765
FXUS06 KWBC 111906
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI OCTOBER 11 2024
6-10 DAY OUTLOOK FOR OCT 17 - 21 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 AND WESTERN MAINLAND ALASKA. MODELS PREDICT A TROUGH AND NEGATIVE
500-HPA HEIGHT ANOMALIES OVER THE WESTERN CONTIGUOUS U.S. (CONUS), AT THE START
OF THE 6-10 DAY PERIOD, IS LIKELY TO RAPIDLY DEAMPLIFY DURING THE PERIOD,
GIVING WAY TO POSITIVE 500-HPA HEIGHT ANOMALIES. ENSEMBLE MEAN MODEL SOLUTIONS
PREDICT AN AMPLIFIED RIDGE OVER EAST-CENTRAL CANADA AND THE MIDWEST AROUND DAY
6 THAT WILL LIKELY PROGRESS EASTWARD OVER THE NORTHEASTERN CONUS DURING THE
PERIOD. A TROUGH AND NORTHERLY FLOW ARE PREDICTED OVER THE ATLANTIC COAST
EARLY IN THE PERIOD. ENSEMBLE MEAN 500-HPA HEIGHT FORECASTS CONSISTENTLY
PREDICT POSITIVE ANOMALIES OVER THE EASTERN HALF OF THE CONUS AND OVER
CALIFORNIA.
BELOW NORMAL TEMPERATURES ARE LIKELY FOR THE EASTERN ALEUTIANS, MUCH OF
SOUTHERN AND EASTERN MAINLAND ALASKA, AND SOUTHEAST ALASKA, UNDER ANOMALOUS
NORTHERLY MID-LEVEL FLOW AHEAD OF THE PREDICTED RIDGE. DYNAMICAL MODELS PREDICT
A RAPID TRANSITION OVER THE WESTERN CONUS WITH RAPID DE-AMPLIFICATION OF A
TROUGH. MODEL TOOLS DIFFER ON THE TEMPERATURE OUTLOOK FOR THE PERIOD. NEAR
NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WEST FROM THE PACIFIC COAST TO
THE ROCKY MOUNTAINS WHILE BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF
THE NORTHWESTERN CONUS, WHERE MODEL TEMPERATURE TOOLS ARE MOST CONSISTENT.
UNDER A PREDICTED RIDGE, ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MUCH OF THE
CENTRAL AND EASTERN CONUS, EXCLUDING MOST OF THE EASTERN SEABOARD. NEAR TO
BELOW NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE EASTERN SEABOARD,
EXCLUDING FLORIDA AND NORTHERN MAINE, UNDER A PREDICTED TROUGH AND NORTHERLY
FLOW EARLY IN THE 6-10 DAY PERIOD. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR
HAWAII, CONSISTENT WITH THE TEMPERATURE CONSOLIDATION OF CALIBRATED MODEL
TEMPERATURE FORECASTS.
BELOW NORMAL PRECIPITATION IS FAVORED FOR MOST OF SOUTHERN ALASKA, UNDER
PREDICTED NORTHERLY FLOW. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED ACROSS
NORTHERN MAINLAND ALASKA, CONSISTENT WITH DYNAMICAL MODEL PRECIPITATION TOOLS.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE WESTERN AND CENTRAL
CONUS, AHEAD OF A PREDICTED TROUGH EARLY IN THE PERIOD AND UNDER SOUTHERLY
SURFACE FLOW IN THE CENTRAL CONUS. 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 OVER MUCH OF
THE EASTERN CONUS, UNDER A PREDICTED RIDGE, EXCEPT FOR THE GULF COAST REGION,
WHERE ABOVE NORMAL PRECIPITATION IS FAVORED, CONSISTENT WITH MOST DYNAMICAL
MODEL FORECASTS. BELOW NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR THE
SOUTHEASTERN ISLANDS OF HAWAII IN THE 6-10 DAY PERIOD, CONSISTENT WITH THE
CONSOLIDATION TOOL.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 45% 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 19 - 25 2024
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 INDICATE EASTWARD PROGRESSION OF THE LARGE-SCALE WAVE PATTERN
RELATIVE TO THE 6-10 DAY PERIOD FORECASTS. A WEAK TROUGH OVER THE WESTERN CONUS
AROUND DAY 8 DE-AMPLIFIES DURING THE PERIOD, LEADING TO AVERAGE POSITIVE
500-HPA HEIGHT ANOMALIES OVER MOST OF THE WEST. POSITIVE 500-HPA HEIGHT
ANOMALIES SPREAD OVER SOUTHEAST ALASKA IN THE 8-14 DAY PERIOD IN MODEL
FORECASTS, WHILE A TROUGH OVER THE NORTHEASTERN PACIFIC DE-AMPLIFIES. A
MID-LEVEL RIDGE PERSISTS BUT DE-AMPLIFIES OVER TIME OVER THE EASTERN CONUS
DURING WEEK-2, WITH POSITIVE 500-HPA HEIGHT ANOMALIES PREDICTED ACROSS MOST OF
THE CONUS IN THE MANUAL BLEND OF DYNAMICAL MODEL FORECASTS.
