588
FXUS06 KWBC 301932
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 30 2024
6-10 DAY OUTLOOK FOR SEP 05 - 09 2024
TODAY’S MODEL SOLUTIONS FROM THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS FOR
500-HPA HEIGHTS AND ANOMALIES ARE IN GOOD AGREEMENT AND ALL DEPICT A WAVETRAIN
PATTERN OVER THE NORTH PACIFIC AND NORTH AMERICA. RIDGING IS FORECAST OVER THE
NORTH PACIFIC NEAR THE ALEUTIANS AND THE WESTERN CONTIGUOUS U.S. (CONUS) AND
TROUGHING AND NEGATIVE HEIGHT ANOMALIES ARE DEPICTED OVER THE GULF OF ALASKA
AND THE NORTHEAST CONUS. THERE IS GOOD RUN-TO-RUN CONSISTENCY ON THESE
FEATURES, WHICH ARE ALSO FAVORED TO PERSIST INTO WEEK-2.
THE RIDGE OVER THE WESTERN CONUS BRINGS AN INCREASED CHANCE FOR ABOVE-NORMAL
TEMPERATURES WEST OF THE ROCKIES AS WELL AS PORTIONS OF THE NORTHERN AND
CENTRAL PLAINS. CONFIDENCE IN THIS OUTCOME IS HIGH; AT LEAST 50% PROBABILITIES
COVER MOST OF THE WEST, WITH CHANCES EXCEEDING 80% FOR MUCH OF THE GREAT BASIN.
TROUGHING OVER THE GREAT LAKES REGION FAVORS BELOW-NORMAL TEMPERATURES FOR THE
EASTERN CONUS. THIS IS WELL-INDICATED BY MOST FORECAST TOOLS, WITH
PROBABILITIES EXCEEDING 50% FOR MUCH OF THE MID-ATLANTIC. SOUTHERLY FLOW OFF
THE GULF OF MEXICO TILTS ODDS ALONG THE IMMEDIATE GULF COAST TOWARDS
ABOVE-NORMAL TEMPERATURES. POSITIVE 500-HPA HEIGHT ANOMALIES OVER NORTHERN
CANADA RESULT IN A TILT TOWARDS ABOVE-NORMAL TEMPERATURES FOR THE EASTERN HALF
OF ALASKA, WHILE TROUGHING OVER THE GULF OF ALASKA SLIGHTLY FAVORS BELOW-NORMAL
TEMPERATURES FOR THE WESTERN COAST OF THE STATE. WEAK POSITIVE HEIGHT ANOMALIES
OVER THE SUBTROPICAL PACIFIC NUDGE OAHU AND KAUAI TOWARDS ABOVE-NORMAL
TEMPERATURES, WHILE NEAR-NORMAL TEMPERATURES ARE MOST LIKELY FOR THE REST OF
THE ISLANDS.
EXPANSIVE POSITIVE HEIGHT ANOMALIES OVER THE WESTERN CONUS RESULT IN
BELOW-NORMAL PRECIPITATION FAVORED FOR MUCH OF THE WESTERN AND NORTHERN CONUS,
ESPECIALLY ALONG PARTS OF THE U.S.-CANADA BORDER WHERE CHANCES EXCEED 50%.
INCREASING ONSHORE FLOW INTO THE WEST COAST LATE IN THE FORECAST PERIOD FAVORS
NEAR-NORMAL PRECIPITATION AS A WHOLE ALONG THE COAST DURING THE 6-10 DAY
PERIOD. A STALLED FRONTAL BOUNDARY OVER THE SOUTHEAST U.S. AND MOIST RETURN
FLOW UNDER THE BASE OF THE BERMUDA HIGH TILTS THE ODDS TOWARDS ABOVE-NORMAL
PRECIPITATION ALONG THE GULF COAST AND UP THE EASTERN SEABOARD, WITH HIGHER
ODDS (>40%) OVER THE SOUTHEAST U.S. TROUGHING OVER THE GULF OF ALASKA WEAKLY
FAVORS ABOVE-NORMAL PRECIPITATION FOR MUCH OF ALASKA EXCEPT FOR THE NORTH SLOPE
WHERE NEAR-NORMAL PRECIPITATION IS MOST LIKELY.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 37% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 38% 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 OUT OF 5, WITH
GOOD RUN-TO-RUN CONTINUITY AMONG FORECAST MODELS AND A PERSISTENT SYNOPTIC
PATTERN, OFFSET BY UNCERTAINTY REGARDING TROPICAL WEATHER OVER THE ATLANTIC
BASIN.
8-14 DAY OUTLOOK FOR SEP 07 - 13 2024
MODEL ENSEMBLES DEPICT A SLIGHT PROGRESSION OF THE SYNOPTIC PATTERN FROM THE
6-10 DAY PERIOD. THE RIDGE OVER THE WESTERN CONUS IS FAVORED TO MOVE SLIGHTLY
EASTWARD AND DEVELOP AN EASTWARD TILT. ENSEMBLE SOLUTIONS ALSO TEND TO FAVOR A
SLIGHT WESTWARD SHIFT IN THE TROUGH OVER THE EAST COAST. THE GENERAL
PERSISTENCE OR SLIGHT PROGRESSION OF SYNOPTIC FEATURES RESULTS IN VERY SIMILAR
OUTLOOKS FOR THE 6-10 AND 8-14 DAY PERIODS.
