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FXUS06 KWBC 291948
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 29 2025
6-10 DAY OUTLOOK FOR OCT 05 - 09 2025
THE MID-LEVEL HEIGHT PATTERN ACROSS NORTH AMERICA IS FAVORED TO DEAMPLIFY
SOMEWHAT AND RETROGRADE DURING THE 6-10 DAY PERIOD. STRONG MID-LEVEL RIDGING IS
ESTABLISHED FROM THE EASTERN NORTH PACIFIC INTO EASTERN ALASKA AND WESTERN
CANADA, AND ALSO ACROSS THE EASTERN CONTIGUOUS UNITED STATES (CONUS). THE
ENSEMBLE MEANS ALL SHOW 500-HPA HEIGHT ANOMALIES OF OVER +18 DM JUST OFFSHORE
FROM SOUTHEASTERN ALASKA, AND +12 TO +18 DM OVER AND JUST NORTH OF THE
NORTHEASTERN CONUS. BETWEEN THESE TWO FEATURES, A STRONG MID-LEVEL TROUGH IS
FORECAST TO STRETCH FROM THE NORTHERN ROCKIES INTO THE SOUTHWEST, WITH THE PEAK
NEGATIVE ANOMALIES BETWEEN -6 AND -12 DM. BY THE END OF THE PERIOD, THE STRONG
MID-LEVEL RIDGE IN THE NORTH PACIFIC IS FORECAST TO RETROGRADE, WITH THE AXIS
EXPECTED TO REACH FROM SOUTH OF THE ALEUTIANS INTO SOUTHERN AND WESTERN ALASKA
AT THE END OF THE PERIOD. THE EUROPEAN ENSEMBLE (ECENS) AND CANADIAN ENSEMBLE
(CNENS) MEANS ACTUALLY FORECAST AN INCREASE IN 500-HPA HEIGHT ANOMALIES BY THE
END OF THE PERIOD, WITH ANOMALIES ABOVE +24 DM DEPICTED SOUTH OF THE ALEUTIANS.
MEANWHILE, THE 500-HPA RIDGE IN THE EASTERN CONUS IS EXPECTED TO HAVE FLATTENED
SOMEWHAT BY DAY 10, WITH SIGNIFICANT POSITIVE HEIGHT ANOMALIES EXTENDING FROM
THE NORTHEASTERN QUARTER OF THE CONUS INTO THE UPPER MISSISSIPPI VALLEY AND
THROUGH CENTRAL AND EASTERN CANADA. THE EUROPEAN ENSEMBLE (ECENS) MEAN IS
FARTHEST WEST AND MOST AMPLIFIED, WITH 500-HPA HEIGHT ANOMALIES ABOVE +12 DM
NORTH OF THE GREAT LAKES ON DAY 10. THE OTHER ENSEMBLE MEANS KEEP ANOMALIES IN
THE +6 TO +12 DM RANGE OVER A FAIRLY BROAD AREA IN THE EASTERN HALF OF CANADA
AND THE NORTHEASTERN CONUS. WITH THE NORTH PACIFIC RIDGE FORECAST TO MAINTAIN
ITS STRENGTH WHILE RETROGRADING OVER THE COURSE OF DAYS 6 THROUGH 10, THE MORE
AMPLIFIED ECENS MEAN IS PREFERRED. HOWEVER, TELECONNECTIONS FOR THE ANOMALY
CENTERS OF THE TWO MID-LEVEL RIDGES ARE INCONSISTENT, INCREASING THE
UNCERTAINTY AND IMPLYING THAT THE PATTERN AT THE END OF THE 6-10 DAY PERIOD MAY
BE TRANSIENT. MEANWHILE, BETWEEN THE TWO MID-LEVEL RIDGES, THE TROUGH OVER THE
WESTERN CONUS IS EXPECTED TO PUSH NORTHEASTWARD AND FADE BEFORE ANOTHER DIGGING
SHORTWAVE DROPS INTO THE EASTERN NORTH PACIFIC, RE-ESTABLISHING THE TROUGH JUST
OFF THE WEST COAST. THE CNENS IS MORE AMPLIFIED WITH THIS FEATURE, AND IS THE
PREFERRED SOLUTION GIVEN THE STRENGTH OF THE UPSTREAM NORTH PACIFIC RIDGE. IN
ANY CASE, THE NORTH PACIFIC RIDGE RETROGRESSION SHOULD ESTABLISH AN UNUSUALLY
STRONG MID-LEVEL JET STREAM ACROSS THE STATE.
STRONG RIDGING OVER EASTERN AND CENTRAL NORTH AMERICA SUPPORTS ELEVATED
PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MOST OF THE CONUS.
