085
FXUS06 KWBC 161923
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 16 2024
6-10 DAY OUTLOOK FOR OCT 22 - 26 2024
THERE IS VERY GOOD AGREEMENT AMONG THE 0Z ECENS, 0Z CMCE, AND THE 6Z GEFS
500-HPA HEIGHT FORECASTS ON THE PREDICTED CIRCULATION PATTERN ACROSS NORTH
AMERICA DURING THE 6-10 DAY PERIOD. DYNAMICAL MODELS PREDICT A HIGHLY ANOMALOUS
ZONAL RIDGE CENTERED OVER THE EASTERN ALEUTIAN ISLANDS AND SOUTHWESTERN
MAINLAND ALASKA. MID-LEVEL TROUGHING AND ASSOCIATED NEGATIVE HEIGHT ANOMALIES
ARE FORECAST OVER NORTHERN ALASKA AND MOST OF CANADA, EXTENDING SOUTHWESTWARD
ACROSS BRITISH COLUMBIA, THE U.S. PACIFIC NORTHWEST, AND PORTIONS OF THE NORTH
PACIFIC. THIS SOUTHWEST EXTENSION OF THE TROUGH AXIS OVER THE NORTH PACIFIC HAS
A POSITIVE TILT TO IT, SIMILAR TO YESTERDAY. A ZONAL MEAN RIDGE AND
ACCOMPANYING POSITIVE HEIGHT ANOMALIES ARE PREDICTED ACROSS MOST OF THE
CONTIGUOUS U.S. (CONUS), CONTINUING EASTWARD OVER THE NORTH ATLANTIC. THIS
BROAD-SCALE CIRCULATION PATTERN IS CONSISTENT WITH A POSITIVE ARCTIC
OSCILLATION, WHICH TYPICALLY FEATURES POSITIVE 500-HPA HEIGHT ANOMALIES
PREDICTED ACROSS THE MIDDLE LATITUDES (INCLUDING THE CONUS), AND NEGATIVE
500-HPA HEIGHT ANOMALIES OVER THE ARCTIC. FOR HAWAII, 500-HPA HEIGHT ANOMALIES
ARE FORECAST TO BE NEAR ZERO, INDICATING HEIGHTS CLOSE TO THE 30-YEAR
CLIMATOLOGY FOR THAT AREA.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR WESTERN AND NORTHERN MAINLAND ALASKA,
UNDER THE PREDICTED AMPLIFIED RIDGE. BELOW NORMAL TEMPERATURES ARE FAVORED FOR
MUCH OF SOUTHEAST ALASKA, UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW. BELOW
NORMAL TEMPERATURES ARE FAVORED FOR THE PACIFIC NORTHWEST, NORTHERN
INTERMOUNTAIN REGION, AND NORTHERN ROCKIES, UNDER A PREDICTED MID-LEVEL TROUGH.
ABOVE NORMAL TEMPERATURES ARE LIKELY ACROSS MOST OF THE CONUS EXCLUDING PARTS
OF THE NORTHWESTERN CONUS, UNDER PREDICTED POSITIVE 500-HPA HEIGHT ANOMALIES.
ODDS SURPASS 70% FROM THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY
NORTHEASTWARD TO THE LOWER GREAT LAKES REGION AND NEW ENGLAND. THIS LARGE AREA
OF FAVORED ABOVE NORMAL TEMPERATURES IS SUPPORTED BY PRACTICALLY ALL THE
TEMPERATURE TOOLS. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR HAWAII, CONSISTENT
WITH THE TEMPERATURE CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF MAINLAND ALASKA, EXCLUDING
THE IMMEDIATE SOUTH COAST, UNDER FAST ZONAL FLOW OVERTOP OF THE PREDICTED
RIDGE. GREATER PRECIPITATION AMOUNTS ARE PREDICTED AT THE START OF THE 6-10 DAY
PERIOD LEADING TO HIGH PROBABILITIES OF ABOVE NORMAL PRECIPITATION, EXCEEDING
60 PERCENT IN SOME AREAS. BELOW NORMAL PRECIPITATION IS FAVORED FOR THE
SOUTHERN PANHANDLE OF ALASKA, UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW. ABOVE
NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR NORTHERN CALIFORNIA, PARTS OF
OREGON, AND ACROSS THE NORTHERN TIER OF THE CONUS FROM THE NORTHERN ROCKIES TO
THE VICINITY OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY, AHEAD OF THE PREDICTED
TROUGH. BELOW NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE SOUTHERN AND
EASTERN CONUS, EXCLUDING THE FLORIDA PENINSULA, UNDER PREDICTED POSITIVE
500-HPA HEIGHT ANOMALIES. THIS LARGE AREA OF FAVORED BELOW NORMAL PRECIPITATION
IS WELL SUPPORTED BY THE RAW AND REFORECAST PRECIPITATION TOOLS. NEAR NORMAL
PRECIPITATION IS FAVORED FOR THE HAWAIIAN ISLANDS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 34% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 33% 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, OFFSET BY
DE-AMPLIFYING ANOMALIES AND WEAKENING SIGNALS IN THE TEMPERATURE AND
PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR OCT 24 - 30 2024
DYNAMICAL MODEL FORECASTS FROM THE ECENS, GEFS AND CMCE ENSEMBLE MEANS ARE IN
FAIRLY GOOD OVERALL AGREEMENT ON THE AVERAGE LARGE SCALE 500-HPA HEIGHT PATTERN
IN THE WEEK-2 PERIOD, DESPITE WEAKENING ANOMALIES AND SEVERAL SUBSTANTIAL