THE WAVETRAIN PATTERN FROM THE 6-10 DAY PERIOD REMAINS, WITH MOST OF THE HEIGHT
CENTERS MAINTAINING SIMILAR AMPLITUDES, THEREFORE THE WEEK-2 TEMPERATURE
OUTLOOK IS LITTLE-CHANGED FROM THE EARLIER PERIOD. ELEVATED CHANCES FOR
ABOVE-NORMAL TEMPERATURES OVER THE WESTERN AND CENTRAL CONUS ARE SHIFTED
SLIGHTLY EASTWARD RELATIVE TO THE 6-10 DAY PERIOD BUT MAINTAIN SIMILAR
MAGNITUDE, EXCEEDING 80% FOR PORTIONS OF MONTANA . A TILT TOWARDS BELOW-NORMAL
TEMPERATURES ALSO REMAINS IN PLACE FOR MUCH OF THE EASTERN CONUS, WITH SLIGHTLY
LOWER PROBABILITIES RELATIVE TO THE EARLY PERIOD DUE TO A WEAKENING TROUGH OVER
THE GREAT LAKES. MOIST SOUTHERLY FLOW OFF THE GULF OF MEXICO CONTINUES TO FAVOR
ABOVE-NORMAL TEMPERATURES ALONG THE GULF COAST. POSITIVE 500-HPA HEIGHT
ANOMALIES OVER NORTHERN CANADA RESULT IN A TILT TOWARDS ABOVE-NORMAL
TEMPERATURES FOR THE EASTERN HALF OF ALASKA, WHILE TROUGHING OVER THE GULF OF
ALASKA SLIGHTLY FAVORS BELOW-NORMAL TEMPERATURES FOR THE WESTERN COAST OF THE
STATE. WEAK POSITIVE HEIGHT ANOMALIES OVER THE SUBTROPICAL PACIFIC NUDGE OAHU
AND KAUAI TOWARDS ABOVE-NORMAL TEMPERATURES, WHILE NEAR-NORMAL TEMPERATURES ARE
MOST LIKELY FOR THE REST OF THE ISLANDS.
THE WEEK-2 PRECIPITATION OUTLOOK IS ALSO QUITE SIMILAR TO THE 6-10 DAY PERIOD.
DURING WEEK-2 THE TROUGH OVER THE GULF OF ALASKA IS FAVORED TO MOVE CLOSER TO
THE PACIFIC NORTHWEST, INCREASING ONSHORE FLOW AND FAVORING ABOVE-NORMAL
PRECIPITATION FOR MUCH OF THE NORTHWEST CONUS. THE RIDGE MENTIONED ABOVE
CONTINUES TO TILT THE ODDS TOWARDS BELOW-NORMAL PRECIPITATION FOR MUCH OF THE
CENTRAL CONUS AS WELL AS THE DESERT SOUTHWEST AND THE GREAT LAKES REGION.
CONTINUED INSTABILITY FROM A DISSIPATING FRONTAL BOUNDARY COMBINED WITH MOIST
TROPICAL AIR RESULTS IN PERSISTENT ELEVATED CHANCES FOR ABOVE-NORMAL
PRECIPITATION ALONG THE GULF COAST AND UP THE EASTERN SEABOARD. PORTIONS OF
ALASKA CONTINUE TO LEAN TOWARDS ABOVE-NORMAL PRECIPITATION UNDER THE INFLUENCE
OF TROUGHING OVER THE GULF OF ALASKA. NEAR-NORMAL PRECIPITATION IS MOST LIKELY
FOR HAWAII GIVEN A GENERAL LACK OF FORCING SYNOPTIC FEATURES DURING WEEK-2 FOR
THE CENTRAL PACIFIC.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 37% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 38% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 25% 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, WITH A
PERSISTENT SYNOPTIC PATTERN, OFFSET BY DIFFERENCES BETWEEN MODELS REGARDING
STRENGTH AND POSITION OF VARIOUS SYNOPTIC FEATURES AND WEAKER ANOMALIES IN SOME
FORECAST FIELDS.
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 - 20020830 - 20050906 - 20030819 - 19530810
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:
20020829 - 20050822 - 19530809 - 20090816 - 20030817
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 05 - 09 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A N
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A B S DAKOTA A B
NEBRASKA N B KANSAS N N OKLAHOMA B N
N TEXAS B N S TEXAS N A W TEXAS N A
MINNESOTA B B IOWA B B MISSOURI B B
ARKANSAS B N LOUISIANA B A WISCONSIN B B
ILLINOIS B B MISSISSIPPI B A MICHIGAN B B
INDIANA B B OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE N A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL N A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N A AK INT BSN A N
AK S INT A A AK SO COAST A A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 07 - 13 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 B NEVADA A N
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS N B S TEXAS A A W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI N B
ARKANSAS N B LOUISIANA N A WISCONSIN A B
ILLINOIS B B MISSISSIPPI N N MICHIGAN N B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B N ALABAMA N A NEW YORK B N
VERMONT N A NEW HAMP N A MAINE A A
MASS B A CONN B A RHODE IS B A
PENN B N 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 B 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 N AK SO COAST A N 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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