147
FXUS06 KWBC 231902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON SEPTEMBER 23 2024
6-10 DAY OUTLOOK FOR SEP 29 - OCT 03, 2024
THE 6-10 DAY MEAN MID-LEVEL HEIGHT PATTERN FROM THE GEFS, ECENS, AND CANADIAN
ENSEMBLE CONTINUE TO FORECAST POSITIVE MID-LEVEL HEIGHT ANOMALIES OVER EASTERN
CANADA AND THE NORTHEASTERN CONTIGUOUS U.S. (CONUS), A BUILDING MID-LEVEL RIDGE
OVER THE WESTERN CONUS, AND NEAR TO BELOW-NORMAL HEIGHTS ACROSS THE
SOUTHEASTERN CONUS. THE POSITIVE ANOMALIES IN EASTERN CANADA ARE MUCH REDUCED
RELATIVE TO THE PREVIOUS SEVERAL DAYS INDICATING MORE UNCERTAINTY IN THE HEIGHT
PATTERN ACROSS THE NORTHEAST. THIS MAY BE THE RESULT OF POTENTIAL TROPICAL
CYCLONE 9 (PTC-9) THAT IS FORECAST TO DEVELOP INTO A TROPICAL CYCLONE IN THE
GULF OF MEXICO. THIS MAY DISRUPT THE RELATIVELY STABLE PATTERN THAT MUCH OF THE
CONUS HAS SEEN OVER THE PAST COUPLE OF WEEKS AND WILL NEED TO BE WATCHED THIS
WEEK. IN ALASKA, A MID-LEVEL TROUGH IS FORECAST ACROSS MUCH OF THE STATE WITH
THE STRONGEST NEGATIVE ANOMALIES FOCUSED ACROSS THE GULF OF ALASKA. IN HAWAII,
NEAR TO ABOVE-NORMAL 500-HPA HEIGHT ANOMALIES ARE FORECAST.
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE CONUS DURING THE 6-10 DAY
PERIOD WITH ONLY TWO EXCEPTIONS. IN THE CENTRAL AND LOWER MISSISSIPPI RIVER
VALLEY NEAR-NORMAL TEMPERATURES ARE FAVORED ASSOCIATED WITH A SHORTWAVE TROUGH
MOVING ACROSS THE EASTERN CONUS, ASSOCIATED WITH SOME REMNANT ENERGY OF PTC-9
THAT IS FORECAST TO LINGER ACROSS THE REGION LATE INTO WEEK-1. NEAR-NORMAL
TEMPERATURES ARE CONSISTENT WITH REFORECAST AND SHORT-TERM BIAS-CORRECTED TOOLS
FROM THE GEFS AND ECENS. A SECOND AREA OF NEAR-NORMAL IS FAVORED IN THE PACIFIC
NORTHWEST WHERE MORE ONSHORE FLOW IS FAVORED. OTHERWISE, THE STRONG POSITIVE
HEIGHT ANOMALIES FAVORED IN THE WEST AND EASTERN CANADA BRING STRONG CHANCES
FOR ABOVE-NORMAL TEMPERATURES. IN ALASKA, NEAR- TO BELOW-NORMAL TEMPERATURES
ARE FAVORED FOR SOUTHERN ALASKA WITH TROUGHING FAVORED ACROSS MUCH OF THE
STATE. AN AREA OF ABOVE-NORMAL TEMPERATURES IS FAVORED IN THE NORTHEASTERN
MAINLAND DISPLACED FROM THE MID-LEVEL TROUGH. NEAR TO ABOVE-NORMAL TEMPERATURES
ARE FAVORED FOR HAWAII CONSISTENT WITH THE AUTOBLEND AND CONSOLIDATION TOOLS.
THE 6-10 DAY PRECIPITATION FORECAST FAVORS ABOVE-NORMAL PRECIPITATION FOR MOST
AREAS EAST OF THE MISSISSIPPI ASSOCIATED WITH THE REMNANTS OF PTC-9. THE ENERGY
ASSOCIATED WITH THIS TROPICAL CYCLONE IS LIKELY TO BRING UNSETTLED WEATHER TO
THE EASTERN CONUS. HOWEVER, ACROSS AREAS WEST OF THE MISSISSIPPI, BELOW-NORMAL
PRECIPITATION IS FAVORED BENEATH A MID-LEVEL RIDGE ACROSS. IN ALASKA,
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS WESTERN AND SOUTHERN ALASKA
ASSOCIATED WITH ONE OR MORE EXTRA-TROPICAL CYCLONES THAT ARE FORECAST TO MOVE
THROUGH THE REGION WITHIN THE BROADER MID-LEVEL TROUGH. IN HAWAII, NEAR-NORMAL
PRECIPITATION IS FAVORED CONSISTENT WITH THE AVAILABLE TOOLS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 35% 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 UNCERTAINTY REGARDING THE
EVOLUTION OF THE HEIGHT PATTERN IN THE SOUTHEAST.
