541
FXUS06 KWBC 272002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED DECEMBER 27 2023
6-10 DAY OUTLOOK FOR JAN 02 - 06 2024
MODEL SOLUTIONS ARE IN GOOD AGREEMENT PREDICTING AN AMPLIFIED 500-HPA
CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING THE
6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE
ENSEMBLE MEANS FROM THE GFS, ECMWF, AND CANADIAN MODELS DUE TO RECENT MODEL
SKILL. THE RESULTANT MANUAL BLEND FEATURES TROUGHING OVER THE BERING SEA AND
ALEUTIAN ISLANDS. RIDGING AND POSITIVE HEIGHT ANOMALIES ARE FORECAST OVER MOST
OF MAINLAND ALASKA, WESTERN CANADA, AND THE NORTHWESTERN CONTIGUOUS U.S.
(CONUS). AN AREA OF NEGATIVE 500-HPA HEIGHT ANOMALIES IS PROGRESSING EASTWARD
ACROSS THE SOUTHERN TIER OF THE CONUS CENTERED OVER THE SOUTHERN ROCKIES DURING
THE PERIOD. ANOTHER AREA OF MID-LEVEL TROUGHING ASSOCIATED WITH BELOW-NORMAL
500-HPA HEIGHTS IS FORECAST OVER THE EASTERN CONUS. ABOVE-NORMAL 500-HPA
HEIGHTS ARE FORECAST FOR HAWAII.
ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER THE NORTHERN TIER OF THE CONUS
SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE FORECAST TOOLS. ASSOCIATED WITH
THESE ABOVE-NORMAL TEMPERATURES ARE AN OVERALL LACK OF SNOW COVER ACROSS THE
NORTHERN CONUS RESULTING IN A WARMER SURFACE LAYER. OVER THE SOUTHERN PORTIONS
OF THE CONUS, NEGATIVE 500-HPA HEIGHT ANOMALIES AND MID-LEVEL TROUGHING FAVOR
BELOW-NORMAL TEMPERATURES, WITH PROBABILITIES EXCEEDING 50% ACROSS FLORIDA AND
PARTS OF THE GULF COAST. CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE INCREASED
FOR ALASKA, DUE TO PREDICTED RIDGING AND SOUTHERLY FLOW. FOR HAWAII, FORECAST
TOOLS FAVOR ABOVE-NORMAL TEMPERATURES FOR THE ENTIRE ISLAND CHAIN.
NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED OVER THE NORTHERN TIER OF THE
CONUS DUE TO POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE PACIFIC NORTHWEST AND
WESTERN CANADA LIMITING MOISTURE INTO THE NORTHERN PARTS OF THE CONUS.
MEANWHILE, ABOVE-NORMAL PRECIPITATION IS MORE LIKELY OVER MUCH OF THE SOUTHERN
CONUS AS THE MEAN STORM TRACK CONTINUES TO BE FAVORED ACROSS THE SOUTHERN TIER.
IN ALASKA, BROAD ONSHORE FLOW PROMOTES ELEVATED CHANCES OF NEAR- TO
ABOVE-NORMAL PRECIPITATION FOR MUCH OF SOUTHERN MAINLAND ALASKA. NEAR-NORMAL IS
FAVORED FOR MUCH OF THE NORTHERN MAINLAND WHERE ENHANCED MOISTURE IS LESS
LIKELY. NEAR-NORMAL IS ALSO FAVORED FOR PARTS OF SOUTHEAST ALASKA WITH POSITIVE
500-HPA HEIGHT ANOMALIES LIMITING ONSHORE FLOW TO THE REGION. SLIGHT
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR THE HAWAIIAN ISLANDS, CONSISTENT WITH
THE GEFS AND ECMWF PRECIPITATION REFORECAST CONSOLIDATION TOOLS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 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 20%
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 AGREEMENT AMONG MODEL SOLUTIONS AND FORECAST TEMPERATURE AND PRECIPITATION
TOOLS.
8-14 DAY OUTLOOK FOR JAN 04 - 10 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT AN AREA OF NEGATIVE
500-HPA HEIGHT ANOMALIES TO BE CENTERED ACROSS THE FOUR CORNERS REGION. THIS
TROUGHING WILL BRING INCREASING CHANCES FOR MORE STORMINESS TO PARTS OF THE
WESTERN CONUS DURING WEEK-2. THE ECMWF AND CANADIAN ARE PREDICTING A MORE
AMPLIFIED PATTERN ACROSS THE ALASKA REGION TO PERSIST INTO THE WEEK-2 TIME
PERIOD. WHEREAS THE GEFS IS MAINTAINING A MORE ZONAL HEIGHT PATTERN ACROSS
ALASKA IN GOOD CONSISTENCY WITH YESTERDAY. THE MANUAL HEIGHT BLEND LEADS
TOWARDS MORE OF A PERSISTENCE OF THE AMPLIFIED PATTERN IN AGREEMENT WITH THE
ECMWF ENSEMBLES. BELOW-NORMAL 500-HPA HEIGHTS ARE GENERALLY FORECAST ACROSS
MUCH OF THE CONUS DURING WEEK-2 WITH A STRONGER TROUGH FORECAST ACROSS THE
EASTERN CONUS. NEAR-NORMAL MEAN 500-HPA HEIGHT ANOMALIES ARE PREDICTED OVER
HAWAII DURING WEEK-2.
