451
FXUS06 KWBC 101908
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU OCTOBER 10 2024
6-10 DAY OUTLOOK FOR OCT 16 - 20 2024
THERE IS GOOD AGREEMENT BETWEEN THE 0Z 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 A RIDGE OVER THE
BERING SEA. A TROUGH IS PREDICTED OVER EASTERN MAINLAND ALASKA AND THE GULF OF
ALASKA. MODELS PREDICT A TROUGH, NEAR THE WEST COAST OF THE CONTIGUOUS U.S.
(CONUS) AROUND DAY 6, TO PROGRESS EASTWARD INTO THE WESTERN CONUS AND DEAMPLIFY
DURING THE 6-10 DAY PERIOD. ALL RECENT ENSEMBLE MEAN MODELS ALSO PREDICT AN
AMPLIFIED RIDGE OVER CENTRAL CANADA AND THE NORTH-CENTRAL CONUS AROUND DAY 6 TO
PROGRESS EASTWARD OVER THE EASTERN CONUS BY DAY 8. NEGATIVE 500-HPA HEIGHT
ANOMALIES AND A TROUGH ARE PREDICTED OVER THE SOUTHEASTERN CONUS EARLY IN THE
PERIOD. THE MANUAL BLEND OF 6-10 DAY 500-HPA HEIGHT FORECASTS PREDICTS POSITIVE
ANOMALIES OVER THE EASTERN TWO-THIRDS OF THE CONUS.
BELOW NORMAL TEMPERATURES ARE LIKELY FOR THE EASTERN ALEUTIANS AND MUCH OF
MAINLAND ALASKA, UNDER NORTHERLY MID-LEVEL FLOW AHEAD OF THE PREDICTED RIDGE.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR SOUTHEAST ALASKA UNDER PREDICTED
NEGATIVE 500-HPA HEIGHT ANOMALIES. DYNAMICAL MODELS PREDICT A RAPID TRANSITION
OVER THE WESTERN CONUS WITH THE EASTWARD PROGRESSION FOLLOWED BY
DE-AMPLIFICATION OF A TROUGH. MODEL TOOLS DIFFER ON THE TEMPERATURE OUTLOOK FOR
THE PERIOD. NEAR NORMAL TEMPERATURES ARE FAVORED FROM THE PACIFIC COAST TO THE
ROCKY MOUNTAINS, CONSISTENT WITH THE ECWMF REFORECAST-CALIBRATED TEMPERATURE
FORECAST AND THE CONSOLIDATION TEMPERATURE TOOL. ABOVE NORMAL TEMPERATURES ARE
LIKELY FROM THE ROCKY MOUNTAINS TO THE LOWER MISSISSIPPI VALLEY AND ACROSS THE
GREAT LAKES REGION, UNDER THE PREDICTED RIDGE AND CONSISTENT WITH DYNAMICAL
MODEL TEMPERATURE FORECASTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE
SOUTHEASTERN CONUS INTO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND COAST, UNDER
A PREDICTED TROUGH EARLY IN THE 6-10 DAY PERIOD. ABOVE NORMAL TEMPERATURES ARE
LIKELY FOR HAWAII, CONSISTENT WITH THE CONSOLIDATION OF CALIBRATED MODEL
TEMPERATURE FORECASTS.
BELOW NORMAL PRECIPITATION IS FAVORED FOR SOUTHWESTERN ALASKA, UNDER PREDICTED
NORTHERLY FLOW. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED ACROSS
NORTHEASTERN MAINLAND ALASKA CONSISTENT WITH DYNAMICAL MODEL PRECIPITATION
TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE WESTERN CONUS
AHEAD OF A PREDICTED TROUGH EARLY IN THE PERIOD. ABOVE NORMAL PRECIPITATION IS
SLIGHTLY FAVORED INTO PARTS OF THE GREAT PLAINS REGION, CONSISTENT WITH
DYNAMICAL MODEL PRECIPITATION FORECASTS AROUND DAY 10. NEAR NORMAL
PRECIPITATION IS INDICATED IN CLIMATOLOGICALLY DRY AREAS OF THE SOUTHWESTERN
CONUS WHERE LITTLE OR NO PRECIPITATION IS PREDICTED. BELOW NORMAL PRECIPITATION
IS FAVORED ACROSS MUCH OF THE EASTERN CONUS, UNDER A PREDICTED RIDGE, EXCEPT
FOR THE FLORIDA PENINSULA AND SOUTHERN GEORGIA WHERE ABOVE NORMAL PRECIPITATION
IS FAVORED CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS. BELOW NORMAL
PRECIPITATION IS SLIGHTLY FAVORED ACROSS HAWAII IN THE 6-10 DAY PERIOD,
CONSISTENT WITH THE CONSOLIDATION TOOL.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 25% 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
RAPIDLY CHANGING PATTERN.
