632  
FXUS06 KWBC 271912  
PMDMRD  
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD  
300 PM EDT WED AUGUST 27 2025  
 
6-10 DAY OUTLOOK FOR SEP 02 - 06 2025  
 
THE ECMWF, GEFS AND CANADIAN ENSEMBLE MODELS AGREE ON THE 500-HPA HEIGHT  
PATTERN FORECAST OVER NORTH AMERICA AND SURROUNDING REGIONS DURING THE 6-10 DAY  
PERIOD, WITH ONLY SMALL VARIATIONS IN THE PATTERN. MODEL ENSEMBLE MEANS  
CONTINUE TO PREDICT AN AMPLIFIED RIDGE AND AN ASSOCIATED LARGE POSITIVE 500-HPA  
HEIGHT ANOMALY CENTERED OVER THE GULF OF ALASKA AND SOUTHEAST ALASKA, WITH SOME  
DEAMPLIFICATION OVER TIME. POSITIVE 500-HPA HEIGHT ANOMALIES EXTEND SOUTHWARD  
INTO THE WESTERN CONTIGUOUS UNITED STATES (CONUS). THE ECMWF ENSEMBLE MEAN  
PREDICTS LARGER MAGNITUDE POSITIVE 500-PA HEIGHT ANOMALIES CENTERED SLIGHTLY TO  
THE EAST OF THE GEFS AND CANADIAN ENSEMBLE MEANS. THE ECMWF, GEFS AND CANADIAN  
ENSEMBLES PREDICT A TROUGH AND ASSOCIATED NEGATIVE 500-HPA HEIGHT ANOMALIES TO  
AMPLIFY AND RETROGRADE WESTWARD OVER THE CONUS, EARLY IN THE PERIOD. LATER IN  
THE PERIOD, THIS TROUGH BEGINS TO RAPIDLY DEAMPLIFY, AS NEGATIVE 500-HPA HEIGHT  
ANOMALIES RETRACT NORTHWARD INTO CANADA. THE ECMWF ENSEMBLE PREDICTS A GREATER  
MAGNITUDE NEGATIVE 500-HPA HEIGHT ANOMALY CENTERED OVER THE WESTERN GREAT LAKES  
REGION DURING THE 6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED ON  
THE MOST RECENT 0Z ENSEMBLE MEANS OF THE ECMWF, GEFS AND CANADIAN MODELS,  
WEIGHING THE ECMWF MODEL GREATER DUE TO RECENT MODEL ANOMALY CORRELATION SKILL.  
 
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE EASTERN ALEUTIANS, MAINLAND  
ALASKA, AND SOUTHEAST ALASKA, UNDER THE PREDICTED AMPLIFIED RIDGE. ABOVE NORMAL  
TEMPERATURES ARE ALSO LIKELY FOR MUCH OF THE WESTERN CONUS, DUE TO PREDICTED  
POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE REGION. UNDER A PREDICTED TROUGH AND  
NEGATIVE 500-HPA HEIGHT ANOMALIES, BELOW NORMAL TEMPERATURES ARE FAVORED OVER  
MOST OF THE CENTRAL AND EASTERN CONUS, WITH PROBABILITIES EXCEEDING 60 PERCENT  
FOR PARTS OF THE CENTRAL CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE  
WESTERN GULF COAST AND FLORIDA PENINSULA, TO THE SOUTH OF A PREDICTED  
STATIONARY FRONT. NEAR-TO-ABOVE NORMAL TEMPERATURES ARE SLIGHTLY FAVORED FOR  
PARTS OF NORTHERN NEW YORK AND NORTHERN NEW ENGLAND, CONSISTENT WITH CALIBRATED  
MODEL FORECASTS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF HAWAII,  
EXCLUDING SOUTHEASTERN AREAS OF THE BIG ISLAND, INFLUENCED BY ABOVE AVERAGE SEA  
SURFACE TEMPERATURES IN THE REGION.  
 
ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE PREDICTED FOR PARTS OF  
THE ALEUTIANS, AND ACROSS WESTERN AND NORTHERN MAINLAND ALASKA, UNDER ENHANCED  
SOUTHWESTERLY ONSHORE FLOW. BELOW NORMAL PRECIPITATION IS LIKELY FOR SOUTHEAST  
ALASKA, AHEAD OF THE AMPLIFIED RIDGE, WITH PROBABILITIES EXCEEDING 60 PERCENT  
IN THE SOUTHERN ALASKA PANHANDLE. BELOW NORMAL PRECIPITATION IS FAVORED FOR  
WESTERN WASHINGTON STATE, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES.  
NEAR-TO-ABOVE NORMAL PRECIPITATION IS FAVORED OVER MOST OF THE CONUS FOR THE  
6-10 DAY PERIOD, CONSISTENT WITH MOST MODEL TOOLS. ENHANCED PROBABILITIES FOR  
ABOVE NORMAL PRECIPITATION EXCEED 50 PERCENT FOR PARTS OF THE SOUTHWEST,  
CONSISTENT WITH CALIBRATED ECMWF AND GEFS ENSEMBLE FORECASTS. NEAR NORMAL  
PRECIPITATION IS FAVORED FOR HAWAII, WHERE FORECAST TOOLS ARE INCONSISTENT OR  
INDICATE WEAK SIGNALS.  
 
