717
FXUS06 KWBC 191941
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 19 2024
6-10 DAY OUTLOOK FOR AUG 25 - 29 2024
THE GEFS, ECENS, AND CMCE ENSEMBLE MEANS ARE IN FAIRLY GOOD AGREEMENT ON THE
MEAN 500-HPA CIRCULATION PATTERN OVER THE FORECAST DOMAIN DURING THE 6-10 DAY
FORECAST PERIOD. IN THE FULL HEIGHT FIELDS, WEAK MID-LEVEL TROUGHS ARE
PREDICTED NEAR THE WEST AND EAST COASTS OF THE CONTIGUOUS U.S. (CONUS), AND A
MID-LEVEL RIDGE IS DEPICTED ACROSS THE VICINITY OF THE GREAT LAKES, THOUGH THE
FLOW PATTERN IS EXPECTED TO BE DE-AMPLIFYING OVER NORTH AMERICA. THE MANUAL
BLEND DEPICTS A 594-DM HEIGHT CONTOUR THAT EXTENDS FROM THE SOUTHWEST INTO THE
LOWER AND MIDDLE MISSISSIPPI VALLEY. IN THE HEIGHT ANOMALY FIELDS, ABOVE-NORMAL
HEIGHTS ARE FAVORED ACROSS MOST OF THE CONUS, WITH THE GREATER ANOMALIES
CENTERED OVER SOUTHEASTERN CANADA AND OFF THE PACIFIC NORTHWEST COAST (BOTH
ANOMALIES EXCEEDING +90 M). A DEEP ANOMALOUS TROUGH IS PREDICTED TO BE CENTERED
OVER THE EASTERN BERING SEA AND WESTERN ALASKA, WITH NEGATIVE 500-HPA HEIGHT
ANOMALIES DEPICTED ACROSS MOST OF THE STATE, EXCLUDING MUCH OF THE PANHANDLE.
AN UNDERCUTTING FLAT RIDGE OVER THE GULF OF ALASKA IS INDICATED EXTENDING
EASTWARD INTO BRITISH COLUMBIA AND THE PACIFIC NORTHWEST. NEAR THE HAWAIIAN
ARCHIPELAGO, MID-LEVEL HEIGHTS ARE PREDICTED TO BE NEAR OR SLIGHTLY ABOVE
NORMAL. ANOMALY CORRELATION SCORES OVER THE PAST 60 DAYS SHOW THE ECENS HAS A
SLIGHT EDGE OVER THE GEFS AND CMCE ENSEMBLE MEANS.
THE 6-10 DAY TEMPERATURE OUTLOOK FAVORS BELOW NORMAL TEMPERATURES OVER A
SIGNIFICANT FRACTION OF THE INTERIOR WEST, CONSISTENT WITH PRACTICALLY ALL OF
THE TEMPERATURE TOOLS. THE RAW AND BIAS-CORRECTED TEMPERATURE TOOLS DEPICT A
SOMEWHAT BROADER COVERAGE OF FAVORED BELOW NORMAL TEMPERATURES COMPARED TO THE
RE-FORECAST TEMPERATURE TOOLS. MANY OF THE TEMPERATURE TOOLS FAVOR ABOVE NORMAL
TEMPERATURES OVER AT LEAST PORTIONS OF THE WEST COAST STATES, ASSOCIATED WITH
THE EASTERN PERIPHERY OF THE FLAT ANOMALOUS RIDGE FORECASTED OVER THE GULF OF
ALASKA. NEAR NORMAL TEMPERATURES ARE FAVORED ACROSS PORTIONS OF THE SOUTHEAST,
THOUGH THERE ARE CONSIDERABLE VARIATIONS IN THE PREDICTED SPATIAL EXTENT OF
THIS SIGNAL. FOR MOST OF THE REMAINDER OF THE CONUS, ABOVE NORMAL TEMPERATURES
ARE FAVORED, SUPPORTED BY NEARLY ALL TEMPERATURE TOOLS AND CONSISTENT WITH A
BROAD MID-LEVEL RIDGE AND ASSOCIATED POSITIVE HEIGHT ANOMALIES. MAXIMUM
PROBABILITIES FAVORING ABOVE NORMAL TEMPERATURES EXCEED 70% FROM THE
SOUTH-CENTRAL PLAINS INTO THE GREAT LAKES REGION. FOR ALASKA, NEARLY ALL TOOLS
AGREE ON FAVORED BELOW NORMAL TEMPERATURES, CONSISTENT WITH THE BROAD MID-LEVEL
TROUGH AND ASSOCIATED NEGATIVE HEIGHT ANOMALIES OVER THAT REGION. MAXIMUM
PROBABILITIES FAVORING BELOW NORMAL TEMPERATURES EXCEED 70% OVER PORTIONS OF
WESTERN ALASKA. ABOVE NORMAL TEMPERATURES ARE INDICATED OVER THE HAWAIIAN
ISLANDS, BASED ON THE ERF-CON AND AUTOMATED TEMPERATURE TOOLS.
