283
FXUS06 KWBC 031902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE SEPTEMBER 03 2024
6-10 DAY OUTLOOK FOR SEP 09 - 13 2024
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED 500-HPA
CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING THE
6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE
ENSEMBLE MEANS FROM THE GEFS, ECMWF AND CANADIAN MODELS DUE TO RECENT MODEL
SKILL. THE RESULTANT MANUAL BLEND FEATURES AN ENHANCED MID-LEVEL WAVE TRAIN
ACROSS THE FORECAST DOMAIN 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 AND CENTRAL CONTIGUOUS U.S. (CONUS).
TROUGHING AND NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FAVORED OVER THE EASTERN
CONUS. NEAR NORMAL 500-HPA HEIGHTS ARE PREDICTED OVER HAWAII.
ENHANCED CHANCES FOR 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
NORTHERN PLAINS. BELOW-NORMAL TEMPERATURES ARE PREDICTED 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, NEAR- TO
ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER MAINLAND ALASKA AND SOUTHEAST
ALASKA, WHILE BELOW-NORMAL TEMPERATURES ARE FORECAST OVER WESTERN ALEUTIANS,
SUPPORTED BY MOST DYNAMICAL TEMPERATURE FORECAST TOOLS. IN HAWAII, NEAR-NORMAL
TEMPERATURES ARE FAVORED, CONSISTENT WITH THE TEMPERATURE CONSOLIDATION
FORECAST TOOL.
MUCH OF THE CONUS IS FAVORED TO SEE BELOW-NORMAL PRECIPITATION DURING THE 6-10
DAY PERIOD DUE TO THE RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS. HOWEVER, A
SLIGHT TILT TOWARDS ABOVE-NORMAL IS FAVORED ALONG THE SOUTHERN EAST COAST AND
ALONG THE GULF OF MEXICO UNDERNEATH A PREDICTED TROUGH. 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, OVER THE
NORTHWESTERN CONUS, 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, NEAR- TO
ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED ACROSS MOST OF THE STATE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% 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 11 - 17 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY CONSISTENT
500-HPA CIRCULATION PATTERN RELATIVE TO THE 6-10 DAY PERIOD ACROSS NORTH
AMERICA AND THE SURROUNDING REGIONS. DURING WEEK-2, ENSEMBLE MEANS FROM THE
GEFS, ECMWF AND CANADIAN MODELS DEPICT A SLIGHT EASTWARD SHIFT OF THE SYNOPTIC
PATTERN FROM THE 6-10 DAY PERIOD WITH A POSITIVELY TILTED RIDGE ACROSS THE
UPPER MISSISSIPPI VALLEY STRETCHING BACK INTO THE SOUTHWESTERN CONUS.
MEANWHILE, TROUGHING IS FORECAST ALONG AND JUST OFFSHORE THE WEST COAST AND
ACROSS MUCH OF THE SOUTHEASTERN CONUS. A WEAK TROUGH AND NEGATIVE 500-HPA
HEIGHT ANOMALIES ARE FORECAST OVER ALASKA. WEAK NEGATIVE 500-HPA HEIGHT
ANOMALIES ARE PREDICTED OVER HAWAII.
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED FOR MUCH OF THE WESTERN AND CENTRAL
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- TO ABOVE-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 OVER ALABAMA, GEORGIA, AND SOUTH AND
NORTH CAROLINA 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 TEMPERATURE
CONSOLIDATION FORECAST TOOL.
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 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 WESTERN CONUS.
MEANWHILE, ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED IN SOUTHERN MAINLAND AND
SOUTHEAST ALASKA AS WELL AS THE ALEUTIANS, CONSISTENT WITH A TROUGH OVER
ALASKA. IN HAWAII, A SLIGHT TILT TOWARDS ABOVE-NORMAL PRECIPITATION IS FAVORED,
SUPPORTED BY AUTO BLEND PRECIPITATION FORECAST TOOL.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 11, 40% 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: AVERAGE, 3 OUT OF 5, FAIR
AGREEMENT AMONG THE TOOLS OFFSET BY A LESS AMPLIFIED AND PROGRESSIVE HEIGHT
PATTERN.
FORECASTER: LUKE H
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:
20030902 - 19960823 - 19800907 - 19530907 - 19950904
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:
20030902 - 19610813 - 19690909 - 19950904 - 19880904
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 09 - 13 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 A NEVADA A N
W MONTANA A A E MONTANA A B WYOMING A B
UTAH A N ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA B B
N TEXAS B B S TEXAS B A W TEXAS B B
MINNESOTA A B IOWA A B MISSOURI B B
ARKANSAS B B LOUISIANA B A WISCONSIN A B
ILLINOIS B B MISSISSIPPI B B MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B A NEW YORK B B
VERMONT B B NEW HAMP B B MAINE N N
MASS B B CONN B B RHODE IS B B
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A N
AK S INT A A AK SO COAST A N AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 11 - 17 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF N A
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA A A E MONTANA A N WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA N A WISCONSIN A B
ILLINOIS A B MISSISSIPPI N A MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY N B
TENNESSEE N B ALABAMA B A NEW YORK N B
VERMONT A B NEW HAMP A N MAINE A B
MASS N N CONN N N RHODE IS N N
PENN N B NEW JERSEY N N W VIRGINIA N B
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N A S CAROLINA B A GEORGIA B A
FL PNHDL N 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 A AK SO COAST A 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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