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FXUS06 KWBC 282003
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST THU DECEMBER 28 2023
6-10 DAY OUTLOOK FOR JAN 03 - 07 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 STRETCHED NEGATIVE 500-HPA HEIGHT ANOMALIES IS FORECAST
ACROSS THE SOUTHWESTERN CONUS AS IT RAPIDLY PROGRESSES EASTWARD DURING THE
PERIOD. ANOTHER AREA OF MID-LEVEL TROUGHING ASSOCIATED WITH BELOW-NORMAL
500-HPA HEIGHTS IS FORECAST OVER THE EASTERN CONUS, AND A NEGATIVE NORTH
AMERICAN OSCILLATION (NAO) PATTERN IS ALSO FORECAST TO BECOME ESTABLISHED
DURING THE PERIOD. NEAR- TO SLIGHTLY BELOW-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 IS 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. CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE INCREASED
FOR MUCH OF ALASKA, DUE TO PREDICTED RIDGING AND SOUTHERLY FLOW. FOR HAWAII,
FORECAST TOOLS FAVOR ABOVE-NORMAL TEMPERATURES FOR THE ENTIRE ISLAND CHAIN.
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE COUNTRY DURING THE 6-10
DAY PERIOD. ABOVE-NORMAL PRECIPITATION CHANCES ARE SLIGHTLY INCREASED RELATIVE
TO YESTERDAY ACROSS THE SOUTHWEST AND REMAIN ELEVATED ACROSS THE GULF COAST.
THE GEFS, ECMWF, AND CANADIAN FORECAST A SHORTWAVE TROUGH TO PROGRESS ACROSS
THE SOUTHERN U.S. IN THE PACIFIC NORTHWEST, A SLIGHT TILT TOWARDS ABOVE-NORMAL
PRECIPITATION IS FORECAST AS A DEEPER TROUGH BEGINS TO BE ESTABLISHED BY THE
END OF THE PERIOD BRINGING MORE MOISTURE INTO THE REGION. HOWEVER, IN PARTS OF
THE GREAT LAKES, MIDWEST, AND NORTHEAST, BELOW-NORMAL PRECIPITATION REMAINS
FAVORED DURING THE PERIOD. THIS AREA REMAINS SLIGHTLY BEHIND THE TROUGH AXIS,
WITH NORTHERLY FLOW BRINGING DRIER AIR INTO THE REGION. IN ALASKA, SOUTHERLY
FLOW, ALONG WITH A CHANCE FOR A STRONG BERING SEA STORM INCREASES CHANCES FOR
ABOVE-NORMAL PRECIPITATION FOR MUCH OF SOUTHERN ALASKA. NEAR- TO BELOW-NORMAL
PRECIPITATION IS FAVORED ACROSS THE NORTHERN HALF OF MAINLAND ALASKA.
ABOVE-NORMAL PRECIPITATION IS STRONGLY FAVORED IN HAWAII TODAY DUE TO LARGE
INCREASES IN PRECIPITATION CHANCES IN THE REFORECAST 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT IN THE HEIGHT PATTERN IS OFFSET BY DISAGREEMENT AMONG THE TEMPERATURE
TOOLS.
8-14 DAY OUTLOOK FOR JAN 05 - 11 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT AN AREA OF NEGATIVE
500-HPA HEIGHT ANOMALIES ACROSS THE WESTERN CONUS, FAVORED TO EVOLVE INTO A
FULL LATITUDE TROUGH ACROSS MUCH OF WESTERN NORTH AMERICA. THIS TROUGHING WILL
BRING INCREASING CHANCES FOR MORE PRECIPITATION TO PARTS OF THE WESTERN CONUS
DURING WEEK-2. IN ALASKA, TOOLS ARE IN BETTER AGREEMENT FOR A PATTERN THAT
REMAINS RELATIVELY AMPLIFIED ACROSS THE REGION. A NEGATIVE NAO PATTERN REMAINS
FORECAST INTO WEEK-2 ACROSS THE NORTH ATLANTIC; THIS BRINGS NEAR-NORMAL HEIGHTS
TO THE EAST COAST FOR THE MEAN WEEK-2 500-HPA HEIGHT PATTERN. NEAR-NORMAL MEAN
500-HPA HEIGHT ANOMALIES ARE PREDICTED OVER HAWAII DURING WEEK-2.
THE OVERALL WEEK-2 FORECAST HAS CONTINUED TO GROW COOLER RELATIVE TO PRIOR
FORECASTS. ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE GREAT LAKES AND
THE NORTHEAST. BUT PARTS OF THE PACIFIC NORTHWEST ARE NOW FAVORED TO SEE
BELOW-NORMAL TEMPERATURES 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 ABOVE-NORMAL TEMPERATURES BEING MORE
STRONGLY FAVORED IN THE REFORECAST TOOLS. BELOW-NORMAL IS FAVORED ACROSS THE
SOUTHERN CONUS ALONG THE SOUTHERN STREAM STORM TRACK WHERE PRECIPITATION IS
FAVORED, LEADING TO MORE CLOUDS AND A LACK OF DIURNAL HEATING THAT LIMITS
DAYTIME MAXIMUM 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 PARTS OF THE GREAT LAKES. 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. A WETTER PATTERN IS
FORECAST FOR THE NORTHEAST TODAY RELATIVE TO PREVIOUS FORECASTS WITH THE
SOUTHERN STREAM STORMS FORECAST TO HAVE MORE INTERACTION WITH THE NORTHEAST. IN
THE MIDWEST, 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 AND THE NORTHERN MAINLAND. IN HAWAII, ABOVE-NORMAL
PRECIPITATION IS LIKELY ACROSS THE ISLAND 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: 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 - 19871208 - 19861227 - 19941224 - 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 - 19661212 - 20060102 - 19941225 - 20030103
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 03 - 07 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 A A WYOMING N A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA A N S DAKOTA N N
NEBRASKA N N KANSAS N N 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 N
TENNESSEE N N ALABAMA B A NEW YORK N B
VERMONT A B NEW HAMP N N MAINE A N
MASS N N CONN N N RHODE IS N N
PENN N B NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N A VIRGINIA N A
N CAROLINA N 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 A N
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 05 - 11 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO B A NEVADA B A
W MONTANA B A E MONTANA N A WYOMING B A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA N A S DAKOTA N A
NEBRASKA N A KANSAS N A OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N N IOWA N A MISSOURI N A
ARKANSAS N A LOUISIANA B A WISCONSIN N N
ILLINOIS N A MISSISSIPPI N A MICHIGAN A N
INDIANA N A OHIO N A KENTUCKY N A
TENNESSEE N A ALABAMA N A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN N A NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN N A AK N SLOPE N N
AK ALEUTIAN A A AK WESTERN A A AK INT BSN N N
AK S INT A A AK SO COAST A A AK PNHDL B 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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