086
FXUS06 KWBC 071916
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT SUN SEPTEMBER 07 2025
6-10 DAY OUTLOOK FOR SEP 13 - 17 2025
TODAY'S NUMERICAL MODELS DEPICT AN AMPLIFIED 500-HPA FLOW PATTERN ACROSS THE
HIGHER LATITUDES NORTH AMERICA AND SURROUNDING AREAS WITH THE MOST PROMINENT
FEATURES BEING A STRONG RIDGE OVER CENTRAL CANADA CENTERED NEAR THE WESTERN
SHORE OF HUDSON BAY AND A DEEP TROUGH OVER THE GULF OF ALASKA. THE CANADIAN
RIDGE REMAINS AMPLIFIED THROUGHOUT THE PERIOD WHILE THE GULF OF ALASKA TROUGH
SHOWS SIGNS OF WEAKENING AND RETROGRESSION BY THE END OF THE PERIOD. AS THIS
TROUGH RETROGRADES LATER IN THE PERIOD, MODELS SUPPORT RIDGE DEVELOPMENT WELL
OFF THE WEST COAST OF THE CONUS BY DAY 10. FARTHER DOWNSTREAM, MULTIPLE
SHORTWAVE TROUGHS ARE FORECAST OVER THE WEST COAST AND GREAT BASIN EARLY IN THE
PERIOD WITH THE INITIAL SHORTWAVE THEN EJECTING INTO THE NORTHERN PLAINS AND
WEAKENING. TROUGHING IS ALSO FORECAST OVER THE EASTERN SEABOARD DOWNSTREAM OF
THE CANADIAN RIDGE. THERE ARE SOME INDICATIONS THAT THIS EAST COAST TROUGH MAY
WEAKEN LATER IN THE PERIOD ACROSS THE NORTHEAST, BUT WEAK CYCLONIC FLOW IS
GENERALLY FORECAST TO PERSIST. A WEAKNESS IN SUBTROPICAL RIDGING IS FORECAST
ACROSS THE SOUTHEAST THROUGHOUT THE PERIOD. SUBTROPICAL RIDGING OF TYPICAL
STRENGTH FOR THIS TIME OF YEAR IS GENERALLY PREDICTED OVER THE SOUTH CENTRAL
CONUS THROUGHOUT MOST OF THE PERIOD. HURRICANE KIKO IS FORECAST TO PASS TO THE
NORTH OF THE HAWAIIAN ISLANDS PRIOR TO THIS 6 TO 10 DAY PERIOD. IN ITS WAKE,
GENERALLY NEAR NORMAL MID-LEVEL HEIGHTS ARE FORECAST FOR THE ISLAND CHAIN.
PREDICTED STRONG MID-LEVEL RIDGING FORECAST OVER CENTRAL CANADA FAVORS ABOVE
NORMAL TEMPERATURES ACROSS THE NORTH CENTRAL CONUS WITH PROBABILITIES OF WARMER
THAN NORMAL CONDITIONS EXCEEDING 70 PERCENT FOR MUCH OF THE NORTHERN PLAINS AND
ADJACENT AREAS OF THE UPPER MISSISSIPPI VALLEY. PREDICTED SUBTROPICAL RIDGING
OVER THE SOUTHERN PLAINS LEADS TO INCREASED CHANCES OF ABOVE NORMAL
TEMPERATURES ACROSS THE REMAINDER OF THE CENTRAL CONUS. ABOVE NORMAL
TEMPERATURES ARE ALSO MOST LIKELY ACROSS SOUTHEASTERN ALASKA AND THE
NORTHWESTERN CONUS, AHEAD OF THE PREDICTED TROUGH OVER THE GULF OF ALASKA.