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES EXCEED 80 PERCENT OVER MUCH OF THE
EASTERN GREAT LAKES AND NORTHEASTERN CONUS. CONVERSELY, TROUGHING OVER OR NEAR
THE WESTERN CONUS FOR MUCH OF THE PERIOD FAVORS BELOW-NORMAL TEMPERATURES FOR
MOST AREAS FROM THE ROCKIES WESTWARD, WITH ODDS EXCEEDING 40 PERCENT FROM PARTS
OF THE NORTHERN INTERMOUNTAIN WEST THROUGH THE GREAT BASIN AND INTO THE
SOUTHWEST. THE LOWER ODDS IN THE WESTERN CONUS REFLECT LESS CONSISTENCY BETWEEN
THE RAW, BIAS-CORRECTED, AND REFORECAST TEMPERATURES DERIVED FROM THE
ENSEMBLES, WHEREAS ALL TOOLS STRONGLY FAVOR WARMTH FARTHER EAST. THERE ARE
SIMILAR DIFFERENCES ACROSS ALASKA, BUT WITH ABOVE-NORMAL 500-HPA HEIGHTS,
WARMER THAN NORMAL WEATHER IS FAVORED OVER MOST OF THE STATE. THE CONSOLIDATION
FORECAST ALSO FAVORS ABOVE-NORMAL TEMPERATURES FOR HAWAII, WITH THE BEST
CHANCES COVERING THE NORTHWESTERN HALF OF THE ISLAND CHAIN .
AMPLIFIED RIDGING OVER THE NORTH PACIFIC FEEDING INTO THE DOWNSTREAM TROUGHING
SHOULD PULL THE STORM TRACK NORTHWARD, RESULTING IN BELOW-NORMAL PRECIPITATION
OVER NORTHERN PORTIONS OF THE WEST COAST. MEANWHILE, LEE CYCLOGENESIS EXPECTED
OVER THE CANADIAN AND AMERICAN GREAT PLAINS FAVORS ABOVE-NORMAL PRECIPITATION
FOR THE NORTH-CENTRAL CONUS, WITH PROBABILITIES EXCEEDING 50% FROM PORTIONS OF
THE NORTHERN ROCKIES INTO THE UPPER MISSISSIPPI VALLEY. THE HEAVIEST AMOUNTS,
ACCORDING TO THE ENSEMBLE MEANS, SHOULD FALL FROM THE EAST-CENTRAL GREAT PLAINS
NORTHWARD INTO THE UPPER MISSISSIPPI VALLEY ALONG A SLOW-MOVING FRONTAL SYSTEM
TRAILING SOUTHWARD FROM THE STORM SYSTEM AS IT ENCROACHES ON SURFACE HIGH
PRESSURE FARTHER EAST. WETTER THAN NORMAL CONDITIONS ARE ALSO FAVORED FROM THE
SOUTHERN GREAT PLAINS THROUGH THE GULF COAST REGION AND ACROSS THE SOUTHEAST
U.S., WHERE MOIST EASTERLY SURFACE FLOW IS FORECAST SOUTH OF A SLOW-MOVING
SURFACE HIGH PRESSURE SYSTEM. MEANWHILE, BELOW-NORMAL PRECIPITATION IS FAVORED
OVER MUCH OF THE NORTHEAST NEAR THE MID-LEVEL RIDGE AND JUST NORTH OF SURFACE
HIGH PRESSURE, ALTHOUGH DIFFERENCES IN THE RAW AND STATISTICALLY-DERIVED
OUTPUTS FROM THE ENSEMBLES INCREASES UNCERTAINTY. THERE IS MUCH BETTER
AGREEMENT AMONG THE TOOLS WITH RESPECT TO PRECIPITATION OVER THE ALASKAN
MAINLAND, WITH A STRONG JET ALOFT COVERING THE STATE. THIS RESULTS IN ENHANCED
PROBABILITIES OF ABOVE-NORMAL PRECIPITATION ACROSS ALASKA, WITH CHANCES
EXCEEDING 60% OVER MUCH OF THE CENTRAL AND EASTERN MAINLAND. IN HAWAII,
ABOVE-NORMAL PRECIPITATION IS MARGINALLY FAVORED ACROSS THE STATE, CONSISTENT
WITH THE HAWAII-CON TOOL.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 10% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 35% OF
TODAY'S OPERATIONAL 0Z ECMWF 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. GOOD
AGREEMENT AMONG THE ENSEMBLE MEANS REGARDING THE DRIVING MID-LEVEL FEATURES IS
OFFSET SOMEWHAT BY SOME DIFFERENCES BETWEEN THE RAW, REFORECAST, AND
BIAS-CORRECTED ENSEMBLE TEMPERATURE AND PRECIPITATION OUTPUTS. IN ADDITION,
TEMPERATURE AND PRECIPITATION ANALOGS ARE INCONSISTENT WITH OTHER TOOLS.
