984
FXUS06 KWBC 091945
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED SEPTEMBER 09 2026
6-10 DAY OUTLOOK FOR SEP 15 - 19 2026
THE 0Z ECMWF, GEFS, AND CMCE ENSEMBLE MODEL FORECASTS CONTINUE TO PREDICT AN
AMPLIFIED 500-HPA RIDGE OVER THE NORTH PACIFIC IN THE 6-10 DAY PERIOD, CENTERED
TO THE SOUTH OF ALASKA IN ALL ENSEMBLE MEANS. POSITIVE 500-HPA HEIGHT ANOMALIES
EXTEND ACROSS THE ALEUTIANS, MAINLAND ALASKA, AND SOUTHEAST ALASKA. A TROUGH IS
PREDICTED TO THE SOUTHEAST OF THE NORTH PACIFIC RIDGE OVER THE NORTHWESTERN
CONTIGUOUS UNITED STATES (CONUS). WHILE ENSEMBLE MEAN FORECASTS GENERALLY AGREE
IN PREDICTING A RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES ACROSS MUCH OF THE
CONUS IN THE 6-10 DAY PERIOD, DIFFERENCES BETWEEN MODELS ARE APPARENT IN THE
EVOLUTION OF THE MID-LEVEL HEIGHT PATTERN DURING THE PERIOD. ENSEMBLE MEANS
PREDICT A SHORTWAVE TROUGH OVER THE NORTHWESTERN CONUS AT THE START OF THE 6-10
DAY PERIOD, WITH A RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE EASTERN
CONUS. LATER IN THE 6-10 DAY PERIOD AS THE RIDGE SHIFTS WESTWARD IN THE ECMWF
ENSEMBLE MEAN, POSITIVE 500-HPA HEIGHT ANOMALIES INCREASE OVER THE NORTHWESTERN
CONUS. HOWEVER, TROUGHING PERSISTS OVER THE WESTERN CONUS IN THE GEFS AND
CANADIAN ENSEMBLE MEANS. A TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES PUSH
SOUTHWARD INTO THE NORTHEASTERN CONUS IN ALL MODELS, WITH A DEEPER TROUGH IN
THE ECMWF ENSEMBLE MEAN. 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 PREDICTED AMPLIFIED RIDGE OVER THE NORTH PACIFIC AND ASSOCIATED POSITIVE
500-HPA HEIGHT ANOMALIES LEAD TO LIKELY ABOVE NORMAL TEMPERATURES FOR ALL OF
ALASKA. DUE TO PREDICTED TROUGHING OVER THE NORTHWESTERN CONUS EARLY IN THE
6-10 DAY PERIOD AND CONSISTENT WITH THE ECMWF FORECASTS, BELOW NORMAL
TEMPERATURES ARE FAVORED FROM THE NORTHERN ROCKIES EASTWARD ACROSS THE NORTHERN
PLAINS. UNDER GENERALLY POSITIVE 500-HPA HEIGHT ANOMALIES, ABOVE NORMAL
TEMPERATURES ARE LIKELY FOR A SUBSTANTIAL PORTION OF THE SOUTHERN TIER AND
EASTERN CONUS, INCLUDING SOUTHERN CALIFORNIA, THE SOUTHWEST, THE SOUTHERN GREAT
PLAINS, AND MOST AREAS EAST OF THE MISSISSIPPI, EXCLUDING THE WESTERN GREAT
LAKES REGION AND NORTHERN MAINE. ABOVE NORMAL TEMPERATURES ARE VERY LIKELY FOR
HAWAII, CONSISTENT WITH THE CONSOLIDATION OF ECMWF AND GEFS REFORECAST
CALIBRATED TEMPERATURE FORECASTS.
THE PREDICTED LOCATION OF THE AMPLIFIED RIDGE OVER THE NORTH PACIFIC AND
SOUTHWESTERLY MID-LEVEL FLOW LEADS TO ELEVATED PROBABILITIES OF ABOVE NORMAL
PRECIPITATION FOR THE EASTERN ALEUTIANS AND MAINLAND ALASKA. BELOW NORMAL
PRECIPITATION IS FAVORED FOR MOST OF SOUTHEAST ALASKA, UNDER THE RIDGE AND
CONSISTENT WITH MOST PRECIPITATION TOOLS. TELECONNECTIONS TO THE NORTH PACIFIC
RIDGE FAVOR BELOW NORMAL PRECIPITATION FOR WESTERN AREAS OF THE PACIFIC
NORTHWEST. DYNAMICAL MODEL FORECASTS FAVOR ELEVATED PROBABILITIES OF ABOVE
NORMAL PRECIPITATION FOR MUCH OF THE REMAINDER OF THE CONUS FROM SOUTHERN
CALIFORNIA, THE GREAT BASIN, AND THE NORTHERN ROCKIES EASTWARD, EXCLUDING THE
GULF AND SOUTHEAST ATLANTIC COASTAL REGIONS. NEAR NORMAL PRECIPITATION IS
FAVORED OVER THESE AREAS OF THE SOUTHEASTERN CONUS, WITH WEAK SIGNALS IN RAW
MODEL PRECIPITATION TOOLS AND UNDER A RIDGE. ABOVE NORMAL PRECIPITATION IS
FAVORED FOR HAWAII CONSISTENT WITH THE PRECIPITATION CONSOLIDATION, WITH
POTENTIAL IMPACTS OF FUTURE TROPICAL SYSTEMS.
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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT BETWEEN MODEL FORECASTS OF THE MEAN LARGE-SCALE MID-LEVEL HEIGHT
PATTERN, OFFSET BY UNCERTAINTY IN THE VARIABLE PATTERN DURING THE PERIOD, AND
DIFFERENCES AMONG MODEL TEMPERATURE TOOLS FOR THE CONUS.