BELOW NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR SOUTHEASTERN AREAS
MAINLAND ALASKA AND SOUTHEAST ALASKA UNDER ANOMALOUS NORTHERLY FLOW, WHILE NEAR
NORMAL TEMPERATURES ARE FAVORED OVER SOUTHWESTERN AREAS OF ALASKA, AS A RIDGE
IS PREDICTED TO PROGRESS EASTWARD ACROSS THE REGION SHIFTING THE MID-LEVEL FLOW
FROM NORTHERLY TO SOUTHERLY. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR
NORTHWESTERN AREAS AND THE NORTHERN COAST OF MAINLAND ALASKA CONSISTENT WITH
MOST DYNAMICAL MODEL FORECASTS. NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED
FOR THE PACIFIC NORTHWEST IN THE 8-14 DAY PERIOD CONSISTENT WITH BIAS-CORRECTED
DYNAMICAL MODEL FORECASTS. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE
REMAINDER OF THE CONUS IN WEEK-2, UNDER PREDICTED AVERAGE POSITIVE 500-HPA
HEIGHT ANOMALIES DURING THE PERIOD.
WITH A CHANGING HEIGHT PATTERN, THERE IS SIGNIFICANT UNCERTAINTY IN
PRECIPITATION FORECASTS AND DIFFERENCES AMONG MODEL TOOLS FOR WEEK-2. BELOW
NORMAL PRECIPITATION REMAINS SLIGHTLY FAVORED FOR THE SOUTHERN COAST OF
MAINLAND ALASKA AND SOUTHEAST ALASKA IN WEEK-2, UNDER ANOMALOUS NORTHERLY FLOW.
ABOVE NORMAL PRECIPITATION IS 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 SLIGHTLY FAVORED FOR PARTS OF THE GREAT PLAINS AND
WESTERN GREAT LAKES REGION, CONSISTENT WITH THE CONSOLIDATION AND PREDICTED
SOUTHERLY SURFACE FLOW. BELOW NORMAL PRECIPITATION CONTINUES TO BE SLIGHTLY
FAVORED FOR PARTS OF THE NORTHEASTERN CONUS IN WEEK-2, UNDER A PREDICTED RIDGE.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF THE GULF COAST IN
WEEK-2, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION. NEAR NORMAL
PRECIPITATION IS FAVORED FOR HAWAII, WITH WEAK PRECIPITATION SIGNALS IN THE
PRECIPITATION CONSOLIDATION.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 45% 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 - 19920929 - 20010928 - 20081001
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 - 20071011 - 20010928 - 20081001 - 19920929
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 17 - 21 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF N N
SRN CALIF N N IDAHO B A NEVADA N N
W MONTANA N A E MONTANA A A WYOMING N A
UTAH N A ARIZONA N N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A A WISCONSIN A A
ILLINOIS A N MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A B
VERMONT A B NEW HAMP N B MAINE A B
MASS N B CONN N B RHODE IS N B
PENN A B NEW JERSEY N B W VIRGINIA N B
MARYLAND N B DELAWARE N B VIRGINIA N B
N CAROLINA N B S CAROLINA B N GEORGIA N N
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN N B AK INT BSN B N
AK S INT B B AK SO COAST B B AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 19 - 25 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N N NRN CALIF A B
SRN CALIF A N IDAHO N N NEVADA A B
W MONTANA N A E MONTANA A N WYOMING A N
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N 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 A A
AK ALEUTIAN B N AK WESTERN N A AK INT BSN N A
AK S INT N N AK SO COAST B B AK PNHDL B B
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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