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FXUS06 KWBC 171902
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 17 2023
6-10 DAY OUTLOOK FOR AUG 23 - 27 2023
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED AMPLIFIED
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 GFS, ECMWF, AND CANADIAN MODEL ENSEMBLES DUE TO RECENT
MODEL SKILL. THE RESULTANT MANUAL BLEND FEATURES A MID-LEVEL RIDGE CENTERED IN
THE CENTRAL CONTIGUOUS UNITED STATES (CONUS) DURING THE 6 TO 10 DAY PERIOD. A
TROUGH IS FORECAST OVER THE BERING SEA. WEAK TROUGHING MAY ALSO DEVELOP ALONG
THE WEST COAST OF THE CONUS AND THAT WOULD ENHANCE SURFACE AND MID-LEVEL
MOISTURE OVER THE WESTERN CONUS. ANOTHER TROUGH IS FORECAST OVER THE NORTHEAST.
POSITIVE 500-HPA HEIGHT ANOMALIES ARE FAVORED OVER MOST OF ALASKA.
THE DOMINANT RIDGE ACROSS THE MIDDLE OF THE CONUS FAVORS ABOVE-NORMAL
TEMPERATURES OVER MOST OF THE CONUS, EXCEPT FOR MUCH OF THE NORTHEAST (DUE TO
BELOW–NORMAL 500 HPA HEIGHTS) AND PORTIONS OF THE SOUTHWEST (DUE TO INCREASED
MOISTURE AS A RESULT OF A GULF SURGE FROM HURRICANE HILARY) WHERE BELOW-NORMAL
TEMPERATURES ARE FAVORED. THE STRONGEST CHANCES FOR ABOVE-NORMAL TEMPERATURES
ARE FOCUSED ACROSS PARTS OF EASTERN TEXAS AND EASTERN OKLAHOMA, THE LOWER
MISSISSIPPI VALLEY, AND THE SOUTHEAST. IN ALASKA, CHANCES FOR ABOVE-NORMAL
TEMPERATURES ARE INCREASED ACROSS THE EASTERN AND CENTRAL PARTS OF THE STATE
BENEATH POSITIVE 500-HPA HEIGHT ANOMALIES, WHILE NEAR- TO BELOW-NORMAL
TEMPERATURES ARE FAVORED OVER MUCH OF THE WESTERN PORTIONS OF THE STATE,
CONSISTENT WITH THE GEFS AND ECMWF REFORECAST CONSOLIDATION TOOLS.
THE SOUTHWEST MONSOON IS FAVORED TO BE STRONGLY REINVIGORATED BY THE 6 TO 10
DAY PERIOD WITH STRONG ODDS TOWARDS ABOVE-NORMAL PRECIPITATION BEING FAVORED
ACROSS MUCH OF THE WESTERN CONUS. HURRICANE HILARY IS FORECASTED BY THE
NATIONAL HURRICANE CENTER (NHC) TO MOVE NORTH AND BRING HEAVY PRECIPITATION AND
ABUNDANT MOISTURE TO LARGE PORTIONS OF THE WESTERN CONUS LEADING TO
ABOVE-NORMAL PRECIPITATION BEING FAVORED ACROSS THE WEST. MEANWHILE, ACROSS
MUCH OF THE CENTRAL AND EASTERN CONUS, BENEATH STRONG POSITIVE 500-HPA HEIGHT
ANOMALIES, NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED. EXCEPTIONS TO THIS
ARE IN NEW ENGLAND, WHERE NEGATIVE 500-HPA HEIGHT ANOMALIES MAY BUILD IN AND
BRING ELEVATED CHANCES FOR PRECIPITATION, AND IN PARTS OF SOUTHWESTERN TEXAS,
WHERE EASTERLY WAVES MAY ALSO BRING INCREASED CHANCES FOR PRECIPITATION. IN
ALASKA, BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS SOUTHEASTERN PORTIONS OF
THE STATE WITH THE STRONGEST PROBABILITIES IN SOUTHEAST ALASKA BENEATH STRONG
POSITIVE 500-HPA HEIGHT ANOMALIES. ABOVE-NORMAL PRECIPITATION IS FAVORED OVER
THE REMAINDER OF THE STATE DUE TO TROUGHING OVER THE BERING SEA AND ASSOCIATED
ENHANCED SOUTHERLY FLOW.
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 NORMAL, 4 OUT OF 5, DUE TO A
PERSISTENT SYNOPTIC PATTERN AND GOOD AGREEMENT AMONG FORECAST MODELS, OFFSET BY
WEAKENING OF THE HIGH AMPLITUDE PATTERN LATE IN THE FORECAST PERIOD.