BELOW NORMAL TEMPERATURES ARE FAVORED BEHIND THIS TROUGH, ACROSS WESTERN
ALASKA. FARTHER TO THE SOUTH, NEAR NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF
THE GREAT BASIN AS WELL AS SOUTHERN CALIFORNIA AND MOST OF ARIZONA, AS
TROUGHING EARLY IN THE PERIOD IS OFFSET BY FORECAST MODEST MID-LEVEL HEIGHT
RISES BY DAY 10. BELOW NORMAL TEMPERATURES ARE MORE LIKELY ALONG THE EASTERN
SEABOARD ASSOCIATED WITH ANOMALOUS TROUGHING. ABOVE NORMAL TEMPERATURES ARE
MODESTLY FAVORED FOR THE SOUTHERN TIP OF FLORIDA NEAR THE PREDICTED FRONTAL
BOUNDARY. ABOVE NORMAL TEMPERATURES IN ADJACENT WATERS ALSO FAVOR WARMER THAN
NORMAL CONDITIONS FOR THIS REGION. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR
THE ENTIRE STATE OF HAWAII ASSOCIATED WITH ABOVE NORMAL SSTS IN THE ADJACENT
PACIFIC, ESPECIALLY NEAR THE WESTERN AND CENTRAL ISLANDS.
AN ACTIVE PATTERN IS FAVORED FOR MUCH OF THE NORTHWESTERN CONUS EASTWARD TO THE
NORTHERN PLAINS CONSISTENT WITH PREDICTED MEAN CYCLONIC FLOW. TELECONNECTIONS
FROM THE POSITIVE HEIGHT ANOMALY CENTERS ASSOCIATED WITH THE PREDICTED CANADIAN
RIDGE AND A MEAN RIDGE WELL OFF THE WEST COAST ALSO SUPPORT INCREASED CHANCES
OF ABOVE NORMAL PRECIPITATION ACROSS THESE REGIONS. A SLIGHTLY ENHANCED CHANCE
OF ABOVE NORMAL PRECIPITATION EXTENDS SOUTHWARD ACROSS NEW MEXICO AND ADJACENT
AREAS OF EASTERN ARIZONA AND WESTERN TEXAS, AS SURFACE HIGH PRESSURE PREDICTED
OVER COLORADO MAY PROMOTE SOUTHEASTERLY LOW LEVEL FLOW AND ASSOCIATED MOISTURE
ADVECTION. UPSTREAM, THE PREDICTED TROUGH OVER THE GULF OF ALASKA SUPPORTS
INCREASED CHANCES OF ABOVE NORMAL PRECIPITATION FOR SOUTHEAST ALASKA AND PARTS
OF THE EASTERN MAINLAND. BELOW NORMAL PRECIPITATION IS MORE LIKELY FOR THE
WESTERN MAINLAND CONSISTENT WITH PREDICTED LOW-LEVEL OFFSHORE FLOW AND
TELECONNECTIONS FROM THE GULF OF ALASKA TROUGH. BELOW NORMAL PRECIPITATION IS
FAVORED FROM THE GREAT LAKES SOUTHWARD TO THE OHIO, TENNESSEE, MUCH OF THE
LOWER AND MIDDLE MISSISSIPPI VALLEYS, AND ADJACENT AREAS OF THE SOUTHERN PLAINS
AND SOUTHEAST DUE TO PREDICTED MEAN SURFACE HIGH PRESSURE. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR THE FLORIDA PENINSULA AND THE COASTAL CAROLINAS
NORTHWARD TO THE DELMARVA PENINSULA DUE TO PREDICTED FRONTAL ACTIVITY
ASSOCIATED WITH THE EASTERN SEABOARD TROUGH. A TRAILING FRONTAL BOUNDARY MAY
ALSO CLIP SOUTHERN TEXAS, LEADING TO SLIGHTLY ELEVATED CHANCES OF ABOVE NORMAL
PRECIPITATION FOR THE SOUTHERN TIP OF TEXAS. NEAR NORMAL PRECIPITATION IS
FAVORED FOR HAWAII AS ANY POTENTIAL RESIDUAL EFFECTS FROM KIKO (OR ITS
REMNANTS) ARE EXPECTED TO OCCUR PRIOR TO THIS 6 TO 10 DAY PERIOD.
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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
FAIR AGREEMENT AMONG TODAY’S ENSEMBLE MEANS.
8-14 DAY OUTLOOK FOR SEP 15 - 21 2025
DURING WEEK-2, AN AMPLIFIED PATTERN IS FAVORED TO PERSIST ACROSS THE HIGHER
LATITUDES OF THE WESTERN HEMISPHERE INTO THE EARLY AND MIDDLE PORTIONS OF THE
PERIOD. THE MOST STABLE FEATURE IS A PREDICTED RIDGE OVER CENTRAL CANADA. THIS
RIDGE IS FORECAST TO REMAIN AMPLIFIED THROUGH THE MIDDLE OF THE PERIOD FOLLOWED
BY A TRANSITION TO ZONAL FLOW TOWARD THE END OF THE PERIOD. THE TROUGH
PREDICTED OVER THE GULF OF ALASKA IS FORECAST TO WEAKEN AND RETROGRADE.
