095
FXUS06 KWBC 211917
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON SEPTEMBER 21 2026
6-10 DAY OUTLOOK FOR SEP 27 - OCT 01, 2026
THE 0Z ECMWF, GEFS, AND CANADIAN ENSEMBLE MODEL FORECASTS PREDICT A RIDGE AND
POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE WESTERN AND CENTRAL ALEUTIAN
ISLANDS. ALL MODELS PREDICT A TROUGH DOWNSTREAM OVER SOUTHERN MAINLAND ALASKA
AND THE NORTHEASTERN PACIFIC. THIS TROUGH IS PREDICTED TO AMPLIFY DURING THE
MIDDLE OF THE 6-10 DAY PERIOD BEFORE DEAMPLIFYING LATER IN THE PERIOD. ALTHOUGH
MODELS AGREE ON THE PREDICTION OF THIS TROUGH OVER THE NORTHEASTERN PACIFIC,
MODEL HEIGHT FORECAST DIFFERENCES ARE SIGNIFICANT OVER THE CONTIGUOUS UNITED
STATES (CONUS). THE MANUAL HEIGHT BLEND IS BASED ON THE 0Z ECMWF, GEFS, AND
CANADIAN MODEL 500-HPA HEIGHT FORECASTS, WEIGHTING THE ECMWF ENSEMBLE MEAN
GREATER DUE TO RECENT MODEL SKILL. THE MANUAL BLEND PREDICTS NEGATIVE 500-HPA
HEIGHT ANOMALIES OVER PARTS OF THE PACIFIC NORTHWEST DURING THE 6-10 DAY
PERIOD, AHEAD OF THE TROUGH. THE ECMWF AND GEFS ENSEMBLE MEAN FORECASTS PREDICT
ANOMALOUS MID-LEVEL RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES EXTENDING
FROM THE CENTRAL ROCKIES TO THE NORTHERN CENTRAL AND NORTHEASTERN CONUS, WITH A
POSITIVE ANOMALY CENTER OVER NORTHERN QUEBEC. A TROUGH AND NEGATIVE 500-HPA
HEIGHT ANOMALIES IS PREDICTED OVER THE EASTERN SEABOARD EARLY IN THE 6-10 DAY
PERIOD BY ALL ENSEMBLE MEANS. A SHORTWAVE TROUGH DEVELOPS OVER THE NORTHERN
CENTRAL CONUS IN ALL MODELS AROUND DAY 8. THIS TROUGH AMPLIFIES SIGNIFICANTLY
IN THE CANADIAN ENSEMBLE MEAN, WHILE THE ECMWF MODEL PREDICTS INCREASING
POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE NORTHERN CENTRAL CONUS AND GREAT
LAKES REGION LATER IN THE PERIOD. A TROPICAL SYSTEM IS PREDICTED TO PASS NEAR
THE SOUTHEASTERN ISLANDS OF HAWAII BY THE ECMWF MODEL IN PARTICULAR.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE ALEUTIAN ISLANDS, UNDER
PREDICTED POSITIVE 500-HPA HEIGHT ANOMALIES. BELOW NORMAL TEMPERATURES ARE
SLIGHTLY FAVORED FOR THE FAR NORTHWESTERN COAST OF MAINLAND ALASKA, CONSISTENT
WITH THE CONSOLIDATION OF CALIBRATED ECMWF AND GEFS FORECASTS. ABOVE NORMAL
TEMPERATURES ARE SLIGHTLY FAVORED FOR SOUTHEASTERN MAINLAND ALASKA, UNDER
PREDICTED ANOMALOUS SOUTHERLY FLOW. UNDER THE PREDICTED RIDGE AND SLIGHTLY
POSITIVE 500-HPA HEIGHT ANOMALIES, ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS
MOST OF THE CONUS, CONSISTENT WITH THE TEMPERATURE CONSOLIDATION. NEAR NORMAL
TEMPERATURES ARE FAVORED FOR MUCH OF THE NORTHWESTERN CONUS, CONSISTENT WITH
THE CONSOLIDATION AND AHEAD OF THE PREDICTED TROUGH OVER THE NORTHEASTERN
PACIFIC. NEAR NORMAL TEMPERATURES ARE FAVORED FOR THE SOUTHERN MID-ATLANTIC AND
SOUTHEAST ATLANTIC COASTS, UNDER A PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES
ARE FAVORED FOR HAWAII WITH HIGHER PROBABILITIES FOR THE BIG ISLAND, CONSISTENT
WITH THE CALIBRATED ECMWF TEMPERATURE FORECAST.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE ALEUTIANS, CONSISTENT
WITH THE AUTOMATED BLEND OF FORECAST TOOLS AND THE CONSOLIDATION OF CALIBRATED
ECMWF AND GEFS FORECASTS. PRECIPITATION SIGNALS ARE WEAK OR INCONSISTENT ACROSS
MUCH OF MAINLAND ALASKA, LEADING TO A FORECAST OF NEAR NORMAL. ABOVE NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR SOUTHEASTERN MAINLAND ALASKA AND THERE IS
ENHANCED PROBABILITY OF ABOVE NORMAL PRECIPITATION FOR SOUTHEAST ALASKA, AHEAD
OF THE PREDICTED TROUGH. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED FOR THE
PACIFIC NORTHWEST AHEAD OF THE TROUGH OVER THE NORTHEASTERN PACIFIC.
PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR THE SOUTHWEST ARE ENHANCED,
EXCEEDING 50 PERCENT IN SOME AREAS, AS MODELS PREDICT ENHANCED MOISTURE FLOW
FROM THE EASTERN PACIFIC INTO THE REGION. ABOVE NORMAL PRECIPITATION IS FAVORED
FOR THE CENTRAL AND SOUTHERN ROCKIES, THE GREAT PLAINS, AND THE MISSISSIPPI
VALLEY, WHILE BELOW NORMAL PRECIPITATION IS FAVORED FOR THE EASTERN OHIO VALLEY
AND EASTERN GREAT LAKES REGION, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION
AND TELECONNECTIONS TO THE POSITIVE HEIGHT ANOMALY CENTER OVER QUEBEC.
DYNAMICAL MODELS FORECASTS CONSISTENTLY FAVOR ABOVE NORMAL PRECIPITATION FOR
THE GULF COAST REGION. ABOVE NORMAL PRECIPITATION IS FAVORED FOR HAWAII, WITH
THE PREDICTION OF A POTENTIAL LOW PRESSURE SYSTEM NEAR THE ISLAND CHAIN.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 45% 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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT BETWEEN MODEL FORECASTS OF THE MEAN LARGE-SCALE MID-LEVEL HEIGHT
PATTERN, OFFSET BY DIFFERENCES AMONG MODEL ENSEMBLE MEAN HEIGHT FORECASTS FOR
THE CONUS.
8-14 DAY OUTLOOK FOR SEP 29 - OCT 05, 2026
THE OVERALL PREDICTED 500-HPA HEIGHT PATTERN IS RELATIVELY SIMILAR IN THE 8-14
DAY PERIOD ENSEMBLE MODEL FORECASTS, WITH SOME EVOLUTION OF THE PATTERN AND
DEAMPLIFICATION RELATIVE TO THE 6-10 DAY PERIOD FORECAST. A RIDGE AND POSITIVE
500-HPA HEIGHT ANOMALIES PERSIST OVER PARTS OF THE WESTERN ALEUTIANS IN THE
8-14 DAY PERIOD IN ALL MODEL FORECASTS, WITH A TROUGH AND NEGATIVE 500-PA
HEIGHT ANOMALIES OVER PARTS OF SOUTHERN MAINLAND ALASKA AND THE NORTHEASTERN
PACIFIC. WHILE ALL MODEL WEEK-2 500-HPA HEIGHT FORECASTS ARE SIMILAR TO THEIR
RESPECTIVE 6-10 DAY FORECASTS, THERE ARE SIGNIFICANT DIFFERENCES IN THE ECMWF,
GEFS AND CANADIAN ENSEMBLE MEANS. THE MANUAL BLEND CONTINUES TO WEIGHT THE
ECMWF MODEL GREATER, PREDICTING POSITIVE 500-HPA HEIGHT ANOMALIES THAT EXTEND
FROM THE GREAT BASIN AND CENTRAL ROCKIES TO THE NORTHERN CENTRAL CONUS. NEAR
AVERAGE 500-HPA HEIGHTS ARE PREDICTED OVER THE PACIFIC NORTHWEST IN THE 8-14
DAY PERIOD MANUAL BLEND, WHILE TROUGHING AND WEAK NEGATIVE 500-HPA HEIGHT
ANOMALIES ARE PREDICTED OVER THE SOUTHEASTERN CONUS.
