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FXUS06 KWBC 132002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST SAT DECEMBER 13 2025
6-10 DAY OUTLOOK FOR DEC 19 - 23 2025
DYNAMICAL MODELS ARE IN GOOD AGREEMENT REGARDING A SIGNIFICANT PATTERN CHANGE
ACROSS MUCH OF THE EASTERN HALF OF THE U.S. BEGINNING LATER NEXT WEEK AND
PERSISTING INTO THE WEEK OF CHRISTMAS. MID-LEVEL RIDGING IS FORECAST TO AMPLIFY
OVER THE CONTIGUOUS U.S. (CONUS) EAST OF THE ROCKIES WITH TROUGHING OVER CANADA
AND EXTENDING ALONG THE WEST COAST OF THE CONUS. TODAY'S 500-HPA MANUAL HEIGHT
BLEND FOR THE 6-10 DAY PERIOD DEPICTS ABOVE-NORMAL HEIGHTS ACROSS MUCH OF THE
CONUS, WITH THE EXCEPTIONS BEING OVER THE PACIFIC NORTHWEST, NORTHERN
CALIFORNIA, NORTHERN GREAT BASIN, AND EXTENDING ACROSS THE NORTH-CENTRAL CONUS
CLOSE TO THE CANADIAN BORDER WHERE BELOW-NORMAL HEIGHTS ARE INDICATED. A
PERSISTENT PATTERN IS FAVORED ACROSS ALASKA WITH A +360 METER POSITIVE HEIGHT
ANOMALY CENTER DEPICTED ACROSS THE ALEUTIANS IN THE MANUAL BLEND, AND
ABOVE-NORMAL HEIGHTS EXTENDING OVER MUCH OF THE MAINLAND. BELOW-NORMAL HEIGHTS
REMAIN FORECAST FOR SOUTHEAST ALASKA CLOSER TO THE TROUGHING OVER CANADA.
NEAR-NORMAL 500-HPA HEIGHTS ARE FORECAST ACROSS HAWAII AS TROUGHING OVER THE
CENTRAL PACIFIC IS PREDICTED TO WEAKEN.
AN EXPANDING RIDGE OVER THE CENTRAL AND EASTERN CONUS FAVORS MUCH WARMER
TEMPERATURES EAST OF THE ROCKIES COMPARED TO THE PRIOR WEEKS. THE 0Z ECMWF,
GEFS, AND CANADIAN ENSEMBLES ALL DEPICT MEAN TEMPERATURES 15-20 DEG F
ABOVE-AVERAGE ACROSS PARTS OF THE SOUTH-CENTRAL CONUS FOR THE 6-10 DAY PERIOD
AS A WHOLE JUSTIFYING HIGH PROBABILITIES (ABOVE 90 PERCENT) FOR ABOVE-NORMAL
TEMPERATURES. ELEVATED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES EXTEND
NORTHWARD THROUGH MUCH OF THE INTERIOR WEST, CENTRAL PLAINS, MIDWEST, AND INTO
THE NORTHEAST. ELONGATED TROUGHING ACROSS CANADA CONTINUES TO FAVOR AN ACTIVE
NORTHERN STREAM AND INTRUSIONS OF COLD AIR ACROSS NORTHERN AREAS OF THE CONUS.
THEREFORE, CHANCES OF NEAR-TO BELOW NORMAL TEMPERATURES REMAIN FAVORED ALONG
THE NORTHERN TIER, AS WELL AS THE NORTHWEST TIED TO AMPLIFYING TROUGHING OFF
THE PACIFIC COAST. DEEP RIDGING ACROSS THE ALEUTIANS AND ASSOCIATED NORTHERLY
MID-LEVEL FLOW OVER ALASKA FAVORS HIGH PROBABILITIES OF BELOW-NORMAL
TEMPERATURES ACROSS MUCH OF EASTERN AND SOUTHERN ALASKA. THIS IS SUPPORTED BY
UNCALIBRATED AND REFORECAST TOOLS, IN ADDITION TO TELECONNECTION ANALYSIS WITH
THE POSITIVE HEIGHT ANOMALY CENTER. CONVERSELY, ODDS FOR ABOVE-NORMAL
TEMPERATURES ARE INCREASED OVER THE ALEUTIANS AND FAR WESTERN MAINLAND. HIGH
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR HAWAII, CONSISTENT
WITH THE CONSOLIDATION REFORECAST TOOL.
