196
FXUS06 KWBC 081914
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 08 2025
6-10 DAY OUTLOOK FOR SEP 14 - 18 2025
THE RECENT ECMWF, GEFS AND CANADIAN ENSEMBLE MEANS 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. MODELS PREDICT A TROUGH AND
ASSOCIATED NEGATIVE 500-HPA HEIGHT ANOMALIES OVER THE NORTH PACIFIC TO THE
SOUTH OF THE ALASKA PENINSULA IN THE 6-10 DAY PERIOD MEAN. MODELS PREDICT
WESTWARD RETROGRESSION OF THE TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES FROM
THE GULF OF ALASKA EARLY IN THE PERIOD TO SOUTH OF THE EASTERN ALEUTIANS LATER
IN THE PERIOD. AN AMPLIFIED RIDGE IS PREDICTED ACROSS CANADA IN THE 6-10 DAY
PERIOD, EXTENDING INTO THE NORTHERN CENTRAL AND NORTHEASTERN CONTIGUOUS UNITED
STATES (CONUS). POSITIVE 500-HPA HEIGHT ANOMALIES ARE PREDICTED ACROSS MOST OF
THE CONUS IN THE 6-10 DAY PERIOD, WHILE WEAK TROUGHING AND NEAR ZERO MID-LEVEL
HEIGHT ANOMALIES ARE PREDICTED OVER THE CALIFORNIA COAST AND THE SOUTHEAST.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE WEST COAST OF MAINLAND ALASKA
UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW, WHILE ABOVE NORMAL TEMPERATURES ARE
MORE LIKELY FOR EASTERN 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 MUCH OF THE CONUS EXCLUDING THE
EASTERN SEABOARD AND PARTS OF THE WEST, INFLUENCED BY THE AMPLIFIED RIDGE AND
POSITIVE 500-HPA HEIGHT ANOMALIES. NEAR TO BELOW NORMAL TEMPERATURES ARE
FAVORED FOR THE EASTERN SEABOARD IN THE 6-10 DAY PERIOD, RELATED TO THE
PREDICTED TROUGH AND WEAK 500-HPA HEIGHT ANOMALIES. 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.
BELOW NORMAL PRECIPITATION IS FAVORED FOR THE WEST COAST OF MAINLAND ALASKA,
UNDER ANOMALOUS NORTHERLY FLOW. ABOVE NORMAL PRECIPITATION IS FAVORED FOR
SOUTHERN AND EASTERN MAINLAND ALASKA AS WELL AS SOUTHEAST ALASKA, AHEAD OF A
PREDICTED TROUGH. ABOVE NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE WEST,
INCLUDING THE PACIFIC NORTHWEST, SOUTHWEST, AND NORTHERN AND CENTRAL PLAINS, IN
THE 6-10 DAY PERIOD, ASSOCIATED WITH THE PREDICTED TROUGH OVER THE WEST COAST.
NEAR NORMAL PRECIPITATION IS INDICATED IN PARTS OF CALIFORNIA AND NEVADA, WHERE
THERE IS A DRY CLIMATOLOGY AND MODEL PRECIPITATION SIGNALS ARE SMALL. BELOW
NORMAL PRECIPITATION IS FAVORED FOR EAST TEXAS, THE LOWER MISSISSIPPI VALLEY,
THE GREAT LAKES REGION, AND NORTHERN NEW ENGLAND, UNDER ANOMALOUS NORTHERLY
FLOW AHEAD OF THE PREDICTED RIDGE AND CONSISTENT WITH THE MOST MODEL
PRECIPITATION FORECASTS. PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE
SLIGHTLY ENHANCED FOR SOUTH FLORIDA AND THE MID-ATLANTIC COAST IN THE 6-10 DAY
PERIOD, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION. NEAR NORMAL
PRECIPITATION IS FAVORED FOR ALL OF 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 16 - 22 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 PATTERN
EVOLVES AND SOMEWHAT DEAMPLIFIES. A TROUGH PERSISTS BUT DEAMPLIFIES TO THE
SOUTHWEST OF MAINLAND ALASKA DURING THE 8-14 DAY PERIOD IN ALL ENSEMBLE MEAN
FORECASTS. AN AMPLIFIED RIDGE AND ASSOCIATED POSITIVE 500-HPA HEIGHT ANOMALIES
PERSISTS OVER CANADA THROUGH THE WEEK-2 PERIOD, WITH POSITIVE 500-HPA HEIGHT
ANOMALIES EXTENDING SOUTHWARD ACROSS NEARLY THE ENTIRE CONUS. POSITIVE 500-HPA
HEIGHT ANOMALIES INCREASE IN AMPLITUDE AND EXPAND SOUTHWARD OVER THE WEST, AS
THE TROUGH IN THE 6-10 DAY PERIOD DEAMPLIFIES. A WEAK TROUGH PERSISTS OVER THE
