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FXUS06 KWBC 241902
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 24 2025
6-10 DAY OUTLOOK FOR SEP 30 - OCT 04, 2025
THE MID-LEVEL HEIGHT PATTERN ACROSS NORTH AMERICA REMAINS HIGHLY AMPLIFIED
DURING THE 6-10 DAY PERIOD WITH STRONG 500-HPA HEIGHT ANOMALIES FORECAST
CENTERED OVER ONTARIO WITH POSITIVE HEIGHT ANOMALIES EXTENDED ACROSS MUCH OF
THE CONTIGUOUS U.S. (CONUS). NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST TO
BE CENTERED SOUTH OF GREENLAND AND OFF THE WEST COAST OF NORTH AMERICA.
NEGATIVE ANOMALIES EXTEND INTO PORTIONS OF THE PACIFIC NORTHWEST, PARTICULARLY
EARLY IN THE PERIOD. IN THE SOUTHEAST CONUS, NEAR-NORMAL 500-HPA HEIGHT
ANOMALIES ARE FORECAST WITH A WIDE DEGREE OF UNCERTAINTY ON WHERE ANY TROPICAL
SYSTEM MAY DEVELOP AND FORECAST TRACK AT THIS TIME. NEAR-NORMAL 500-HPA HEIGHTS
ARE ALSO FORECAST ACROSS MUCH OF ALASKA.
STRONG RIDGING OVER EASTERN AND CENTRAL NORTH AMERICA SUPPORTS ELEVATED
PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MOST OF THE CONUS.
PROBABILITIES EXCEED 90 PERCENT OVER PORTIONS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY. THE STRONG TROUGHING AND INCREASED PRECIPITATION CHANCES
INDICATES THAT NEAR-NORMAL TEMPERATURES ARE THE MOST LIKELY OUTCOME ACROSS
PARTS OF THE WEST. ENHANCED PACIFIC FLOW COMBINED WITH ABOVE-NORMAL SEA SURFACE
TEMPERATURES (SSTS) OVER THE EASTERN PACIFIC SUPPORT INCREASED CHANCES OF
ABOVE-NORMAL TEMPERATURES OVER THE REMAINDER OF THE WEST WHERE PRECIPITATION
CHANCES ARE REDUCED. ALONG THE EAST COAST A PASSING FRONTAL SYSTEM COMBINED
WITH THE POTENTIAL FOR A TROPICAL SYSTEM OFFSHORE BRING INCREASED CHANCES FOR
NEAR-NORMAL TEMPERATURES. NEAR- TO BELOW-NORMAL TEMPERATURE CHANCES ARE
INCREASED ACROSS MUCH OF ALASKA (EXCLUDING THE ALEUTIANS WHERE ABOVE-NORMAL
TEMPERATURES ARE MORE LIKELY) DUE TO THE TREND TOWARD MORE TROUGHING ACROSS THE
STATE AND WITH SUPPORT FROM THE UNCALIBRATED ECENS AND GEFS, AND THE ECENS
REFORECAST TOOL. ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR MOST OF HAWAII,
WITH THE EXCEPTION OF PARTS OF THE BIG ISLAND WHERE NEAR-NORMAL TEMPERATURES
ARE FAVORED.