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED OVER THE WESTERN THIRD
OF THE CONUS TIED TO CONTINUED ATMOSPHERIC RIVER ACTIVITY. THE HIGHEST
PROBABILITIES (GREATER THAN 70 PERCENT) ARE FAVORED ACROSS NORTHERN CALIFORNIA
AND INTO THE GREAT BASIN. HOWEVER, ELEVATED PROBABILITIES FOR ABOVE-NORMAL
PRECIPITATION ALSO EXTEND INTO SOUTHERN CALIFORNIA, CONSISTENT WITH A SOUTHWARD
SHIFT IN THE STRONGEST MOISTURE ADVECTION TOWARD THE END OF THE PERIOD. RIDGING
DOWNSTREAM FAVORS ELEVATED PROBABILITIES FOR BELOW-NORMAL PRECIPITATION ACROSS
PARTS OF THE CENTRAL AND SOUTHERN PLAINS, GULF COAST, AND SOUTHEAST. AN ACTIVE
NORTHERN STREAM SLIGHTLY INCREASES THE ODDS FOR ABOVE-NORMAL PRECIPITATION OVER
MUCH OF THE NORTH-CENTRAL CONUS EASTWARD INTO THE OHIO VALLEY AND NORTHEAST,
WITH SEVERAL QUICK MOVING CLIPPER-LIKE SYSTEMS. OVER ALASKA, OFFSHORE FLOW
SUPPORTS ELEVATED CHANCES OF BELOW-NORMAL PRECIPITATION ACROSS SOUTHERN AND
SOUTHEASTERN PARTS OF THE STATE, WHILE A MORE NORTHWARD ORIENTED STORM TRACK
FAVORS ELEVATED CHANCES FOR ABOVE-NORMAL PRECIPITATION OVER THE NORTHERN
TWO-THIRDS OF THE MAINLAND. PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE
INCREASED ACROSS NORTHWESTERN HAWAII, AND DECREASE SOUTHEASTWARD AS TROUGHING
OVER THE CENTRAL PACIFIC WEAKENS, WITH BELOW-NORMAL PRECIPITATION FAVORED FOR
MOST OF THE BIG ISLAND.
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, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT REGARDING THE MID-LEVEL PATTERN, OFFSET BY SOME
UNCERTAINTY REGARDING NORTHERN STREAM ENERGY AND A POTENTIAL SOUTHWARD SHIFT OF
ATMOSPHERIC RIVER ACTIVITY INTO CALIFORNIA LATER IN THE PERIOD.
8-14 DAY OUTLOOK FOR DEC 21 - 27 2025
THE 500-HPA PATTERN DISCUSSED IN THE 6-10 OUTLOOK IS LIKELY TO PERSIST INTO
WEEK-2. THE 0Z ECMWF AND CANADIAN ENSEMBLES SIGNIFICANTLY AMPLIFY TROUGHING OFF
THE WEST COAST OF THE CONUS WHILE THE GEFS IS A BIT LESS ROBUST. HOWEVER, THE
PATTERN PROGRESSION REMAINS CONSISTENT WITH ATMOSPHERIC RIVER ACTIVITY
CONTINUING TO SHIFT SOUTH, EVEN INTO PARTS OF SOUTHERN CALIFORNIA DURING THE
PERIOD. FURTHER DOWNSTREAM, THE MID-LEVEL HEIGHT PATTERN DURING WEEK-2
RESEMBLES A POSITIVE PHASE OF THE ARCTIC OSCILLATION (+AO), WITH ABOVE-NORMAL
HEIGHTS OVER THE LOWER LATITUDES OF THE CONUS, AND BELOW-NORMAL HEIGHTS ACROSS
CANADA AND THE ARCTIC. THE WEEK-2 MANUAL HEIGHT BLEND SUPPORTS THIS, WITH
BROADLY POSITIVE HEIGHT ANOMALIES EAST OF THE ROCKIES, PEAKING AT +150 METERS
OVER THE MIDDLE MISSISSIPPI VALLEY. BELOW-NORMAL HEIGHTS ARE DEPICTED ACROSS
PARTS OF THE WESTERN CONUS, NORTHERN NEW ENGLAND, AND EASTERN ALASKA, WITH
ABOVE-NORMAL HEIGHTS INDICATED OVER WESTERN ALASKA TIED TO A PERSISTENT RIDGE
AXIS CENTERED OVER THE ALEUTIANS. NEAR-NORMAL HEIGHTS ARE FORECAST ACROSS
HAWAII, ALTHOUGH RISING MID-LEVEL HEIGHTS ARE POSSIBLE ACROSS THE NORTHERN
ISLANDS LATER IN THE PERIOD AS POSITIVE HEIGHT ANOMALIES ORIGINATING OVER
ALASKA EXPAND FURTHER SOUTHWARD OVER THE PACIFIC.