THE 6-10 DAY PRECIPITATION OUTLOOK FAVORS ABOVE NORMAL PRECIPITATION FROM THE
NORTHERN INTERMOUNTAIN REGION EASTWARD INTO THE UPPER MISSISSIPPI VALLEY. THIS
IS GENERALLY CONSISTENT WITH THE PRECIPITATION TOOLS, THOUGH THERE ARE
DIFFERENCES IN THE SPATIAL COVERAGE AND ORIENTATION OF THESE ANOMALIES. ABOVE
NORMAL PRECIPITATION IS ALSO FAVORED ALONG PORTIONS OF THE GULF COAST, SOUTH OF
THE BERMUDA HIGH SURFACE RIDGE AXIS THAT EXTENDS FROM THE WESTERN ATLANTIC
ACROSS SOUTH-CENTRAL PORTIONS OF THE EASTERN CONUS. BELOW NORMAL PRECIPITATION
IS FAVORED FOR A WIDESPREAD REGION THAT EXTENDS ACROSS MUCH OF THE EAST AND
INTO THE SOUTH-CENTRAL PLAINS, COINCIDENT WITH THE BROAD MID-LEVEL RIDGE AND
POSITIVE HEIGHT DEPARTURES PREDICTED OVER THAT REGION. BELOW NORMAL
PRECIPITATION IS ALSO FAVORED FROM THE CENTRAL PACIFIC COAST EASTWARD ACROSS
MUCH OF NEVADA AND UTAH. ELSEWHERE, WHICH INCLUDES A LARGE PORTION OF THE
CONUS, NEAR NORMAL PRECIPITATION IS FAVORED. THIS INCLUDES MOST OF THE
SOUTHWESTERN QUARTER OF THE CONUS, AND IS RELATED TO EITHER LIMITED INFLUX OF
MONSOON MOISTURE INTO THE REGION, OR THE ARID CLIMATOLOGY OF THE AREA. IN
ALASKA, THERE IS EXCELLENT AGREEMENT AMONG THE PRECIPITATION TOOLS FOR ABOVE
NORMAL PRECIPITATION ACROSS PRACTICALLY THE ENTIRE STATE, ASSOCIATED WITH
WIDESPREAD ONSHORE FLOW AT LOW-LEVELS AND MID-LEVELS ACCOMPANYING AND AHEAD OF
THE TROUGH PREDICTED OVER THE EASTERN BERING SEA AND WESTERN ALASKA. FOR
HAWAII, THE ERF-CON TOOL FAVORS ABOVE NORMAL PRECIPITATION DURING THE 6-10 DAY
PERIOD, ASSOCIATED WITH THE POTENTIAL FOR A TROPICAL SYSTEM. PROBABILITIES
FAVORING ABOVE NORMAL RAINFALL EXCEED 50% OVER THE HAWAIIAN ISLANDS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 25% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4, ON A SCALE OF
1-5, DUE TO FAIRLY GOOD AGREEMENT AMONG THE VARIOUS HEIGHT FORECASTS AND
SURFACE TEMPERATURE AND PRECIPITATION FIELDS.
8-14 DAY OUTLOOK FOR AUG 27 - SEP 02, 2024
DURING WEEK-2, THE ENSEMBLE MEANS ARE IN GOOD OVERALL AGREEMENT ON THE MEAN
CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN. IN THE FULL HEIGHT FIELDS, A
WEAK TROUGH IS DEPICTED NEAR THE WEST COAST AND A BROAD RIDGE IS INDICATED OVER
THE WEST-CENTRAL CONUS. A VERY SHALLOW, LOW-AMPLITUDE TROUGH IS PREDICTED OVER
THE EAST. IN THE HEIGHT ANOMALY FIELD, MOST OF THE CONUS IS EXPECTED TO BE
UNDER ABOVE NORMAL 500-HPA HEIGHTS, WITH THE TWO LARGER POSITIVE HEIGHT ANOMALY
CENTERS (>60 M) LOCATED OVER THE SOUTHERN CANADIAN MARITIMES AND NEAR THE
BRITISH COLUMBIA COAST, BOTH OF WHICH ARE SITUATED NEAR 50N LATITUDE. THE
MAXIMUM HEIGHTS FOR THE 7-DAY FORECAST PERIOD ARE PREDICTED TO AVERAGE AROUND
590-DM ON THE MANUAL HEIGHT BLEND, INDICATING A SLIGHT REDUCTION IN FORECASTED
500-HPA HEIGHTS ACROSS THE SOUTHWESTERN AND SOUTH-CENTRAL CONUS, COMPARED TO
THE EARLIER 6-10 DAY PERIOD. IN ALASKA, A TROUGH IS STILL PREDICTED OVER THE
EASTERN BERING SEA AND WESTERN ALASKA, BUT THE EASTERN FLANK OF THIS TROUGH IS
EXPECTED TO GIVE WAY TO RISING 500-HPA HEIGHTS, ASSOCIATED WITH THE ANOMALOUS
RIDGE CENTERED NEAR BRITISH COLUMBIA. WELL TO THE SOUTH, HEIGHTS ARE FORECAST
TO BE NEAR OR SLIGHTLY ABOVE NORMAL IN THE VICINITY OF THE HAWAIIAN ISLANDS.