8-14 DAY OUTLOOK FOR OCT 07 - 13 2025
DURING THE 8-14 DAY PERIOD TROUGHING IS FAVORED TO REDEVELOP NEAR THE WEST
COAST WHILE THE MID-LEVEL RIDGES TO THE EAST AND WEST DEAMPLIFY, PARTICULARLY
ACROSS THE EASTERN CONUS. STILL, POSITIVE 500-HPA HEIGHT ANOMALIES ARE EXPECTED
TO HANG ON OVER MUCH OF THE NORTHERN CONUS AND EASTERN CANADA DESPITE THE
DECLINE IN AMPLITUDE. THE MID-LEVEL RIDGE IN THE NORTH PACIFIC IS EXPECTED TO
DEAMPLIFY SLOWLY AS THE POSITIVE 500-HPA HEIGHT ANOMALY PATTERN FLATTENS AND
EXPANDS EASTWARD THROUGH THE NORTH PACIFIC TO NEAR THE SOUTHEASTERN ALASKA OR
WESTERN CANADA COAST.
THE AMPLIFIED RIDGE EARLY IN WEEK-2, COMBINED THE MID-LEVEL TROUGH MEANDERING
AROUND THE WESTERN CONUS AND THE DETERIORATING MID-LEVEL RIDGE FARTHER EAST,
COMBINE TO SUPPORT ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR
MOST OF THE CONUS DURING WEEK-2. ODDS EXCEEDING 50% ARE ALMOST UNIVERSAL EAST
OF THE HIGH PLAINS, WITH CHANCES TOPPING 70% FOR MUCH OF NEW ENGLAND CLOSEST TO
THE GREATEST POSITIVE 500-HPA HEIGHT ANOMALIES. THE RENEWED TROUGHING AND
ONSHORE FLOW LATE IN THE WEEK-2 PERIOD WILL LIKELY BRING INCREASED CLOUDINESS
AND MODERATING TEMPERATURES FROM THE PACIFIC OCEAN. MARGINALLY ENHANCED CHANCES
FOR BELOW NORMAL TEMPERATURES ARE RESTRICTED TO SOME AREAS IN AND ADJACENT TO
THE GREAT BASIN, WHERE MOST OF THE RAW AND STATISTICALLY-DERIVED ENSEMBLE
OUTPUT IS IN BETTER AGREEMENT THAN IN OTHER PARTS OF THE WEST. MEANWHILE, THE
TROUGHING NEAR THE WEST COAST AND PERSISTENT EASTERLY FLOW OVER PARTS OF THE
SOUTHERN CONUS RESULT IN SLIGHTLY INCREASED CHANCES FOR SURPLUS PRECIPITATION
ACROSS A LARGE PART OF THE COUNTRY. THE BEST ODDS COVER PARTS OF THE
INTERMOUNTAIN WEST (WHERE REFORECAST ENSEMBLE OUTPUT IS IN BEST AGREEMENT) AND
FROM THE SOUTHWEST INTO THE CENTRAL GREAT PLAINS (WHERE TROUGHING TO THE WEST
AND NORTH SHOULD FAVOR CYCLONICALLY-CURVED MID-LEVEL FLOW AND SURFACE FRONTAL
DEVELOPMENT). THE STRONG BUT DEAMPLIFYING MID-LEVEL RIDGE OVER THE GULF OF
ALASKA WILL CONTINUE TO FAVOR WARMER AND WETTER THAN NORMAL CONDITIONS ACROSS
MOST OF THE STATE, WITH ODDS FOR SURPLUS PRECIPITATION EXCEEDING 50 PERCENT IN
CENTRAL AND WEST-CENTRAL PARTS OF THE MAINLAND. ABOVE NORMAL TEMPERATURES
REMAIN FAVORED ACROSS HAWAII, ALTHOUGH WITH LOWER ODDS THAN DURING THE 6 TO 10
DAY PERIOD. THIS IS SUPPORTED BY THE CONSOLIDATION, WHICH ALSO CONTINUES TO
NOMINALLY FAVOR WETTER THAN NORMAL CONDITIONS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF YESTERDAY'S 18Z GFS ENSEMBLE MEAN
CENTERED ON DAY 10, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 25% OF
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 35% 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. GOOD
AGREEMENT ON THE MID-LEVEL FLOW PATTERN AMONG THE MODELS IS OFFSET BY SOME
DISAGREEMENT BETWEEN THE RAW AND STATISTICALLY-DERIVED ENSEMBLE TEMPERATURE AND
PRECIPITATION OUTPUT. IN PARTICULAR, THE RAW PRECIPITATION OUTPUT IS
CONSIDERABLY LESS THAN THE REFORECAST AMOUNTS OVER THE CENTRAL AND WESTERN
CONUS.
FORECASTER: RICH TINKER
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:
19551008 - 19620926 - 20071008 - 19920927 - 20020909
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:
19551006 - 20020908 - 19920926 - 19611012 - 19620928
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 05 - 09 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF B N
SRN CALIF B N IDAHO B A NEVADA B N
W MONTANA B A E MONTANA N A WYOMING N A
UTAH N A ARIZONA A N 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 N LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A N OHIO A N 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 B
PENN A N NEW JERSEY A N W VIRGINIA A N
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 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 OCT 07 - 13 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF N A
SRN CALIF N N IDAHO N A NEVADA N A
W MONTANA N A E MONTANA A A WYOMING A A
UTAH N 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 N S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A N 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 N
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 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 N 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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