790
FXUS06 KWBC 051916
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI SEPTEMBER 05 2025
6-10 DAY OUTLOOK FOR SEP 11 - 15 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 JUST TO THE WEST OF
HUDSON BAY AND AND A DEEP TROUGH OVER THE GULF OF ALASKA. NOTABLY, THE TROUGH
OVER THE GULF OF ALASKA HAS TRENDED SIGNIFICANTLY STRONGER RELATIVE TO
YESTERDAY WHICH, IN TURN, FAVORS A STRONGER DOWNSTREAM RIDGE ACROSS
NORTHWESTERN CANADA. FARTHER TO THE SOUTH, A TOUGH IN THE SOUTHERN STREAM IS
PREDICTED OVER CALIFORNIA AND NEVADA EARLY IN THE PERIOD. TROUGHING IS ALSO
FORECAST OVER THE EASTERN SEABOARD DOWNSTREAM OF THE CANADIAN RIDGE. A WEAKNESS
IN THE SUBTROPICAL RIDGE IS FORECAST OVER THE SOUTHEAST, STEMMING FROM THE
EASTERN SEABOARD TROUGH. SUBTROPICAL RIDGING IS PREDICTED OVER THE SOUTHERN
PLAINS EARLY IN THE PERIOD AND IS EXPECTED TO FLATTEN TO A MORE ZONAL
CONFIGURATION BY THE END OF THE PERIOD. 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
MOSTLY PRIOR TO THIS 6 TO 10 DAY PERIOD, INTERESTS IN HAWAII SHOULD MONITOR
UPDATES FROM NHC FOR THE LATEST INFORMATION ON KIKO.
PREDICTED STRONG MID-LEVEL RIDGING FORECAST OVER CENTRAL CANADA FAVORS ABOVE
NORMAL TEMPERATURES ACROSS THE NORTHERN PLAINS WITH PROBABILITIES OF WARMER
THAN NORMAL CONDITIONS EXCEEDING 60 PERCENT FOR PARTS OF THE NORTHERN HIGH
PLAINS. 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,
MOST OF NEVADA AND ADJACENT AREAS OF THE GREAT BASIN AND SOUTHWEST. PREDICTED
SUBTROPICAL RIDGING OVER THE SOUTHERN PLAINS LEADS TO AN INCREASED CHANCE OF
ABOVE NORMAL TEMPERATURES ACROSS THE CENTRAL CONUS. BELOW NORMAL TEMPERATURES
ARE MORE LIKELY ALONG THE EASTERN SEABOARD ASSOCIATED WITH ANOMALOUS TROUGHING.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR SOUTHERN 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 MOST OF THE WEST, WITH THE MAIN EXCEPTION BEING SOUTHERN
CALIFORNIA AND PARTS OF WESTERN ARIZONA. 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 NORTHWESTERN 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 INTERIOR NORTHEAST SOUTHWARD
TO THE OHIO, TENNESSEE, AND MUCH OF THE LOWER AND MIDDLE MISSISSIPPI VALLEYS,
DUE TO PREDICTED MEAN SURFACE HIGH PRESSURE. ABOVE NORMAL PRECIPITATION IS
FAVORED FOR THE FLORIDA PENINSULA NORTHWARD TO THE COASTAL CAROLINAS 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.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR HAWAII DUE, IN PART, TO POTENTIAL
RESIDUAL EFFECTS FROM KIKO (OR ITS REMNANTS). THE GREATEST CHANCES OF ABOVE
NORMAL PRECIPITATION IS INDICATED FOR THE WESTERN ISLANDS WHERE POTENTIAL
IMPACTS MAY BE LAST TO DEPART.
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: ABOVE AVERAGE, 3 OUT OF 5, DUE TO
FAIR AGREEMENT AMONG TODAY’S ENSEMBLE MEANS.
8-14 DAY OUTLOOK FOR SEP 13 - 19 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 WEEK-2 IN THE ECMWF AND CANADIAN ENSEMBLE MEAN SOLUTIONS.