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 8, AND 25% 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 AGREEMENT BETWEEN ENSEMBLE MODEL FORECASTS OF AN AMPLIFIED MID-LEVEL  
HEIGHT PATTERN, OFFSET BY SOME DIFFERENCES AMONG TEMPERATURE AND PRECIPITATION  
FORECAST TOOLS FOR SOME AREAS.  
 
8-14 DAY OUTLOOK FOR SEP 04 - 10 2025  
 
ENSEMBLE MEAN FORECASTS FOR THE 500-HPA HEIGHT PATTERN OVER NORTH AMERICA  
REMAIN IN GENERAL AGREEMENT DURING THE 8-14 DAY PERIOD, WHILE THE OVERALL  
PATTERN DEAMPLIFIES. A RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES DEAMPLIFY  
AND RETROGRADE OVER THE GULF OF ALASKA INTO THE WEEK-2 PERIOD. POSITIVE 500-HPA  
HEIGHT ANOMALIES EXTEND SOUTHWARD OVER THE WESTERN CONUS IN THE WEEK-2 MANUAL  
BLEND FORECAST, WITH THE ECMWF ENSEMBLE MEAN PREDICTING MORE EXTENSIVE POSITIVE  
500-HPA HEIGHT ANOMALIES OVER THE WEST THAN THE GEFS ENSEMBLE MEAN. IN THE 8-14  
DAY PERIOD MANUAL BLEND, A WEAK TROUGH IS PREDICTED OVER THE EAST-CENTRAL  
CONUS, WHICH HAS DEAMPLIFIED SIGNIFICANTLY FROM THE 6-10 DAY PERIOD. WHERE  
NEGATIVE 500-HPA HEIGHT ANOMALIES WERE PREDICTED OVER MOST OF THE EAST COAST IN  
THE 6-10 DAY PERIOD, SLIGHTLY POSITIVE MID-LEVEL HEIGHT ANOMALIES ARE PREDICTED  
IN THE WEEK-2 PERIOD.  
 
ABOVE NORMAL TEMPERATURES CONTINUE TO BE LIKELY FOR MOST OF ALASKA, EXCLUDING  
NORTHERN MAINLAND ALASKA, UNDER CONTINUED POSITIVE 500-HPA HEIGHT ANOMALIES.  
ABOVE NORMAL TEMPERATURES ARE ALSO LIKELY FOR MUCH OF THE WEST IN THE WEEK-2  
PERIOD, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. PROBABILITIES FOR BELOW NORMAL  
TEMPERATURES ARE ENHANCED FROM THE GREAT PLAINS ACROSS THE MISSISSIPPI VALLEY  
TO THE APPALACHIANS, UNDER A WEAK TROUGH AND CONSISTENT WITH MOST MODEL TOOLS.  
PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE ENHANCED FOR THE GULF COAST IN  
THE WEEK-2 PERIOD, TO THE SOUTH OF A STATIONARY FRONT. NEAR NORMAL TEMPERATURES  
ARE SLIGHTLY FAVORED FOR MOST OF THE EAST COAST UNDER RISING MID-LEVEL HEIGHTS.  
POSITIVE SEA SURFACE TEMPERATURES IN THE REGION FAVOR ABOVE NORMAL TEMPERATURES  
FOR HAWAII, WITH GREATER PROBABILITIES FOR THE NORTHWESTERN ISLANDS.  
 