ABOVE NORMAL TEMPERATURES CONTINUE TO BE FAVORED ACROSS MOST OF THE ALEUTIANS
IN WEEK 2, UNDER PERSISTENT POSITIVE 500-HPA HEIGHT ANOMALIES. BELOW NORMAL
TEMPERATURES ARE FAVORED FOR THE WESTERN MAINLAND, UNDER INCREASING TROUGHING
AND CONSISTENT WITH THE TEMPERATURE CONSOLIDATION. ABOVE NORMAL TEMPERATURES
ARE SLIGHTLY FAVORED FOR SOUTHEASTERN MAINLAND ALASKA AND SOUTHEAST ALASKA,
UNDER ANOMALOUS SOUTHERLY FLOW. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS
NEARLY THE ENTIRE CONUS IN WEEK 2, AS A PREDICTED RIDGE PERSISTS WITH POSITIVE
500-HPA HEIGHT ANOMALIES FROM THE SOUTHWESTERN TO THE NORTHERN CENTRAL CONUS.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE ENTIRE EAST COAST IN WEEK 2, AS
MID-LEVEL HEIGHTS ARE PREDICTED TO RISE FROM THE 6-10 DAY PERIOD FORECAST IN
THE MANUAL BLEND. NEAR NORMAL TEMPERATURES ARE FAVORED FOR COASTAL AREAS OF THE
PACIFIC NORTHWEST, AHEAD OF A PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES ARE
FAVORED FOR HAWAII WITH GREATER PROBABILITIES FOR THE BIG ISLAND, CONSISTENT
WITH THE TEMPERATURE CONSOLIDATION.
ABOVE NORMAL PRECIPITATION CONTINUES TO BE FAVORED ACROSS MOST OF THE ALEUTIANS
IN WEEK 2, CONSISTENT WITH THE AUTOMATED BLEND OF FORECAST TOOLS. PRECIPITATION
SIGNALS ARE WEAK ACROSS MOST OF MAINLAND ALASKA, FAVORING NEAR NORMAL. ABOVE
NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR SOUTHEASTERN MAINLAND ALASKA,
SOUTHEAST ALASKA, AND THE PACIFIC NORTHWEST, AHEAD OF THE PREDICTED TROUGH OVER
THE NORTHEASTERN PACIFIC. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE
SOUTHWEST, WITH CONTINUED MOISTURE FLOW FROM THE EASTERN PACIFIC. NEAR NORMAL
PRECIPITATION IS FORECAST IN CLIMATOLOGICALLY ARID AND SEMI-ARID REGIONS OF THE
WEST WHERE THE PRECIPITATION CONSOLIDATION ANOMALIES ARE SMALL. CONSISTENT WITH
TELECONNECTIONS TO THE POSITIVE 500-HPA HEIGHT ANOMALY CENTER OVER QUEBEC AND
THE PRECIPITATION CONSOLIDATION, ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH
OF THE CENTRAL CONUS. ABOVE NORMAL PRECIPITATION IS INCREASINGLY FAVORED TO THE
EAST OF THE MISSISSIPPI VALLEY IN WEEK 2, EXCLUDING THE NORTHEAST, AS THE
PREDICTED TROUGH OVER THE SOUTHEAST DEAMPLIFIES. ABOVE NORMAL PRECIPITATION IS
FAVORED FOR HAWAII, CONSISTENT WITH THE CALIBRATED ECMWF PRECIPITATION FORECAST.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 45% 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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT BETWEEN MODEL FORECASTS OF THE MEAN LARGE-SCALE MID-LEVEL HEIGHT
PATTERN, OFFSET BY CONTINUED DIFFERENCES AMONG MODEL ENSEMBLE MEAN HEIGHT
FORECASTS FOR THE CONUS.
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 (GRAY, "N") NORMAL.
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 (GRAY, "N")
NORMAL. 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
2026-09-21.
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:
20240904 - 20200920 - 20171005 - 20250910 - 20190912
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:
20171004 - 20230902 - 20240831 - 20251004 - 20050919
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 27 - OCT 01, 2026
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N N NRN CALIF A N
SRN CALIF A A IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N 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 A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A N
INDIANA A N OHIO A B KENTUCKY A N
TENNESSEE A N ALABAMA A A 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 B NEW JERSEY A N W VIRGINIA A B
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA N N GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N
AK S INT N N AK SO COAST A A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 29 - OCT 05, 2026
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
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 A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A 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 A
MARYLAND A N DELAWARE A N VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN B N AK INT BSN N N
AK S INT N N 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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