8-14 DAY OUTLOOK FOR OCT 18 - 24 2024
DYNAMICAL MODEL FORECASTS FROM THE ECMWF, GEFS AND CANADIAN ENSEMBLE MEANS ARE
IN GOOD OVERALL AGREEMENT ON THE AVERAGE LARGE SCALE 500-HPA HEIGHT PATTERN IN
THE WEEK-2 PERIOD. RECENT MODEL FORECASTS FROM THE GEFS, ECMWF AND CANADIAN
ENSEMBLE MEANS FOR THE 8-14 DAY PERIOD INDICATE EASTWARD PROGRESSION OF THE
LARGE-SCALE WAVE PATTERN RELATIVE TO THE 6-10 DAY PERIOD FORECASTS. A TROUGH
AND NEGATIVE 500-HPA HEIGHT ANOMALIES OVER THE WESTERN CONUS AROUND DAY 8
DE-AMPLIFY RAPIDLY DURING THE PERIOD, LEADING TO AVERAGE POSITIVE 500-HPA
HEIGHT ANOMALIES OVER MOST OF THE WEST. POSITIVE 500-HPA HEIGHT ANOMALIES
SPREAD OVER EASTERN MAINLAND ALASKA IN THE 8-14 DAY PERIOD IN MODEL FORECASTS,
WHILE A TROUGH OVER THE NORTHEASTERN PACIFIC DE-AMPLIFIES. A MID-LEVEL RIDGE
CONTINUES TO BE PREDICTED OVER EASTERN NORTH AMERICA DURING WEEK-2, WITH
POSITIVE 500-HPA HEIGHT ANOMALIES ACROSS THE EASTERN CONUS IN THE MANUAL BLEND
OF DYNAMICAL MODEL FORECASTS.
BELOW NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR MOST OF SOUTHERN AND
EASTERN MAINLAND ALASKA AND SOUTHEAST ALASKA UNDER ANOMALOUS NORTHERLY FLOW.
ABOVE NORMAL TEMPERATURES ARE FAVORED ALONG THE NORTHERN COAST OF MAINLAND
ALASKA CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS. BELOW NORMAL
TEMPERATURES ARE SLIGHTLY FAVORED FOR MUCH OF THE PACIFIC NORTHWEST IN THE 8-14
DAY PERIOD UNDER A TROUGH THROUGH MUCH OF THE PERIOD. ABOVE NORMAL TEMPERATURES
ARE SLIGHTLY FAVORED FOR PARTS OF CALIFORNIA AND NEVADA IN WEEK-2, AS 500-HPA
HEIGHTS ARE PREDICTED TO RISE. ABOVE NORMAL TEMPERATURES ARE LIKELY ACROSS THE
CENTRAL AND EASTERN CONUS IN WEEK-2, UNDER A PREDICTED RIDGE, WITH A RAPID
WARMING IN DYNAMICAL MODEL TEMPERATURE FORECASTS OVER THE EAST AT THE START OF
WEEK-2.
WITH A CHANGING HEIGHT PATTERN, PRECIPITATION FORECASTS SHOW INCREASING
UNCERTAINTY AND DIFFERENCES AMONG MODEL TOOLS FOR WEEK-2. BELOW NORMAL
PRECIPITATION REMAINS SLIGHTLY FAVORED FOR THE SOUTHERN COAST OF WESTERN
MAINLAND ALASKA IN WEEK-2, UNDER ANOMALOUS NORTHERLY FLOW. ABOVE NORMAL
PRECIPITATION IS SLIGHTLY FAVORED ACROSS CENTRAL AND NORTHERN MAINLAND ALASKA,
CONSISTENT WITH MOST DYNAMICAL MODEL FORECAST TOOLS. ABOVE NORMAL PRECIPITATION
IS FAVORED FOR PARTS OF THE PACIFIC NORTHWEST IN THE 8-14 DAY PERIOD, AHEAD OF
PREDICTED TROUGHING IN MOST DYNAMICAL MODEL FORECASTS. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR MUCH OF THE CENTRAL CONUS FROM THE HIGH PLAINS
INTO THE GREAT PLAINS AND WESTERN GREAT LAKES REGION, CONSISTENT WITH MOST
DYNAMICAL MODEL FORECAST TOOLS AND THE CONSOLIDATION. BELOW NORMAL
PRECIPITATION CONTINUES TO BE SLIGHTLY FAVORED FROM THE CENTRAL MISSISSIPPI
VALLEY INTO THE OHIO VALLEY AND NORTHEASTERN CONUS IN WEEK-2, UNDER A PREDICTED
RIDGE. NEAR TO ABOVE NORMAL PRECIPITATION CONTINUES TO BE FAVORED FOR PARTS OF
THE SOUTHEAST IN WEEK-2, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION. BELOW
NORMAL PRECIPITATION IS FAVORED FOR THE BIG ISLAND OF HAWAII, CONSISTENT WITH
THE PRECIPITATION CONSOLIDATION.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 25% 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 RAPIDLY EVOLVING
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
OCTOBER 17.
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:
20051022 - 20071011 - 19920928 - 20010924 - 19870920
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:
20051021 - 20071010 - 20010926 - 19620928 - 19870919
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 16 - 20 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF N A
SRN CALIF N N IDAHO N A NEVADA N A
W MONTANA N A E MONTANA A A WYOMING A A
UTAH A A ARIZONA N N COLORADO A A
NEW MEXICO A N N DAKOTA A N S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A N
N TEXAS A N S TEXAS A A W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA N B WISCONSIN A N
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY N B
TENNESSEE B B ALABAMA B B NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS B B CONN B B RHODE IS B B
PENN N B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B N FL PENIN B A AK N SLOPE B A
AK ALEUTIAN B B AK WESTERN B B AK INT BSN B N
AK S INT B B AK SO COAST B B AK PNHDL B N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 18 - 24 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF A N
SRN CALIF A N IDAHO N A NEVADA N N
W MONTANA N A E MONTANA A A WYOMING A A
UTAH N A ARIZONA N N COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A B LOUISIANA A N WISCONSIN A A
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A B W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA A B
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN N A AK INT BSN B A
AK S INT B N AK SO COAST B B 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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