THE TROUGH PREDICTED OVER THE GULF OF ALASKA IS FORECAST TO REMAIN UNTIL THE
MIDDLE OF THE PERIOD AND THEN WEAKEN. 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, POTENTIALLY TRANSITIONING
TO MORE ZONAL FLOW AS THE UPSTREAM GULF OF ALASKA TROUGH WEAKENS. A SOUTHERN
STREAM FEATURE PREDICTED OVER THE SOUTHWESTERN CONUS DURING THE 6 TO 10 DAY
PERIOD IS FORECAST TO SIGNIFICANTLY WEAKEN BY THE BEGINNING OF WEEK-2. THERE IS
GENERAL AGREEMENT AMONG THE MODELS THAT SUBTROPICAL RIDGING WILL BE PRESENT
ACROSS THE SOUTHERN PLAINS. THE CENTER OF THIS SUBTROPICAL RIDGE IS SLOWLY
FORECAST TO DRIFT WESTWARD NEAR THE SOUTHERN HIGH PLAINS BY THE END OF WEEK-2.
UNCERTAINTY IS HIGH ACROSS THE EAST AS A TROUGH NEAR THE SEABOARD EARLY IN THE
PERIOD IS FORECAST TO WEAKEN. HOWEVER, REMNANT WEAK CYCLONIC FLOW IS FORECAST
TO PERSIST NEAR THE EAST COAST FOR MUCH OF THE PERIOD. SLOW HEIGHT RISES ARE
FORECAST FOR THE SOUTHEAST, BUT A GENERAL WEAKNESS IN SUBTROPICAL RIDGING STILL
PERSISTS ACROSS THE REGION AT VARIOUS TIMES DURING WEEK-2, WITH EACH ENSEMBLE
MEAN DIFFERING IN THE SPECIFIC TIMING AND MAGNITUDE OF THIS WEAKNESS. AN ACTIVE
TROPICAL DISTURBANCE CURRENTLY IN THE CENTRAL ATLANTIC WILL ALSO NEED TO BE
MONITORED FOR ANY POTENTIAL IMPACTS TO THE OVERALL FLOW PATTERN ACROSS THE
EAST. ACROSS HAWAII, KIKO (OR ITS REMNANT LOW) IS GENERALLY FORECAST TO HAVE
PASSED BY THE ISLAND CHAIN PRIOR TO WEEK-2. INTERESTS IN HAWAII SHOULD CONTINUE
TO MONITOR THE LATEST UPDATES FROM THE NHC FOR ANY CHANGES IN FORECAST TRACK OR
TIMING OF THIS SYSTEM.
PERSISTENT RIDGING OVER CENTRAL CANADA LEADS TO INCREASED CHANCES OF ABOVE
NORMAL TEMPERATURES ACROSS THE NORTHERN PLAINS, WITH PROBABILITIES OF ABOVE
NORMAL TEMPERATURES EXCEEDING 60 PERCENT FOR MOST OF NORTH DAKOTA AND ADJACENT
AREAS OF MINNESOTA AND 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 A SOUTHERN STREAM TROUGH
FORECAST DURING THE 6 TO 10 DAY PERIOD WEAKENS AND MID-LEVEL HEIGHTS BEGIN TO
RISE. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR SOUTHEASTERN 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 MOST OF
THE INTERIOR EAST 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 AND DUE TO UNCERTAINTY REGARDING THE TROPICS. NEAR NORMAL
PRECIPITATION IS FAVORED FOR EASTERN HAWAII AS KIKO (OR ITS REMNANTS) EXITS THE
PICTURE. A SLIGHT TILT TOWARD ABOVE NORMAL PRECIPITATION IS INDICATED FOR THE
WESTERN AND CENTRAL 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 - 19710918 - 19790823 - 19740831 - 19770818
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:
19860905 - 19740831 - 19890911 - 19710918 - 20040815
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 11 - 15 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON N A NRN CALIF N A
SRN CALIF B N IDAHO N A NEVADA B 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 N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS N B LOUISIANA N B WISCONSIN N N
ILLINOIS N B MISSISSIPPI N B MICHIGAN N B
INDIANA N B OHIO N B KENTUCKY N 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 B RHODE IS B N
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B N VIRGINIA B B
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL N N FL PENIN N A AK N SLOPE N A
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 13 - 19 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF N N IDAHO A A NEVADA A A
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 A OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO N B KENTUCKY N B
TENNESSEE N B ALABAMA N N NEW YORK N B
VERMONT B B NEW HAMP B B MAINE N B
MASS B N CONN B N RHODE IS B N
PENN N B 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 N N FL PENIN A A AK N SLOPE N B
AK ALEUTIAN A N 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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page