INCREASED PACIFIC FLOW FAVORS ABOVE-NORMAL PRECIPITATION ACROSS MUCH OF THE
WESTERN CONUS INTO THE NORTHERN AND CENTRAL PLAINS, WITH CHANCES EXCEEDING 60
PERCENT OVER PARTS OF OREGON AND NORTHERN CALIFORNIA. CHANCES FOR BELOW-NORMAL
PRECIPITATION ARE INCREASED FROM THE SOUTHERN PLAINS THROUGH THE MISSISSIPPI
VALLEY, OHIO VALLEY, GREAT LAKES, AND NORTHEAST UNDERNEATH THE MID-LEVEL RIDGE
AND SURFACE HIGH PRESSURE. FOR THE SOUTHEAST, THE NATIONAL HURRICANE CENTER IS
MONITORING TWO SEPARATE DISTURBANCES IN THE TROPICAL ATLANTIC. THE SYSTEMS ARE
IN CLOSE PROXIMITY TO EACH OTHER AND THIS MAY BE IMPACTING HOW THE MODELS ARE
RESOLVING THESE SYSTEMS. THIS INCREASES UNCERTAINTY FOR THE FORECAST IN THE
SOUTHEAST. HOWEVER, THE MOST LIKELY OUTCOME AT THIS TIME IS ABOVE-NORMAL
PRECIPITATION ASSOCIATED WITH AT LEAST ONE OF THESE SYSTEMS POTENTIALLY
INTERACTING WITH A FRONTAL BOUNDARY DRAPED THROUGH THE SOUTHEAST, BUT
UNCERTAINTY REMAINS HIGHER THAN NORMAL FOR THIS PERIOD. A TRANSITIONAL
MID-LEVEL HEIGHT PATTERN ACROSS ALASKA AND SOME DISCREPANCIES IN THE TOOLS
FAVORS NEAR-NORMAL PRECIPITATION FORECAST FOR MUCH OF ALASKA, WITH WEAK CHANCES
FOR ABOVE-NORMAL PRECIPITATION FAVORED OVER PORTIONS OF EASTERN AND
SOUTHEASTERN ALASKA, CLOSER TO THE TROUGHING OVER THE NORTHEAST PACIFIC.
SURFACE LOW PRESSURE IS FORECAST TO THE NORTH OF HAWAII PRIOR TO THE START OF
THE PERIOD, WITH A DRYING TREND LIKELY FURTHER SOUTH. AS A RESULT, A SLIGHT
TILT TOWARD ENHANCED PROBABILITIES FOR ABOVE- (NEAR TO BELOW) NORMAL
PRECIPITATION IS FAVORED ACROSS KAUAI AND OAHU (THE BIG ISLAND).
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, GOOD
AGREEMENT ON THE 500-HPA HEIGHT PATTERN IS OFFSET BY DECREASED CONFIDENCE IN
THE SOUTHEAST.
8-14 DAY OUTLOOK FOR OCT 02 - 08 2025
THE STRONG POSITIVE 500-HPA HEIGHT ANOMALIES FORECAST TO BE CENTERED OVER
ONTARIO AND OVERSPREAD MUCH OF THE CONUS REMAINS DURING THE WEEK-2 PERIOD. THE
OVERALL AMPLITUDE OF THE FEATURE IS REDUCED RELATIVE TO THE PRIOR PERIOD BUT
MAY BE THE RESULT OF INCREASED ENSEMBLE SPREAD OVER TIME. THE TROUGH IMPACTING
THE NORTHWEST DURING THE 6-10 DAY PERIOD, RETROGRADES AND WEAKENS CONSIDERABLY
ACROSS THE GULF OF ALASKA. MEANWHILE, CONTINUED UNCERTAINTY ACROSS THE GULF OF
AMERICA AND EASTERN SEABOARD LEND NEAR-NORMAL HEIGHTS IN THE REGION. POSITIVE
500-HPA HEIGHT ANOMALIES ARE BUILDING INTO NORTHERN ALASKA TIED TO AN EXPANDING
REGION OF ABOVE-NORMAL MID-LEVEL HEIGHTS OVER THE ARCTIC.
THE AMPLIFIED RIDGE EARLY IN WEEK-2 COMBINED WITH INCREASING PACIFIC FLOW
SUPPORTS ELEVATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE CONUS
DURING THE PERIOD. AS IN THE 6-10 DAY PERIOD, THE LARGEST PROBABILITIES
(GREATER THAN 60 PERCENT) ARE ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI
VALLEY CONSISTENT WITH THE STRONGEST SIGNALS IN THE TOOLS. SOME LINGERING
TROUGHING AND MOISTURE EARLY IN THE WEEK-2 PERIOD REDUCES CHANCES FOR
ABOVE-NORMAL TEMPERATURES SLIGHTLY ACROSS PARTS OF THE WEST. IN THE SOUTHEAST,
CONTINUED CHANCES FOR TROPICAL SYSTEMS NEAR OR INTO THE EAST COULD ENHANCE
MARITIME FLOW INTO THE MID-ATLANTIC, REDUCING CHANCES FOR ABOVE-NORMAL
TEMPERATURES IN THIS REGION. TROUGHING OVER THE GULF OF ALASKA FAVORS
INCREASING SOUTHERLY TO SOUTHWESTERLY FLOW ACROSS SOUTHEASTERN MAINLAND ALASKA,
WITH BOTH THE GEFS AND ECENS REFORECAST TOOLS SUPPORTING INCREASED CHANCES FOR
ABOVE-NORMAL TEMPERATURES OVER THE REGION. THE SIGNALS ARE LESS CLEAR OVER THE
REMAINDER OF ALASKA. NEAR-NORMAL TEMPERATURES ARE FORECAST FOR MUCH OF THE
WESTERN AND NORTHERN MAINLAND WHERE THE ECENS (GEFS) FAVORS BELOW- (ABOVE)
NORMAL TEMPERATURES. ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE INCREASED
ACROSS HAWAII, SUPPORTED BY THE CONSOLIDATED REFORECAST TOOL.
