413
FXUS06 KWBC 101903
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU AUGUST 10 2023
6-10 DAY OUTLOOK FOR AUG 16 - 20 2023
A PATTERN TRANSITION IS FAVORED TO OCCUR DURING THE 6 TO 10 DAY PERIOD. AT THE
ONSET OF THE PERIOD, MID-LEVEL RIDGING IS FORECAST ACROSS THE WESTERN AND
SOUTHERN CONTIGUOUS U.S. (CONUS) AND MID-LEVEL TROUGHING ACROSS THE
NORTH-CENTRAL CONUS. HOWEVER, THE TROUGHING IN THE NORTH LOOKS LIKELY TO WEAKEN
AND RETRACT INTO CANADA, AND RIDGING ACROSS THE SOUTHERN CONUS IS LIKELY TO
SUBSIDE AS WELL. BY THE END OF THE PERIOD, RIDGING MAY BEGIN DEVELOPING ACROSS
THE NORTHEASTERN CONUS. NEVERTHELESS, THE MEAN 500-HPA HEIGHT PATTERN FOR THE
6-10 DAY PERIOD REMAINS QUITE CONSISTENT RELATIVE TO PREVIOUS FORECASTS WITH
ANONYMOUSLY HIGH MID-LEVEL HEIGHTS FORECAST TO BE CENTERED IN THE NORTHEAST
PACIFIC STRETCHING INTO THE PACIFIC NORTHWEST AND NORTH INTO ALASKA. WEAK
TROUGHING REMAINS FORECAST ACROSS PARTS OF THE ALEUTIAN ISLANDS AND ACROSS THE
NORTH-CENTRAL CONTIGUOUS U.S. (CONUS). MEANWHILE, HEIGHTS ARE FORECAST TO BE
NEAR-NORMAL ACROSS MUCH OF THE SOUTHERN CONUS AS THE SUBTROPICAL RIDGING
WEAKENS.
DURING THE 6 TO 10 DAY PERIOD, MUCH OF THE CONUS IS FAVORED TO SEE ABOVE-NORMAL
TEMPERATURES. THERE ARE TWO AREAS OF MAXIMUM PROBABILITIES FOR ABOVE-NORMAL
TEMPERATURES EXCEEDING 70% IN PORTIONS OF THE PACIFIC NORTHWEST AND IN THE
SOUTHERN PLAINS AND GULF COAST. CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE
GENERALLY SLIGHTLY WEAKER ALONG THE SOUTHERN TIER OF THE CONUS TODAY RELATIVE
TO YESTERDAY AS THE SUBTROPICAL RIDGE, THAT HAS HELD FIRM MOST OF THE SUMMER,
SUBSIDES. ALONG THE EAST COAST, ABOVE-NORMAL TEMPERATURES ARE FAVORED AHEAD OF
A TROUGH ACROSS THE NORTH-CENTRAL CONUS THAT BRINGS NEAR- TO BELOW-NORMAL
TEMPERATURES TO PORTIONS OF THE UPPER MISSISSIPPI AND GREAT LAKES REGIONS. IN
ALASKA, ABOVE-NORMAL TEMPERATURES ARE FAVORED IN SOUTHEAST WHERE REFORECAST
TOOLS AND THE 500-HPA RIDGE SUPPORT ABOVE-NORMAL. IN THE ALEUTIAN ISLANDS AND
THE SOUTHWEST MAINLAND, BELOW-NORMAL TEMPERATURES ARE FAVORED WITH WEAK
TROUGHING IN THE REGION.
THE PRECIPITATION FORECAST ACROSS THE CONUS REMAINS LOW-CONFIDENCE WITH WEAK
AND MIXED SIGNALS COMING FROM THE MODEL GUIDANCE. HOWEVER, REFORECAST TOOLS
GENERALLY SUPPORT WEAK CHANCES FOR ABOVE-NORMAL PRECIPITATION IN MUCH OF THE
INTERIOR WEST AS THE SOUTHWEST MONSOON MAY MAKE A RESURGENCE. ABOVE-NORMAL IS
ALSO SLIGHTLY FAVORED IN THE GREAT LAKES AND INTERIOR NORTHEAST AT THE BASE OF
THE MID-LEVEL TROUGH. BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE
GREAT PLAINS, MIDDLE MISSISSIPPI, OHIO, AND TENNESSEE RIVER VALLEYS WHERE
RIDGING IS LIKELY TO BUILD INTO THE REGIONS BY THE END OF THE PERIOD AND IS
SUPPORTED BY THE REFORECAST TOOLS AND ANALOG GUIDANCE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 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 20%
OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: NEAR-AVERAGE, 3 OUT OF 5, ONGOING
PATTERN CHANGE REDUCES CONFIDENCE BUT STRONG AGREEMENT AMONGST THE HEIGHT AND
TEMPERATURE TOOLS INCREASES CONFIDENCE.
