314
FXUS06 KWBC 232011
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST MON DECEMBER 23 2024
6-10 DAY OUTLOOK FOR DEC 29, 2024 - JAN 02, 2025
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED 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 GEFS, ECMWF AND CANADIAN MODELS DUE TO RECENT MODEL
SKILL. THE RESULTANT MANUAL BLEND FEATURES BROAD RIDGING WITH A LARGE POSITIVE
500-HPA HEIGHT ANOMALY CENTER (GREATER THAN +360 METERS) OVER EASTERN CANADIAN
EXTENDING SOUTHWARD TO THE NORTHEASTERN CONTIGUOUS U.S. (CONUS). TROUGHING IS
PREDICTED ACROSS THE BERING SEA AND THE ALEUTIANS. ANOMALOUS RIDGING AND
POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST OVER MAINLAND ALASKA AND THE
WESTERN CONUS, WHILE A TROUGH IS PREDICTED OVER THE EASTERN CONUS. NEAR-NORMAL
HEIGHTS ARE PREDICTED ACROSS HAWAII.
ENHANCED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE STRONGLY FAVORED BENEATH THE
MID-LEVEL RIDGE AND ABOVE-NORMAL 500-HPA HEIGHTS ACROSS MOST OF THE CONUS
DURING THE 6-10 DAY PERIOD. CHANCES EXCEED 80% FOR ABOVE-NORMAL TEMPERATURES
ACROSS THE NORTHEASTERN CONUS, SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE
FORECAST TOOLS. PREDICTED TROUGHING OVER THE BERING SEA FAVORS INCREASED
SOUTHERLY FLOW DEVELOPING ACROSS PARTS OF SOUTHERN MAINLAND ALASKA LEADING TO
ELEVATED ODDS OF ABOVE-NORMAL TEMPERATURES. MOST DYNAMICAL TEMPERATURE FORECAST
TOOLS FAVOR BELOW-NORMAL TEMPERATURES OVER PARTS OF NORTHERN MAINLAND ALASKA.
ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS HAWAII, CONSISTENT WITH THE GEFS
AND ECENS REFORECAST TEMPERATURE CONSOLIDATION.
THE 6-10 DAY PRECIPITATION FORECAST FAVORS BELOW-NORMAL PRECIPITATION FROM
SOUTHERN CALIFORNIA EXTENDING EASTWARD TO THE THE SOUTHERN PLAINS AND THE LOWER
MISSISSIPPI VALLEY DUE TO THE RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS.
ABOVE-NORMAL PRECIPITATION IS FORECAST OVER MUCH OF THE NORTHERN AND EASTERN
CONUS, SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION FORECAST TOOLS.
ABOVE-NORMAL PRECIPITATION IS FORECAST FOR SOUTHERN ALASKA UNDERNEATH THE
ONSHORE FLOW, WHILE MOST DYNAMICAL PRECIPITATION FORECAST TOOLS FAVOR
BELOW-NORMAL PRECIPITATION OVER NORTHERN MAINLAND ALASKA. ABOVE-NORMAL
PRECIPITATION IS FAVORED ACROSS HAWAII CONSISTENT WITH THE CONSOLIDATED
PRECIPITATION FORECAST TOOL.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 30% 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. GOOD
AGREEMENT AMONG THE DYNAMICAL TOOLS IS OFFSET BY A MORE PROGRESSIVE PATTERN BY
THE END OF THE PERIOD.
8-14 DAY OUTLOOK FOR DEC 31, 2024 - JAN 06, 2025
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY CONSISTENT
500-HPA CIRCULATION PATTERN RELATIVE TO THE 6-10 DAY PERIOD ACROSS NORTH
AMERICA AND THE SURROUNDING REGIONS. TROUGHING INITIALLY OVER THE NORTHEAST
PACIFIC IS FORECAST TO RETREAT, WITH THE 0Z GEFS, ECENS, AND CMCE DEPICTING
RIDGING DEVELOPING ALONG THE WEST COAST OF NORTH AMERICA BY THE END OF WEEK-2,
AND EVIDENCE OF MORE BROAD LONGWAVE TROUGHING BECOMING ESTABLISHED OVER THE
EASTERN CONUS. ABOVE-NORMAL HEIGHTS ARE FAVORED OVER MOST OF MAINLAND ALASKA
TIED TO THE AFOREMENTIONED RIDGING PREDICTED TO DEVELOP, WITH BELOW-NORMAL
HEIGHTS REMAINING FORECAST ACROSS THE ALEUTIANS. NEAR TO BELOW-NORMAL HEIGHTS
ARE FORECAST ACROSS HAWAII TIED TO TROUGHING DEVELOPING TO THE EAST OF THE
ISLANDS.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN CONUS AND PARTS
OF SOUTHWESTERN TEXAS DURING WEEK-2 BENEATH THE FORECAST RIDGE AND ABOVE-NORMAL
500-HPA HEIGHTS ACROSS THE REGION WITH GOOD AGREEMENT AMONG THE TOOLS.
