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FXUS06 KWBC 091922
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED OCTOBER 09 2024
6-10 DAY OUTLOOK FOR OCT 15 - 19 2024
THERE IS GOOD AGREEMENT BETWEEN THE 0Z ECMWF, GEFS AND CANADIAN ENSEMBLE MEAN
500-HPA HEIGHT FORECASTS ON THE CIRCULATION PATTERN ACROSS NORTH AMERICA.
DYNAMICAL MODELS PREDICT A RIDGE OVER THE BERING SEA. A TROUGH IS PREDICTED
OVER EASTERN MAINLAND ALASKA AND THE GULF OF ALASKA. AN AMPLIFIED RIDGE IS
PREDICTED OVER CENTRAL CANADA AND THE NORTH-CENTRAL CONUS. NEGATIVE 500-HPA
HEIGHT ANOMALIES AND A TROUGH ARE PREDICTED OVER THE SOUTHEASTERN CONUS EARLY
IN THE PERIOD AND IN THE 6-10 DAY AVERAGE 500-HPA HEIGHT FORECASTS.
BELOW NORMAL TEMPERATURES ARE SLIGHTLY FAVORED FOR WESTERN 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. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR NEARLY ALL OF THE
WESTERN CONTIGUOUS U.S. (CONUS) AND THE NORTH-CENTRAL CONUS, UNDER THE
PREDICTED RIDGE AND CONSISTENT WITH DYNAMICAL MODEL TEMPERATURE FORECASTS.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR SOUTH TEXAS AND LIKELY FOR THE
CENTRAL AND LOWER MISSISSIPPI VALLEY AND ACROSS THE EASTERN CONUS, UNDER A
PREDICTED TROUGH 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 SOUTHWEST ALASKA, UNDER PREDICTED
NORTHERLY FLOW. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED ACROSS
NORTHEASTERN MAINLAND ALASKA AHEAD OF A WEAK TROUGH AND CONSISTENT WITH
DYNAMICAL MODEL PRECIPITATION TOOLS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR
THE NORTHWESTERN CONUS AHEAD OF A PREDICTED TROUGH OVER THE NORTHEAST PACIFIC.
BELOW NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE REMAINDER OF THE
CONUS, UNDER A PREDICTED RIDGE, EXCEPT FOR AREAS OF THE SOUTHEASTERN ATLANTIC
COAST WHERE ABOVE NORMAL PRECIPITATION IS FAVORED AHEAD OF A PREDICTED TROUGH.
NEAR NORMAL PRECIPITATION IS INDICATED IN CLIMATOLOGICALLY DRY AREAS OF THE
WESTERN CONUS WHERE LITTLE OR NO PRECIPITATION IS PREDICTED. NEAR NORMAL
PRECIPITATION IS FAVORED ACROSS HAWAII IN THE 6-10 DAY PERIOD, CONSISTENT WITH
THE AUTO PRECIPITATION FORECAST.
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: ABOVE-AVERAGE, 4 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 FOR SOME
AREAS AND A CHANGING PATTERN LATER IN THE PERIOD.
8-14 DAY OUTLOOK FOR OCT 17 - 23 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. MODEL CIRCULATION PATTERN FORECASTS FOR THE 8-14 DAY PERIOD
INDICATE SIGNIFICANT EASTWARD PROGRESSION OF LARGE-SCALE WAVES AND
DE-AMPLIFICATION OF 500-HPA HEIGHT ANOMALY CENTERS RELATIVE TO THE 6-10 DAY
PERIOD FORECASTS.
POSITIVE 500-HPA HEIGHT ANOMALIES SPREAD OVER MAINLAND ALASKA IN THE 8-14 DAY
PERIOD, WHILE A TROUGH, OVER THE NORTHEASTERN PACIFIC IN THE 6-10 DAY PERIOD
MODEL FORECASTS, DE-AMPLIFIES AND PROGRESSES EASTWARD INTO WESTERN NORTH
AMERICA. THE PREDICTED MID-LEVEL RIDGE OVER CENTRAL NORTH AMERICA PROGRESSES
EASTWARD IN THE WEEK-2 PERIOD, WITH POSITIVE 500-HPA HEIGHT ANOMALIES ACROSS
THE EASTERN CONUS IN THE MANUAL BLEND OF DYNAMICAL MODEL FORECASTS. WITH A
CHANGING HEIGHT PATTERN, TEMPERATURE AND PRECIPITATION FORECASTS SHOW
INCREASING UNCERTAINTY AND DIFFERENCES AMONG MODEL TOOLS.
