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FXUS06 KWBC 292004
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST FRI DECEMBER 29 2023
6-10 DAY OUTLOOK FOR JAN 04 - 08 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 RESULTANT MANUAL 500-HPA HEIGHT BLEND IS BASED ON THE
GEFS, ECMWF, AND CANADIAN. THIS BLEND FEATURES TROUGHING OVER THE BERING SEA
AND ALEUTIAN ISLANDS WITH NEAR-NORMAL HEIGHTS FAVORED FOR MOST OF MAINLAND
ALASKA. NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST TO OVERSPREAD MOST OF
THE REMAINDER OF NORTH AMERICA WITH TWO CENTERS LOCATED ACROSS THE HUDSON BAY
AND FOUR CORNERS REGION. AN EXCEPTION TO THIS IS NEAR-NORMAL 500-HPA HEIGHTS
CENTERED ACROSS THE GREAT LAKES. A NEGATIVE NORTH ATLANTIC OSCILLATION (NAO)
PATTERN IS ALSO FORECAST TO BECOME ESTABLISHED DURING THE PERIOD IN THE NORTH
ATLANTIC. NEAR- TO SLIGHTLY BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST FOR
HAWAII.
ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER THE NORTHERN TIER OF THE CONUS FROM
THE NORTHERN PLAINS THROUGH PARTS OF NEW ENGLAND SUPPORTED BY MOST OF THE
DYNAMICAL TEMPERATURE FORECAST TOOLS. ASSOCIATED WITH THESE ABOVE-NORMAL
TEMPERATURES IS AN OVERALL LACK OF SNOW COVER, RELATIVE TO NORMAL, 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. HOWEVER, PARTS
OF NORTHERN ALASKA ARE FAVORED TO SEE NEAR-NORMAL TEMPERATURES, WITH SURFACE
ARCTIC HIGH PRESSURE BRINGING CHANCES FOR COOLER TEMPERATURES. 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. AND THEN TURN NORTHWARD ALONG THE ATLANTIC COAST INCREASING
CHANCES FOR ABOVE-NORMAL PRECIPITATION ALONG THE EASTERN SEABOARD. 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 AND AWAY FROM THE STORM TRACK ALONG THE EAST COAST.
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 06 - 12 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT AN AREA OF NEGATIVE
500-HPA HEIGHT ANOMALIES ACROSS MOST OF THE CONUS, FAVORED TO EVOLVE INTO A
FULL LATITUDE TROUGH ACROSS MUCH OF NORTH AMERICA. THIS TROUGHING WILL BRING
INCREASING CHANCES FOR MORE PRECIPITATION TO MUCH OF THE CONUS DURING WEEK-2.
IN ALASKA, TOOLS ARE IN BETTER AGREEMENT FOR A PATTERN THAT REMAINS RELATIVELY
AMPLIFIED ACROSS THE REGION WITH NEGATIVE 500-HPA HEIGHTS FAVORED ACROSS
EASTERN SIBERIA INTO THE BERING SEA AND POSITIVE 500-HPA ANOMALIES INTO THE
GULF OF ALASKA. 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 ACROSS THE WESTERN CONUS. ABOVE-NORMAL TEMPERATURES REMAIN FAVORED
ACROSS THE GREAT LAKES AND THE NORTHEAST. NEAR-NORMAL TEMPERATURES ARE FAVORED
ACROSS MUCH OF THE EASTERN CONUS DURING THE PERIOD AS AN ACTIVE STORM PATTERN
BRINGS OPPORTUNITIES FOR RAPID CHANGES IN TEMPERATURE. ACROSS THE WESTERN
CONUS, THERE CONTINUES TO BE INCREASING AGREEMENT FOR BELOW-NORMAL TEMPERATURES
TO DEVELOP DURING THE WEEK-2 PERIOD. THE FULL LATITUDE TROUGH WOULD FAVOR
BELOW-NORMAL TEMPERATURES AS SUPPORTED BY THE STATISTICAL TOOLS AND SUPPORTED
BY THE RAW AND SHORT TERM BIAS CORRECTED DYNAMICAL TOOLS. HOWEVER, REFORECAST
TOOLS FROM THE GEFS AND EUROPEAN CONTINUE TO MAINTAIN A MUCH WARMER SOLUTION IN
THE WESTERN CONUS. PERHAPS, IN PART DUE TO RELATIVE LOW SNOW COVER ACROSS THE
REGION AND GENERALLY PERSISTENT WARMER THAN NORMAL CONDITIONS IN THE PREVIOUS
WEEKS. NEVERTHELESS, THE REFORECAST TOOLS ARE SHOWING WEAKER SIGNALS RELATIVE
TO PREVIOUS DAYS FOR ABOVE-NORMAL TEMPERATURES ACROSS THE WEST. THEREFORE, THE
OFFICIAL OUTLOOK HAS STRONGER PROBABILITIES FOR BELOW-NORMAL TEMPERATURES
RELATIVE TO PRIOR FORECASTS. THERE IS THEREFORE QUITE A BIT OF UNCERTAINTY
REGARDING THE TEMPERATURE FORECAST FOR THE PERIOD. IN ALASKA, ABOVE-NORMAL
TEMPERATURES REMAIN FAVORED ACROSS MUCH OF THE STATE EXCLUDING THE NORTH SLOPE
AND SOUTHEAST ALASKA WHERE NEAR-NORMAL TO BELOW-NORMAL TEMPERATURES ARE
FAVORED. IN HAWAII, ABOVE-NORMAL IS FAVORED ACROSS THE ISLAND CHAIN AS
SUPPORTED BY REFORECAST GUIDANCE.
GENERALLY ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF THE CONUS
BENEATH AN ACTIVE 500-HPA HEIGHT PATTERN. 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 LIKELY WITH AN ACTIVE SOUTHERN STREAM JET FAVORED TO BRING SEVERAL
CHANCES FOR PRECIPITATION TO THE REGION DURING THE 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 AS
THEY PROGRESS UP THE EASTERN SEABOARD. IN THE CENTER OF THE COUNTRY,
ABOVE-NORMAL PRECIPITATION IS FAVORED SLIGHTLY AS THE STRONG FULL-LATITUDE
TROUGH SHIFTS EASTWARD DURING THE PERIOD BRINGING CHANCES FOR PRECIPITATION TO
THE PLAINS AND GREAT LAKES. 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:
19661213 - 19941224 - 19861228 - 20061210 - 20030104
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:
19661212 - 20060102 - 19941226 - 20030103 - 19791228
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 04 - 08 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF B A
SRN CALIF B A IDAHO N A NEVADA B A
W MONTANA N A E MONTANA N A WYOMING N A
UTAH B A ARIZONA B A COLORADO N A
NEW MEXICO B A N DAKOTA A A S DAKOTA A A
NEBRASKA N A KANSAS N A OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A A IOWA N N MISSOURI N N
ARKANSAS B A LOUISIANA B A WISCONSIN A N
ILLINOIS N N MISSISSIPPI B A MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY N N
TENNESSEE N A ALABAMA B A NEW YORK N N
VERMONT N N NEW HAMP N N MAINE N N
MASS N A CONN N A RHODE IS N A
PENN N N NEW JERSEY N A W VIRGINIA N N
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA B A
FL PNHDL B A FL PENIN N 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 N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 06 - 12 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B 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 B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A A IOWA N A MISSOURI N A
ARKANSAS B A LOUISIANA B A WISCONSIN A A
ILLINOIS N A MISSISSIPPI N A MICHIGAN A A
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 A A NEW JERSEY A 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 N 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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