488
FXUS06 KWBC 082035
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED JANUARY 08 2025
6-10 DAY OUTLOOK FOR JAN 14 - 18 2025
THERE IS GOOD AGREEMENT BETWEEN THE LATEST ECMWF, GEFS, AND CANADIAN ENSEMBLE
MEAN 500-HPA HEIGHT FORECASTS ON THE PREDICTED CIRCULATION PATTERN ACROSS NORTH
AMERICA FOR THE 6-10 DAY PERIOD. DYNAMICAL MODELS PREDICT CHANGES IN THE
PATTERN OVER TIME, WHICH IS REFLECTED IN CHANGES RELATIVE TO YESTERDAY’S
FORECASTS. IN PARTICULAR, A TROUGH OVER WESTERN MAINLAND ALASKA AT THE START OF
THE PERIOD IS PREDICTED TO MOVE NORTHWESTWARD OVER THE BERING SEA AND SIBERIA,
AS A RIDGE EXTENDS FROM THE NORTH PACIFIC INTO THE ALEUTIANS. DOWNSTREAM,
MODELS PREDICT POSITIVE 500-HPA HEIGHT ANOMALIES OVER SOUTHEAST ALASKA AND THE
NORTHWESTERN CONTIGUOUS U.S. (CONUS) ASSOCIATED WITH THE NORTH PACIFIC RIDGE TO
DEAMPLIFY, AS A TROUGH DEVELOPS OVER THE WESTERN CONUS LATER IN THE PERIOD.
CONCURRENTLY, MODELS PREDICT A TROUGH AND ASSOCIATED NEGATIVE 500-HPA HEIGHT
ANOMALIES OVER THE EASTERN HALF OF THE CONUS TO MOVE EASTWARD INTO THE
ATLANTIC. ENSEMBLE MEANS PREDICT AN EXTENSION OF THE TROUGH OVER THE
SOUTHWESTERN CONUS THROUGHOUT THE 6-10 DAY PERIOD. THERE ARE DIFFERENCES AMONG
ENSEMBLE MEANS ON THE CHANGING PATTERN, WITH THE GEFS DEVELOPING GREATER
AMPLITUDE NEGATIVE 500-HPA HEIGHT ANOMALIES OVER THE WEST MORE RAPIDLY THAN THE
ECMWF ENSEMBLE MODEL.
ABOVE-NORMAL TEMPERATURES ARE LIKELY OVER THE ALEUTIANS, UNDER THE DEVELOPING
RIDGE. ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER NORTHEASTERN MAINLAND ALASKA,
CONSISTENT WITH MOST DYNAMICAL MODEL FORECAST TOOLS. ABOVE-NORMAL TEMPERATURES
ARE FAVORED OVER SOUTHEAST ALASKA, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES AND
ONSHORE FLOW. UNDER THE PREDICTED TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES,
BELOW-NORMAL TEMPERATURES ARE LIKELY ACROSS A LARGE AREA OF THE EASTERN CONUS,
EXCLUDING THE WESTERN GREAT LAKES REGION AND NORTHERN AREAS OF THE NORTHEAST.
BELOW-NORMAL TEMPERATURES ARE FAVORED OVER THE INTERIOR WEST, AS A TROUGH
DEVELOPS OVER THE REGION. NEAR-NORMAL TEMPERATURES ARE FAVORED OVER SOME AREAS
OF THE WEST, WHERE TEMPERATURE TOOLS ARE INCONSISTENT. ABOVE-NORMAL
TEMPERATURES ARE FAVORED FOR PARTS OF THE NORTHERN PLAINS, CONSISTENT WITH MOST
DYNAMICAL MODEL FORECAST TOOLS.
ABOVE-NORMAL PRECIPITATION IS LIKELY ACROSS MOST OF ALASKA, INCLUDING THE
EASTERN ALEUTIANS, MAINLAND ALASKA, AND SOUTHEAST ALASKA, EAST OF THE
PREDICTED TROUGH AXIS. BELOW-NORMAL PRECIPITATION IS LIKELY ACROSS MOST OF THE
WESTERN CONUS, UNDER AND AHEAD OF A PREDICTED RIDGE. ABOVE-NORMAL PRECIPITATION
IS FAVORED FOR WESTERN AREAS OF THE CENTRAL AND NORTHERN PLAINS AND PARTS OF
THE SOUTHWEST AND SOUTHERN PLAINS CONSISTENT WITH MOST DYNAMICAL MODEL
PRECIPITATION TOOLS AND THE PRECIPITATION CONSOLIDATION. BELOW-NORMAL
PRECIPITATION IS SLIGHTLY FAVORED OVER THE EASTERN SEABOARD, UNDER ANOMALOUS
NORTHERLY FLOW BEHIND THE CENTER OF NEGATIVE 500-HPA HEIGHT ANOMALIES OVER THE
ATLANTIC.
ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL PRECIPITATION ARE FAVORED FOR THE
HAWAIIAN ISLANDS, LARGELY DUE TO THE INFLUENCE OF POSITIVE SEA SURFACE
TEMPERATURE ANOMALIES AROUND THE ISLANDS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 10%
OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS AND AN AMPLIFIED
PATTERN, OFFSET BY DIFFERENCES IN TEMPERATURE AND PRECIPITATION TOOLS AND A
CHANGING PATTERN.
