925
FXUS06 KWBC 061902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT SAT SEPTEMBER 06 2025
6-10 DAY OUTLOOK FOR SEP 12 - 16 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. THESE TWO
FEATURES REMAIN AMPLIFIED THROUGHOUT THE PERIOD, MOST NOTABLY THE CANADIAN
RIDGE. FARTHER TO THE SOUTH, MULTIPLE SHORTWAVE TROUGHS ARE FORECAST OVER THE
WEST COAST AND GREAT BASIN EARLY IN THE PERIOD WITH THE INITIAL SHORTWAVE THEN
EJECTING INTO THE ROCKIES AND 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,
PARTICULARLY OVER THE NORTHEAST. HOWEVER, THE ECMWF ENSEMBLE MEAN MAINTAINS
CYCLONIC FLOW ACROSS THE REGION THROUGHOUT THE PERIOD. A WEAKNESS IN THE
SUBTROPICAL RIDGE IS FORECAST OVER THE SOUTHEAST, STEMMING FROM THE EASTERN
SEABOARD TROUGH. SUBTROPICAL RIDGING IS GENERALLY PREDICTED OVER THE SOUTH
CENTRAL CONUS THROUGHOUT THE PERIOD WITH THE GEFS BEING THE EXCEPTION IN
WEAKENING THE RIDGE ACROSS ALMOST THE ENTIRETY OF THE GULF COAST. ACCORDING TO
NHC, HURRICANE KIKO, CURRENTLY IN THE EASTERN PACIFIC, IS FORECAST TO APPROACH
THE HAWAIIAN ISLANDS EARLY TO MIDDLE PORTION OF NEXT WEEK. WHILE THIS APPROACH
IS LIKELY TO OCCUR PRIOR TO THIS 6 TO 10 DAY PERIOD, INTERESTS IN HAWAII SHOULD
MONITOR UPDATES FROM NHC FOR THE LATEST INFORMATION.
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 PARTS OF THE NORTHERN PLAINS.
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, TROUGHING EARLY IN THE PERIOD OVER THE
SOUTHWESTERN CONUS FAVORS BELOW NORMAL TEMPERATURES ACROSS SOUTHERN CALIFORNIA,
SOUTHERN NEVADA AND ADJACENT AREAS OF WESTERN ARIZONA. BELOW NORMAL
TEMPERATURES ARE MORE LIKELY ALONG THE EASTERN SEABOARD ASSOCIATED WITH
ANOMALOUS TROUGHING. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE SOUTHERN TIP
OF FLORIDA TO THE SOUTH OF A PREDICTED FRONTAL BOUNDARY. ABOVE NORMAL
TEMPERATURES IN ADJACENT WATERS ALSO FAVOR WARMER THAN NORMAL CONDITIONS FOR
THIS REGION. ABOVE NORMAL TEMPERATURES ARE ALSO 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 WEST DUE, IN PART, TO AN ANOMALOUS
SOUTHERN STREAM TROUGH PREDICTED OVER THE SOUTHWESTERN CONUS EARLY IN THE
PERIOD. TELECONNECTIONS FROM THE POSITIVE HEIGHT ANOMALY CENTER ASSOCIATED WITH
THE PREDICTED CANADIAN RIDGE ALSO SUPPORTS INCREASED CHANCES OF ABOVE NORMAL
PRECIPITATION ACROSS MUCH OF THE WEST, WITH THE MAIN EXCEPTION BEING SOUTHERN
CALIFORNIA AND ADJACENT AREAS OF ARIZONA AND NEVADA. UPSTREAM, THE PREDICTED
TROUGH OVER THE GULF OF ALASKA SUPPORTS INCREASED CHANCES OF ABOVE NORMAL
PRECIPITATION FOR SOUTHEAST ALASKA AND ADJACENT AREAS OF THE MAINLAND.
TELECONNECTIONS FROM THE PREDICTED RIDGE OVER CANADA AND THE TROUGH OVER THE
GULF OF ALASKA BOTH SUPPORT A WEAK WET SIGNAL FOR NORTHEASTERN MAINLAND ALASKA
LEADING TO A SLIGHT TILT TOWARD ABOVE NORMAL PRECIPITATION THERE. BELOW NORMAL
PRECIPITATION IS MORE LIKELY FOR THE WESTERN MAINLAND CONSISTENT WITH PREDICTED
LOW-LEVEL OFFSHORE FLOW AND TELECONNECTIONS FROM THE PREDICTED GULF OF ALASKA
TROUGH. BELOW NORMAL PRECIPITATION IS FAVORED FROM THE GREAT LAKES AND MUCH OF
THE NORTHEAST SOUTHWARD TO THE OHIO, TENNESSEE, MUCH OF THE LOWER AND MIDDLE
MISSISSIPPI VALLEYS, AND ADJACENT AREAS OF THE SOUTHERN PLAINS DUE TO PREDICTED
MEAN SURFACE HIGH PRESSURE. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE
FLORIDA PENINSULA NORTHWARD TO THE COASTAL CAROLINAS AND EXTREME SOUTHEASTERN
VIRGINIA 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 POTENTIAL RESIDUAL
EFFECTS FROM KIKO (OR ITS REMNANTS) ARE LARGELY 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 14 - 20 2025
DURING WEEK-2, AN AMPLIFIED PATTERN PERSISTS 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 LINGER THROUGHOUT MOST OF WEEK-2 WITH INCREASED UNCERTAINTY AS TO ITS
CONFIGURATION TOWARD THE END OF THE PERIOD. THE TROUGH PREDICTED OVER THE GULF
OF ALASKA IS FORECAST TO REMAIN FOR MOST OF THE PERIOD WITH VARYING INTENSITY.