SOUTHEASTERN CONUS IN THE 8-14 DAY 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. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS
ALMOST THE ENTIRE CONUS EXCLUDING MOST OF THE EAST COAST IN THE WEEK-2 PERIOD,
UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. AREAS OF ENHANCED PROBABILITIES OF
NEAR NORMAL TEMPERATURES FOR THE EAST COAST ARE ASSOCIATED WITH A PERSISTENT
TROUGH OVER THE SOUTHEAST. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR HAWAII,
CONSISTENT WITH THE TEMPERATURE CONSOLIDATION AND ABOVE AVERAGE SEA SURFACE
TEMPERATURES AROUND THE NORTHWESTERN ISLANDS..
NEAR TO BELOW NORMAL PRECIPITATION CONTINUES TO BE SLIGHTLY FAVORED FOR
NORTHWESTERN MAINLAND ALASKA UNDER PRIMARILY ANOMALOUS NORTHERLY FLOW IN THE
EVOLVING CIRCULATION PATTERN. ABOVE NORMAL PRECIPITATION CONTINUES TO BE
FAVORED FOR SOUTHERN AND EASTERN MAINLAND ALASKA AND SOUTHEAST ALASKA IN THE
8-14 DAY PERIOD, CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS. DESPITE A
FORECAST OF ABOVE NORMAL PRECIPITATION IN THE 6-10 DAY PERIOD, BELOW NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF THE OREGON AND WASHINGTON COASTS
IN WEEK 2, AS POSITIVE 500-PA HEIGHT ANOMALIES INCREASE AND ALSO CONSISTENT
WITH NEARLY ALL MODEL FORECAST TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED
FROM THE SOUTHWEST ACROSS THE HIGH PLAINS AND PARTS OF THE NORTHERN AND CENTRAL
PLAINS CONSISTENT WITH THE PRECIPITATION CONSOLIDATION. NEAR TO BELOW NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR MOST OF THE EASTERN CONUS, UNDER
ANOMALOUS NORTHERLY FLOW AHEAD OF THE PREDICTED RIDGE. ABOVE NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR THE SOUTHEAST ATLANTIC AND THE SOUTHERN
MID-ATLANTIC COASTS. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR MOST
ISLANDS OF HAWAII, EXCLUDING THE BIG ISLAND, 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 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:
20070913 - 19860907 - 19740901 - 19730916 - 19930908
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:
19730916 - 20070912 - 19930907 - 19860908 - 19650821
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 14 - 18 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF N N IDAHO A A NEVADA N 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 N
N TEXAS A B S TEXAS A B W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS B N CONN B N RHODE IS B N
PENN N N NEW JERSEY B A W VIRGINIA N N
MARYLAND B A DELAWARE B A VIRGINIA N A
N CAROLINA B A S CAROLINA B N GEORGIA N N
FL PNHDL N N FL PENIN N A AK N SLOPE N N
AK ALEUTIAN N A AK WESTERN B B 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 16 - 22 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO A A NEVADA A N
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 N
N TEXAS A N S TEXAS A N W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS A B MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A N ALABAMA A N NEW YORK A B
VERMONT A B NEW HAMP N B MAINE A B
MASS N B CONN N N RHODE IS N N
PENN A B NEW JERSEY N N W VIRGINIA A N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N A S CAROLINA N A GEORGIA A N
FL PNHDL A A FL PENIN A A 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 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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