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FXUS06 KWBC 111916
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED SEPTEMBER 11 2024
6-10 DAY OUTLOOK FOR SEP 17 - 21 2024
THERE IS GOOD AGREEMENT BETWEEN THE 0Z ECMWF, GEFS AND CANADIAN ENSEMBLE MEAN
500-HPA HEIGHT FORECASTS ON AN AMPLIFIED CIRCULATION PATTERN ACROSS NORTH
AMERICA. DYNAMICAL MODELS PREDICT A TROUGH OVER THE BERING SEA AND MAINLAND
ALASKA. AN AMPLIFIED TROUGH IS PREDICTED OVER WESTERN CANADA AND THE WESTERN
CONTIGUOUS U.S. (CONUS), WITH SOME EASTWARD PROGRESSION RELATIVE TO YESTERDAY’S
6-10 DAY FORECASTS. AN AMPLIFIED RIDGE IS PREDICTED OVER EASTERN CANADA AND THE
NORTHEASTERN CONUS. NEGATIVE 500-HPA HEIGHT ANOMALIES AND A TROUGH ARE
PREDICTED OVER THE SOUTHEASTERN CONUS. DYNAMICAL MODELS PREDICT WEAKENING
ANOMALIES ASSOCIATED WITH THE TROUGH OVER THE WESTERN CONUS TOWARDS THE END OF
THE PERIOD.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE EASTERN ALEUTIANS AND
THE WEST COAST OF MAINLAND ALASKA, UNDER A PREDICTED TROUGH. NEAR NORMAL
TEMPERATURES ARE FAVORED FOR MUCH OF SOUTHERN MAINLAND ALASKA AND SOUTHEAST
ALASKA, WHERE TEMPERATURE TOOLS DISAGREE. ABOVE NORMAL TEMPERATURES ARE FAVORED
FOR NORTHEASTERN MAINLAND ALASKA, UNDER ANOMALOUS SOUTHERLY FLOW. BELOW NORMAL
TEMPERATURES ARE LIKELY ACROSS THE WESTERN CONUS FROM THE COAST TO THE ROCKY
MOUNTAINS, UNDER A PREDICTED TROUGH. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR
MOST OF THE REMAINDER OF THE CONUS, UNDER A PREDICTED RIDGE AND CONSISTENT WITH
DYNAMICAL MODEL TEMPERATURE FORECASTS. PROBABILITIES FOR ABOVE NORMAL
TEMPERATURES EXCEED 90 PERCENT FOR MUCH OF THE GREAT LAKES REGION, UNDER LARGE
POSITIVE 500-HPA HEIGHT ANOMALIES. NEAR NORMAL IS FAVORED FOR A SMALL AREA OF
THE SOUTHEAST WHERE DYNAMICAL MODEL TEMPERATURE TOOLS DISAGREE. ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR MOST OF THE HAWAIIAN ISLANDS EXCLUDING
SOUTHEASTERN AREAS OF THE BIG ISLAND, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR MOST OF ALASKA, EXCLUDING
PARTS OF THE NORTHWESTERN COAST OF MAINLAND ALASKA, UNDER AND AHEAD OF A
PREDICTED TROUGH AND CONSISTENT WITH DYNAMICAL MODEL PRECIPITATION FORECASTS.
ABOVE NORMAL PRECIPITATION IS LIKELY FOR ACROSS MUCH OF THE WESTERN AND CENTRAL
CONUS, EXCLUDING PARTS OF THE SOUTHWEST AND TEXAS, AHEAD OF THE PREDICTED
TROUGH. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF SOUTHWEST AND THE
WESTERN GULF COAST REGION, WHERE PRECIPITATION TOOLS ARE CONSISTENT. ABOVE
NORMAL PRECIPITATION IS LIKELY FOR PARTS OF THE SOUTHEAST AND MID-ATLANTIC
COASTS, WITH PREDICTED DEVELOPMENT OF A STORM SYSTEM OFF THE COAST. BELOW
NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE NORTHEASTERN CONUS, UNDER THE
PREDICTED RIDGE. ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR HAWAII,
CONSISTENT WITH THE PRECIPITATION CONSOLIDATION.
