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FXUS06 KWBC 151902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE AUGUST 15 2023
6-10 DAY OUTLOOK FOR AUG 21 - 25 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 STRONG 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. 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 PARTS 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 A TROPICAL SYSTEM) WHERE BELOW-NORMAL
TEMPERATURE ARE EXPECTED. THE STRONGEST CHANCES FOR ABOVE-NORMAL TEMPERATURES
ARE FOCUSED ACROSS PARTS OF EASTERN TEXAS, LOWER MISSISSIPPI AND TENNESSEE
VALLEYS, AND THE SOUTHEAST, CONSISTENT WITH THE GEFS AND ECMWF REFORECAST
CONSOLIDATION TOOLS. IN ALASKA, CHANCES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES
ARE ALSO INCREASED ACROSS MUCH OF THE STATE BENEATH POSITIVE 500-HPA HEIGHT
ANOMALIES.
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. A TROPICAL SYSTEM IS FAVORED TO DEVELOP AND
WILL ENHANCE MIDDLE AND LOWER LEVEL MOISTURE ACROSS MUCH OF THE WEST HELPING TO
INITIATE PRECIPITATION. MEANWHILE, ACROSS MUCH OF THE CENTRAL AND EASTERN
CONUS, BENEATH STRONG POSITIVE 500-HPA HEIGHT ANOMALIES, BELOW-NORMAL
PRECIPITATION IS FAVORED. EXCEPTIONS TO THIS ARE IN NEW ENGLAND, WHERE NEGATIVE
500-HPA HEIGHTS MAY BUILD IN AND BRING ELEVATED CHANCES FOR PRECIPITATION, AND
IN PARTS OF SOUTHERN 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. IN THE
WESTERN AND NORTHERN MAINLAND, ABOVE-NORMAL PRECIPITATION IS FAVORED 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 23 - 29 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 EASTERN CONUS IS FORECAST TO WEAKEN, AS POSITIVE 500-HPA
HEIGHT ANOMALIES DECREASE AND RETRACT ACROSS THE NORTH 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 ALASKA, EXCEPT FOR THE
WESTERN ALEUTIANS WHERE BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST.
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 NORTHEAST WHERE BELOW-NORMAL TEMPERATURES ARE EXPECTED
DUE TO THE PREDICTED TROUGH OVER THE REGION.THE STRONGEST CHANCES, GREATER THAN
70%, FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS PORTIONS OF THE
LOWER-MISSISSIPPI VALLEY REGION, SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE
FORECAST TOOLS. IN THE WEST, CONTINUED ENHANCED MOISTURE FROM AN ADDITIONAL
TROPICAL SYSTEM MAY HELP TO INCREASE CLOUD COVER AND REDUCE TEMPERATURES.
THEREFORE, ONLY A SLIGHT TILT TOWARDS NEAR- TO ABOVE-NORMAL TEMPERATURES IS
FORECAST ACROSS THE INTERIOR WEST. IN ALASKA, NEAR- TO ABOVE-NORMAL
TEMPERATURES REMAIN FAVORED ACROSS THE STATE BENEATH POSITIVE MID-LEVEL HEIGHT
ANOMALIES.
ABOVE-NORMAL PRECIPITATION REMAINS FAVORED IN MUCH OF THE WEST, CONSISTENT WITH
ERF CONSOLIDATION PRECIPITATION FORECAST TOOL. BELOW-NORMAL PRECIPITATION IS
FAVORED ACROSS TENNESSEE, OHIO, AND MISSISSIPPI RIVER VALLEYS DURING THE WEEK-2
PERIOD. AS THE 500-HPA HEIGHT ANOMALIES WEAKEN BY THE MIDDLE AND END OF THE
PERIOD AND UNCERTAINTY INCREASES, THE PROBABILITIES ARE REDUCED FROM THE 6 TO
10 DAY PERIOD BUT REMAIN IN MUCH THE SAME VICINITY. ABOVE-NORMAL PRECIPITATION
IS FAVORED IN THE NORTHEAST AS BELOW-NORMAL 500-HPA HEIGHTS BEGIN TO DEVELOP.
MEANWHILE, A SLIGHT TILT TOWARDS ABOVE-NORMAL PRECIPITATION IS FAVORED IN
SOUTHERN TEXAS WHERE SOME EASTERLY WAVES MAY HELP TO INCREASE PRECIPITATION. IN
ALASKA, NEAR- TO BELOW-NORMAL PRECIPITATION IS FORECAST IN SOUTHEAST ALASKA,
WHILE ABOVE-NORMAL PRECIPITATION IS FAVORED OVER 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
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:
19920803 - 19610828 - 19910818 - 19560822 - 19860826
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:
20020725 - 19640821 - 19920817 - 20090725 - 19580822
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 21 - 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 B A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH B A ARIZONA B A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A A W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK A N
VERMONT B N NEW HAMP B N MAINE B N
MASS N N CONN A N RHODE IS N N
PENN A N NEW JERSEY A N W VIRGINIA A B
MARYLAND A N DELAWARE A N VIRGINIA A B
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 N N AK WESTERN N A AK INT BSN A A
AK S INT A A AK SO COAST A N AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 23 - 29 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 A N DAKOTA N A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN N N
INDIANA A N OHIO A 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 N N NEW JERSEY N N W VIRGINIA A N
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 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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