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FXUS06 KWBC 251901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU SEPTEMBER 25 2025
6-10 DAY OUTLOOK FOR OCT 01 - 05 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 THE SOUTHERN HUDSON BAY 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, BUT THE NEGATIVE HEIGHT CENTER IS
RETROGRADING THROUGH THE PERIOD INTO THE GULF OF ALASKA. IN THE SOUTHEAST
CONUS, NEAR-NORMAL 500-HPA HEIGHT ANOMALIES ARE FORECAST WITH A LARGE AMOUNT OF
UNCERTAINTY ON WHERE ANY TROPICAL SYSTEM MAY DEVELOP AND THE POTENTIAL 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 80 PERCENT OVER PORTIONS OF THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY. THE STRONG TROUGHING OVER THE EASTERN PACIFIC WILL HAVE A
REDUCED IMPACT ON PRECIPITATION AND TEMPERATURES IN THE 6-10 DAY PERIOD
RELATIVE TO YESTERDAY AND A CORRESPONDING INCREASE IN ABOVE-NORMAL TEMPERATURES
CHANCES IS FORECAST ACROSS MUCH OF THE WEST. AS THE TROUGH WITHDRAWS ZONAL FLOW
FROM THE PACIFIC WILL BECOME ESTABLISHED. SEA SURFACE TEMPERATURES ARE WELL
ABOVE-NORMAL ACROSS MUCH OF THE EAST PACIFIC BRINGING INCREASED CHANCES FOR
ABOVE-NORMAL TEMPERATURES TO MUCH OF THE WEST. ALONG THE EAST COAST A PASSING
FRONTAL SYSTEM COMBINED WITH THE POTENTIAL FOR A TROPICAL SYSTEM OFFSHORE BRING
INCREASED CHANCES FOR NEAR TO BELOW-NORMAL TEMPERATURES AS A RESULT OF CLOUDS,
PRECIPITATION, AND ONSHORE MARITIME FLOW. NEAR- TO BELOW-NORMAL TEMPERATURE
CHANCES ARE INCREASED ACROSS MUCH OF MAINLAND ALASKA. THE EXCEPTIONS ARE AROUND
THE EDGES WHERE ABOVE-NORMAL TEMPERATURE CHANCES ARE ELEVATED ALONG THE WEST
COAST OF MAINLAND ALASKA, SOUTHEAST ALASKA, AND THE ALEAUTIANS. 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 50
PERCENT OVER PARTS OF OREGON AND WASHINGTON. 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 SYSTEMS IN THE TROPICAL ATLANTIC. THE FIRST, TROPICAL
STORM HUMBERTO, IS FORECAST TO REMAIN OUT TO SEA. THE SECOND DISTURBANCE HAS A
HIGH CHANCE OF DEVELOPING INTO A TROPICAL SYSTEM OVER THE NEXT 48 HOURS
ACCORDING TO THE NHC. THERE REMAINS A HIGH DEGREE OF UNCERTAINTY REGARDING THE
TRACK OF THIS SECOND SYSTEM BUT IT MAY CAUSE IMPACTS ACROSS THE SOUTHEAST. AS
SUCH, THERE ARE INCREASED CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS THE
SOUTHERN ATLANTIC STATES. THERE IS BETTER AGREEMENT AMONG THE TOOLS FOR NEAR TO
BELOW-NORMAL PRECIPITATION ACROSS MUCH OF MAINLAND ALASKA BEHIND A TROUGH AXIS.
ABOVE-NORMAL PRECIPITATION REMAINS FAVORED FOR THE SOUTHEAST. IN HAWAII,
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE ISLAND CHAIN, EXCLUDING
THE BIG ISLAND, WHERE NEAR-NORMAL IS FORECAST.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 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 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 03 - 09 2025
POSITIVE 500-HPA HEIGHT ANOMALIES REMAIN FORECAST OVER MUCH OF THE NORTHERN
CONUS AND CANADA 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 BUT
MAY TRY TO APPROACH THE NORTHWEST BY THE END OF WEEK-2 ONCE AGAIN. MEANWHILE,
CONTINUED UNCERTAINTY ACROSS THE GULF OF AMERICA AND EASTERN SEABOARD BRING
NEAR-NORMAL HEIGHTS OVER 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 70 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, LACKING MAJOR FEATURES AT THIS LEAD.
A PACIFIC FLOW PATTERN FORECAST TO DEVELOP GENERALLY FAVORS NEAR- TO WEAKLY
ABOVE-NORMAL PRECIPITATION PROBABILITIES ALONG THE WEST COAST, FURTHER INLAND,
DRIER THAN NORMAL CONDITIONS ARE FORECAST ACROSS THE INTERIOR WEST SUPPORTED BY
THE REFORECAST GUIDANCE AND RAW TOOLS. AN AREA OF NEAR TO ABOVE-NORMAL
PRECIPITATION IS FAVORED IN THE LEE OF THE ROCKIES DURING WEEK-2 WHERE SOME
MODEL GUIDANCE SUGGESTS AN AREA OF LOW-PRESSURE MAY DEVELOP. RAW GUIDANCE IS
LESS SUPPORTIVE OF ABOVE-NORMAL BUT REFORECAST TOOLS SUGGEST A MORE ROBUST
EVENT IS POSSIBLE. A SLIGHT TILT TOWARD BELOW-NORMAL PRECIPITATION IS FAVORED
ACROSS THE NORTHEAST, GREAT LAKES, OHIO AND MIDDLE MISSISSIPPI VALLEYS, AND
SOUTHERN PLAINS TIED TO SURFACE HIGH PRESSURE DISPLACED FROM THE POSSIBLE STORM
TRACK. 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 - 20040922 - 20010923 - 19870919 - 20071009
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:
20010928 - 19870918 - 20010922 - 19621003 - 20040924
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 01 - 05 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A 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 N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A N ALABAMA A N NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS N B CONN N B RHODE IS B N
PENN N B NEW JERSEY B N W VIRGINIA N B
MARYLAND B N DELAWARE B N VIRGINIA B A
N CAROLINA B A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN A B AK WESTERN N B AK INT BSN B N
AK S INT N N AK SO COAST A N AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 03 - 09 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 B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A N ALABAMA A N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A N RHODE IS A N
PENN A B NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A A VIRGINIA A N
N CAROLINA A A S CAROLINA A A GEORGIA N A
FL PNHDL A A FL PENIN A A AK N SLOPE N B
AK ALEUTIAN A 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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