DOMINANT MID-LEVEL RIDGING CONTINUES TO FAVOR UNSEASONABLY WARM TEMPERATURES
ACROSS MUCH OF THE CONUS DURING WEEK-2, WITH THE HIGHEST PROBABILITIES (GREATER
THAN 90 PERCENT) OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. MANY OF
THESE AREAS ARE FAVORED TO HAVE A WARM CHRISTMAS BY CLIMATOLOGICAL STANDARDS
AND A WELCOME REPRIEVE FROM SOME OF THE COLDER WEATHER EXPERIENCED EARLIER IN
DECEMBER. THE STRONGEST SIGNALS FOR BELOW-NORMAL TEMPERATURES REMAIN ACROSS THE
PACIFIC NORTHWEST AND THE NORTHERN TIER INCLUDING NEW ENGLAND WHERE A MORE
CYCLONIC FLOW PATTERN IS PREDICTED WITH GREATER INFLUENCE FROM TROUGHING.
ANOMALOUSLY COLD WEATHER IS FAVORED TO PERSIST ACROSS ALASKA TIED TO THE
RIDGING UPSTREAM OVER THE ALEUTIANS. THE HIGHEST CHANCES FOR BELOW-NORMAL
TEMPERATURES ARE FAVORED ACROSS THE SOUTHEASTERN PORTION OF THE STATE,
CONSISTENT WITH THE ECMWF AND GEFS REFORECAST TOOLS. SOME AREAS ARE LIKELY TO
EXPERIENCE TEMPERATURES AT LEAST 10 TO UPWARDS OF 20 DEG F BELOW-AVERAGE BASED
ON UNCALIBRATED GUIDANCE, ALONG WITH DANGEROUSLY COLD WIND CHILLS. CONVERSELY,
HIGH PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS HAWAII
BASED ON THE CONSOLIDATED REFORECAST TOOL.
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED FROM THE ROCKIES
WESTWARD ASSOCIATED WITH CONTINUED ATMOSPHERIC RIVER ACTIVITY. PROBABILITIES
ARE ALSO FURTHER INCREASED OVER SOUTHERN CALIFORNIA (ABOVE 50 PERCENT) GIVEN
THE PREDICTED SOUTHWARD SHIFT IN STRONGEST ONSHORE FLOW. THE 0Z ECMWF, GEFS,
AND CANADIAN ENSEMBLES CONTINUE TO INDICATE SEVERAL INCHES OF RAIN (HIGH
ELEVATION SNOW) ALONG PORTIONS OF THE WEST COAST DURING WEEK-2 RESULTING IN
SIGNIFICANT FLOODING CONCERNS OVER SOME AREAS GIVEN THE PERSISTENT PATTERN.
RIDGING FAVORS A MUCH DRIER PATTERN ACROSS THE CENTRAL AND SOUTHEASTERN CONUS,
WITH BELOW-NORMAL PRECIPITATION CHANCES INCREASED OVER THESE AREAS. AS IN THE
6-10 DAY OUTLOOK, AN ACTIVE NORTHERN STREAM SUPPORTS SLIGHTLY ELEVATED CHANCES
FOR ABOVE-NORMAL PRECIPITATION OVER THE NORTHERN PLAINS, THROUGH PARTS OF THE
MIDWEST, OHIO VALLEY, AND NORTHEAST. REFORECAST TOOLS ARE IN GOOD AGREEMENT
SUPPORTING CONTINUED BELOW-NORMAL PRECIPITATION CHANCES OVER SOUTHERN ALASKA,
WITH ABOVE-NORMAL PRECIPITATION MORE LIKELY OVER THE CENTRAL AND NORTHERN
MAINLAND. WHILE ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE REDUCED COMPARED
TO THE 6-10 DAY PERIOD OVER NORTHWESTERN HAWAII, THEY STILL TILT ABOVE-NORMAL.
NEAR- TO BELOW NORMAL PRECIPITATION IS FORECAST FURTHER SOUTHEASTWARD ACROSS
THE ISLAND CHAIN.
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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT REGARDING THE PLACEMENT OF AMPLIFIED FEATURES.
FORECASTER: THOMAS COLLOW
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 (GRAY, "N") NORMAL.
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 (GRAY, "N")
NORMAL. 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
DECEMBER 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:
19951129 - 20101210 - 19951124 - 20131215 - 20121125
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:
19951130 - 20131214 - 19951125 - 20101211 - 19951205
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 19 - 23 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA N A E MONTANA B A WYOMING A A
UTAH A A ARIZONA A B COLORADO A A
NEW MEXICO A B N DAKOTA B A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA B A IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN N N
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A N ALABAMA A N NEW YORK A A
VERMONT N A NEW HAMP N A MAINE N A
MASS A A CONN A N RHODE IS A N
PENN A A NEW JERSEY A N W VIRGINIA A A
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A B
FL PNHDL A B FL PENIN A B AK N SLOPE B A
AK ALEUTIAN A B AK WESTERN B A AK INT BSN B A
AK S INT B B AK SO COAST B B AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 21 - 27 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA B A E MONTANA B A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA B A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA B A IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK N A
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN N N RHODE IS B N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A B AK N SLOPE B A
AK ALEUTIAN A B AK WESTERN B A AK INT BSN B A
AK S INT B B AK SO COAST B B AK PNHDL B 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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