8-14 DAY OUTLOOK FOR OCT 01 - 07 2024
THE WEEK-2 HEIGHT FORECAST IS VERY SIMILAR TO THE 6-10 DAY PERIOD, WITH
CONTINUED GOOD AGREEMENT AMONG THE MODELS FOR ABOVE-NORMAL 500-HPA HEIGHTS
ACROSS THE WESTERN CONUS AND EASTERN CANADA. MEANWHILE, NEAR TO SLIGHTLY
BELOW-NORMAL HEIGHTS REMAIN FORECAST IN THE SOUTHEASTERN CONUS WITH UNCERTAINTY
REGARDING THE EVOLUTION OF THE PATTERN FOLLOWING A TROPICAL DISTURBANCE
EMERGING FROM THE GULF OF MEXICO. IN ALASKA, TROUGHING CONTINUES WITH
BELOW-NORMAL 500-HPA HEIGHTS, THE STRONGEST NEGATIVE ANOMALIES ARE FOUND IN THE
GULF OF ALASKA, A BIT FURTHER SOUTH RELATIVE TO THE 6-10 DAY PERIOD. IN HAWAII,
NEAR-NORMAL 500-HPA HEIGHTS ARE FORECAST.
DURING WEEK-2, ABOVE-NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE CONUS,
EXCLUDING PORTIONS OF THE CENTRAL AND SOUTHERN MISSISSIPPI AND TENNESSEE RIVER
VALLEYS. IN THESE AREAS NEAR-NORMAL TEMPERATURES ARE FORECAST WITH CONTINUED
ENERGY FROM THE REMNANTS OF A TROPICAL CYCLONE LINGERING IN THE REGION AND WEAK
SHORT-WAVE TROUGHING IN THE REGION. ELSEWHERE, CONTINUED MID-LEVEL RIDGING AND
POSITIVE MID-LEVEL HEIGHT ANOMALIES BRING STRONG CHANCES FOR ABOVE-NORMAL
TEMPERATURES TO MUCH OF THE INTERIOR WEST AND NORTHERN TIER OF THE CONUS. IN
ALASKA, ABOVE-NORMAL TEMPERATURES REMAIN FORECAST IN NORTHEASTERN MAINLAND WITH
NEAR TO BELOW-NORMAL TEMPERATURES FAVORED ALONG THE WESTERN AND SOUTHERN
COASTAL REGIONS OF THE STATE. IN HAWAII, NEAR- TO ABOVE-NORMAL TEMPERATURES ARE
FAVORED.
DURING THE WEEK-2 PERIOD, ABOVE-NORMAL PRECIPITATION REMAINS FAVORED FOR AREAS
EAST OF THE APPALACHIAN MOUNTAINS DUE TO CONTINUED UNSETTLED WEATHER ASSOCIATED
WITH A SHORTWAVE TROUGH PROGRESSING ACROSS THE REGION. BELOW-NORMAL
PRECIPITATION IS FAVORED FOR MUCH OF THE PLAINS AND INTERIOR WEST BENEATH
FORECAST MID-LEVEL RIDGE. IN THE PACIFIC NORTHWEST, A SLIGHT TILT TOWARDS
ABOVE-NORMAL PRECIPITATION IS FORECAST WITH A MID-LEVEL TROUGH MOVING SOUTHEAST
ALONG THE BRITISH COLUMBIA COAST. IN ALASKA, ABOVE-NORMAL PRECIPITATION IS
FAVORED BENEATH A MID-LEVEL TROUGH THAT IS FORECAST TO MAINTAIN UNSETTLED
WEATHER IN THE REGION. IN HAWAII, NEAR-NORMAL PRECIPITATION IS FORECAST
CONSISTENT WITH THE MAJORITY OF AVAILABLE TOOLS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% 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: AVERAGE, 3 OUT OF 5, FAIR
AGREEMENT AMONG THE TOOLS OFFSET BY A LESS AMPLIFIED AND PROGRESSIVE HEIGHT
PATTERN.
FORECASTER: RYAN BOLT
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:
19870913 - 20081007 - 19680924 - 20050905 - 20091001
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:
19870912 - 19680924 - 20081006 - 20030921 - 20050904
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 29 - OCT 03, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A B
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA N B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A N IOWA A N MISSOURI N A
ARKANSAS N N LOUISIANA A B WISCONSIN A N
ILLINOIS A A MISSISSIPPI N N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A B
MASS A N CONN A N RHODE IS A N
PENN A A NEW JERSEY A N 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 A N
AK ALEUTIAN B N AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 01 - 07 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A B
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI N B
ARKANSAS N B LOUISIANA A N WISCONSIN A B
ILLINOIS A B MISSISSIPPI N N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE N N ALABAMA N 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 A N
AK ALEUTIAN B N AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST N A 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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