8-14 DAY OUTLOOK FOR JAN 16 - 22 2025
DYNAMICAL MODEL FORECASTS FROM THE ECMWF, GEFS, AND CANADIAN ENSEMBLE MEANS ARE
IN GENERAL OVERALL AGREEMENT ON THE AVERAGE LARGE SCALE 500-HPA HEIGHT PATTERN
IN THE WEEK-2 PERIOD. THE GEFS, ECMWF AND CANADIAN ENSEMBLE MEANS FOR THE 8-14
DAY PERIOD PREDICT A RETROGRESSION OF THE RIDGE AND ASSOCIATED POSITIVE 500-HPA
HEIGHT ANOMALIES OVER THE NORTH PACIFIC, TO BE CENTERED OVER THE ALASKA
PENINSULA AND SOUTHWESTERN MAINLAND ALASKA, WITH POSITIVE 500-HPA HEIGHT
ANOMALIES PREDICTED ACROSS ALL OF ALASKA. DOWNSTREAM, A TROUGH AND NEGATIVE
500-HPA HEIGHT ANOMALIES DEVELOP OVER THE WESTERN CONUS IN THE WEEK-2 PERIOD.
IN THE 8-14 DAY MEAN MANUAL BLEND, NEGATIVE 500-HPA HEIGHT ANOMALIES PERSIST
OVER MOST OF THE EASTERN CONUS, WHILE POSITIVE 500-HPA HEIGHT ANOMALIES PERSIST
OVER THE PACIFIC COAST STATES.
ABOVE-NORMAL TEMPERATURES CONTINUE TO BE FAVORED OVER THE EASTERN ALEUTIANS AND
THE SOUTHWESTERN COAST OF MAINLAND ALASKA, UNDER THE PREDICTED RIDGE.
ABOVE-NORMAL TEMPERATURES ARE FAVORED TO PERSIST OVER EASTERN MAINLAND ALASKA,
UNDER PRIMARILY WESTERLY FLOW AND POSITIVE 500-HPA HEIGHT ANOMALIES.
BELOW-NORMAL TEMPERATURES CONTINUE TO BE FAVORED ACROSS ALMOST ALL OF THE CONUS
IN WEEK-2, EXCLUDING ONLY NORTHERN MAINE, UNDER A TROUGH AND ANOMALOUS
NORTHERLY FLOW. PROBABILITIES OF BELOW-NORMAL TEMPERATURES ARE ELEVATED ACROSS
THE WESTERN CONUS RELATIVE TO THE 6 TO 10 DAY PERIOD, AS A TROUGH DEVELOPS OVER
THE REGION DURING WEEK-2.
ABOVE-NORMAL PRECIPITATION CONTINUES TO BE FAVORED OVER ALMOST ALL OF ALASKA,
EXCLUDING THE WESTERN ALEUTIANS, CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS
AND THE PRECIPITATION CONSOLIDATION. BELOW-NORMAL PRECIPITATION IS FAVORED FOR
MUCH OF THE WESTERN CONUS FROM THE PACIFIC COAST TO THE NORTHERN AND CENTRAL
GREAT BASIN, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES THROUGH MUCH OF THE
PERIOD. ABOVE-NORMAL PRECIPITATION IS FAVORED FROM THE SOUTHWEST AND THE ROCKY
MOUNTAINS EASTWARD ACROSS MOST OF THE GREAT PLAINS, AS THE TROUGH DEVELOPS OVER
THE WEST, INCREASING THE CHANCES OF PRECIPITATION TO THE REGION. ABOVE-NORMAL
PRECIPITATION IS FAVORED FOR MOST OF THE SOUTHEASTERN CONUS, WITH A
PRECIPITATION EVENT PREDICTED FOR THIS REGION LATER IN WEEK-2. ABOVE-NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF THE WESTERN GREAT LAKES REGION
AND BELOW-NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR NORTHERN AREAS OF THE
NORTHEAST, WHERE MODEL PRECIPITATION FORECASTS ARE CONSISTENT.
ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL PRECIPITATION CONTINUE TO BE FAVORED
FOR THE HAWAIIAN ISLANDS, DUE TO THE INFLUENCE OF POSITIVE SEA SURFACE
TEMPERATURE ANOMALIES AROUND THE ISLANDS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 15% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 10%
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, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS, OFFSET BY
DIFFERENCES IN TEMPERATURE AND PRECIPITATION TOOLS AND A CHANGING MID-LEVEL
HEIGHT PATTERN FORECAST.
FORECASTER: D COLLINS
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 16.
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:
20001227 - 19850110 - 19951222 - 19770116 - 19951228
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:
20001229 - 19951228 - 19951222 - 19850109 - 19770120
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 14 - 18 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N B OREGON N B NRN CALIF N B
SRN CALIF B B IDAHO B B NEVADA B B
W MONTANA N B E MONTANA N A WYOMING B A
UTAH B B ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA A A S DAKOTA N N
NEBRASKA N N KANSAS N N OKLAHOMA B N
N TEXAS B A S TEXAS B A W TEXAS N A
MINNESOTA A N IOWA N N MISSOURI B N
ARKANSAS B N LOUISIANA B N WISCONSIN N N
ILLINOIS B N MISSISSIPPI B N MICHIGAN B A
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B N NEW YORK B B
VERMONT B B NEW HAMP B B MAINE N B
MASS B B CONN B B RHODE IS B B
PENN B N NEW JERSEY B B W VIRGINIA B N
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B N
FL PNHDL B N FL PENIN B B AK N SLOPE A A
AK ALEUTIAN A A AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 16 - 22 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF B B
SRN CALIF B B IDAHO B N NEVADA B B
W MONTANA B N E MONTANA B A WYOMING B A
UTAH B N ARIZONA B N COLORADO B A
NEW MEXICO B A N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA B N IOWA B N MISSOURI B A
ARKANSAS B A LOUISIANA B A WISCONSIN B N
ILLINOIS B N MISSISSIPPI B A MICHIGAN B A
INDIANA B N OHIO B N KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK B N
VERMONT B B NEW HAMP B N MAINE N B
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B N
MARYLAND B N DELAWARE B N 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 A
AK ALEUTIAN A A AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST A A AK PNHDL N A
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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