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FXUS06 KWBC 261928
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE AUGUST 26 2025
6-10 DAY OUTLOOK FOR SEP 01 - 05 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. AT THE START OF THE 6-10 DAY
PERIOD, ALL MODELS PREDICT A MID-LEVEL RIDGE WITH ASSOCIATED POSITIVE 500-HPA
HEIGHT ANOMALIES ACROSS CANADA. MODEL ENSEMBLE MEANS PREDICT A TROUGH AND
NEGATIVE 500-HPA HEIGHT ANOMALIES TO AMPLIFY OVER THE EASTERN CONTIGUOUS UNITED
STATES (CONUS) AND RETROGRADE WESTWARD, AS THE PERIOD PROGRESSES, WHILE A RIDGE
WITH AN AREA OF AMPLIFIED POSITIVE 500-HPA HEIGHT ANOMALIES CENTERED OVER
SOUTHEAST ALASKA AND THE GULF OF ALASKA, AT THE START OF THE PERIOD, SHIFTS
WESTWARD IN ALL ENSEMBLE MEAN SOLUTIONS. THE ECMWF ENSEMBLE PREDICTS THE MOST
AMPLIFIED POSITIVE 500-HPA HEIGHT ANOMALY OVER THE GULF OF ALASKA RELATIVE TO
THE CANADIAN AND GEFS. THE MANUAL 500-HPA HEIGHT BLEND IS BASED ON THE MOST
RECENT ENSEMBLE MEANS OF THE ECMWF, GEFS AND CANADIAN MODELS, WEIGHING THE
ECMWF MODEL GREATER DUE TO RECENT MODEL ANOMALY CORRELATION SKILL. AMPLIFIED
POSITIVE 500-HPA HEIGHT ANOMALIES ARE CENTERED OVER THE GULF OF ALASKA AND
NORTHEASTERN QUEBEC IN THE 6-10 DAY MEAN MANUAL BLEND, WITH WEAK ANOMALIES OVER
CENTRAL CANADA AND A NEGATIVE 500-HPA HEIGHT ANOMALY ASSOCIATED WITH A TROUGH
ARE PREDICTED TO EXTEND FROM THE UPPER MISSISSIPPI VALLEY TO THE MID-ATLANTIC
AND CAROLINAS.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE EASTERN ALEUTIANS, MOST OF
MAINLAND ALASKA, AND SOUTHEAST ALASKA, EXCLUDING THE NORTHWEST COAST OF
MAINLAND ALASKA, UNDER THE PREDICTED AMPLIFIED RIDGE. ABOVE NORMAL TEMPERATURES
ARE ALSO LIKELY FOR MUCH OF THE WESTERN CONUS, DUE TO THE PREDICTED RIDGE AND
POSITIVE 500-HPA HEIGHT ANOMALIES. WITH A TROUGH PREDICTED TO AMPLIFY AND
RETROGRADE FROM THE EASTERN CONUS TO THE CENTRAL CONUS, BELOW NORMAL
TEMPERATURES ARE FAVORED OVER MOST OF THE CENTRAL AND EASTERN CONUS.
PROBABILITIES EXCEED 50 PERCENT FOR PARTS OF THE CENTRAL EAST COAST, DUE TO
TROUGHING EARLY IN THE PERIOD, AND OVER PARTS OF THE CENTRAL CONUS, AS THE
TROUGH RETROGRADES. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE WESTERN GULF
COAST AND SOUTHERN FLORIDA PENINSULA, TO THE SOUTH OF A PREDICTED STATIONARY
FRONT. MEAN POSITIVE 500-HPA HEIGHT ANOMALIES LEAD TO A FORECAST OF ENHANCED
PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR PARTS OF NORTHERN NEW YORK AND
NORTHERN NEW ENGLAND. 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.
A TROUGH AT THE START OF THE PERIOD OVER THE BERING SEA LEADS TO ENHANCED
PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR THE EASTERN ALEUTIANS, AND
ACROSS CENTRAL AND NORTHERN MAINLAND ALASKA. BELOW NORMAL PRECIPITATION IS
LIKELY FOR SOUTHEAST ALASKA, AHEAD OF THE AMPLIFIED RIDGE, WITH PROBABILITIES
EXCEEDING 60 PERCENT IN THE SOUTHERN ALASKA PENINSULA. NEAR-TO-ABOVE NORMAL
PRECIPITATION IS FAVORED OVER MOST OF THE CONUS FOR THE 6-10 DAY PERIOD,
CONSISTENT WITH MOST MODEL TOOLS. NEAR-TO-BELOW NORMAL PRECIPITATION IS FAVORED
FOR THE PACIFIC NORTHWEST, UNDER THE PREDICTED POSITIVE 500-HPA HEIGHT ANOMALY.