BELOW-NORMAL TEMPERATURES ARE FORECAST OVER SOUTHEASTERN CONUS DUE TO A
PREDICTED TROUGH OVER THE EASTERN CONUS. MOST DYNAMICAL TEMPERATURE FORECAST
TOOLS SUPPORT ABOVE-NORMAL TEMPERATURES OVER PARTS OF THE NORTHEASTERN CONUS
AND BELOW-NORMAL TEMPERATURES OVER MONTANA. RIDGING AND ABOVE-NORMAL 500-HPA
HEIGHT OVER ALASKA LEAD TO INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER
THE STATE. HAWAII CONTINUES TO TILT TOWARDS ABOVE-NORMAL TEMPERATURES,
CONSISTENT WITH THE ECENS AND GEFS REFORECAST CONSOLIDATION.
PROBABILITIES ARE ELEVATED FOR BELOW-NORMAL PRECIPITATION OVER THE SOUTHWESTERN
CONUS, DUE TO AN INFLUENCE FROM MID-LEVEL RIDGING. BELOW-NORMAL PRECIPITATION
IS ALSO FAVORED OVER THE SOUTHEASTERN CONUS, CONSISTENT WITH THE GEFS AND ECENS
CALIBRATED REFORECAST PRECIPITATION TOOLS. ABOVE-NORMAL PRECIPITATION IS MORE
LIKELY OVER PARTS OF SOUTHERN TEXAS, THE NORTHEAST AND PORTIONS OF THE
NORTH-CENTRAL CONUS, SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION FORECAST
TOOLS. TROUGHING OVER THE BERING SEA AND THE ALEUTIANS FAVORS NEAR- TO
ABOVE-NORMAL PRECIPITATION OVER SOUTHERN ALASKA, WHILE BELOW-NORMAL
PRECIPITATION REMAINS FAVORED OVER NORTHERN MAINLAND ALASKA. ABOVE-NORMAL
PRECIPITATION IS FAVORED ACROSS HAWAII, CONSISTENT WITH THE ECENS AND GEFS
REFORECAST CONSOLIDATION.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z 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: ABOVE-AVERAGE, 4 OUT OF 5. GOOD
AGREEMENT AMONG THE DYNAMICAL TOOLS IS OFFSET BY A MORE PROGRESSIVE PATTERN BY
THE END OF THE PERIOD.
FORECASTER: LUKE H
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:
20051220 - 20061207 - 19631223 - 20051225 - 19691219
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:
20051224 - 19691219 - 20051219 - 19631224 - 20061207
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 29, 2024 - JAN 02, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A B IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A B COLORADO A A
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N 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 A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE B B
AK ALEUTIAN A A AK WESTERN N N AK INT BSN N B
AK S INT A A AK SO COAST A A AK PNHDL A N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 31, 2024 - JAN 06, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON A N NRN CALIF A B
SRN CALIF A B IDAHO N N NEVADA A B
W MONTANA B N E MONTANA B A WYOMING N A
UTAH A N ARIZONA A B COLORADO N A
NEW MEXICO A N N DAKOTA N A S DAKOTA N A
NEBRASKA N A KANSAS N A OKLAHOMA N N
N TEXAS N N S TEXAS N A W TEXAS N N
MINNESOTA N A IOWA N A MISSOURI N N
ARKANSAS N N LOUISIANA B N WISCONSIN A A
ILLINOIS N N MISSISSIPPI B N MICHIGAN A N
INDIANA N N OHIO N N KENTUCKY N N
TENNESSEE N N ALABAMA B N 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 N NEW JERSEY A A W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE A B
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 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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