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, SUCH AS TEMPERATURE FORECASTS FOR PARTS OF ALASKA AND THE SOUTHEAST.
8-14 DAY OUTLOOK FOR SEP 19 - 25 2024
DYNAMICAL MODEL FORECASTS FROM THE ECMWF, GEFS AND CANADIAN ENSEMBLE MEANS ARE
IN GOOD AGREEMENT ON THE EVOLUTION OF THE LARGE SCALE 500-HPA HEIGHT PATTERN IN
THE WEEK-2 PERIOD. THE PATTERN IS OVERALL SIMILAR TO THE 6-10 DAY PERIOD
FORECASTS, WITH INCREASING NEGATIVE 500-HPA HEIGHT ANOMALIES OVER THE GULF OF
ALASKA AND A DECREASE IN AMPLITUDE OF THE TROUGH OVER THE WESTERN CONUS WITH
RISING HEIGHTS LATER IN THE PERIOD. A RIDGE AND POSITIVE 500-HPA HEIGHT
ANOMALIES PERSIST OVER MUCH OF EASTERN NORTH AMERICA, EXCLUDING PARTS OF THE
SOUTHEASTERN CONUS.
BELOW NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR THE EASTERN ALEUTIANS AND
PARTS OF THE WEST COAST OF MAINLAND ALASKA, UNDER A PREDICTED TROUGH. ABOVE
NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF NORTHEASTERN MAINLAND ALASKA,
UNDER ANOMALOUS SOUTHERLY FLOW. NEAR-TO-BELOW NORMAL TEMPERATURES CONTINUE TO
BE FAVORED OVER MUCH OF THE WESTERN CONUS, ALTHOUGH PROBABILITIES FOR BELOW
NORMAL TEMPERATURES HAVE DECREASED SUBSTANTIALLY IN WEEK-2, AS HEIGHTS ARE
PREDICTED TO RISE. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE EASTERN
TWO-THIRDS OF THE CONUS, CONSISTENT WITH THE REFORECAST-CALIBRATED GEFS AND
ECMWF TEMPERATURE FORECASTS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF
THE HAWAIIAN ISLANDS, EXCLUDING THE BIG ISLAND, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR THE EASTERN ALEUTIANS AND
EASTERN MAINLAND ALASKA IN WEEK-2, UNDER AND AHEAD OF THE PREDICTED TROUGH,
WITH ENHANCED PROBABILITIES FOR ABOVE NORMAL PRECIPITATION FOR SOUTHEAST
ALASKA, AHEAD OF AN AMPLIFYING TROUGH. ABOVE NORMAL PRECIPITATION IS FAVORED
FROM THE PACIFIC NORTHWEST EASTWARD INTO THE NORTHERN AND CENTRAL PLAINS, AHEAD
OF THE PREDICTED TROUGH. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE
SOUTHWEST, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION AND MOST
PRECIPITATION TOOLS. BELOW NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR THE
WESTERN GULF COAST REGION, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE SOUTHEAST CONSISTENT
WITH MOST PRECIPITATION TOOLS AND POTENTIAL DEVELOPMENT OF A STORM SYSTEM NEAR
THE COAST. BELOW NORMAL PRECIPITATION CONTINUES TO BE FAVORED FOR PARTS OF THE
NORTHEAST, UNDER THE PREDICTED RIDGE. ABOVE NORMAL PRECIPITATION IS SLIGHTLY
FAVORED ACROSS HAWAII, 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
SEPTEMBER 19.
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:
20050827 - 20050902 - 20060827 - 20050822 - 19540829
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:
20050825 - 20050831 - 19530821 - 20060826 - 19970821
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 17 - 21 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA A A WYOMING B A
UTAH B A ARIZONA B B COLORADO A A
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A B W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO A B 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 N CONN A N RHODE IS A N
PENN A N NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA N A GEORGIA N A
FL PNHDL N N FL PENIN A A AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 19 - 25 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF B N
SRN CALIF B N IDAHO B A NEVADA B N
W MONTANA N A E MONTANA A A WYOMING N A
UTAH B B ARIZONA B B COLORADO A N
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A B W TEXAS A A
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 N
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 N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A N FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B A AK WESTERN N N AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL N A
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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