THE 8-14 DAY TEMPERATURE OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES OVER MOST OF
THE LOWER 48 STATES, SUPPORTED BY THE GEFS AND ECENS REFORECAST TEMPERATURES,
AND RAW TEMPERATURES FROM THE 0Z ECENS AND THE 6Z GEFS. BIAS-CORRECTED
TEMPERATURES FROM THE VARIOUS ENSEMBLE MEANS DEPICT AREAS OF BELOW NORMAL
TEMPERATURES OVER A SIGNIFICANT FRACTION OF THE WESTERN AND/OR CENTRAL CONUS,
CORRECTING FOR RECENT ENSEMBLE FORECASTS THAT HAVE BEEN TOO WARM OVER THIS
BROAD AREA. IN ALASKA, BELOW NORMAL TEMPERATURES ARE STILL FAVORED OVER MOST OF
THE STATE, WITH THE EXCEPTION OF NEAR TO SLIGHTLY ABOVE NORMAL TEMPERATURES FOR
THE SOUTHERN PANHANDLE AND NORTHEASTERN SECTIONS OF THE MAINLAND. THE ERF-CON
TOOL SUPPORTS ABOVE NORMAL TEMPERATURES ACROSS HAWAII, SIMILAR TO THE EARLIER
6-10 DAY TEMPERATURE OUTLOOK.
THE 8-14 DAY PRECIPITATION OUTLOOK IS CHARACTERIZED BY MUCH UNCERTAINTY, AS
INDICATED BY THE VERY LARGE EXPANSE OF FAVORED NEAR NORMAL TEMPERATURES ACROSS
THE LOWER 48 STATES. RAW ENSEMBLE MEAN PRECIPITATION FORECASTS FROM THE GEFS
AND CMCE FAVOR SLIGHT TILTS TOWARDS ABOVE NORMAL PRECIPITATION ACROSS PORTIONS
OF THE GULF COAST REGION, PARTS OF THE NORTHEAST, AND FROM CENTRAL PORTIONS OF
THE PACIFIC COAST EASTWARD ACROSS MOST OF NEVADA AND WESTERN UTAH. ODDS FAVOR
BELOW NORMAL PRECIPITATION FROM ABOUT THE CENTRAL PLAINS EASTWARD ACROSS THE
MISSISSIPPI VALLEY, LOWER OHIO VALLEY, TENNESSEE, AND THE SOUTHERN
APPALACHIANS. THIS IS MORE IN LINE WITH THE RAW PRECIPITATION TOOLS THAN THE
REFORECAST PRECIPITATION TOOLS WHICH APPEAR TO BE TOO WET TODAY. THE RAW ECENS
PRECIPITATION FORECAST HAS, BY FAR, THE BROADEST COVERAGE OF FAVORED BELOW
NORMAL PRECIPITATION ACROSS MUCH OF THE CONUS. MOST TOOLS CONTINUE TO FAVOR
ANOMALOUS WETNESS FOR ALASKA AND HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 35% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR AVERAGE, 3, ON A SCALE OF
1-5, DUE TO REASONABLE AGREEMENT AMONG THE VARIOUS HEIGHT FORECASTS AND SURFACE
TEMPERATURE FORECASTS, BUT SUBSTANTIALLY OFFSET BY POOR AGREEMENT AMONG THE
PRECIPITATION TOOLS.
FORECASTER: ANTHONY A
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:
19830830 - 19630824 - 19730820 - 19540825 - 20000803
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:
19730821 - 19540826 - 19830830 - 19900824 - 20000803
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 25 - 29 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON A B NRN CALIF A B
SRN CALIF A N IDAHO B A NEVADA B B
W MONTANA B A E MONTANA B A WYOMING B N
UTAH B N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A A W TEXAS A N
MINNESOTA A A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
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 B
VERMONT A B NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A B NEW JERSEY A B W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA A B
N CAROLINA A B S CAROLINA A N GEORGIA A N
FL PNHDL A N 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 B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 27 - SEP 02, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF A N IDAHO A N NEVADA A A
W MONTANA A N E MONTANA N N WYOMING N N
UTAH A A ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA N N S DAKOTA N N
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A A W TEXAS A N
MINNESOTA N N IOWA N B MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A B MISSISSIPPI A N MICHIGAN A N
INDIANA A B OHIO A N KENTUCKY A B
TENNESSEE A B ALABAMA A N NEW YORK A N
VERMONT A A NEW HAMP A A MAINE A A
MASS A A 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 N FL PENIN A A AK N SLOPE N 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 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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