036
FXUS06 KWBC 261902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON AUGUST 26 2024
6-10 DAY OUTLOOK FOR SEP 01 - 05 2024
THERE IS GOOD AGREEMENT AMONG THE DYNAMICAL TOOLS FOR THE EVOLUTION OF THE
500-HPA HEIGHT PATTERN ACROSS NORTH AMERICA TODAY. AN AREA OF NEGATIVE 500-HPA
HEIGHT ANOMALIES AND MID-LEVEL TROUGHING IS FORECAST FOR MUCH OF ALASKA.
MID-LEVEL RIDGING IS FORECAST FOR WESTERN CANADA AND THE CONTIGUOUS U.S.
(CONUS) WITH THE STRONGEST POSITIVE 500-HPA HEIGHT ANOMALIES OVER THE CANADIAN
PRAIRIES. A WEAK SHORT-WAVE TROUGH IS FORECAST TO UNDERCUT THE MID-LEVEL
RIDGING ALONG THE COAST OF CALIFORNIA. HOWEVER, THE DOMINANT RIDGE MAY WASH THE
TROUGH OUT AS IT TRIES TO MOVE INLAND. MEANWHILE, MID-LEVEL TROUGHING IS
FORECAST ACROSS THE EASTERN CONUS, THE STRONGEST 500-HPA HEIGHT ANOMALIES ARE
FORECAST OVER QUEBEC WITH NEAR-NORMAL HEIGHTS FAVORED OVER MUCH OF THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS.
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS MOST OF THE WESTERN CONUS BENEATH
MID-LEVEL RIDGING. THERE IS A SLIGHT WEAKNESS IN THE PROBABILITIES ACROSS
PORTIONS OF CALIFORNIA WHERE A SHORTWAVE TROUGH WILL BE PROGRESSING INTO THE
STATE. ABOVE-NORMAL TEMPERATURES ARE AGAIN FAVORED FOR PORTIONS OF THE
SOUTHEASTERN CONUS NEAR THE GULF OF MEXICO, WHERE NORMALIZED 500-HPA HEIGHT
ANOMALIES ARE 1 TO 2 STANDARD DEVIATIONS ABOVE-NORMAL BY THE END OF THE 6-10
DAY PERIOD. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR THE GREAT LAKES AND
NORTHEAST WHERE MID-LEVEL TROUGHING IS STRONGEST. BELOW-NORMAL TO NEAR-NORMAL
TEMPERATURES ARE FAVORED TO LINGER ACROSS PORTIONS OF THE MISSISSIPPI VALLEY
AND PLAINS AHEAD OF THE MID-LEVEL RIDGE THAT WILL BE BUILDING INTO THE REGION
BY THE END OF THE PERIOD. IN ALASKA, BELOW-NORMAL TEMPERATURES ARE FAVORED IN
THE ALEUTIANS AND SOUTHWESTERN MAINLAND, WHILE ABOVE-NORMAL TEMPERATURES ARE
FAVORED ACROSS THE EASTERN INTERIOR AND SOUTHEAST ALASKA. FOR HAWAII,
ABOVE-NORMAL TEMPERATURES ARE STRONGLY FAVORED ACROSS MUCH OF THE STATE.