HOWEVER, PERSISTENT CYCLONIC FLOW IS FORECAST OVER THE EASTERN BERING SEA
THROUGHOUT MOST OF THE PERIOD. FARTHER TO THE SOUTH, WEAK CYCLONIC FLOW IS
FORECAST ACROSS MUCH OF THE WEST EARLY IN THE PERIOD, WITH GENERALLY LOW
AMPLITUDE FLOW FORECAST THEREAFTER. THERE IS GENERAL AGREEMENT AMONG THE MODELS
THAT SUBTROPICAL RIDGING OF TYPICAL STRENGTH FOR THIS TIME OF YEAR WILL BE
PRESENT ACROSS THE SOUTHERN PLAINS FOR MUCH OF THE PERIOD. THE CENTER OF THIS
SUBTROPICAL RIDGE IS SLOWLY FORECAST TO DRIFT TOWARD NORTHERN MEXICO BY THE END
OF WEEK-2. UNCERTAINTY IS HIGH ACROSS THE NORTHEAST AS WEAK CYCLONIC FLOW IS
FORECAST UNTIL THE MIDDLE OF THE PERIOD FOLLOWED BY PREDICTED HEIGHT RISES
THEREAFTER. A WEAKNESS IN SUBTROPICAL RIDGING IS GENERALLY FORECAST TO CONTINUE
ACROSS THE SOUTHEAST, BUT WITH EACH ENSEMBLE MEAN DIFFERING IN THE SPECIFIC
TIMING AND MAGNITUDE OF THIS WEAKNESS. ACROSS HAWAII, NEAR NORMAL HEIGHTS ARE
FORECAST IN THE MEAN.
STRONG RIDGING OVER CENTRAL CANADA LEADS TO INCREASED CHANCES OF ABOVE NORMAL
TEMPERATURES ACROSS THE NORTH CENTRAL CONUS, WITH PROBABILITIES OF ABOVE NORMAL
TEMPERATURES EXCEEDING 70 PERCENT FOR THE NORTHEASTERN HALF OF NORTH DAKOTA AND
NORTHERN MINNESOTA. WEAK SUBTROPICAL RIDGING PREDICTED OVER THE SOUTHERN PLAINS
FAVORS MODESTLY ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ACROSS THE
REMAINDER OF THE CENTRAL CONUS. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR
MOST OF THE WEST, CONSISTENT WITH PREDICTED MODESTLY ABOVE NORMAL MEAN
MID-LEVEL HEIGHTS. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR EASTERN AND
SOUTHERN ALASKA AHEAD OF THE PREDICTED TROUGHS OVER THE GULF AND EASTERN BERING
SEA. NEAR NORMAL TEMPERATURES ARE MORE LIKELY FOR MOST OF THE REMAINDER OF THE
STATE, CONSISTENT WITH TELECONNECTIONS FROM PREDICTED NEGATIVE 500-HPA ANOMALY
CENTER ASSOCIATED WITH THE GULF OF ALASKA TROUGH. NEAR OR BELOW NORMAL
TEMPERATURES ARE FAVORED ALONG MUCH OF THE EASTERN SEABOARD ASSOCIATED WITH
PREDICTED REMNANT CYCLONIC FLOW. ABOVE NORMAL TEMPERATURES REMAIN MORE LIKELY
FOR THE SOUTHERN FLORIDA PENINSULA, INFLUENCED BY ABOVE NORMAL SSTS IN THE
ADJACENT ATLANTIC AND GULF. ABOVE NORMAL TEMPERATURES ARE ALSO LIKELY FOR
HAWAII, ASSOCIATED WITH ABOVE NORMAL SSTS IN THE ADJACENT PACIFIC, PARTICULARLY
FOR THE WESTERN AND CENTRAL ISLANDS.
