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FXUS06 KWBC 111901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU SEPTEMBER 11 2025
6-10 DAY OUTLOOK FOR SEP 17 - 21 2025
THE ECMWF, GEFS AND CANADIAN ENSEMBLE MODELS BROADLY AGREE ON THE 500-HPA
HEIGHT PATTERN OVER NORTH AMERICA AND SURROUNDING REGIONS DURING THE 6-10 DAY
PERIOD, WITH ONLY MINOR VARIATIONS AMONG THE MODELS IN TERMS OF AMPLITUDE AND
PHASE OF PREDICTED WAVE FEATURES. THE MANUAL HEIGHT BLEND IS BASED ON ENSEMBLE
MEANS, WEIGHING THE ECMWF MODEL GREATER DUE TO RECENT MODEL ANOMALY CORRELATION
SKILL. THE MANUAL BLEND SHOWS A WEAK TROUGH OVER EASTERN ALEUTIAN ISLANDS AND
THE ALASKA PENINSULA IN THE 6-10 DAY PERIOD. AN AMPLIFIED RIDGE IS PREDICTED
ACROSS CANADA IN THE 6-10 DAY PERIOD, EXTENDING INTO THE NORTH-CENTRAL
CONTIGUOUS UNITED STATES (CONUS). IN THE MANUAL BLEND OF MODEL FORECASTS,
POSITIVE 500-HPA HEIGHT ANOMALIES ARE PREDICTED ACROSS MOST OF THE CONUS IN THE
6-10 DAY PERIOD, WHILE WEAK TROUGHING AND NEAR NORMAL MID-LEVEL HEIGHTS ARE
PREDICTED OVER THE SOUTHEAST. NEAR TO SLIGHTLY BELOW NORMAL 500-HPA HEIGHTS ARE
PREDICTED ACROSS HAWAII.
NEAR NORMAL TEMPERATURES ARE FAVORED FOR PORTIONS OF NORTHWESTERN MAINLAND
ALASKA UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW, WHILE ABOVE NORMAL
TEMPERATURES ARE MORE LIKELY FOR THE REMAINDER OF MAINLAND ALASKA AND SOUTHEAST
ALASKA UNDER MEAN POSITIVE 500-HPA HEIGHT ANOMALIES AND SOUTHERLY FLOW. IN THE
6-10 DAY PERIOD, ABOVE NORMAL TEMPERATURES ARE LIKELY ACROSS MOST OF THE CONUS
EXCLUDING PARTS OF WYOMING AND MONTANA, INFLUENCED BY THE AMPLIFIED RIDGE AND
POSITIVE 500-HPA HEIGHT ANOMALIES, SUPPORTED BY MOST OF THE DYNAMICAL
TEMPERATURE FORECAST TOOLS. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR HAWAII,
CONSISTENT WITH THE CONSOLIDATION OF CALIBRATED ECMWF AND GEFS FORECASTS AND
ABOVE AVERAGE SEA SURFACE TEMPERATURES ACROSS MUCH OF THE REGION.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF MAINLAND ALASKA, AHEAD OF A
PREDICTED TROUGH. NEAR TO BELOW NORMAL PRECIPITATION IS FORECAST FOR SOUTHERN
PORTIONS OF SOUTHEAST ALASKA.. AS MID-LEVEL HEIGHTS RISE OVER THE WESTERN
CONUS, PRECIPITATION IS PREDICTED TO DECREASE LEADING TO ENHANCED PROBABILITIES
OF BELOW NORMAL PRECIPITATION OVER PARTS OF NORTHWESTERN CONUS. ABOVE NORMAL
PRECIPITATION IS FAVORED IN THE 6-10 DAY PERIOD FOR CENTRAL AND SOUTHERN
CALIFORNIA, THE SOUTHWEST, THE NORTHERN ROCKIES, THE HIGH PLAINS, THE UPPER
AND MIDDLE MISSISSIPPI VALLEY, AND THE UPPER GREAT LAKES, CONSISTENT WITH MOST
MODEL FORECAST TOOLS AND THE CONSOLIDATION. BELOW NORMAL PRECIPITATION IS
FAVORED FOR PARTS OF SOUTHEASTERN TEXAS, THE LOWER MISSISSIPPI VALLEY, THE
SOUTHEAST, THE TENNESSEE VALLEY, AND THE OHIO VALLEY, UNDER ANOMALOUS NORTHERLY
FLOW AHEAD OF THE PREDICTED RIDGE AND CONSISTENT WITH MOST MODEL PRECIPITATION
FORECASTS. PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE SLIGHTLY ENHANCED
FOR THE FLORIDA PENINSULA IN THE 6-10 DAY PERIOD, CONSISTENT WITH THE
PRECIPITATION CONSOLIDATION. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE
HAWAIIAN ISLANDS, CONSISTENT WITH THE AUTO BLEND OF PRECIPITATION FORECAST
TOOL.