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE SOUTHERN TIER OF THE
CONUS DURING THE 6-10 DAY PERIOD. THE STRONGEST CHANCES FOR ABOVE-NORMAL
PRECIPITATION ARE ACROSS PORTIONS OF WESTERN TEXAS. CLIMATOLOGIES ARE
RELATIVELY LOW ACROSS THIS REGION BUT MANY OF THE RAW TOOLS PREDICT A HALF INCH
TO AN INCH OF PRECIPITATION ACROSS THE REGION AT THIS TIME. FURTHER EAST, THE
MID-LEVEL TROUGH PROGRESSING EASTWARD MAY BRING ONE OR MORE FRONTS TO THE
REGION INCREASING ABOVE-NORMAL PRECIPITATION CHANCES FOR THE SOUTHEAST. BEHIND
THIS FRONTAL SYSTEM ACROSS THE GREAT LAKES AND UPPER MISSISSIPPI VALLEY
BELOW-NORMAL PRECIPITATION IS FAVORED. BELOW-NORMAL PRECIPITATION IS AGAIN
FAVORED FOR PORTIONS OF THE SOUTHWESTERN CONUS, WHERE MONSOON MOISTURE IS
FORECAST TO BE LIMITED. A SMALL AREA OF ENHANCED CHANCES FOR ABOVE-NORMAL
PRECIPITATION IS FORECAST FOR PORTIONS OF NORTHERN CALIFORNIA AND OREGON WHERE
A SHORTWAVE TROUGH MAY INDUCE SOME PRECIPITATION. CLIMATOLOGIES REMAIN VERY LOW
ACROSS THESE REGIONS AND VERY LITTLE PRECIPITATION WOULD BRING ABOVE-NORMAL
PRECIPITATION FOR THE PERIOD. IN ALASKA, ABOVE-NORMAL PRECIPITATION IS FAVORED
ACROSS SOUTHEAST AND THE SOUTHERN MAINLAND WHILE BELOW-NORMAL PRECIPITATION IS
LIKELY OVER PARTS OF THE NORTHWESTERN MAINLAND. NEAR- TO BELOW-NORMAL
PRECIPITATION IS GENERALLY FAVORED IN HAWAII DURING THE 6-10 DAY PERIOD.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 20%
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. GOOD
AGREEMENT AMONG THE DYNAMICAL TOOLS IS OFFSET BY DIFFERENCES IN TEMPERATURE AND
PRECIPITATION PATTERNS ACROSS THE EASTERN CONUS.
8-14 DAY OUTLOOK FOR SEP 03 - 09 2024
THE WEEK-2 HEIGHT FORECAST IS RELATIVELY UNCHANGED RELATIVE TO THE 6-10 DAY
PERIOD; ALTHOUGH THE PATTERN HAS PROGRESSED SLIGHTLY EASTWARD. MUCH OF ALASKA
REMAINS BENEATH MID-LEVEL TROUGHING WITH THE TROUGH AXIS PROGRESSING EASTWARD
BRINGING REDUCED HEIGHTS TO PORTIONS OF SOUTHEAST ALASKA, RELATIVE TO THE PRIOR
PERIOD. THE MID-LEVEL RIDGE ACROSS WESTERN NORTH AMERICA IN THE 6-10 DAY PERIOD
HAS ALSO PROGRESSED WITH STRONGEST ANOMALIES NOW FOCUSED ACROSS PORTIONS OF
MANITOBA AND WESTERN ONTARIO AND THE CORRESPONDING RIDGE AXIS PROGRESSING
EASTWARD ACROSS THE CONUS. WEAK MID-LEVEL TROUGHING REMAINS ACROSS THE EASTERN
CONUS.
ABOVE-NORMAL TEMPERATURES REMAIN STRONGLY FAVORED FOR MUCH OF THE WESTERN CONUS
DURING WEEK-2 BENEATH MID-LEVEL RIDGING. A SECOND AREA OF ABOVE-NORMAL
TEMPERATURES IS FAVORED ACROSS THE GULF COAST AND FLORIDA WHERE SLIGHTLY
POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST. BELOW-NORMAL TEMPERATURES ARE
FAVORED FOR PORTIONS OF THE NORTHEAST, MID-ATLANTIC, AND SOUTHEAST BENEATH
MID-LEVEL TROUGHING. A BROADER AREA OF NEAR-NORMAL TEMPERATURES ARE FAVORED
ACROSS THE GREAT LAKES AND MISSISSIPPI VALLEY SOUTHERN PLAINS WHERE MANY OF THE
TOOLS ARE MIXED. THE PATTERN IS RELATIVELY PROGRESSIVE ACROSS THIS REGION WHICH
FURTHER INCREASES UNCERTAINTY. IN ALASKA, ABOVE-NORMAL TEMPERATURES ARE FAVORED
FOR THE EASTERN MAINLAND AND SOUTHEAST ALASKA AHEAD OF A MID-LEVEL TROUGH AXIS.