NEAR NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR HAWAII, WHERE FORECAST TOOLS
ARE INCONSISTENT OR INDICATE WEAK SIGNALS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 30% 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 03 - 09 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. AN AMPLIFIED POSITIVE 500-HPA ANOMALY DEAMPLIFIES AND
RETROGRADES OVER THE GULF OF ALASKA INTO THE WEEK-2 PERIOD. POSITIVE 500-HPA
HEIGHT ANOMALIES PERSIST OVER THE NORTHWESTERN CONUS IN THE WEEK-2 MANUAL BLEND
FORECAST. IN THE 8-14 DAY PERIOD, A TROUGH IS PREDICTED OVER THE CENTRAL AND
EASTERN CONUS BY ALL ENSEMBLE MEAN SOLUTIONS, WHICH DEAMPLIFIES SOMEWHAT FROM
THE 6-10 DAY PERIOD. WHERE NEGATIVE 500-HPA HEIGHT ANOMALIES WERE PREDICTED
OVER THE CENTRAL EAST COAST IN THE 6-10 DAY MANUAL BLEND, NEAR ZERO MID-LEVEL
HEIGHT ANOMALIES ARE PREDICTED IN THE WEEK-2 PERIOD.
ABOVE NORMAL TEMPERATURES CONTINUE TO BE LIKELY FOR MOST OF ALASKA, EXCLUDING
PARTS OF NORTHWESTERN MAINLAND ALASKA, UNDER CONTINUED POSITIVE 500-HPA HEIGHT
ANOMALIES. ABOVE NORMAL TEMPERATURES CONTINUE TO BE LIKELY FOR MUCH OF THE WEST
IN THE WEEK-2 PERIOD, CONSISTENT WITH PERSISTENT RIDGING. PROBABILITIES FOR
BELOW NORMAL TEMPERATURES ARE ENHANCED FROM THE HIGH PLAINS ACROSS THE CENTRAL
CONUS TO THE APPALACHIANS, UNDER A PREDICTED 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 THE CAROLINAS, MID-ATLANTIC, AND
SOUTHERN NEW ENGLAND, WITH DIFFERENCES AMONG FORECAST TOOLS RELATED TO RISING
MID-LEVEL HEIGHTS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR A SMALL AREA OF
NORTHERN NEW ENGLAND, UNDER MEAN POSITIVE 500-HPA HEIGHT ANOMALIES. POSITIVE
SEA SURFACE TEMPERATURES IN THE REGION FAVOR ABOVE NORMAL TEMPERATURES FOR MOST
OF HAWAII, EXCLUDING SOUTHEASTERN AREAS OF THE BIG ISLAND.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR MUCH OF NORTHERN MAINLAND
ALASKA, SUPPORTED BY 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. SIGNALS ARE WEAK BUT GENERALLY CONSISTENT
AMONG MODELS. 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.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 30% 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:
19940816 - 20040810 - 19870830 - 19600808 - 19940828
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:
19940817 - 20040810 - 19930805 - 19870830 - 19940828
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 01 - 05 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA N A WYOMING B A
UTAH A A ARIZONA N A COLORADO B A
NEW MEXICO B A N DAKOTA B A S DAKOTA B A
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 A MISSOURI B A
ARKANSAS B A LOUISIANA B A WISCONSIN B A
ILLINOIS B A MISSISSIPPI B A MICHIGAN N A
INDIANA B A OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK N N
VERMONT N N NEW HAMP N A MAINE A N
MASS B A CONN B A RHODE IS B A
PENN N N NEW JERSEY B A W VIRGINIA B N
MARYLAND B N DELAWARE B A VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B A
FL PNHDL B 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 N AK SO COAST A N AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 03 - 09 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA B A WYOMING B 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 N IOWA B N MISSOURI B A
ARKANSAS B A LOUISIANA A A WISCONSIN B N
ILLINOIS B A MISSISSIPPI B A MICHIGAN B A
INDIANA B A OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA N A NEW YORK N A
VERMONT N A NEW HAMP N A MAINE A A
MASS N A CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA B N
MARYLAND N N DELAWARE N N VIRGINIA N N
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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