834
FXUS06 KWBC 091927
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 09 2024
6-10 DAY OUTLOOK FOR SEP 15 - 19 2024
THERE IS GOOD AGREEMENT BETWEEN THE 0Z ENSEMBLE MEAN SOLUTIONS OF THE ECMWF,
GEFS AND CANADIAN ENSEMBLE MEAN, 500-HPA HEIGHT FORECASTS, ON A PERSISTENT
CIRCULATION PATTERN ACROSS NORTH AMERICA. DYNAMICAL MODELS PREDICT A
LARGE-SCALE WAVE PATTERN WITH A RIDGE OVER THE ALEUTIAN ISLANDS, A TROUGH
EXTENDING FROM MAINLAND ALASKA SOUTHEASTWARD OVER WESTERN CANADA AND THE
WESTERN CONTIGUOUS U.S. (CONUS), A RIDGE OVER EASTERN CANADA AND THE
NORTHEASTERN CONUS, AND WEAK NEGATIVE 500-HPA HEIGHT ANOMALIES AND A TROUGH
OVER THE SOUTHEASTERN CONUS. DYNAMICAL MODELS GENERALLY PREDICT PERSISTENCE OF
THIS PATTERN THROUGH THE 6-10 DAY PERIOD WITH WEAKENING ANOMALIES ASSOCIATED
WITH THE TROUGH OVER WESTERN NORTH AMERICA LATER IN THE PERIOD.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE EASTERN ALEUTIANS, PARTS
OF THE WEST COAST OF MAINLAND ALASKA, AND SOUTHEAST ALASKA, UNDER A PREDICTED
TROUGH. NEAR NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF SOUTHERN MAINLAND
ALASKA, WHERE TEMPERATURE TOOLS DISAGREE. ABOVE NORMAL TEMPERATURES ARE LIKELY
FOR MOST OF NORTHERN 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 EXCEED 80 PERCENT FOR
ABOVE NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN AND CENTRAL CONUS, UNDER
LARGE POSITIVE 500-HPA HEIGHT ANOMALIES. NEAR NORMAL IS FAVORED FOR PARTS OF
THE SOUTHEAST WHERE DYNAMICAL MODEL TEMPERATURE TOOLS DISAGREE. ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR HAWAII, CONSISTENT WITH THE TEMPERATURE
CONSOLIDATION.
ABOVE NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR MOST OF ALASKA, EXCLUDING
THE NORTH SLOPE, UNDER AND AHEAD OF A PREDICTED TROUGH AND CONSISTENT WITH
DYNAMICAL MODEL PRECIPITATION FORECASTS. ABOVE NORMAL PRECIPITATION IS LIKELY
FOR THE NORTHWESTERN CONUS FROM THE PACIFIC NORTHWEST INTO THE NORTHERN
ROCKIES, AHEAD OF THE PREDICTED TROUGH. NEAR TO ABOVE NORMAL PRECIPITATION IS
SLIGHTLY FAVORED ACROSS MUCH OF THE CONUS, CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION. PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE SLIGHTLY
ELEVATED ABOVE 40 PERCENT FOR PARTS OF THE SOUTHEAST COAST, WHERE THERE IS AN
ENHANCED CHANCE OF DEVELOPMENT OF A TROPICAL SYSTEM. NEAR NORMAL PRECIPITATION
IS FAVORED ACROSS MUCH OF THE SOUTH-CENTRAL CONUS, WHERE PRECIPITATION TOOLS
ARE INCONSISTENT. A NARROW AREA OF SLIGHTLY ENHANCED PROBABILITIES FOR BELOW
NORMAL PRECIPITATION IS FORECAST FOR PARTS OF THE CENTRAL GULF COAST, WHERE
PRECIPITATION TOOLS ARE CONSISTENT. 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 DYNAMICAL MODEL
PRECIPITATION FORECASTS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z 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, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS AND TOOLS AND
DAY-TO-DAY RUN CONSISTENCY, OFFSET BY DIFFERENCES IN TEMPERATURE AND
PRECIPITATION TOOLS FOR SOME AREAS, SUCH AS PRECIPITATION FORECASTS FOR THE
SOUTH-CENTRAL CONUS AND TEMPERATURE FORECASTS FOR PARTS OF THE SOUTHEAST.
