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FXUS06 KWBC 121902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI SEPTEMBER 12 2025
6-10 DAY OUTLOOK FOR SEP 18 - 22 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 SOUTHWESTERN MAINLAND ALASKA
AND EASTERN ALEUTIAN ISLANDS IN THE 6-10 DAY PERIOD. AN AMPLIFIED RIDGE AND
ABOVE NORMAL 500-HPA HEIGHT ARE PREDICTED ACROSS CANADA IN THE 6-10 DAY PERIOD,
WITH POSITIVE 500-HPA HEIGHT ANOMALIES EXTENDING INTO THE NORTH-CENTRAL AND
NORTHEASTERN CONTIGUOUS UNITED STATES (CONUS). IN THE MANUAL BLEND OF MODEL
FORECASTS, WEAK TROUGHS AND WEAK BELOW NORMAL MID-LEVEL HEIGHTS ARE PREDICTED
OVER THE WEST COAST AND 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 THE ENTIRE CONUS,
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.
NEAR TO ABOVE NORMAL PRECIPITATION IS FAVORED FOR MAINLAND ALASKA AND SOUTHEAST
ALASKA, AHEAD OF A PREDICTED TROUGH. NEAR TO ABOVE NORMAL PRECIPITATION IS ALSO
FAVORED IN THE 6-10 DAY PERIOD FOR WESTERN AND CENTRAL CONUS EXTENDING EASTWARD
TO THE UPPER AND MIDDLE MISSISSIPPI VALLEY, AND THE WESTERN UPPER GREAT LAKES,
CONSISTENT WITH MOST MODEL FORECAST TOOLS AND THE CONSOLIDATION. BELOW NORMAL
PRECIPITATION IS FAVORED FOR MUCH OF TEXAS AND THE LOWER MISSISSIPPI VALLEY,
WITH A STORM TRACK TO THE NORTH AND CONSISTENT WITH MOST MODEL PRECIPITATION
FORECASTS. PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE SLIGHTLY ENHANCED
FOR THE SOUTHERN ATLANTIC COAST, WHILE BELOW NORMAL PRECIPITATION IS FORECAST
OVER PARTS OF THE NORTHEASTERN CONUS, 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 20 - 26 2025
ENSEMBLE MEAN FORECASTS FOR THE 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA
REMAIN IN GOOD AGREEMENT. A TROUGH IS FORECAST OVER THE EASTERN ALEUTIAN
ISLANDS, THE GULF OF ALASKA, AND THE PACIFIC NORTHWEST 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 NORTH-CENTRAL AND NORTHEASTERN 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, WHILE NEAR TO BELOW NORMAL
TEMPERATURES ARE FAVORED OVER PARTS OF NORTHWESTERN MAINLAND ALASKA, CONSISTENT
WITH MOST OF THE TEMPERATURE FORECAST TOOLS. ABOVE NORMAL TEMPERATURES ARE
FAVORED ACROSS THE ENTIRE CONUS, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES AND
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, AND UPPER AND MIDDLE MISSISSIPPI VALLEY IN WEEK 2,
DOWNSTREAM OF A MID-LEVEL TROUGH AND CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION AND MOST MODEL TOOLS. A TILT TOWARDS DRY FOR WEEK-2 IS FORECAST
ACROSS PARTS OF SOUTHEASTERN TEXAS, THE LOWER MISSISSIPPI VALLEY, AND THE
NORTHEAST, WHILE ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF
THE SOUTHEAST, 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:
20090913 - 20090827 - 20010924 - 19810917 - 20030903
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:
20090914 - 20090826 - 20090909 - 20010925 - 19810915
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 18 - 22 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N 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 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 N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A A 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 B NEW HAMP A N MAINE A N
MASS A N CONN A B 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 A S CAROLINA A A GEORGIA A N
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN A N 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 20 - 26 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 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 N S TEXAS A N W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
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 N FL PENIN A A AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN A N AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A A
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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