THE OVERALL WEEK-2 FORECAST HAS GROWN COOLER RELATIVE TO PRIOR FORECASTS.
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE GREAT LAKES BUT MUCH OF THE
NORTHERN CONUS IS NOW FAVORED TO SEE NEAR-NORMAL CONDITIONS DURING WEEK-2.
STATISTICAL GUIDANCE AND SHORT-TERM BIASED CORRECTED TOOLS ARE SIGNIFICANTLY
COLDER RELATIVE TO DYNAMICAL REFORECAST TOOLS. THERE IS THEREFORE QUITE A BIT
OF UNCERTAINTY REGARDING THE TEMPERATURE FORECAST FOR THE PERIOD. THE LACK OF
DEEP SNOW COVER IN THE NORTHERN CONUS MAY BE PLAYING A ROLE IN THE ABOVE-NORMAL
TEMPERATURES BEING MORE STRONGLY FAVORED IN THE REFORECAST TOOLS. BELOW-NORMAL
IS FAVORED ACROSS THE SOUTHERN CONUS WHERE PRECIPITATION IS FAVORED LEADING TO
MORE CLOUDS AND LACK OF DIURNAL HEATING LIMITING TEMPERATURES. IN ALASKA,
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS MUCH OF THE STATE EXCLUDING THE
NORTH SLOPE WHERE NEAR-NORMAL IS FAVORED. IN HAWAII, ABOVE-NORMAL IS FAVORED
ACROSS THE ISLAND CHAIN.
GENERALLY ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF THE CONUS
EXCLUDING THE NORTHEASTERN QUADRANT. BENEATH THE NEGATIVE 500-HPA HEIGHT
ANOMALIES ACROSS THE WESTERN CONUS ABOVE-NORMAL PRECIPITATION IS SLIGHTLY
FAVORED DURING THE WEEK-2 PERIOD. THE STRONGEST PROBABILITIES FOR ABOVE-NORMAL
PRECIPITATION REMAIN ACROSS SOUTHERN PORTIONS OF THE SOUTHWEST, WHERE
CLIMATOLOGY REMAINS QUITE DRY. ACROSS THE SOUTHEAST, ABOVE-NORMAL PRECIPITATION
REMAINS FAVORED WITH AN ACTIVE SOUTHERN STREAM JET LIKELY TO BRING SEVERAL
CHANCES FOR PRECIPITATION TO THE REGION DURING THIS PERIOD. IN THE MIDWEST AND
UPPER NORTHEAST, NEAR-NORMAL PRECIPITATION IS FAVORED SLIGHTLY BEHIND A TROUGH
AXIS LIMITING PRECIPITATION CHANCES. IN ALASKA, ABOVE-NORMAL IS GENERALLY
FAVORED ACROSS THE SOUTHERN MAINLAND WITH NEAR-NORMAL REMAINING FAVORED IN
PARTS OF SOUTHEAST ALASKA. IN HAWAII, ABOVE-NORMAL PRECIPITATION IS FAVORED FOR
MUCH OF THE STATE; HOWEVER, NEAR-NORMAL IS FAVORED FOR THE BIG ISLAND.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 11, 35% 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, GOOD
AGREEMENT AMONG MODEL HEIGHT SOLUTIONS IS OFFSET BY POOR AGREEMENT FOR THE
FORECAST TEMPERATURE BETWEEN THE REFORECAST AND RAW MODEL GUIDANCE.
FORECASTER: RYAN BOLT
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES. IN
THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT ISSUED.
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
JANUARY 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:
20061210 - 19941224 - 19861227 - 20061228 - 19791226
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:
20061210 - 19941223 - 20061227 - 19861226 - 19941218
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 02 - 06 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF N A
SRN CALIF N A IDAHO N N NEVADA N N
W MONTANA N N E MONTANA A N WYOMING N N
UTAH N N ARIZONA B A COLORADO N A
NEW MEXICO B A N DAKOTA A N S DAKOTA N N
NEBRASKA N N KANSAS N A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA N B MISSOURI N B
ARKANSAS B A LOUISIANA B A WISCONSIN A B
ILLINOIS N B MISSISSIPPI B A MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY N B
TENNESSEE B N ALABAMA B A NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS N B CONN N B RHODE IS N N
PENN N B NEW JERSEY N N W VIRGINIA N B
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE A N
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A N
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 04 - 10 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF N A
SRN CALIF B A IDAHO N A NEVADA B A
W MONTANA N A E MONTANA N A WYOMING B A
UTAH N A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA N A S DAKOTA N A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA N N MISSOURI N N
ARKANSAS B A LOUISIANA B A WISCONSIN A N
ILLINOIS N N MISSISSIPPI B A MICHIGAN A N
INDIANA N N OHIO N N KENTUCKY B N
TENNESSEE B A ALABAMA B A NEW YORK N N
VERMONT N N NEW HAMP N N MAINE N N
MASS N N CONN N A RHODE IS N A
PENN N A NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N N
AK ALEUTIAN A A AK WESTERN A A AK INT BSN N A
AK S INT A A AK SO COAST A A AK PNHDL A N
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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