8-14 DAY OUTLOOK FOR SEP 17 - 23 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, AS UNCERTAINTY
INCREASES. THE AMPLIFIED RIDGE OVER THE NORTH PACIFIC PROGRESSES EASTWARD INTO
SOUTHEAST ALASKA AND DEAMPLIFIES SOMEWHAT IN ALL ENSEMBLE MEAN FORECASTS DURING
THE WEEK-2 PERIOD. A RIDGE AND WEAK POSITIVE 500-HPA HEIGHT ANOMALIES PERSIST
OVER MOST OF THE CONUS IN ENSEMBLE MEANS AND THE MANUAL BLEND. A WEAK TROUGH
REMAINS NEAR THE COAST OF NORTHERN CALIFORNIA THROUGH MOST OF WEEK 2, AND A
TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES EXPAND OVER THE NORTHEASTERN CONUS
LATER IN THE PERIOD. MID-LEVEL HEIGHT ANOMALIES DEAMPLIFY ACROSS THE CONUS
LATER IN THE 8-14 DAY PERIOD, AS MODEL FORECAST DIFFERENCES INCREASE. WEAK
POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST ACROSS NEARLY THE ENTIRE CONUS
IN THE WEEK-2 MANUAL BLEND, WITH NEAR AVERAGE 500-HPA HEIGHTS PREDICTED OVER
NORTHERN CALIFORNIA AND NORTHERN NEW ENGLAND.
UNDER POSITIVE 500-HPA HEIGHT ANOMALIES, ABOVE NORMAL TEMPERATURES CONTINUE TO
BE FAVORED FOR THE ALEUTIANS, SOUTHEAST ALASKA, AND MOST OF MAINLAND ALASKA
EXCLUDING PARTS OF THE NORTHWESTERN AND NORTHERN MAINLAND. ABOVE NORMAL
TEMPERATURE PROBABILITIES ARE ELEVATED FOR THE WESTERN CONUS FROM THE COAST TO
THE ROCKIES AND MOST OF THE CENTRAL AND SOUTHERN GREAT PLAINS, CONSISTENT WITH
MOST MODEL FORECASTS AND A WESTWARD SHIFT OF THE MEAN LOCATION OF THE RIDGE
FROM THE 6-10 DAY PERIOD. UNDER A PREDICTED TROUGH LATER IN THE WEEK-2 PERIOD,
BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE NORTHERN PLAINS, WESTERN
GREAT LAKES REGION, AND NORTHERN AREAS OF THE NORTHEAST, CONSISTENT WITH THE
CONSOLIDATION. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR THE LOWER MIDWEST, THE
MID-ATLANTIC, AND THE SOUTHEASTERN CONUS, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION. MOST MODEL TOOLS AGREE ON A FORECAST OF HIGH PROBABILITIES OF
ABOVE NORMAL TEMPERATURES FOR HAWAII.
DESPITE SOME DEAMPLIFICATION, THE RIDGE OVER SOUTHEAST ALASKA IN WEEK 2
CONTINUES TO SLIGHTLY FAVOR ABOVE NORMAL PRECIPITATION FOR THE EASTERN
ALEUTIANS AND MOST OF MAINLAND ALASKA, EXCLUDING PARTS OF THE NORTHERN
MAINLAND, WHILE BELOW NORMAL PRECIPITATION IS FAVORED FOR LOWER SOUTHEAST
ALASKA, UNDER THE RIDGE. BELOW NORMAL PRECIPITATION CONTINUES TO BE SLIGHTLY
FAVORED FOR PARTS OF THE PACIFIC NORTHWEST, CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION. DYNAMICAL MODEL PRECIPITATION TOOLS AND THE CONSOLIDATION
CONTINUE TO FAVOR ABOVE NORMAL PRECIPITATION ACROSS MOST OF THE CONUS, OUTSIDE
OF NORTHERN CALIFORNIA, THE PACIFIC NORTHWEST, AND ALONG THE CANADIAN BORDER
FROM THE NORTHERN ROCKIES TO THE WESTERN GREAT LAKES REGION. PRECIPITATION
SIGNALS ARE LESS CONSISTENT FOR THE EASTERN CONUS, WITH A VARIABLE CIRCULATION
PATTERN AND DIFFERENCES AMONG MODEL FORECASTS. ABOVE NORMAL PRECIPITATION IS
FAVORED ACROSS HAWAII WITH GREATER PROBABILITIES FOR THE BIG ISLAND, CONSISTENT
WITH THE ECMWF REFORECAST CALIBRATED PRECIPITATION.
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: BELOW AVERAGE, 2 OUT OF 5, DUE TO
GENERAL AGREEMENT AMONG DYNAMICAL MODELS ON THE 500-HPA HEIGHT PATTERN, OFFSET
BY DIFFERENCES AMONG MODEL TEMPERATURE FORECASTS AND WEAK PRECIPITATION SIGNALS
OVER THE EASTERN 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
SEPTEMBER 17.
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:
20050910 - 20220919 - 20240820 - 20190918 - 20140824
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:
20050908 - 20240819 - 20220918 - 20190918 - 20140824
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 15 - 19 2026
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON N N NRN CALIF N N
SRN CALIF A A IDAHO N A NEVADA N N
W MONTANA B A E MONTANA B A WYOMING N A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA B A S DAKOTA N A
NEBRASKA N A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A N W TEXAS A A
MINNESOTA N A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN N A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A 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 B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 17 - 23 2026
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A N
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A N E MONTANA N N WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA N N S DAKOTA N A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA B N IOWA N A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN N N
ILLINOIS A A MISSISSIPPI A A MICHIGAN N A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK N A
VERMONT N A NEW HAMP N A MAINE B A
MASS N A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A 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 A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A 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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