PERSISTENT CYCLONIC FLOW IS FORECAST NEAR THE BERING STRAIT THROUGHOUT THE
PERIOD. FARTHER TO THE SOUTH, CYCLONIC FLOW IS FORECAST ACROSS MUCH OF THE WEST
EARLY IN THE PERIOD, WITH MODEST HEIGHT RISES GENERALLY 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. THE
CENTER OF THIS SUBTROPICAL RIDGE IS SLOWLY FORECAST TO CONSOLIDATE OVER THE
SOUTHERN HIGH PLAINS OR ADJACENT NORTHERN MEXICO BY THE END OF WEEK-2.
UNCERTAINTY IS HIGH ACROSS THE NORTHEAST AS A TROUGH NEAR THE EASTERN SEABOARD
EARLY IN THE PERIOD IS FORECAST TO WEAKEN. THEREAFTER, A VARIABLE PATTERN IS
PREDICTED WITH MODEL SOLUTIONS RANGING FROM A PERSISTENCE OF WEAK TROUGHING TO
THE DEVELOPMENT OF TRANSIENT RIDGING. 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, GENERALLY NEAR NORMAL HEIGHTS ARE FORECAST AS KIKO (OR ITS REMNANTS) IS
LIKELY TO HAVE DEPARTED FROM THE VICINITY PRIOR TO THIS WEEK-2 PERIOD.
PERSISTENT RIDGING OVER CENTRAL CANADA LEADS TO INCREASED CHANCES OF ABOVE
NORMAL TEMPERATURES ACROSS THE NORTHERN PLAINS, WITH PROBABILITIES OF ABOVE
NORMAL TEMPERATURES EXCEEDING 70 PERCENT FOR NORTHWESTERN NORTH DAKOTA AND
NORTHEASTERN MONTANA. 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, AS MID-LEVEL HEIGHTS BEGIN TO RISE. ABOVE NORMAL
TEMPERATURES ARE LIKELY FOR EASTERN ALASKA AHEAD OF THE PREDICTED TROUGH OVER
THE GULF. 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. 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 REMAINS FAVORED FOR SOUTHEASTERN ALASKA AND THE NORTHWESTERN
CONUS, AHEAD OF THE PREDICTED TROUGH OVER THE GULF OF ALASKA. TELECONNECTIONS
FROM THIS TROUGH FAVOR A DRIER THAN NORMAL PATTERN ACROSS THE WESTERN MAINLAND.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE NORTHERN PLAINS, SUPPORTED BY
TELECONNECTIONS FROM THE POSITIVE ANOMALY CENTER ASSOCIATED WITH THE RIDGE
FORECAST OVER CENTRAL CANADA. BELOW NORMAL PRECIPITATION IS FAVORED FOR THE
GREAT LAKES, MUCH OF THE NORTHEAST, AS WELL AS THE OHIO, TENNESSEE, AND
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. 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:
19860905 - 19740901 - 19710918 - 19750920 - 20070912
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:
19860906 - 19740831 - 20040816 - 19930907 - 19710918
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 12 - 16 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N A
SRN CALIF B N IDAHO N A NEVADA N A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH N A ARIZONA N A COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO N B KENTUCKY A B
TENNESSEE N B ALABAMA N B NEW YORK B B
VERMONT B B NEW HAMP B B MAINE B B
MASS B B CONN B N RHODE IS B N
PENN B B NEW JERSEY B N W VIRGINIA B B
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B N GEORGIA B N
FL PNHDL B A FL PENIN N A AK N SLOPE N N
AK ALEUTIAN N B 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 14 - 20 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 A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A N LOUISIANA N B WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY N B
TENNESSEE N B ALABAMA N N NEW YORK N B
VERMONT N B NEW HAMP N B MAINE A B
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 N S CAROLINA B N GEORGIA B N
FL PNHDL B A FL PENIN N A AK N SLOPE A N
AK ALEUTIAN N N AK WESTERN N B AK INT BSN A N
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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