8-14 DAY OUTLOOK FOR AUG 25 - 31 2023
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY PERSISTENT
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS. THE
MEAN RIDGING OVER THE CENTRAL CONUS DURING THE 6 TO 10 DAY PERIOD IS FORECAST
TO WEAKEN FOR WEEK-2. MEANWHILE, TROUGHING IS FORECAST OVER THE NORTHEAST WITH
NEAR TO SLIGHTLY NEGATIVE 500-HPA HEIGHT ANOMALIES IN THIS REGION. ALONG THE
WEST COAST OF THE CONUS, NEAR TO BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST DUE
TO TROUGHING OVER THE REGION. POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST
OVER MUCH OF ALASKA, EXCEPT FOR THE ALEUTIANS WHERE BELOW-NORMAL 500-HPA
HEIGHTS ARE FAVORED.
RIDGING ACROSS MUCH OF THE CONUS AT THE BEGINNING OF THE PERIOD BRINGS
INCREASED CHANCES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE
COUNTRY, EXCEPT FOR THE NORTHEASTERN CONUS (DUE TO THE PREDICTED TROUGH OVER
THE REGION) AND PORTIONS OF THE SOUTHWEST (CONTINUED ENHANCED MOISTURE FROM AN
ADDITIONAL TROPICAL SYSTEM MAY HELP TO INCREASE CLOUD COVER AND REDUCE
TEMPERATURES) WHERE BELOW-NORMAL TEMPERATURES ARE FAVORED. THE STRONGEST
CHANCES, GREATER THAN 70%, FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS
PORTIONS OF THE LOWER-MISSISSIPPI VALLEY REGION AND EASTERN TEXAS, SUPPORTED BY
MOST OF THE DYNAMICAL TEMPERATURE FORECAST TOOLS. IN ALASKA, ABOVE-NORMAL
TEMPERATURES ARE FAVORED ACROSS EASTERN AND CENTRAL PORTIONS OF THE STATE
BENEATH POSITIVE MID-LEVEL HEIGHT ANOMALIES, WHILE BELOW-NORMAL TEMPERATURES
ARE FORECAST OVER PARTS OF THE WESTERN MAINLAND ALASKA.
ABOVE-NORMAL PRECIPITATION REMAINS FAVORED IN MUCH OF THE WEST, WHILE
BELOW-NORMAL PRECIPITATION IS FORECAST ACROSS PARTS OF THE SOUTHERN AND CENTRAL
PLAINS, THE MIDDLE AND LOWER MISSISSIPPI VALLEY, THE TENNESSEE VALLEY, AND THE
OHIO VALLEY DURING THE WEEK-2 PERIOD, CONSISTENT WITH ERF CONSOLIDATION
PRECIPITATION FORECAST TOOL. ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED IN THE
NORTHEAST AS BELOW-NORMAL 500-HPA HEIGHTS BEGIN TO DEVELOP. IN ALASKA,
BELOW-NORMAL PRECIPITATION IS FORECAST IN SOUTHEAST ALASKA, WHILE ABOVE-NORMAL
PRECIPITATION IS FAVORED OVER MOST OF THE REMAINDER OF THE STATE WITH THE
HEIGHT PATTERN NOT CHANGING MUCH FROM THE 6 TO 10 DAY PERIOD.
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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
FAIR AGREEMENT AMONG MODEL ENSEMBLES ON THE PERSISTENT SYNOPTIC PATTERN, OFFSET
BY WEAKER ANOMALIES REDUCING FORECAST CONFIDENCE.
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 21.
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:
19910819 - 19970812 - 20020811 - 19720805 - 19580823
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:
19910819 - 19970811 - 19870809 - 20020820 - 20020811
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 23 - 27 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF B A IDAHO A A NEVADA B A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A A W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A B 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 B N
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA A B
MARYLAND N N DELAWARE B N VIRGINIA A N
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN A A AK WESTERN N A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 25 - 31 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N A
SRN CALIF B A IDAHO N A NEVADA B A
W MONTANA N A E MONTANA N A WYOMING N A
UTAH N A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA N A S DAKOTA A A
NEBRASKA A A KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA N N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN N N
ILLINOIS A N MISSISSIPPI A N MICHIGAN B N
INDIANA A N OHIO N N KENTUCKY A N
TENNESSEE A N ALABAMA A N NEW YORK B N
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA A N
MARYLAND B N DELAWARE B 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 A AK INT BSN A A
AK S INT A A AK SO COAST A A 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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