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FXUS06 KWBC 111903
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI AUGUST 11 2023
6-10 DAY OUTLOOK FOR AUG 17 - 21 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 IS FAVORED TO WEAKEN
AND RETRACT INTO CANADA, AND RIDGING ACROSS THE SOUTHERN CONUS MAY ALSO
SUBSIDE. BY THE END OF THE PERIOD, RIDGING IS FAVORED TO BEGIN DEVELOPING
ACROSS THE NORTHEASTERN AND CENTRAL CONUS WITH PERHAPS WEAK TROUGHING
DEVELOPING ALONG THE WEST COAST. THE MEAN 500-HPA HEIGHT PATTERN FOR THE 6-10
DAY PERIOD REMAINS CONSISTENT RELATIVE TO PREVIOUS FORECASTS WITH ANONYMOUSLY
HIGH MID-LEVEL HEIGHTS FORECAST TO BE CENTERED IN THE NORTHEAST PACIFIC
STRETCHING TO NEAR THE PACIFIC NORTHWEST AND NORTH INTO ALASKA. WEAK TROUGHING
IS CONFINED TO CENTRAL CANADA WITH NEAR TO ABOVE-NORMAL MID-LEVEL HEIGHTS
FORECAST ACROSS MUCH OF THE CONUS.
DURING THE 6 TO 10 DAY PERIOD, MUCH OF THE CONUS IS FAVORED TO SEE ABOVE-NORMAL
TEMPERATURES. THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE IN
THE SOUTHERN PLAINS AND ALONG THE GULF COAST. FORECAST GUIDANCE HAS ONCE AGAIN
INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES IN THESE REGIONS. ABOVE-NORMAL
TEMPERATURE CHANCES HAVE ALSO INCREASED FURTHER NORTH INTO THE GREAT LAKES AND
UPPER-MISSISSIPPI. THERE REMAINS SOME DISAGREEMENT AMONG THE TOOLS IN THESE
REGIONS WITH RAW MODEL GUIDANCE GENERALLY REMAINING COOLER THAN THE REFORECAST
TOOLS, PARTICULARLY EARLY IN THE PERIOD. NEVERTHELESS, WITH A BUILDING 500-HPA
RIDGE IN THESE REGIONS, ABOVE-NORMAL TEMPERATURES ARE SLIGHTLY FAVORED.
ABOVE-NORMAL TEMPERATURE CHANCES ARE REDUCED IN THE PACIFIC NORTHWEST RELATIVE
TO YESTERDAY AS TROUGHING MAY DIG INTO THE REGION BY THE MIDDLE AND END OF THE
PERIOD. IN ALASKA, ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS EASTERN
PORTIONS OF THE STATE WHEREAS BELOW-NORMAL IS FAVORED IN THE WESTERN PORTIONS
CLOSER TO A WEAK TROUGH.
THE PRECIPITATION FORECAST ACROSS THE CONUS REMAINS LOWER-CONFIDENCE WITH WEAK
AND MIXED SIGNALS COMING FROM THE MODEL GUIDANCE. HOWEVER, REFORECAST TOOLS
GENERALLY SUPPORT CHANCES FOR ABOVE-NORMAL PRECIPITATION IN MUCH OF THE
INTERIOR WEST AS THE SOUTHWEST MONSOON MAY MAKE A RESURGENCE. ALONG THE
CALIFORNIA COAST, GUIDANCE IS VERY SUPPORTIVE OF ABOVE-NORMAL PRECIPITATION,
HOWEVER, THESE AREAS RARELY SEE PRECIPITATION DURING AUGUST. THEREFORE, ONLY A
VERY SLIGHT TILT TOWARDS ABOVE-NORMAL IS FORECAST. ABOVE-NORMAL IS ALSO
SLIGHTLY FAVORED IN PARTS OF THE NORTHERN GREAT LAKES AND NORTHERN NORTHEAST AT
THE BASE OF A MID-LEVEL TROUGH THAT IS RETRACTING INTO CANADA. BELOW-NORMAL
PRECIPITATION IS FAVORED ACROSS MUCH OF THE GREAT PLAINS, MIDDLE MISSISSIPPI,
OHIO, AND TENNESSEE RIVER VALLEYS WHERE RIDGING IS FORECAST TO BUILD DURING THE
PERIOD AND IS SUPPORTED BY THE REFORECAST TOOLS AND ANALOG GUIDANCE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% 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 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 19 - 25 2023
DURING THE WEEK-2 PERIOD, THE MEAN 500-HPA HEIGHT FORECAST HAS GROWING
CONFIDENCE RELATIVE TO PRIOR FORECASTS AS MODEL GUIDANCE IS BECOMING MORE
COHERENT. MID-LEVEL RIDGING IS NOW FAVORED TO DEVELOP ACROSS THE CENTRAL CONUS
WITH POSITIVE 500-HPA HEIGHT ANOMALIES FORECAST ACROSS THE NORTHEASTERN AND
NORTH-CENTRAL CONUS. NEAR-NORMAL 500-HPA HEIGHTS ARE FAVORED ACROSS THE
SOUTHERN TIER AND WEAK TROUGHING MAY DEVELOP OFF THE WEST COAST OF THE CONUS.
