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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 THU AUGUST 15 2024
6-10 DAY OUTLOOK FOR AUG 21 - 25 2024
TODAY’S MODEL SOLUTIONS FROM THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS FOR
500-HPA HEIGHT ANOMALIES ARE ONCE AGAIN IN GOOD AGREEMENT AND ALL DEPICT AN
OMEGA PATTERN OVER NORTH AMERICA, WITH TROUGHING AND NEGATIVE HEIGHT ANOMALIES
OVER THE NORTHWEST AND NORTHEASTERN CONTIGUOUS U.S. (CONUS) AND AN EXPANSIVE
RIDGE OVER THE CENTER OF THE CONTINENT AND STRONG POSITIVE HEIGHT ANOMALIES
OVER NORTHERN CANADA. AN AMPLIFIED TROUGH OVER THE BERING SEA AND POSITIVE
HEIGHT ANOMALIES OVER THE NORTH PACIFIC RESULT IN A TIGHT PRESSURE GRADIENT AND
MORE ACTIVE WEATHER FOR THE ALASKA REGION.
THE OMEGA PATTERN DESCRIBED ABOVE BRINGS AN INCREASED CHANCE FOR BELOW-NORMAL
TEMPERATURES TO PORTIONS OF THE WEST COAST AND THE GREAT LAKES. TODAY’S MODEL
SOLUTIONS DEPICT A SLIGHTLY DEEPER TROUGH OVER THE GREAT LAKES, ENHANCING
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS MUCH OF THE MIDWEST AND
NORTHEAST. THE REST OF THE CONUS IS FAVORED TO HAVE ABOVE-NORMAL TEMPERATURES,
ESPECIALLY THE SOUTHERN TIER WITH PROBABILITIES EXCEEDING 80% FOR PORTIONS OF
WEST TEXAS AND THE DESERT SOUTHWEST. WITH TROUGHING OVER THE BERING SEA, MUCH
OF THE ALASKAN MAINLAND LEANS TOWARDS BELOW-NORMAL TEMPERATURES, WHILE
ABOVE-NORMAL TEMPERATURES ARE SLIGHTLY FAVORED ALONG THE NORTHERN COAST AND
LIKELY FOR SOUTHEAST ALASKA. ABOVE-NORMAL TEMPERATURES ARE THE MOST LIKELY FOR
MOST OF HAWAII, WITH PROBABILITIES INCREASING FROM SOUTHEAST TO NORTHWEST,
CONSISTENT WITH THE HAWAII CON TOOL. WITH THE INCREASING POTENTIAL FOR TROPICAL
CONVECTION IN THE HAWAII REGION LATE IN THE PERIOD, NEAR-NORMAL TEMPERATURES
ARE MOST LIKELY FOR THE BIG ISLAND.
TROUGHING OVER BOTH COASTS RESULTS IN A TILT TOWARDS ABOVE-NORMAL PRECIPITATION
FOR THE NORTHWESTERN CONUS AND FOR COASTAL PORTIONS OF THE MID-ATLANTIC AND
SOUTHEAST U.S., CONSISTENT WITH MODEL GUIDANCE. MODELS ALSO DEPICT INCREASED
MONSOON ACTIVITY DURING THE 6-10 DAY PERIOD, INCREASING THE PROBABILITY OF
ABOVE-NORMAL PRECIPITATION FOR PORTIONS OF THE GREAT BASIN AND NORTHERN ROCKIES
AS WELL. ONSHORE FLOW BOTH AT THE SURFACE AND ALOFT FAVORS ABOVE-NORMAL
PRECIPITATION FOR MOST OF THE ALASKAN MAINLAND, WHILE POSITIVE HEIGHT ANOMALIES
OVER THE NORTH PACIFIC RESULT IN A TILT TOWARDS BELOW-NORMAL PRECIPITATION FOR
SOUTHEASTERN ALASKA AND NEAR-NORMAL PRECIPITATION FOR THE SOUTHERN COAST.
INCREASED TROPICAL CONVECTION IN THE HAWAII REGION TILTS THE ISLANDS TOWARDS
ABOVE-NORMAL PRECIPITATION, WITH HIGHER PROBABILITIES (>40%) FOR THE BIG ISLAND.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 34% 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: VERY HIGH, 5 OUT OF 5, WITH GOOD
RUN-TO-RUN CONTINUITY AMONG FORECAST MODELS AND A PERSISTENT SYNOPTIC PATTERN.
8-14 DAY OUTLOOK FOR AUG 23 - 29 2024
MODEL ENSEMBLES DEPICT A WEAKENING OF THE SYNOPTIC PATTERN FROM THE 6-10 DAY
PERIOD. THE MOST NOTABLE DIFFERENCE IS A WEAKENING OF THE TROUGH OVER THE
BERING SEA, RELAXING THE PRESSURE GRADIENT OVER ALASKA. ENSEMBLE SOLUTIONS ALSO
TEND TO FAVOR A WEAKER TROUGH OVER THE EAST COAST, AND SMALLER HEIGHT ANOMALIES
OVERALL. ALTHOUGH WEAKER, THE GENERAL PERSISTENCE OF SYNOPTIC FEATURES RESULTS
IN VERY SIMILAR OUTLOOKS FOR THE 6-10 AND 8-14 DAY PERIODS.