MEANWHILE, BELOW-NORMAL TEMPERATURES ARE FAVORED FOR THE WESTERN COASTAL
REGIONS AND THE ALEUTIAN ISLANDS. ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR
HAWAII CONSISTENT WITH THE CONSOLIDATION TOOL.
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR THE SOUTHEASTERN CONUS AND GULF COAST
REGIONS AHEAD AND ALONG A COLD FRONT PROGRESSING THROUGH THE REGION EARLY IN
THE WEEK-2 PERIOD. BEHIND THIS FRONTAL SYSTEM AND A MEAN MID-LEVEL TROUGH AXIS,
BELOW-NORMALPRECIPITATION IS FAVORED IN THE NORTHEAST, GREAT LAKES AND
UPPER AND MIDDLE MISSISSIPPI VALLEY. NEAR-NORMAL PRECIPITATION IS FAVORED
ACROSS MUCH OF THE PLAINS. THE GEFS BASED TOOLS GENERALLY FAVOR A WETTER
SOLUTION ACROSS THIS REGION, WHILE THE ECENS BASED TOOLS ARE FAVORING A DRIER
SOLUTION ACROSS THESE AREAS. DUE TO THESE DIFFERENCES NEAR-NORMAL PRECIPITATION
IS FAVORED. FURTHER WEST, ACROSS DESERT SOUTHWEST, GREAT BASIN, AND NORTHERN
ROCKIES, DRIER CONDITIONS ARE FAVORED BY BOTH THE GEFS AND ECENS, BENEATH THE
MID-LEVEL RIDGE. HOWEVER, THE PACIFIC NORTHWEST IS FAVORED TO SEE ABOVE-NORMAL
PRECIPITATION WITH INCREASED ONSHORE FLOW INTO THESE AREAS. IN ALASKA,
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS THE SOUTHERN MAINLAND AND
SOUTHEAST ALASKA WITH NEAR TO BELOW-NORMAL FAVORED OVER THE REST OF THE STATE.
NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 20%
OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, FAIR
AGREEMENT AMONG THE TOOLS OFFSET BY A LESS AMPLIFIED AND PROGRESSIVE HEIGHT
PATTERN.
FORECASTER: RYAN BOLT
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:
20050905 - 20050824 - 20060830 - 20050829 - 19980806
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:
20050904 - 20050827 - 20060829 - 19930812 - 20050822
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 01 - 05 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A A NRN CALIF A N
SRN CALIF A B IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A B WYOMING A N
UTAH A N ARIZONA A B COLORADO A A
NEW MEXICO N A N DAKOTA A B S DAKOTA A N
NEBRASKA A N KANSAS N N OKLAHOMA N A
N TEXAS N A S TEXAS A A W TEXAS N A
MINNESOTA N B IOWA B B MISSOURI B B
ARKANSAS N A LOUISIANA A A WISCONSIN B B
ILLINOIS B B MISSISSIPPI A A MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY N N
TENNESSEE A A ALABAMA A A NEW YORK B N
VERMONT B N NEW HAMP B N MAINE N N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY N N W VIRGINIA N N
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN A N
AK S INT A A AK SO COAST N A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 03 - 09 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A B
W MONTANA A N E MONTANA A B WYOMING A N
UTAH A B ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA N N
N TEXAS N N S TEXAS A A W TEXAS N N
MINNESOTA A N IOWA N B MISSOURI N B
ARKANSAS N N LOUISIANA A A WISCONSIN N B
ILLINOIS N B MISSISSIPPI N A MICHIGAN N B
INDIANA N B OHIO B B KENTUCKY B N
TENNESSEE N A ALABAMA N A NEW YORK B B
VERMONT B B NEW HAMP B B MAINE B B
MASS B B CONN B B RHODE IS B N
PENN B B NEW JERSEY B B W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B A GEORGIA N A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN A N
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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