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FXUS06 KWBC 161908
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 16 2024
6-10 DAY OUTLOOK FOR AUG 22 - 26 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. THIS FEATURE HAS BEEN WEAKENING IN MODEL DEPICTIONS AS
THE WEEK HAS PROGRESSED AND ITS PEAK AMPLITUDE IS NOW AT THE OUTSET OF THE 6-10
DAY PERIOD. 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 EASTERN CONUS. TODAY’S MODEL
SOLUTIONS DEPICT A SLIGHTLY WEAKER TROUGH OVER THE GREAT LAKES, WEAKENING
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES RELATIVE TO YESTERDAY’S OUTLOOK.
THE REST OF THE CONUS IS FAVORED TO HAVE ABOVE-NORMAL TEMPERATURES, ESPECIALLY
THE GREAT PLAINS AND SOUTHERN ROCKIES WITH PROBABILITIES EXCEEDING 70%. WITH
TROUGHING OVER THE BERING SEA, BELOW-NORMAL TEMPERATURES ARE FAVORED FOR THE
ALASKAN MAINLAND, ESPECIALLY THE WESTERN COAST WHERE PROBABILITIES EXCEED 70%,
WHILE NEAR-NORMAL TEMPERATURES ARE SLIGHTLY FAVORED ALONG THE NORTHERN COAST
AND 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. BELOW-NORMAL PRECIPITATION IS FAVORED FOR A SWATH FROM WESTERN TEXAS
NORTHEASTWARD TO NEW ENGLAND, WITH SLIGHTLY HIGHER PROBABILITIES FOR PORTIONS
OF THE MIDDLE MISSISSIPPI AND OHIO VALLEYS AND THE SOUTHERN GREAT LAKES.
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 FAVOR NEAR-NORMAL PRECIPITATION FOR SOUTHEASTERN ALASKA AND 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: ABOVE AVERAGE, 4 OUT OF 5, WITH
GOOD RUN-TO-RUN CONTINUITY AMONG FORECAST MODELS AND A PERSISTENT SYNOPTIC
PATTERN, OFFSET BY A WEAKENING OF THE OMEGA PATTERN LATE IN THE FORECAST PERIOD.
8-14 DAY OUTLOOK FOR AUG 24 - 30 2024
MODEL ENSEMBLES DEPICT A CONTINUED WEAKENING OF THE SYNOPTIC PATTERN FROM THE
6-10 DAY PERIOD. THE MOST NOTABLE DIFFERENCE IS A WEAKENING OF THE TROUGH OVER
THE EAST COAST LEADING TO NEARLY ZONAL FLOW OVER MUCH OF THE CONUS, AND SMALLER
HEIGHT ANOMALIES OVERALL. ALSO NOTEWORTHY IS A SHARP INCREASE IN THE AMPLITUDE
OF THE TROUGH OVER THE BERING SEA, MAINTAINING ONSHORE FLOW ALOFT AND AT THE
SURFACE FOR ALASKA.
WITH THE OMEGA PATTERN FAVORED TO BREAK DOWN AND ZONAL FLOW TO BECOME
ESTABLISHED THE ENTIRE CONUS IS FAVORED FOR ABOVE-NORMAL TEMPERATURES DURING
THE WEEK-2 PERIOD. ODDS GENERALLY EXCEED 40% AND ARE ABOVE 50% FOR MUCH OF THE
SOUTHERN AND CENTRAL CONUS, AS WELL AS FOR THE NORTHERN PLAINS AND NEW ENGLAND.
INCREASED TROUGHING OVER THE BERING SEA MAINTAINS CHANCES FOR BELOW-NORMAL
TEMPERATURES FOR ALASKA, WITH THE WEEK-2 OUTLOOK LARGELY UNCHANGED FROM THE
6-10 DAY PERIOD. MODEL GUIDANCE FOR HAWAII CONTINUES TO FAVOR ABOVE-NORMAL
TEMPERATURES FOR THE STATE, WITH ODDS INCREASING FROM SOUTHEAST TO NORTHWEST.
PERSISTENT TROUGHING OVER THE WEST COAST FAVORS ABOVE-NORMAL PRECIPITATION FOR
THE NORTHWESTERN CONUS, AND MODELS GENERALLY DEPICTED CONTINUED MONSOON
ACTIVITY, TILTING ODDS TOWARDS ABOVE-NORMAL PRECIPITATION FOR PORTIONS OF THE
DESERT SOUTHWEST AND GREAT BASIN. BROAD POSITIVE HEIGHT ANOMALIES OVER CENTRAL
NORTH AMERICA RESULTS IN ELEVATED CHANCES FOR BELOW-NORMAL PRECIPITATION FOR
MUCH OF THE CENTRAL CONUS, PARTICULARLY THE CENTRAL PLAINS AND MIDDLE
MISSISSIPPI VALLEY. MUCH OF ALASKA CONTINUES TO TILT TOWARD ABOVE-NORMAL
PRECIPITATION, BUT CONTINUED POSITIVE HEIGHT ANOMALIES OVER THE NORTH PACIFIC
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
CHANCES FOR ABOVE-NORMAL PRECIPITATION FOR HAWAII, EXCEEDING 40% 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 WEAK ANOMALIES AND PROBABILITIES FROM
MODEL GUIDANCE.
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 - 19970828 - 19540804 - 19830830
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:
20050825 - 19960730 - 19970827 - 19820812 - 19800818
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 22 - 26 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON B A NRN CALIF B A
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA A A E MONTANA A N WYOMING A N
UTAH A A 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 N S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI N B
ARKANSAS A B LOUISIANA A N WISCONSIN A B
ILLINOIS B B MISSISSIPPI A N MICHIGAN A B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA A N NEW YORK N B
VERMONT N B NEW HAMP N B MAINE A N
MASS N B CONN B B RHODE IS B B
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B N S CAROLINA B N GEORGIA B A
FL PNHDL A A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B N AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 24 - 30 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
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 N S TEXAS A N W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A A WISCONSIN A B
ILLINOIS A B MISSISSIPPI A N MICHIGAN A B
INDIANA A B OHIO A N KENTUCKY A B
TENNESSEE A N ALABAMA A N 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 N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B A 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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