAKES AND THE NORTHEAST, DUE TO ANOMALOUS NORTHERLY FLOW.  
 
ABOVE NORMAL PRECIPITATION IS FAVORED FOR NORTHWESTERN AND NORTHEASTERN PARTS  
OF MAINLAND ALASKA, THE ALASKA PANHANDLE, DUE TO THE FORECAST TROUGH THERE AND  
ONSHORE FLOW. BELOW NORMAL PRECIPITATION IS MOST LIKELY FOR SOUTHWESTERN  
REGIONS OF MAINLAND ALASKA, AHEAD OF A PREDICTED RIDGE AND OFFSHORE FLOW. ABOVE  
NORMAL PRECIPITATION IS MOST LIKELY FOR NORTHERN AND CENTRAL CALIFORNIA,  
NORTHWESTERN NEVADA, THE PACIFIC NORTHWEST, THE NORTHERN INTERMOUNTAIN WEST AND  
THE NORTHERN ROCKIES, EAST OF A PREDICTED TROUGH OVER THE NORTH PACIFIC. ABOVE  
NORMAL PRECIPITATION IS FAVORED FOR FLORIDA PENINSULA, DUE TO FRONTAL ACTIVITY.  
BELOW NORMAL PRECIPITATION IS FORECAST FOR MOST OF THE REMAINING AREAS OF THE  
CONUS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 8, 10% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8, 10% OF  
TODAY'S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN  
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON  
DAY 8, AND 15% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8  
 
 
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO  
FAIR MODEL AGREEMENT ON THE EXPECTED CIRCULATION PATTERN, OFFSET BY POOR  
AGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION TOOLS OVER THE SOUTHEAST U.S.  
 
8-14 DAY OUTLOOK FOR NOV 23 - 29 2017  
 
THE OVERALL 500-HPA CIRCULATION PATTERN PREDICTED FOR THE WEEK 2 PERIOD IS  
QUITE SIMILAR TO THE 6-10 DAY PERIOD, ALTHOUGH AN UPPER-LEVEL PATTERN IS  
FORECAST TO DEAMPLIFY OVER FORECAST REGION. THE ENSEMBLE SPAGHETTI DIAGRAMS  
INDICATE MODERATE TO LARGE SPREAD ACROSS THE MAJORITY OF THE FORECAST DOMAIN.  
THE GREATEST WEIGHT FOR THE BLENDED 500-HPA HEIGHT FIELD WAS GIVEN TO THE ECMWF  
ENSEMBLE MEAN BASED ON CONSIDERATIONS OF RECENT SKILL AND ANALOG CORRELATIONS.  
 
BELOW NORMAL TEMPERATURES ARE MOST LIKELY FOR MUCH OF MAINLAND ALASKA WITH  
PREDICTED BELOW NORMAL 500-HPA HEIGHTS AND PERSISTENT OFFSHORE FLOW. ABOVE  
NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE EXTREME WESTERN ALEUTIANS, THE  
NORTHWESTERN AND NORTHEASTERN SLOPE OF MAINLAND ALASKA, DUE TO ABOVE NORMAL SEA  
SURFACE TEMPERATURES IN SURROUNDING AREA. ABOVE NORMAL TEMPERATURES ARE LIKELY  
FOR MOST OF THE WESTERN AND CENTRAL CONUS, UNDER PREDICTED ABOVE NORMAL 500-HPA  
HEIGHTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MOST AREAS FROM PARTS OF THE  
MID-ATLANTIC COASTAL REGIONS TO THE NORTHEAST IN THE WEEK 2 PERIOD, ASSOCIATED  
WITH THE PREDICTED NORTHERLY FLOW.  
 
ABOVE NORMAL PRECIPITATION IS MOST LIKELY FROM CENTRAL AND NORTH CALIFORNIA,  
THE PACIFIC NORTHWEST EASTWARD TO NORTHERN PARTS OF THE NORTHERN PLAINS, AHEAD  
OF A PREDICTED TROUGH. BELOW NORMAL PRECIPITATION IS INDICATED FOR MOST OF THE  
REMAINING AREAS OF THE CONUS. AREAS OF SOUTHERN ALASKA ARE PREDICTED TO HAVE  
BELOW NORMAL PRECIPITATION IN THE WEEK 2 PERIOD, WHILE ABOVE NORMAL  
PRECIPITATION IS LIKELY FOR NORTHEASTERN, NORTHWESTERN ALASKA AND ALEUTIANS,  
UNDER PREDICTED ONSHORE FLOW.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED  
ON DAY 11, 10% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11, 40% 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 IS: ABOUT AVERAGE, 3 OUT OF 5, DUE  
TO GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS ON THE 500-HPA CIRCULATION  
PATTERN DURING WEEK 2, OFFSET BY MODERATE TO LARGE SPREAD AMONG THE ENSEMBLE  
MEMBERS  
 
FORECASTER: Y. FAN  
 
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  
NOVEMBER 16  
 
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:  
19661114 - 19701129 - 19731110 - 19731128 - 20061122  
 
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:  
19661116 - 20061122 - 19701128 - 19731110 - 19731128  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR NOV 21 - 25 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A A OREGON A A NRN CALIF A A  
SRN CALIF A N IDAHO A A NEVADA A N  
W MONTANA A A E MONTANA A N WYOMING A B  
UTAH A B ARIZONA A N COLORADO A B  
NEW MEXICO A B N DAKOTA A N S DAKOTA A B  
NEBRASKA A B KANSAS A B OKLAHOMA A B  
N TEXAS N B S TEXAS N B W TEXAS A N  
MINNESOTA A B IOWA A B MISSOURI N B  
ARKANSAS N B LOUISIANA B B WISCONSIN N B  
ILLINOIS N B MISSISSIPPI B B MICHIGAN N B  
INDIANA B B OHIO B B KENTUCKY B B  
TENNESSEE B B ALABAMA B B NEW YORK B B  
VERMONT B B NEW HAMP B B MAINE B B  
MASS B B CONN B B RHODE IS B B  
PENN B B NEW JERSEY B B W VIRGINIA B B  
MARYLAND B B DELAWARE B B VIRGINIA B B  
N CAROLINA B B S CAROLINA B B GEORGIA B B  
FL PNHDL B B FL PENIN N A AK N SLOPE B N  
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B B  
AK S INT B B AK SO COAST B B AK PNHDL B A  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR NOV 23 - 29 2017  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A A OREGON A A NRN CALIF A A  
SRN CALIF A N IDAHO A A NEVADA A N  
W MONTANA A A E MONTANA A A WYOMING A N  
UTAH A B ARIZONA A B COLORADO A B  
NEW MEXICO A B N DAKOTA A A S DAKOTA A N  
NEBRASKA A B KANSAS A B OKLAHOMA A B  
N TEXAS A B S TEXAS A B W TEXAS A B  
MINNESOTA A N IOWA A B MISSOURI A B  
ARKANSAS A B LOUISIANA A B WISCONSIN A B  
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B  
INDIANA A B OHIO N B KENTUCKY N B  
TENNESSEE N B ALABAMA N B NEW YORK B B  
VERMONT B B NEW HAMP B B MAINE B N  
MASS B B CONN B B RHODE IS B B  
PENN N B NEW JERSEY B B W VIRGINIA N B  
MARYLAND B B DELAWARE B B VIRGINIA B B  
N CAROLINA B B S CAROLINA B B GEORGIA N B  
FL PNHDL N B FL PENIN N N AK N SLOPE A N  
AK ALEUTIAN N A AK WESTERN B N AK INT BSN B B  
AK S INT B B AK SO COAST B B 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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