BELOW NORMAL TEMPERATURES CONTINUE TO BE SLIGHTLY FAVORED FOR THE EASTERN
ALEUTIANS UNDER ANOMALOUS NORTHERLY FLOW. HOWEVER, TEMPERATURES ARE PREDICTED
TO MODERATE OVER MUCH OF MAINLAND ALASKA, WHERE NEAR NORMAL TEMPERATURES ARE
PRIMARILY FAVORED FOR THE 8-14 DAY PERIOD. ABOVE NORMAL TEMPERATURES ARE
FAVORED ALONG THE NORTHERN COAST OF MAINLAND ALASKA CONSISTENT WITH MOST
DYNAMICAL MODEL FORECASTS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF
SOUTHEASTERN MAINLAND ALASKA AND SOUTHEAST ALASKA, CONSISTENT WITH MOST
DYNAMICAL MODEL FORECASTS. BELOW NORMAL TEMPERATURES ARE SLIGHTLY FAVORED FOR
WESTERN WASHINGTON STATE IN THE 8-14 DAY PERIOD WHERE A POTENTIAL WEAK TROUGH
AND NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST BY SOME DYNAMICAL MODELS.
ABOVE NORMAL TEMPERATURES CONTINUE TO BE LIKELY ACROSS MOST OF THE CONUS IN THE
WEEK-2 MODEL FORECASTS, UNDER A PREDICTED RIDGE. NEAR NORMAL TEMPERATURES ARE
FAVORED FOR MOST OF THE SOUTHEASTERN CONUS, WHERE A TRANSITION FROM A TROUGH TO
A RIDGE DURING THE 8-14 DAY PERIOD IS PREDICTED BY DYNAMICAL MODELS.
BELOW NORMAL PRECIPITATION CONTINUES TO BE FAVORED FOR THE EASTERN ALEUTIANS
AND PARTS OF THE ALASKA PENINSULA 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, AS THE
PATTERN TRANSITIONS. ABOVE NORMAL PRECIPITATION IS FAVORED FOR THE NORTHWESTERN
QUARTER OF THE CONUS IN THE 8-14 DAY PERIOD, AHEAD OF PREDICTED TROUGHING IN
MOST DYNAMICAL MODEL FORECASTS. THERE IS INCREASED UNCERTAINTY IN THE
PRECIPITATION OUTLOOK ACROSS THE CONUS IN WEEK-2, AS THE PATTERN TRANSITIONS.
BELOW NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF THE EASTERN CONUS IN
WEEK-2, UNDER A PREDICTED RIDGE. NEAR TO ABOVE NORMAL PRECIPITATION CONTINUES
TO BE FAVORED FOR PARTS OF THE SOUTHEAST ATLANTIC COAST IN WEEK-2, CONSISTENT
WITH THE PRECIPITATION CONSOLIDATION. ABOVE NORMAL PRECIPITATION IS FAVORED FOR
MOST ISLANDS OF HAWAII, EXCLUDING THE BIG ISLAND, 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: ABOUT-AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS AND MOST TEMPERATURE
AND PRECIPITATION TOOLS, OFFSET BY DIFFERENCES IN TEMPERATURE AND PRECIPITATION
TOOLS FOR SOME AREAS AND AN 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:
19920928 - 20010922 - 20051022 - 19551011 - 19870919
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:
20051022 - 19870918 - 19920929 - 19551010 - 20010925
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 15 - 19 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A B
NEW MEXICO A N N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA N B
N TEXAS B B S TEXAS B B W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI B B
ARKANSAS B B LOUISIANA B B WISCONSIN A B
ILLINOIS B B MISSISSIPPI B B MICHIGAN N B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B NEW YORK B B
VERMONT B B NEW HAMP B B MAINE B B
MASS B B CONN B B RHODE IS B N
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B N VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B B FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B B AK INT BSN N A
AK S INT N B AK SO COAST B B AK PNHDL B N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 17 - 23 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N A NRN CALIF A N
SRN CALIF A N IDAHO N A NEVADA A N
W MONTANA N A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A N
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE N B ALABAMA N B NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A N
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 N B VIRGINIA N B
N CAROLINA N N S CAROLINA N N GEORGIA N N
FL PNHDL N N FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN N A AK INT BSN N A
AK S INT N N AK SO COAST N N 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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