080
FXUS06 KWBC 221902
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 22 2023
6-10 DAY OUTLOOK FOR AUG 28 - SEP 01, 2023
THE 6-10 DAY 500-HPA HEIGHT ANOMALIES AS DEPICTED BY TODAY’S WEIGHTED BLEND OF
THE ECMWF, GEFS, AND CANADIAN ENSEMBLE MEANS FEATURE POSITIVE HEIGHT ANOMALIES
FOR MUCH OF WESTERN NORTH AMERICA, WITH THE LARGEST DEPARTURES OVER SOUTHEAST
ALASKA, AS WELL AS ANOMALOUS RIDGING OVER THE NORTH ATLANTIC. BROAD WEAK
TROUGHING IS FAVORED OVER THE EASTERN CONTIGUOUS U.S. (CONUS), WITH SHORTWAVE
TROUGH SITUATED OFF THE COAST OF THE PACIFIC NORTHWEST. THIS PATTERN RESULTS IN
ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE WESTERN AND SOUTHERN CONUS AND
BELOW-NORMAL TEMPERATURES FOR THE NORTHEAST U.S. TROUGHING OFF THE WEST COAST
TILTS THE ODDS TOWARDS ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE WESTERN
CONUS, WHILE THE GREAT PLAINS, MISSISSIPPI AND OHIO VALLEYS ARE FAVORED FOR
BELOW-NORMAL PRECIPITATION DOWNSTREAM OF THE RIDGE AXIS OVER WESTERN NORTH
AMERICA.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN AND SOUTHERN
CONUS WITH CONTINUED RIDGING OVER THE WEST. PROBABILITIES ARE GREATEST FOR
PORTIONS OF TEXAS AND THE GULF COAST, AS WELL AS MUCH OF THE INTERMOUNTAIN WEST
(AT LEAST 50%, OVER 70% FOR EASTERN MONTANA AND THE WESTERN DAKOTAS).
MEANWHILE, NEGATIVE HEIGHT ANOMALIES OVER MUCH OF THE EASTERN U.S. RESULTS IN
ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES, WITH HIGHEST PROBABILITIES
CENTERED OVER THE CENTRAL APPALACHIANS (OVER 50% CHANCE). FOR ALASKA, STRONG
POSITIVE HEIGHT ANOMALIES OVER WESTERN CANADA FAVOR ABOVE-NORMAL TEMPERATURES
FOR SOUTHEASTERN ALASKA AND MUCH OF THE CENTRAL AND EASTERN MAINLAND, WHILE
TROUGHING OVER THE BERING SEA RESULT IN A TILT TOWARDS BELOW-NORMAL
TEMPERATURES ALONG THE WESTERN COAST OF ALASKA.
THE DEPICTED SHORTWAVE TROUGH OFF THE PACIFIC NORTHWEST COAST AND CONTINUED
AVAILABLE TROPICAL MOISTURE FROM THE GULF OF CALIFORNIA TILTS ODDS TOWARDS
ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE WESTERN CONUS, ESPECIALLY FOR
WASHINGTON STATE AND NORTHERN OREGON, EXCEPT FOR CENTRAL CALIFORNIA AND
ADJACENT NEVADA WHERE NEAR-NORMAL PRECIPITATION IS FAVORED. DOWNSTREAM OF THE
RIDGE AXIS, A BROAD AREA OF BELOW-NORMAL PRECIPITATION IS MOST LIKELY FOR A
SWATH FROM THE TEXAS-OKLAHOMA BORDER NORTH THROUGH MUCH OF THE GREAT PLAINS,
THE GREAT LAKES REGION, AS WELL AS THE MIDDLE AND UPPER MISSISSIPPI AND OHIO
VALLEYS, WITH HIGHEST PROBABILITIES OVER THE MIDWEST STATES (>50%). A STALLED
FRONTAL BOUNDARY AND AVAILABLE TROPICAL MOISTURE RESULTS IN A TILT TOWARDS
ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE EAST COAST EAST OF THE APPALACHIANS
FROM THE EASTERN GULF COAST ALL THE WAY UP TO MAINE, WITH HIGHER PROBABILITIES
FOR PORTIONS OF FLORIDA, GEORGIA, AND SOUTH CAROLINA. TROUGHING OVER THE BERING
SEA FAVORS ABOVE-NORMAL PRECIPITATION FOR THE ALASKAN MAINLAND, WHILE RIDGING
OVER WESTERN CANADA MAKES NEAR-NORMAL PRECIPITATION MOST LIKELY FOR
SOUTHEASTERN ALASKA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 34% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 33% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, WITH
GOOD AGREEMENT AMONG FORECAST TOOLS, OFFSET BY NOTABLE DIFFERENCES IN 500-HPA
ANOMALY SOLUTIONS AMONG MODEL ENSEMBLES.