SIGNALS FOR PRECIPITATION ARE WEAK ACROSS THE CONUS DURING WEEK-2 AS THE
MID-LEVEL PATTERN BECOMES LESS AMPLIFIED, AND NO MAJOR FEATURES ARE APPARENT IN
THE MODELS AT THIS LEAD. THE ENHANCED PACIFIC FLOW PATTERN FORECAST TO DEVELOP
GENERALLY FAVORS NEAR- TO WEAKLY ABOVE-NORMAL PRECIPITATION PROBABILITIES
ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS, WHICH IS SUPPORTED BY THE ECENS
AND GEFS REFORECAST TOOLS. IN GENERAL THE RAW FORECAST GUIDANCE LEANS DRIER
ACROSS MUCH OF THE COUNTRY RELATIVE TO THE REFORECAST GUIDANCE. A SLIGHT TILT
TOWARD ENHANCED PROBABILITIES OF BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS
THE NORTHEAST, GREAT LAKES, OHIO AND MIDDLE MISSISSIPPI VALLEYS, AND SOUTHERN
PLAINS TIED TO SURFACE HIGH PRESSURE. THERE IS BETTER AGREEMENT ACROSS THE
SOUTHEAST AND FLORIDA WHERE CONTINUED FRONTAL ACTIVITY SUPPORTS AN UPTICK IN
ABOVE-NORMAL PRECIPITATION CHANCES. ENHANCED CHANCES FOR ABOVE-NORMAL
PRECIPITATION ARE FORECAST ACROSS SOUTHEASTERN ALASKA DURING WEEK-2 TIED TO
INCREASING ONSHORE FLOW AND SURFACE LOW PRESSURE OVER THE GULF OF ALASKA.
BELOW-NORMAL PRECIPITATION IS FORECAST ACROSS THE WESTERN AND NORTHERN PORTIONS
OF THE MAINLAND WHERE BUILDING MID-LEVEL HEIGHTS MAY REDUCE CHANCES FOR
PRECIPITATION. THE PRECIPITATION FORECAST ACROSS HAWAII REMAINS VARIABLE WITH A
SLIGHT TILT TOWARD ENHANCED ABOVE NORMAL PRECIPITATION ODDS OVER MUCH OF HAWAII
EXCLUDING THE BIG ISLAND WHERE NEAR-NORMAL IS FORECAST.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 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 20%
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, A
WEAKENING MID-LEVEL HEIGHT PATTERN ALONG WITH POTENTIAL TROPICAL SYSTEMS IN THE
SOUTHEAST IS OFFSET BY FAIR AGREEMENT IN THE DYNAMICAL MODEL GUIDANCE.
FORECASTER: RYAN BOLT
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
OCTOBER 16.
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:
20010928 - 19870919 - 19620930 - 20071008 - 20010923
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:
19870918 - 20010927 - 19620929 - 20010922 - 20050903
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 30 - OCT 04, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON N A NRN CALIF N 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 N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A B
ILLINOIS A B MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A N
TENNESSEE A A ALABAMA A A NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS N B CONN N B RHODE IS N B
PENN A B NEW JERSEY N B W VIRGINIA A N
MARYLAND N N DELAWARE N N VIRGINIA A A
N CAROLINA N A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE B N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN B N
AK S INT N N AK SO COAST A N AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 02 - 08 2025
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 A NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A A ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A A KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A N 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 A NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A N W VIRGINIA A B
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N B
AK ALEUTIAN N N AK WESTERN N B AK INT BSN N N
AK S INT A N AK SO COAST A N 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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