8-14 DAY OUTLOOK FOR AUG 18 - 24 2023
DURING THE WEEK-2 PERIOD, THE MEAN 500-HPA HEIGHT FORECAST GENERALLY HAS LOW
CONFIDENCE AS MUCH OF THE CONUS IS FORECAST TO BE IN THE MIDST OF MID-LEVEL
HEIGHT PATTERN CHANGE. THE TROUGHING THAT HAS BEEN PERSISTENT ACROSS THE
NORTHERN CONUS FOR MUCH OF THE SUMMER IS FORECAST TO WEAKEN AND WITHDRAW
NORTHWARD INTO CANADA. ABOVE-NORMAL 500-HPA HEIGHT ANOMALIES THEN DEVELOP
ACROSS THE NORTHEASTERN CONUS. ACROSS THE SOUTHERN AND WESTERN CONUS,
NEAR-NORMAL HEIGHTS ARE FAVORED. AS WITH THE 6-10 DAY FORECAST, A LARGE
POSITIVE 500-HPA HEIGHT ANOMALY CENTER IS FOCUSED ACROSS THE NORTHEAST PACIFIC
BUT IS CENTERED FURTHER WEST RELATIVE TO THE 6-10 DAY FORECAST.
AS IN THE 6 TO 10 DAY, THE WEEK-2 TEMPERATURE FORECAST INDICATES CHANCES FOR
ABOVE-NORMAL TEMPERATURES ACROSS MOST OF THE CONUS. THE STRONGEST CHANCES,
GREATER THAN 60%, REMAIN ACROSS THE SOUTHERN PLAINS, LOWER MISSISSIPPI AND
SOUTHEAST. STRONGER CHANCES ARE CONTINUING TO BUILD INTO THE NORTHEASTERN CONUS
RELATIVE TO THE 6 TO 10 DAY FORECAST AS MID-LEVEL RIDGING BUILDS INTO THE
REGION. IN THE WEST, ABOVE-NORMAL TEMPERATURES REMAIN FAVORED BUT PROBABILITIES
ARE REDUCED RELATIVE TO PRIOR FORECASTS WITH NEAR-NORMAL 500-HPA HEIGHTS AND
STRONGER SIGNALS FOR A RESUMPTION OF THE SOUTHWEST MONSOON. IN ALASKA,
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHEAST AND EASTERN MAINLAND
WHERE THE STRONGEST POSITIVE HEIGHT ANOMALIES AND SOUTHERLY FLOW BRING WARMER
TEMPERATURES. ACROSS THE WESTERN MAINLAND, NEAR-NORMAL IS FAVORED DUE TO A
GENERAL WEAK AND CONFLICTING SIGNALS.
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE INTERIOR WEST DUE TO
RESURGENCE OF THE SOUTHWEST MONSOON, AIDED BY INCREASED MID-LEVEL MOISTURE FROM
THE REMNANTS OF TROPICAL CYCLONE EUGENE. ALONG THE IMMEDIATE WEST COAST, SOME
OF THE TOOLS INDICATE ABOVE-NORMAL PRECIPITATION CHANCES IN THESE REGIONS,
HOWEVER, DURING THE FORECAST PERIOD THESE AREAS ARE CONSIDERED ARID AND RARELY
SEE MEASURABLE RAINFALL AND THIS IS SHOWN IN SOME OF THE DETERMINISTIC AND RAW
ENSEMBLES SHOWING NEAR ZERO PRECIPITATION. THE HIGHEST PRECIPITATION TOTALS ARE
SHOWN IN THE SOUTHERN COASTAL MOUNTAIN RANGES NEAR LOS ANGELES. THEREFORE,
THESE AREAS ARE SLIGHTLY FAVORED TO SEE ABOVE-NORMAL PRECIPITATION. ACROSS THE
SOUTHERN PLAINS AND INTO THE OHIO RIVER VALLEY, BELOW-NORMAL PRECIPITATION IS
FAVORED WITH GOOD AGREEMENT AMONG REFORECAST TOOLS AND STATISTICAL GUIDANCE.
ELSEWHERE IN THE EASTERN CONUS, CONFLICTING AND LOW CHANCES AMONG THE FORECAST
GUIDANCE LEND TO A LARGE AREA OF NEAR-NORMAL PRECIPITATION BEING FORECAST. IN
ALASKA, BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS THE SOUTHERN COAST WITH
STRONG AGREEMENT FROM THE FORECAST GUIDANCE. ABOVE-NORMAL PRECIPITATION IS
FAVORED IN NORTHERN ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 20% 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: BELOW AVERAGE, 2 OUT 5, AN ONGOING
PATTERN CHANGE AND REDUCED SIGNALS IN THE PRECIPITATION FORECAST ACROSS THE
CONUS IS OFFSET BY BETTER AGREEMENT IN THE TEMPERATURE TOOLS.
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
AUGUST 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:
19640811 - 19800814 - 19980721 - 19640816 - 20090721
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:
19640810 - 19640815 - 20070822 - 19800815 - 20090720
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 16 - 20 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A A IDAHO A N NEVADA A A
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A A COLORADO A N
NEW MEXICO A N N DAKOTA B N S DAKOTA N N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA B N IOWA N N MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN B N
ILLINOIS N N MISSISSIPPI A N MICHIGAN N A
INDIANA N N OHIO N N KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A A
VERMONT A N NEW HAMP A N MAINE A A
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A B
N CAROLINA A B S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B N AK INT BSN N N
AK S INT N N AK SO COAST N B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 18 - 24 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA N A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A B MISSISSIPPI A N MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A B
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN N N AK INT BSN A N
AK S INT A B AK SO COAST A B AK PNHDL A B
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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