AN ACTIVE PATTERN IS FAVORED FOR THE NORTHERN PLAINS TO THE PACIFIC NORTHWEST,
CONSISTENT WITH TELECONNECTIONS FROM THE STRONG RIDGE FORECAST OVER CENTRAL
CANADA. BELOW NORMAL PRECIPITATION IS FAVORED FOR THE GREAT LAKES, PARTS OF THE
INTERIOR NORTHEAST, AS WELL AS THE OHIO, TENNESSEE, AND LOWER AND MIDDLE
MISSISSIPPI VALLEYS DUE TO PREDICTED EXPANSIVE SURFACE HIGH PRESSURE. NEAR OR
ABOVE NORMAL PRECIPITATION IS MORE LIKELY ALONG MUCH OF THE IMMEDIATE EAST
COAST DUE TO PREDICTED ONSHORE FLOW TO THE SOUTHEAST OF THE PREDICTED MEAN
SURFACE HIGH POSITION. PROBABILITIES FOR ABOVE NORMAL PRECIPITATION EXCEED 40
PERCENT FOR SOUTHERN FLORIDA DUE TO THE POTENTIAL FOR STALLED FRONTAL ACTIVITY.
CHANCES OF ABOVE NORMAL PRECIPITATION ALSO EXCEED 40 PERCENT FOR PARTS OF THE
MID ATLANTIC, CONSISTENT WITH MULTIPLE TELECONNECTIONS AND SUGGESTIVE OF
POTENTIAL SURFACE LOW DEVELOPMENT ALONG THE EAST COAST TROUGH. A SLIGHT TILT
TOWARD ABOVE NORMAL PRECIPITATION IS INDICATED FOR PARTS OF THE SOUTHWEST, DUE
TO POTENTIAL MOISTURE ADVECTION ASSOCIATED WITH PREDICTED MEAN SOUTHEASTERLY
LOW-LEVEL FLOW. ABOVE NORMAL PRECIPITATION REMAINS FAVORED FOR SOUTHEASTERN
ALASKA, AHEAD OF THE PREDICTED TROUGHS OVER THE GULF OF ALASKA AND EASTERN
BERING SEA. TELECONNECTIONS FROM THE GULF OF ALASKA TROUGH FAVOR A DRIER THAN
NORMAL PATTERN ACROSS THE WESTERN MAINLAND. A SLIGHT TILT TOWARD ABOVE NORMAL
PRECIPITATION IS INDICATED FOR THE WESTERN AND CENTRAL HAWAIIAN ISLANDS,
CONSISTENT WITH CALIBRATED PRECIPITATION AMOUNTS FROM THE GEFS AND ECMWF
ENSEMBLES.
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: BELOW AVERAGE, 2 OUT OF 5, DUE TO
UNCERTAINTIES SURROUNDING THE EVOLUTION OF THE 500-HPA FLOW PATTERN ACROSS MUCH
OF THE FORECAST DOMAIN.
FORECASTER: SCOTT H
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:
19740901 - 19860906 - 20070912 - 19930908 - 19650821
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:
19740831 - 19860907 - 19930907 - 19730916 - 19650821
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 13 - 17 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 N
W MONTANA A A E MONTANA A A WYOMING A A
UTAH N A ARIZONA N N COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
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 B WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO N B KENTUCKY N B
TENNESSEE N B ALABAMA N B NEW YORK N N
VERMONT N N NEW HAMP B N MAINE N N
MASS B N CONN B N RHODE IS B N
PENN N N NEW JERSEY B N W VIRGINIA N B
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B N GEORGIA B B
FL PNHDL B N FL PENIN B A AK N SLOPE N N
AK ALEUTIAN B N AK WESTERN B B AK INT BSN A N
AK S INT A N AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 15 - 21 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 A E MONTANA A A WYOMING A A
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A N OKLAHOMA A N
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA A A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA N B NEW YORK A B
VERMONT A B NEW HAMP A N MAINE A B
MASS N N CONN N A RHODE IS N A
PENN A N NEW JERSEY N A W VIRGINIA N N
MARYLAND N A DELAWARE B A VIRGINIA N A
N CAROLINA N A S CAROLINA N N GEORGIA N N
FL PNHDL N N FL PENIN N A AK N SLOPE N B
AK ALEUTIAN N A AK WESTERN N B AK INT BSN A B
AK S INT A N 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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