012
FXUS06 KWBC 021902
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 02 2024
6-10 DAY OUTLOOK FOR SEP 08 - 12 2024
THERE IS GOOD AGREEMENT AMONG THE DYNAMICAL TOOLS REGARDING THE 500-HPA HEIGHT
PATTERN ACROSS MUCH OF NORTH AMERICA. AN ENHANCED MID-LEVEL WAVE TRAIN IS
FORECAST ACROSS THE DOMAIN TODAY BEGINNING WITH POSITIVE 500-HPA HEIGHT
ANOMALIES FAVORED OVER AND TO THE SOUTH OF THE ALEUTIAN ISLANDS. MID-LEVEL
TROUGHING AND NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST IN THE GULF OF
ALASKA EXTENDING SOUTH TOWARDS THE PACIFIC NORTHWEST. POSITIVE 500-HPA HEIGHTS,
AND MID-LEVEL RIDGING ARE FAVORED ACROSS MUCH OF THE WESTERN CONTIGUOUS U.S.
(CONUS). FINALLY, TROUGHING AND NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FAVORED
OVER THE EASTERN CONUS. THERE ARE SOME DIFFERENCES AMONG THE ENSEMBLES IN THE
POSITIONING OF THE TROUGH ALONG AND OFFSHORE THE PACIFIC NORTHWEST, WITH THE
ECENS AND CANADIAN BRINGING THIS TROUGH CLOSER TO THE NORTHWEST WHILE THE GEFS
REMAINS FURTHER OFFSHORE.
ABOVE-NORMAL TEMPERATURES ARE STRONGLY FAVORED BENEATH THE STRONG MID-LEVEL
RIDGE ACROSS THE WESTERN U.S. DURING THE 6-10 DAY PERIOD. CHANCES EXCEED 80%
FOR ABOVE-NORMAL TEMPERATURES ACROSS PORTIONS OF THE GREAT BASIN AND NORTHERN
ROCKIES. THE PROGRESSIVE PATTERN WILL SHIFT THE WARMER TEMPERATURES EASTWARD
WITH TIME DISPLACING BELOW-NORMAL TEMPERATURES THAT WERE FAVORED ACROSS THE
PLAINS IN YESTERDAY’S FORECAST. HOWEVER, BELOW-NORMAL TEMPERATURES REMAIN
FAVORED ACROSS MOST AREAS EAST OF THE MISSISSIPPI RIVER AND IN THE SOUTHERN
PLAINS. THE EXCEPTION IS IN FLORIDA WHERE ABOVE-NORMAL TEMPERATURES REMAIN
FAVORED. IN ALASKA, ABOVE-NORMAL TEMPERATURES ARE FAVORED, PARTICULARLY ACROSS
THE NORTHEASTERN MAINLAND WITH GOOD MODEL AGREEMENT AMONG THE TOOLS DEPICTING
WEAKER SIGNALS ACROSS THE SOUTHERN PORTIONS OF THE STATE. IN HAWAII,
NEAR-NORMAL TEMPERATURES ARE FAVORED CONSISTENT WITH THE DYNAMICAL TOOLS.
MUCH OF THE CONUS IS FAVORED TO SEE BELOW-NORMAL PRECIPITATION DURING THE 6-10
DAY PERIOD. WITH THE 500-HPA HEIGHT RIDGE ACROSS THE WEST AND BEHIND THE
500-HPA TROUGH AXIS ACROSS THE EASTERN CONUS, THE STRONGEST SIGNAL FOR
BELOW-NORMAL PRECIPITATION IS ACROSS THE NORTHERN PLAINS AND UPPER-MISSISSIPPI
VALLEY. HOWEVER, A SLIGHT TILT TOWARDS ABOVE-NORMAL IS FAVORED ALONG THE
IMMEDIATE EAST COAST AND ALONG THE GULF OF MEXICO ALONG A MEAN FRONTAL ZONE.
THERE REMAINS SOME CONCERN FOR A TROPICAL SYSTEM TO MOVE INTO THE GULF OF
MEXICO BY THE END OF WEEK-1 AND INTO WEEK-2 BUT CONFIDENCE REMAINS LOW.
MEANWHILE, IN THE PACIFIC NORTHWEST, THE MEAN TROUGH IN THE NORTH PACIFIC MAY
BRING ONSHORE FLOW AND INCREASED CHANCES FOR PRECIPITATION TO THE REGION. IN
ALASKA, ABOVE-NORMAL PRECIPITATION IS FAVORED FOR THE SOUTHWESTERN PORTIONS OF
THE MAINLAND AND THE ALEUTIANS WITH NEAR-NORMAL PRECIPITATION FAVORED
ELSEWHERE. IN HAWAII, BELOW-NORMAL PRECIPITATION IS SLIGHTLY FAVORED ACROSS
MOST OF THE STATE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 40% 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 A MORE PROGRESSIVE PATTERN BY
THE END OF THE PERIOD.