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 19 - 25 2025
ENSEMBLE MEAN FORECASTS FOR THE 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA
REMAIN IN GENERAL AGREEMENT AND A TRANSITION IN THE 500-HPA PATTERN IS WELL
UNDERWAY ACROSS MUCH OF THE COUNTRY DURING THE 8-14 DAY PERIOD. AS TIME
PROGRESSES, THE PATTERN EVOLVES AND SOMEWHAT DEAMPLIFIES. A WEAK TROUGH
PERSISTS OVER THE EASTERN ALEUTIAN ISLANDS BUT DEAMPLIFIES DURING THE 8-14 DAY
PERIOD IN ALL ENSEMBLE MEAN FORECASTS. AN AMPLIFIED RIDGE AND ASSOCIATED
POSITIVE 500-HPA HEIGHT ANOMALIES PERSIST OVER CANADA THROUGH THE 8-14 DAY
PERIOD, WITH POSITIVE 500-HPA HEIGHT ANOMALIES EXTENDING SOUTHWARD ACROSS MOST
OF THE NORTHERN CONUS. A WEAK TROUGH AND SLIGHTLY NEGATIVE 500-HPA HEIGHT
ANOMALIES PERSIST OVER THE SOUTHEASTERN CONUS IN THE 8-14 DAY PERIOD MANUAL
BLEND. GENERALLY NEAR TO BELOW NORMAL HEIGHTS ARE FORECAST FOR HAWAII
THROUGHOUT THE PERIOD.
ABOVE NORMAL TEMPERATURES ARE LIKELY OVER A LARGER AREA OF MAINLAND AND
SOUTHEAST ALASKA IN THE 8-14 DAY PERIOD, EXCLUDING PARTS OF NORTHWESTERN
MAINLAND ALASKA, AS THE PREDICTED TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES
TO THE SOUTH OF THE STATE DEAMPLIFY AND POSITIVE 500-HPA HEIGHT ANOMALIES
INCREASE IN MAGNITUDE AND EXTENT ACROSS MAINLAND ALASKA. ABOVE NORMAL
TEMPERATURES ARE FAVORED ACROSS THE ENTIRE CONUS, UNDER POSITIVE 500-HPA HEIGHT
ANOMALIES, SUPPORTED BY MOST OF THE TEMPERATURE FORECAST TOOLS. ABOVE NORMAL
TEMPERATURES ARE LIKELY FOR HAWAII, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION AND ABOVE AVERAGE SEA SURFACE TEMPERATURES AROUND THE
NORTHWESTERN ISLANDS.
NEAR TO ABOVE NORMAL PRECIPITATION CONTINUES TO BE FAVORED FOR MAINLAND ALASKA
AND SOUTHEAST ALASKA IN THE 8-14 DAY PERIOD, CONSISTENT WITH MOST DYNAMICAL
MODEL FORECASTS. NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE
WESTERN AND CENTRAL CONUS (EXCEPT FOR WESTERN WASHINGTON, WHERE BELOW NORMAL
PRECIPITATION IS FAVORED UNDER POSITIVE 500-PA HEIGHT ANOMALIES) IN WEEK 2,
CONSISTENT WITH THE PRECIPITATION CONSOLIDATION AND MOST MODEL TOOLS. A TILT
TOWARDS DRY FOR WEEK-2 ACROSS PARTS OF SOUTHEASTERN TEXAS, THE LOWER
MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, AND THE OHIO VALLEY, WHILE ABOVE
NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF THE SOUTHEAST, AND THE
NORTHEAST, BASED ON THE UNCALIBRATED 7-DAY ECENS AND ALSO SUPPORTED BY SOME
DYNAMICAL PRECIPITATION FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS SLIGHTLY
FAVORED FOR THE HAWAIIAN ISLANDS, CONSISTENT WITH THE AUTO FORECAST BLEND.
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
DEAMPLIFYING PATTERN AND WEAK SIGNALS IN THE PRECIPITATION TOOLS FOR MANY AREAS.
FORECASTER: LUKE H
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:
19510904 - 19950907 - 20060907 - 20030902 - 20090827
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:
19510903 - 20090826 - 19950907 - 20030901 - 20090914
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 17 - 21 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A B
SRN CALIF A A IDAHO A B NEVADA A A
W MONTANA A N E MONTANA A A WYOMING N A
UTAH A 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 B S TEXAS A B W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A A AK N SLOPE N 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 A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 19 - 25 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A N NEVADA A A
W MONTANA A N E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A N
NEW MEXICO A A N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A N NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A A FL PENIN A N AK N SLOPE A A
AK ALEUTIAN A N AK WESTERN A N AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A 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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