UNDER A LESS AMPLIFIED CIRCULATION PATTERN, NEAR NORMAL PRECIPITATION IS  
FAVORED ACROSS MOST OF ALASKA IN THE WEEK-2 PERIOD. ABOVE NORMAL PRECIPITATION  
IS SLIGHTLY FAVORED FOR PARTS OF NORTHERN MAINLAND ALASKA, SUPPORTED BY  
CALIBRATED MODEL PRECIPITATION FORECASTS. PROBABILITIES OF BELOW NORMAL  
PRECIPITATION ARE ENHANCED FOR SOUTHEAST ALASKA, AHEAD OF THE DEAMPLIFYING  
RIDGE. NEAR NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR HAWAII, WITH  
UNCERTAINTY IN MODEL FORECAST TOOLS. NEAR-TO-ABOVE NORMAL PRECIPITATION IS  
SLIGHTLY FAVORED ACROSS THE ENTIRE CONUS IN THE WEEK-2 PERIOD, CONSISTENT WITH  
MOST DYNAMICAL MODEL FORECAST TOOLS. ENHANCED PROBABILITIES EXCEEDING 40  
PERCENT FOR ABOVE NORMAL PRECIPITATION ARE FORECAST FOR PARTS OF THE SOUTHERN  
PLAINS IN THE WEEK-2 PERIOD, SUPPORTED PRIMARILY BY CALIBRATED ECMWF ENSEMBLE  
PRECIPITATION FORECASTS. ENHANCED PROBABILITIES FOR ABOVE NORMAL PRECIPITATION  
ARE ALSO FORECAST FOR MUCH OF THE PACIFIC NORTHWEST WITH A MORE ZONAL ONSHORE  
FLOW PATTERN LATER IN THE WEEK.  
 
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z GFS  
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN  
CENTERED ON DAY 11, AND 25% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON  
DAY 11  
 
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR AVERAGE, 3 OUT OF 5, DUE TO  
GOOD OVERALL AGREEMENT ON THE MID-LEVEL HEIGHT FORECAST, OFFSET BY A  
LOW-AMPLITUDE PATTERN AND WEAK SIGNALS IN THE PRECIPITATION TOOLS FOR MOST  
AREAS.  
 
FORECASTER: D COLLINS  
 
NOTES:  
 
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 1991-2020 BASE PERIOD MEANS AS REFERENCE IN  
THE CLIMATE OUTLOOKS.  
 
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON  
SEPTEMBER 18.  
 
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:  
20040811 - 19600808 - 19940816 - 20090830 - 19630816  
 
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:  
20040811 - 19870903 - 19630815 - 19600808 - 19860905  
 
6-10 DAY OUTLOOK TABLE  
OUTLOOK FOR SEP 02 - 06 2025  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A B OREGON A A NRN CALIF A A  
SRN CALIF A A IDAHO A A NEVADA A A  
W MONTANA A N E MONTANA N N WYOMING N A  
UTAH A A ARIZONA A A COLORADO B A  
NEW MEXICO B A N DAKOTA B N S DAKOTA B N  
NEBRASKA B A KANSAS B A OKLAHOMA B A  
N TEXAS B A S TEXAS A A W TEXAS B A  
MINNESOTA B A IOWA B N MISSOURI B A  
ARKANSAS B A LOUISIANA N N WISCONSIN B A  
ILLINOIS B A MISSISSIPPI B N MICHIGAN B A  
INDIANA B A OHIO B A KENTUCKY B A  
TENNESSEE B A ALABAMA B A NEW YORK B A  
VERMONT N A NEW HAMP N A MAINE A A  
MASS B A CONN B A RHODE IS B A  
PENN B A NEW JERSEY B A W VIRGINIA B A  
MARYLAND B A DELAWARE B A VIRGINIA B A  
N CAROLINA B A S CAROLINA B A GEORGIA B A  
FL PNHDL N A FL PENIN A A AK N SLOPE A A  
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A  
AK S INT A B AK SO COAST A B AK PNHDL A B  
 
 
 
8-14 DAY OUTLOOK TABLE  
OUTLOOK FOR SEP 04 - 10 2025  
 
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN  
WASHINGTON A A OREGON A A NRN CALIF A A  
SRN CALIF A A IDAHO A A NEVADA A A  
W MONTANA A A E MONTANA A A WYOMING A A  
UTAH A A ARIZONA A A COLORADO B A  
NEW MEXICO B A N DAKOTA B N S DAKOTA B N  
NEBRASKA B A KANSAS B A OKLAHOMA B A  
N TEXAS B A S TEXAS B A W TEXAS B A  
MINNESOTA B N IOWA B N MISSOURI B N  
ARKANSAS B N LOUISIANA N N WISCONSIN B N  
ILLINOIS B N MISSISSIPPI B N MICHIGAN B N  
INDIANA B N OHIO B N KENTUCKY B N  
TENNESSEE B N ALABAMA N N NEW YORK B A  
VERMONT N N NEW HAMP N N MAINE N N  
MASS N A CONN N A RHODE IS N A  
PENN B A NEW JERSEY N A W VIRGINIA B A  
MARYLAND N A DELAWARE N A VIRGINIA N A  
N CAROLINA N A S CAROLINA N A GEORGIA N A  
FL PNHDL A A FL PENIN A A AK N SLOPE N A  
AK ALEUTIAN A N AK WESTERN A N AK INT BSN A A  
AK S INT A N AK SO COAST A N AK PNHDL A 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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