8-14 DAY OUTLOOK FOR SEP 10 - 16 2024
THE WEEK-2 FORECASTED MID-LEVEL HEIGHTS REMAIN IN FAIRLY GOOD AGREEMENT AMONG
THE DYNAMICAL ENSEMBLES. THE ECENS AND CANADIAN FAVOR MORE AMPLIFIED SOLUTIONS
BUT ALL THE TOOLS DEPICT A SLIGHT EASTWARD SHIFT OF THE SYNOPTIC PATTERN FROM
THE 6-10 DAY PERIOD WITH A POSITIVELY TILTED RIDGE ACROSS THE PLAINS STRETCHING
BACK INTO THE SOUTHWESTERN CONUS. MEANWHILE, TROUGHING IS FORECAST ALONG AND
JUST OFFSHORE THE WEST COAST AND ACROSS MUCH OF THE EASTERN CONUS. HOWEVER, THE
TROUGH ACROSS THE EAST IS WEAKER RELATIVE TO THE 6-10 DAY PERIOD WITH
NEAR-NORMAL HEIGHTS FAVORED IN THE DYNAMICAL TOOLS.
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED FOR THE WESTERN CONUS DURING WEEK-2
BENEATH THE FORECAST RIDGE ACROSS THE REGION. THE RIDGE DOES HOWEVER EXPAND AND
PROGRESS EASTWARD DISPLACING BELOW-NORMAL TEMPERATURES IN THE 6-10 DAY WITH
ABOVE-NORMAL TEMPERATURES ACROSS THE PLAINS AND UPPER MISSISSIPPI VALLEY INTO
THE GREAT LAKES. NEAR-NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE REST
OF THE EAST AS THE RIDGE BEGINS TO BRING WARMER TEMPERATURES BY THE MIDDLE TO
END OF THE WEEK-2 PERIOD. THERE ARE LINGERING CHANCES FOR BELOW-NORMAL
TEMPERATURES ALONG THE MID-ATLANTIC AND NORTHEASTERN COAST WHERE THE
BELOW-NORMAL TEMPERATURES ARE LIKELY TO HANG ON THE LONGEST. AS WITH THE 6-10
DAY PERIOD, ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR ALASKA WITH A SIMILAR
MID-LEVEL HEIGHT PATTERN PERSISTING. IN HAWAII, ABOVE-NORMAL TEMPERATURES ARE
SLIGHTLY FAVORED CONSISTENT WITH THE DYNAMICAL TOOLS.
BELOW-NORMAL PRECIPITATION REMAINS FAVORED ACROSS MOST OF THE CONUS DURING THE
WEEK-2 PERIOD BENEATH AN EXPANDING MID-LEVEL RIDGE AND BEHIND A TROUGH AXIS
NEAR THE EASTERN SEABOARD. ABOVE-NORMAL PRECIPITATION REMAINS SLIGHTLY FAVORED
ACROSS PORTIONS OF THE GULF COAST AND SOUTHEAST AT THE BASE OF A TROUGH AND
WITH CONTINUED CHANCES FOR A TROPICAL DISTURBANCE TO BRING UNSETTLED WEATHER
INTO THE GULF OF MEXICO. A TROUGH NEAR THE NORTHWESTERN CONUS BRINGS INCREASED
CHANCES FOR ABOVE-NORMAL PRECIPITATION TO PORTIONS OF THE PACIFIC NORTHWEST.
MEANWHILE, ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED IN SOUTHERN MAINLAND AND
SOUTHEAST ALASKA CONSISTENT WITH A TROUGH IN THE GULF OF ALASKA. IN HAWAII, A
SLIGHT TILT TOWARDS BELOW-NORMAL PRECIPITATION IS FAVORED.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 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 20%
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
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:
19960823 - 20030902 - 20080915 - 19550903 - 19530907
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:
20080915 - 20030902 - 19610812 - 19600914 - 20000915
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 08 - 12 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 B E MONTANA A B WYOMING A B
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS N B OKLAHOMA N B
N TEXAS B B S TEXAS B A W TEXAS A B
MINNESOTA N B IOWA N B MISSOURI N B
ARKANSAS B B LOUISIANA B N WISCONSIN N B
ILLINOIS N B MISSISSIPPI B B MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B NEW YORK B N
VERMONT B A NEW HAMP B A MAINE N A
MASS B A CONN B A RHODE IS B A
PENN B N NEW JERSEY B N W VIRGINIA B B
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B A
FL PNHDL B A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN A N AK INT BSN A N
AK S INT A N AK SO COAST A N AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 10 - 16 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
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 B COLORADO A N
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS N B S TEXAS N A W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS N B LOUISIANA N A WISCONSIN A B
ILLINOIS A B MISSISSIPPI N N MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY N B
TENNESSEE N B ALABAMA N A NEW YORK N B
VERMONT N B NEW HAMP N N MAINE A N
MASS N N CONN N N RHODE IS B N
PENN N B NEW JERSEY B B W VIRGINIA N B
MARYLAND B N DELAWARE B N VIRGINIA N N
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN A N AK INT BSN A N
AK S INT A N AK SO COAST A A AK PNHDL A 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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