AS WITH THE 6-10 DAY FORECAST, A LARGE POSITIVE 500-HPA HEIGHT ANOMALY CENTER
IS FOCUSED ACROSS THE NORTHEAST PACIFIC EXTENDING INTO MUCH OF ALASKA.
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 70%, REMAIN ACROSS THE SOUTHERN AND CENTRAL 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, BELOW-NORMAL IS
FAVORED DUE TO WEAK TROUGHING WEST OF THE STATE AND STRONG NEGATIVE HEIGHT
ANOMALIES NORTH OF EASTERN SIBERIA.
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, AS IN
THE 6 TO 10 DAY FORECAST, MANY TOOLS ARE HIGHLY SUPPORTIVE OF ABOVE-NORMAL
PRECIPITATION. HOWEVER, THESE REGIONS RARELY SEE MUCH PRECIPITATION DURING THE
MONTH OF AUGUST. THEREFORE, ONLY A SLIGHT TILT TOWARDS ABOVE-NORMAL
PRECIPITATION IS FORECAST FOR THE WEEK-2 PERIOD. ACROSS THE SOUTHERN AND
CENTRAL PLAINS, THE OHIO RIVER, LOWER AND MIDDLE MISSISSIPPI RIVER, AND
TENNESSEE RIVER VALLEYS, AND ALSO MUCH OF THE SOUTHEAST, BELOW-NORMAL
PRECIPITATION IS FAVORED WITH GOOD AGREEMENT AMONG REFORECAST TOOLS AND
STATISTICAL GUIDANCE BENEATH POSITIVE 500-HPA HEIGHT ANOMALIES. ELSEWHERE IN
THE EASTERN CONUS, CONFLICTING AND LOW CHANCES AMONG THE FORECAST GUIDANCE LEND
TO NEAR-NORMAL PRECIPITATION BEING FORECAST IN PARTS OF THE NORTHEAST, GREAT
LAKES, AND GULF COAST. 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 CLOSER TO STRONG
NEGATIVE ANOMALIES OVER THE ARCTIC OCEAN.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% 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:
19640812 - 19800813 - 19920726 - 19640817 - 19620817
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:
19640815 - 19620819 - 19640810 - 19800813 - 19920726
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 17 - 21 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA N N S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA N N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN N N
ILLINOIS A B MISSISSIPPI A B MICHIGAN N N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B 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 B DELAWARE A B VIRGINIA A B
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A N FL PENIN A N AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B A AK INT BSN N A
AK S INT N B AK SO COAST B B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 19 - 25 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A 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 B OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE N N
MASS A N CONN A N RHODE IS A N
PENN A B NEW JERSEY A N W VIRGINIA A B
MARYLAND A B DELAWARE A N VIRGINIA A B
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A N FL PENIN A N AK N SLOPE N A
AK ALEUTIAN N N AK WESTERN B A AK INT BSN A A
AK S INT A N 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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