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FXUS06 KWBC 262003
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST TUE DECEMBER 26 2023
6-10 DAY OUTLOOK FOR JAN 01 - 05 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). 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 MUCH OF THE WESTERN CONUS AND
NORTHERN TIER OF THE CONUS SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE
FORECAST TOOLS. OVER THE SOUTHEASTERN QUARTER OF THE CONUS, NEGATIVE 500-HPA
HEIGHT ANOMALIES AND MID-LEVEL TROUGHING FAVOR BELOW-NORMAL TEMPERATURES, WITH
PROBABILITIES EXCEEDING 50% ACROSS MOST OF FLORIDA. 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 MOST OF
THE ISLANDS EXCEPT THE BIG ISLAND, WHERE NEAR-NORMAL TEMPERATURES ARE FAVORED.
NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED OVER THE NORTHERN TIER OF THE
CONUS DUE TO STRONG 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 FORECAST 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 FAIRED FOR PARTS OF SOUTHEAST ALASKA WITH POSITIVE
500-HPA HEIGHT ANOMALIES LIMITING ONSHORE FLOW TO THE REGION. NEAR-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 03 - 09 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY PERSISTENT BUT
LESS AMPLIFIED 500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING
REGIONS. THE GEFS AND ECMWF ARE IN GOOD AGREEMENT REGARDING THE WEAKENING OF A
TROUGH OVER THE BERING SEA AND RIDGING OVER ALASKA AND WESTERN CANADA.
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 MUCH OF ALASKA AND
HAWAII DURING WEEK-2.
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE NORTHERN HALF OF THE CONUS
DURING THE WEEK-2 PERIOD. THE STRONGEST CHANCES FOR ABOVE-NORMAL TEMPERATURES
ARE IN PARTS OF THE NORTHERN PLAINS AND UPPER-MISSISSIPPI VALLEY. THIS IS
GENERALLY SUPPORTED BY THE DYNAMICAL TOOLS AND THE LACK OF DEEP SNOW COVER IN
THE NORTHERN CONUS MAY BE PLAYING A ROLE IN THE ABOVE-NORMAL TEMPERATURES.
NEAR- TO BELOW-NORMAL IS FAVORED ACROSS THE SOUTHERN CONUS WHERE PRECIPITATION
IS FAVORED LEADING TO MORE CLOUDS AND LACK OF DIURNAL HEATING LIMITING
TEMPERATURES. THIS LEADS TO A LARGE AREA BEING FORECAST FOR NEAR-NORMAL
TEMPERATURES TODAY AND IS SUPPORTED BY THE REFORECAST TOOLS. 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. AS THE MID-LEVEL FLOW BECOMES MORE ZONAL
AND LESS AMPLIFIED IN WEEK-2 ABOVE-NORMAL PRECIPITATION BEGINS TO EXPAND
NORTHWARD RELATIVE TO THE 6-10 DAY PERIOD. ABOVE-NORMAL PRECIPITATION IS NOW
SLIGHTLY FAVORED FOR MUCH OF THE NORTHWEST. ACROSS THE SOUTHERN TIER OF THE
COUNTRY, ABOVE-NORMAL REMAINS FAVORED DUE TO CONTINUED ONSHORE FLOW INTO THE
WESTERN CONUS AND CONTINUED ACTIVITY OF THE SOUTHERN STREAM JET. MEANWHILE,
NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED IN THE GREAT LAKES AND NORTHEAST
SUPPORTED BY THE DYNAMICAL TOOLS AND BEING BEHIND THE MEAN TROUGH AXIS. IN
ALASKA, ABOVE-NORMAL IS GENERALLY FAVORED ACROSS THE SOUTHERN MAINLAND WITH
NEAR-NORMAL REMAINING FAVORED IN PARTS OF SOUTHEAST ALASKA AND THE NORTH SLOPE.
IN HAWAII, ABOVE-NORMAL PRECIPITATION IS FAVORED FOR THE WESTERN ISLANDS AND
NEAR-NORMAL IS FAVORED FOR THE EASTERN HALF OF THE CHAIN.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 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 20%
OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR AVERAGE, 3 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:
19941224 - 20061211 - 19861227 - 19791226 - 19941216
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:
19941225 - 19941218 - 20061210 - 19861226 - 20061227
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 01 - 05 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF N A IDAHO A N NEVADA A A
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A A ARIZONA N A COLORADO N A
NEW MEXICO N A N DAKOTA A B S DAKOTA A N
NEBRASKA N N KANSAS N A OKLAHOMA N A
N TEXAS N A S TEXAS N A W TEXAS N A
MINNESOTA A B IOWA N B MISSOURI N N
ARKANSAS N A LOUISIANA N A WISCONSIN A B
ILLINOIS N B MISSISSIPPI B A MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY N N
TENNESSEE B N ALABAMA B A NEW YORK N B
VERMONT N B NEW HAMP N B MAINE A B
MASS N B CONN N B RHODE IS N B
PENN N B NEW JERSEY N B W VIRGINIA N B
MARYLAND N B DELAWARE N B VIRGINIA B N
N CAROLINA B N 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 03 - 09 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N A
SRN CALIF B A IDAHO A A NEVADA N A
W MONTANA A A E MONTANA A N WYOMING N A
UTAH N A ARIZONA B A COLORADO N A
NEW MEXICO N A N DAKOTA A N S DAKOTA A N
NEBRASKA N A KANSAS N A OKLAHOMA N A
N TEXAS N A S TEXAS N A W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI N A
ARKANSAS N A LOUISIANA N A WISCONSIN A N
ILLINOIS A N MISSISSIPPI N A MICHIGAN A B
INDIANA N N OHIO N B KENTUCKY N N
TENNESSEE N A ALABAMA N A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN B A AK N SLOPE N N
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A 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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