DIFFERENCES AMONG THE ENSEMBLE MEANS. THERE IS INCREASING UNCERTAINTY REGARDING
THE LOCATION AND AMPLITUDE OF THE MID-LEVEL TROUGH FORECASTED ACROSS THE
NORTHWESTERN CONUS, WITH THE ECENS PREDICTING A MORE AMPLIFIED TROUGH AND THE
CMCE FORECASTING A MORE ZONAL PATTERN. IN ADDITION, THERE ARE NOTICEABLE
DIFFERENCES AMONG THE MODELS REGARDING THE PREDICTED STRENGTH OF THE ALEUTIAN
RIDGE DURING WEEK-2. THE ECENS (AND ESPECIALLY GEFS) FORECASTS A SIGNIFICANT
REDUCTION IN THE MAGNITUDE OF POSITIVE ANOMALIES RELATIVE TO THE EARLIER 6-10
DAY PERIOD (THOUGH THEY ARE STILL LARGE), WHILE THE CMCE MAINTAINS ANOMALY
VALUES COMPARABLE TO THAT OF THE EARLIER 6-10 DAY PERIOD.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF ALASKA, UNDER A PREDICTED
RIDGE AND POSITIVE 500-HPA HEIGHT ANOMALIES, BUT THERE IS CONSIDERABLE
DISAGREEMENT AMONG THE VARIOUS TEMPERATURE TOOLS. BELOW NORMAL TEMPERATURES ARE
LIKELY FOR SOUTHEAST ALASKA, UNDER ANOMALOUS NORTHERLY MID-LEVEL FLOW. BELOW
NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE NORTHWESTERN CONUS, UNDER A
PREDICTED TROUGH IN THE MANUAL BLEND OF MODEL 500-HPA HEIGHT FORECASTS. ABOVE
NORMAL TEMPERATURES ARE FAVORED FROM MOST OF THE FOUR CORNERS REGION AND GREAT
PLAINS EASTWARD TO THE ATLANTIC COAST, UNDER PERSISTENT POSITIVE 500-HPA HEIGHT
ANOMALIES, AND IS WELL SUPPORTED BY PRACTICALLY ALL TOOLS. ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR HAWAII IN WEEK 2, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF ALASKA, UNDER ZONAL
MID-LEVEL FLOW. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED FOR MUCH OF THE
WESTERN CONUS, THE DAKOTAS AND EASTERN PARTS OF THE CENTRAL PLAINS, MOST OF THE
MISSISSIPPI VALLEY, THE GREAT LAKES, AND MOST OF THE OHIO AND TENNESSEE
VALLEYS. THIS IS CONSISTENT WITH THE WEEK-2 PRECIPITATION CONSOLIDATION. BELOW
NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR PORTIONS OF THE SOUTHWEST AND
SOUTHERN HIGH PLAINS, AND ALSO NEAR THE ATLANTIC COAST FROM MAINE TO NORTHERN
FLORIDA, CONTINUING WESTWARD ACROSS THE EASTERN GULF COAST REGION INTO
MISSISSIPPI. THESE TWO AREAS OF FAVORED BELOW NORMAL PRECIPITATION ARE
ASSOCIATED WITH PREDICTED MID-LEVEL RIDGES, WITH GOOD SUPPORT FROM THE RAW
PRECIPITATION TOOLS. FOR THE HAWAIIAN ISLANDS, ODDS FAVOR ABOVE NORMAL
PRECIPITATION CHANCES FOR KAUAI AND OAHU, WITH NEAR NORMAL PRECIPITATION
FAVORED ELSEWHERE.
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 OVERALL AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS, OFFSET BY
VARIABILITY OF THE PREDICTED FORECAST PATTERN AND WEAKENING HEIGHT ANOMALIES
DURING THIS PERIOD.
FORECASTER: ANTHONY A
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:
20081002 - 20051025 - 19881013 - 19991024 - 20001007
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:
20051025 - 20081001 - 20010926 - 20001008 - 19881009
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 22 - 26 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B A NRN CALIF A A
SRN CALIF A N IDAHO B A NEVADA A N
W MONTANA B A E MONTANA N A 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 B KANSAS A N 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 B AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST B A AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 24 - 30 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF N A
SRN CALIF N N IDAHO B A NEVADA N A
W MONTANA B A E MONTANA N A WYOMING N A
UTAH A A ARIZONA A B COLORADO A N
NEW MEXICO A B N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A N ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A B CONN A N RHODE IS A B
PENN A N NEW JERSEY A B W VIRGINIA A N
MARYLAND A N DELAWARE A B VIRGINIA A N
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 A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A 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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