808
FXUS06 KWBC 141902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON OCTOBER 14 2024
6-10 DAY OUTLOOK FOR OCT 20 - 24 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 DURING THE 6-10 DAY PERIOD. DYNAMICAL MODELS PREDICT AN AMPLIFIED RIDGE
CENTERED OVER THE EASTERN ALEUTIAN ISLANDS AND WESTERN MAINLAND ALASKA. MODELS
PREDICT A POSITIVELY TILTED TROUGH EXTENDING SOUTHWESTWARD FROM WESTERN CANADA
INTO THE PACIFIC OCEAN NEAR THE COAST OF THE PACIFIC NORTHWEST. DYNAMICAL
MODELS FAVOR A POSITIVE ARCTIC OSCILLATION THROUGH THE PERIOD INTO WEEK 2 WITH
POSITIVE 500-HPA HEIGHT ANOMALIES PREDICTED FROM THE SOUTHWEST ACROSS THE
CENTRAL AND EASTERN CONTIGUOUS U.S. (CONUS) AND NEGATIVE 500-HPA HEIGHT
ANOMALIES PREDICTED OVER THE ARCTIC. A SHORTWAVE 500-HPA TROUGH IS PREDICTED TO
PASS OVER THE FOUR CORNERS REGION AT THE START OF THE 6-10 DAY PERIOD BY BOTH
THE 0Z ECMWF AND GEFS ENSEMBLE MEANS.
ABOVE NORMAL TEMPERATURES ARE LIKELY FOR WESTERN AND NORTHERN MAINLAND ALASKA,
UNDER THE PREDICTED AMPLIFIED RIDGE. BELOW NORMAL TEMPERATURES ARE LIKELY FOR
SOUTHEASTERN MAINLAND ALASKA AND SOUTHEAST ALASKA, UNDER ANOMALOUS NORTHERLY
MID-LEVEL FLOW. DYNAMICAL MODEL TEMPERATURE TOOLS DISAGREE ON THE TEMPERATURE
FORECAST FOR MUCH OF THE WEST COAST OF THE CONUS, AHEAD OF A PREDICTED TROUGH,
AND FOR PARTS OF THE SOUTHWEST, UNDER A PASSING SHORTWAVE EARLY IN THE PERIOD.
NEAR NORMAL IS FAVORED FOR MOST OF THESE REGIONS. BELOW NORMAL TEMPERATURES ARE
FAVORED FOR PARTS OF THE PACIFIC NORTHWEST, WHERE DYNAMICAL MODEL FORECASTS ARE
MORE CONSISTENT. ABOVE NORMAL TEMPERATURES ARE LIKELY ACROSS MOST OF THE CONUS
FROM THE ROCKY MOUNTAINS TO THE ATLANTIC COAST, UNDER PREDICTED POSITIVE
500-HPA HEIGHT ANOMALIES. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR HAWAII,
CONSISTENT WITH THE TEMPERATURE CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS LIKELY FOR CENTRAL AND NORTHERN MAINLAND ALASKA,
UNDER FAST ZONAL FLOW OVERTOP OF THE PREDICTED RIDGE. BELOW NORMAL
PRECIPITATION IS FAVORED FOR THE SOUTH COAST OF MAINLAND ALASKA AND SOUTHEAST
ALASKA, UNDER NORTHERLY MID-LEVEL FLOW. ABOVE NORMAL PRECIPITATION IS FAVORED
FROM CENTRAL CALIFORNIA INTO THE PACIFIC NORTHWEST, NORTHERN ROCKIES, AND
NORTHERN PLAINS, AHEAD OF THE PREDICTED TROUGH. ABOVE NORMAL PRECIPITATION IS
FAVORED OVER PARTS OF ARIZONA, WEST TEXAS, AND THE CENTRAL PLAINS, WITH THE
PASSAGE OF A SHORTWAVE TROUGH EARLY IN THE 6-10 DAY PERIOD. BELOW NORMAL
PRECIPITATION IS LIKELY FOR MOST OF THE EASTERN CONUS, EXCLUDING THE FLORIDA
PENINSULA, UNDER PREDICTED POSITIVE 500-HPA HEIGHT ANOMALIES. NEAR NORMAL
PRECIPITATION IS FAVORED FOR HAWAII, CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 50% 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: MUCH ABOVE AVERAGE, 5 OUT OF 5,
DUE TO GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS, AN AMPLIFIED
AND LESS VARIABLE HEIGHT PATTERN, AND CONSISTENT TEMPERATURE AND PRECIPITATION
TOOLS.