8-14 DAY OUTLOOK FOR SEP 17 - 23 2024
DYNAMICAL MODEL FORECASTS FROM THE ECMWF, GEFS AND CANADIAN ENSEMBLE MEANS
REMAIN IN GOOD AGREEMENT ON THE 500-HPA HEIGHT PATTERN PERSISTING INTO THE
WEEK-2 PERIOD. THE PATTERN IS OVERALL SIMILAR TO THE 6-10 DAY PERIOD FORECASTS,
WITH SOME WEAKENING OF THE TROUGH OVER THE WESTERN CONUS. A RIDGE AND POSITIVE
500-HPA HEIGHT ANOMALIES PERSIST OVER MUCH OF EASTERN NORTH AMERICA, EXCLUDING
THE SOUTHEASTERN CONUS.
BELOW NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR THE EASTERN ALEUTIANS, THE
WEST COAST OF MAINLAND ALASKA, AND SOUTHEAST ALASKA, UNDER A PREDICTED TROUGH.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR NORTHEASTERN MAINLAND ALASKA, UNDER
ANOMALOUS SOUTHERLY FLOW. THE TEMPERATURE PATTERN OVER THE CONUS IN THE 6-10
DAY PERIOD FORECAST PERSISTS INTO WEEK-2. BELOW NORMAL TEMPERATURES CONTINUE TO
BE FAVORED FOR THE WEST, WHILE ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE
EASTERN TWO-THIRDS OF THE CONUS, EXCLUDING PARTS OF THE SOUTHEAST COAST. 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 ALASKA IN WEEK-2, EXCLUDING
THE NORTH SLOPE, UNDER AND AHEAD OF THE PREDICTED TROUGH. ABOVE NORMAL
PRECIPITATION IS FAVORED FROM CENTRAL CALIFORNIA AND THE PACIFIC NORTHWEST
EASTWARD INTO THE NORTHERN AND CENTRAL PLAINS, AHEAD OF THE PREDICTED TROUGH.
NEAR TO BELOW NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR PARTS OF THE
SOUTHWEST, CONSISTENT WITH THE PRECIPITATION CONSOLIDATION AND MOST
PRECIPITATION TOOLS. BELOW NORMAL PRECIPITATION IS SLIGHTLY FAVORED FOR A
NARROW AREA OF THE WESTERN GULF COAST, CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION. ABOVE NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE SOUTHEAST
CONSISTENT WITH MOST PRECIPITATION TOOLS AND A POTENTIAL TROPICAL STORM SYSTEM
NEAR THE COAST. BELOW NORMAL PRECIPITATION CONTINUES TO BE FAVORED FOR MUCH OF
THE NORTHEASTERN CONUS, 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, 35% 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: ABOVE-AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE DYNAMICAL MODEL HEIGHT FORECASTS AND TEMPERATURE AND
PRECIPITATION TOOLS, OFFSET BY DIFFERENCES IN TEMPERATURE AND PRECIPITATION
TOOLS FOR SOME AREAS AND A SLIGHTLY LESS AMPLIFIED 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:
20050822 - 19870922 - 19820903 - 20090830 - 19530908
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:
20050824 - 19970820 - 20050830 - 19870921 - 20090828
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 15 - 19 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO B A NEVADA B A
W MONTANA B A E MONTANA A A WYOMING A A
UTAH B A ARIZONA B A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A N
ILLINOIS A A MISSISSIPPI A N MICHIGAN A N
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A 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 N NEW JERSEY A B W VIRGINIA A A
MARYLAND A A DELAWARE A N VIRGINIA A A
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL A N FL PENIN A A AK N SLOPE A N
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 B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 17 - 23 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 A A
UTAH B A ARIZONA B N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A B
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 B RHODE IS A B
PENN A N NEW JERSEY A N 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 A N 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 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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