8-14 DAY OUTLOOK FOR AUG 30 - SEP 05, 2023
MODEL SOLUTIONS FOR 500-HPA HEIGHT ANOMALIES AT THE 8-14 DAY TIME PERIOD ARE
SIMILAR TO THE EARLIER FORECAST PERIOD, ALTHOUGH THE TROUGHING FEATURES OFF
BOTH COASTS OF THE CONUS ARE SUBSTANTIALLY WEAKENED IN THE LATER PERIOD. WITH
LITTLE CHANGE IN THE SYNOPTIC PATTERN, THE TEMPERATURE AND PRECIPITATION
OUTLOOKS BEAR A CLOSE RESEMBLANCE TO THE 6-10 DAY PERIOD.
ABOVE-NORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR MUCH OF THE CONUS. THE
HIGHEST PROBABILITIES ARE CENTERED OVER CENTRAL TEXAS (>60%), AND THE CONSENSUS
AMONG THE FORECAST TOOLS ONCE AGAIN FAVORS SLIGHTLY LOWER PROBABILITIES FOR
PORTIONS OF CALIFORNIA AND OREGON. AS TROUGHING WEAKENS OVER THE EAST COAST
TEMPERATURES ARE FAVORED TO MODERATE FOR THE NORTHEAST CONUS, RESULTING IN
NEAR-NORMAL TEMPERATURES. CONTINUED RIDGING OVER WESTERN CANADA RESULTS IN
ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR MOST OF ALASKA, WITH
THE EXCEPTION OF THE WESTERNMOST COAST WHERE NEAR-NORMAL TEMPERATURES ARE MOST
LIKELY.
FORECAST TOOLS AND MODEL GUIDANCE CONTINUE TO INDICATE A TILT TOWARDS
ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE WESTERN CONUS WITH HIGHER ODDS
(>40%) CENTERED OVER WASHINGTON AND PORTIONS OF THE DESERT SOUTHWEST.
BELOW-NORMAL PRECIPITATION IS WEAKLY FAVORED FOR MOST OF THE CENTRAL CONUS AND
THE GREAT LAKES, BEING DOWNSTREAM OF THE RIDGE OVER THE WESTERN CONUS.
INCREASED TROPICAL ACTIVITY IN THE GULF OF MEXICO IS FAVORED TO CONTINUE,
TILTING THE ODDS TOWARDS ABOVE-NORMAL PRECIPITATION FOR THE SOUTHEAST U.S.
PERSISTENT TROUGHING OVER THE BERING SEA FAVORS ABOVE-NORMAL PRECIPITATION FOR
MOST OF ALASKA, WITH SLIGHTLY HIGHER PROBABILITIES OVER THE SOUTHEASTERN
MAINLAND.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 34% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 33% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 33% 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: DANIEL BARANDIARAN
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:
19800825 - 19850901 - 19900826 - 20070804 - 19900902
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:
19850830 - 19850904 - 19900903 - 19590821 - 20000827
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 28 - SEP 01, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A N WYOMING A N
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A B IOWA A B MISSOURI B B
ARKANSAS B B LOUISIANA A N WISCONSIN A B
ILLINOIS B B MISSISSIPPI A A MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B N ALABAMA A A NEW YORK B B
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN B A RHODE IS B A
PENN B B NEW JERSEY B A W VIRGINIA B N
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN N A AK WESTERN B A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 30 - SEP 05, 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 N 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 A N WISCONSIN A B
ILLINOIS A B MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO N B KENTUCKY N B
TENNESSEE N N ALABAMA A A NEW YORK N N
VERMONT N N NEW HAMP N N MAINE N N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA N A GEORGIA A A
FL PNHDL A A FL PENIN A A 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 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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