8-14 DAY OUTLOOK FOR OCT 22 - 28 2024
DYNAMICAL MODEL FORECASTS FROM THE ECMWF, GEFS AND CANADIAN ENSEMBLE MEANS ARE
IN GOOD AGREEMENT ON THE AVERAGE LARGE SCALE 500-HPA HEIGHT PATTERN IN THE
WEEK-2 PERIOD. DURING THE WEEK-2 PERIOD, DYNAMICAL MODELS PREDICT WEAKENING OF
PREDICTED POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE NORTHEASTERN CONUS, AS THE
TROUGH OVER THE PACIFIC NORTHWEST SEPARATES FROM A BROAD TROUGH THAT PROGRESSES
OVER CENTRAL CANADA. AN AMPLIFIED RIDGE PERSISTS AND PROGRESSES SLIGHTLY
EASTWARD OVER SOUTHWESTERN MAINLAND ALASKA IN WEEK 2.
ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MOST OF ALASKA, EXCLUDING SOUTHEASTERN
MAINLAND ALASKA AND SOUTHEAST ALASKA, UNDER A PREDICTED RIDGE AND POSITIVE
500-HPA HEIGHT ANOMALIES. BELOW NORMAL TEMPERATURES ARE LIKELY FOR SOUTHEAST
ALASKA, UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW. BELOW NORMAL TEMPERATURES ARE
SLIGHTLY FAVORED FOR THE PACIFIC COAST OF THE CONUS AND ACROSS THE FAR NORTHERN
ROCKIES, UNDER A PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES ARE LIKELY FROM
THE CENTRAL AND SOUTHERN ROCKIES INTO THE GREAT PLAINS AND ACROSS THE EASTERN
HALF OF THE CONUS, UNDER PERSISTENT POSITIVE 500-HPA HEIGHT ANOMALIES. ABOVE
NORMAL TEMPERATURES ARE LIKELY FOR HAWAII IN WEEK 2, CONSISTENT WITH THE
TEMPERATURE CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF CENTRAL AND NORTHERN
MAINLAND ALASKA, UNDER FAST ZONAL MID-LEVEL FLOW. BELOW NORMAL PRECIPITATION IS
FAVORED FOR THE SOUTHEASTERN COAST OF MAINLAND ALASKA AND SOUTHEAST ALASKA,
UNDER ANOMALOUS NORTHERLY FLOW. ABOVE NORMAL PRECIPITATION IS LIKELY FOR MUCH
OF THE WESTERN CONUS INTO THE NORTHERN PLAINS, AHEAD OF A PREDICTED TROUGH.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR THE UPPER MISSISSIPPI VALLEY
AND GREAT LAKES REGION, CONSISTENT WITH MOST DYNAMICAL MODEL PRECIPITATION
FORECASTS. BELOW NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE REMAINDER
OF THE SOUTHERN AND EASTERN CONUS, UNDER POSITIVE 500-HPA HEIGHT ANOMALIES AND
CONSISTENT WITH THE PRECIPITATION CONSOLIDATION. ABOVE NORMAL PRECIPITATION IS
SLIGHTLY FAVORED FOR THE NORTHWESTERN HAWAIIAN ISLAND OF KAUAI, CONSISTENT WITH
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, 50% 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS, AND ACROSS MOST
TEMPERATURE AND PRECIPITATION TOOLS, OFFSET BY PREDICTED EVOLUTION OF THE
FORECAST PATTERN AND WEAKENING HEIGHT ANOMALIES DURING THE PERIOD.
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:
19991023 - 20031017 - 19901025 - 19531009 - 19801008
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:
20031017 - 19991024 - 19531008 - 19651005 - 19801007
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 20 - 24 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N A NRN CALIF N A
SRN CALIF N N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A N 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 N MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B 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 B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N B AK WESTERN A A AK INT BSN A A
AK S INT N B AK SO COAST B B AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 22 - 28 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF N A IDAHO N A NEVADA N A
W MONTANA B A E MONTANA N A WYOMING A A
UTAH A A ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A B OKLAHOMA A N
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A A
INDIANA A N OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B 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 B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN A A AK INT BSN A A
AK S INT A N AK SO COAST A 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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