THE OMEGA PATTERN FROM THE 6-10 DAY PERIOD REMAINS, ALTHOUGH DEPICTED AS WEAKER
IN WEEK-2, THEREFORE THE WEEK-2 TEMPERATURE OUTLOOK IS LITTLE-CHANGED FROM THE
EARLIER PERIOD. CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER THE CENTRAL AND
SOUTHERN CONUS ARE SLIGHTLY REDUCED BUT STILL EXCEED 70% FOR PORTIONS OF WEST
TEXAS AND THE DESERT SOUTHWEST. A WEAKENING TROUGH OVER THE WEST COAST RESULTS
IN NEAR-NORMAL TEMPERATURES LIKELY FOR PORTIONS OF THE NORTHWESTERN CONUS.
NORTHERN NEW ENGLAND IS FAVORED FOR ABOVE-NORMAL TEMPERATURES, CONSISTENT WITH
MOST FORECAST TOOLS. THE TROUGHS OVER BOTH COASTS ARE FAVORED TO WEAKEN BUT
STILL HAVE A MODERATING EFFECT ALTHOUGH THE LARGEST COOLING EFFECT IS NOW IN
WEEK-1, SO NEAR-NORMAL TEMPERATURES ARE MOST LIKELY FOR THE GREAT LAKES AND
OHIO VALLEY AS WELL AS NORTHERN PORTIONS OF THE WEST COAST. WITH WEAKER BUT
PERSISTENT TROUGHING OVER THE BERING SEA, MUCH OF THE ALASKAN MAINLAND LEANS
TOWARDS BELOW-NORMAL TEMPERATURES, WHILE NEAR-NORMAL TEMPERATURES ARE MOST
LIKELY ACROSS SOUTHEASTERN ALASKA. ABOVE-NORMAL TEMPERATURES ARE THE MOST
LIKELY FOR MUCH OF HAWAII, WITH PROBABILITIES INCREASING FROM SOUTHEAST TO
NORTHWEST, CONSISTENT WITH THE HAWAII CON TOOL. NEAR-NORMAL TEMPERATURES
CONTINUE TO BE FAVORED FOR THE BIG ISLAND.
THE WEEK-2 PRECIPITATION OUTLOOK IS ALSO QUITE SIMILAR TO THE 6-10 DAY PERIOD.
PORTIONS OF THE NORTHWESTERN CONUS, COASTAL MID-ATLANTIC, AND SOUTHEAST U.S.
TILT TOWARDS ABOVE-NORMAL PRECIPITATION UNDER THE INFLUENCE OF THE TROUGH
PORTIONS OF THE OMEGA PATTERN. CONTINUED MONSOON ACTIVITY FAVORS ABOVE-NORMAL
PRECIPITATION FOR PORTIONS OF THE GREAT BASIN. BROAD POSITIVE HEIGHT ANOMALIES
OVER CENTRAL NORTH AMERICA RESULTS IN ELEVATED CHANCES FOR BELOW-NORMAL
PRECIPITATION FOR THE CENTRAL CONUS. MUCH OF ALASKA CONTINUES TO TILT TOWARD
ABOVE-NORMAL PRECIPITATION, BUT THE WEAKENING NEGATIVE HEIGHT ANOMALIES OVER
THE BERING SEA FAVOR NEAR-NORMAL PRECIPITATION FOR THE SOUTHERN ALASKAN COAST
AND THE PANHANDLE. AN INCREASED POTENTIAL FOR CONVECTION AND THE CHANCE FOR A
TROPICAL CYCLONE FORMING IN THE CENTRAL PACIFIC DURING THE WEEK-2 PERIOD
RESULTS IN ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION FOR HAWAII WITH ODDS
INCREASING FROM NORTHWEST TO SOUTHEAST, EXCEEDING 50% FOR THE BIG ISLAND.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 34% 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: ABOVE AVERAGE, 4 OUT OF 5, WITH A
PERSISTENT SYNOPTIC PATTERN, OFFSET BY DIFFERENCES BETWEEN MODELS REGARDING
STRENGTH AND POSITION OF VARIOUS SYNOPTIC FEATURES.
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 19.
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:
20050824 - 19960730 - 19540804 - 19850820 - 19980804
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:
20050824 - 19960731 - 19540803 - 19680826 - 19850820
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 21 - 25 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B A NRN CALIF B N
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A N
NEW MEXICO A B N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A N IOWA B N MISSOURI B B
ARKANSAS A B LOUISIANA A N WISCONSIN B B
ILLINOIS B B MISSISSIPPI A B MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B 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 B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL A N FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B N AK SO COAST N N AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 23 - 29 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A N OHIO N N KENTUCKY N N
TENNESSEE A N ALABAMA A N NEW YORK N N
VERMONT A N NEW HAMP A N MAINE A N
MASS A 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 A S CAROLINA A A GEORGIA A N
FL PNHDL A N FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL N N
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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