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FXUS06 KWBC 041902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON SEPTEMBER 04 2023
6-10 DAY OUTLOOK FOR SEP 10 - 14 2023
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED AMPLIFIED
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING
THE 6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE
ENSEMBLE MEANS FROM THE GFS, ECMWF, AND CANADIAN MODEL ENSEMBLES DUE TO RECENT
MODEL SKILL. THE RESULTANT MANUAL BLEND FEATURES A MID-LEVEL RIDGE OVER THE
NORTH PACIFIC, ASSOCIATED WITH POSITIVE 500-HPA GEOPOTENTIAL HEIGHT ANOMALIES
ACROSS THE ALEUTIANS. TROUGHING AND NEGATIVE 500-HPA HEIGHT ANOMALIES ARE
FORECAST ACROSS SOUTHWESTERN MAINLAND ALASKA AND THE GULF OF ALASKA, WHILE
POSITIVE 500-HPA HEIGHT GEOPOTENTIAL HEIGHT ANOMALIES ARE FORECAST OVER
NORTHERN AND EASTERN MAINLAND ALASKA. ALL ENSEMBLE MODELS FAVOR RIDGING AND
POSITIVE 500-HPA HEIGHT ANOMALIES OVER MOST OF THE WESTERN CONTIGUOUS UNITED
STATES (CONUS), WHILE A TROUGH IS FORECAST OVER THE EASTERN CONUS.
ENHANCED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER WESTERN AND
CENTRAL CONUS, ASSOCIATED WITH MID-LEVEL RIDGING AND/OR ABOVE-AVERAGE 500-HPA
HEIGHTS. THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES (IN EXCESS OF
80 PERCENT) ARE INDICATED OVER PARTS OF SOUTHERN TEXAS. ABOVE-NORMAL
TEMPERATURES ARE ALSO FORECAST OVER MOST OF THE SOUTHEASTERN CONUS, CONSISTENT
WITH THE GEFS AND ECMWF REFORECAST CONSOLIDATION TOOLS. CONVERSELY, A TILT
TOWARD BELOW-NORMAL TEMPERATURES IS INDICATED FOR MUCH OF THE NORTHEASTERN
CONUS ASSOCIATED WITH A TROUGH PREDICTED OVER THE EASTERNCONUS. IN ALASKA,
CHANCES FOR BELOW-NORMAL TEMPERATURES ARE INCREASED ACROSS THE SOUTHWESTERN
PARTS OF THE STATE BENEATH NEGATIVE 500-HPA HEIGHT ANOMALIES, WHILE
ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER PARTS OF SOUTHEASTERN ALASKA DUE TO
POSITIVE 500-HPA HEIGHT ANOMALIES
THE RIDGE PREDICTED ACROSS THE WESTERN CONUS FAVORS NEAR- TO BELOW-NORMAL
PRECIPITATION ACROSS MUCH OF THE WESTERN CONUS. ABOVE-NORMAL PRECIPITATION IS
FORECAST OVER PARTS OF THE MID-ATLANTIC AND THE NORTHEAST DUE TO A TROUGH
PREDICTED OVER THE EASTERN CONUS. ABOVE-NORMAL PRECIPITATION IS FORECAST OVER
THE CENTRAL CONUS, WHILE BELOW-NORMAL PRECIPITATION IS PREDICTED OVER PORTIONS
OF THE GREAT LAKE, SOUTHERN TEXAS, AND SOUTHERN FLORIDA, SUPPORTED BY MOST
DYNAMICAL MODEL FORECAST TOOLS. AHEAD OF A MEAN MID-LEVEL TROUGH OVER THE
NORTHEAST PACIFIC, ABOVE-NORMAL PRECIPITATION IS FAVORED FOR SOUTHEASTERN
ALASKA, SUPPORTED BY THE PRECIPITATION CONSOLIDATION.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 30% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE NORMAL, 4 OUT OF 5, DUE TO A
PERSISTENT SYNOPTIC PATTERN AND GOOD AGREEMENT AMONG FORECAST MODELS, OFFSET BY
WEAKENING OF THE HIGH AMPLITUDE PATTERN LATE IN THE FORECAST PERIOD.
8-14 DAY OUTLOOK FOR SEP 12 - 18 2023
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY PERSISTENT
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS.
RIDGING AND POSITIVE 500-HPA GEOPOTENTIAL HEIGHT ANOMALIES ARE PREDICTED ACROSS
THE WESTERN CONUS IN THE MANUAL BLEND OF MODELS, AND A WEAK TROUGH AND
BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST OVER THE EASTERN CONUS. NEGATIVE
500-HPA HEIGHT ANOMALIES ARE FAVORED ACROSS SOUTHWESTERN MAINLAND ALASKA AND
THE GULF OF ALASKA, WHILE POSITIVE 500-HPA HEIGHT GEOPOTENTIAL HEIGHT ANOMALIES
ARE FORECAST OVER NORTHERN AND EASTERN MAINLAND ALASKA.
THE TEMPERATURE PATTERN FORECAST FOR THE WEEK 2 PERIOD IS SIMILAR TO THE 6-10
DAY OUTLOOK PERIOD. THERE ARE ENHANCED PROBABILITIES OF ABOVE NORMAL
TEMPERATURES ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS, ASSOCIATED WITH A
MID-LEVEL HIGH RIDGE PREDICTED OVER THE WESTERN CONUS. THE HIGHEST
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES (IN EXCESS OF 60 PERCENT) ARE
INDICATED OVER PARTS OF THE SOUTHERN PLAINS. ABOVE-NORMAL TEMPERATURES ARE ALSO
FORECAST OVER MOST OF THE SOUTHEASTERN CONUS, CONSISTENT WITH THE GEFS AND
ECMWF REFORECAST CONSOLIDATION TOOLS. CONVERSELY, A TILT TOWARD BELOW-NORMAL
TEMPERATURES IS INDICATED FOR THE NORTHEASTERN CONUS UNDERNEATH A TROUGH
PREDICTED OVER THE EASTERN CONUS. IN ALASKA, CHANCES FOR ABOVE-NORMAL
TEMPERATURES ARE INCREASED ACROSS THE NORTHERN AND EASTERN PORTIONS OF THE
STATE DUE TO MEAN SOUTHERLY FLOW OVER THE REGION, SUPPORTED BY MOST DYNAMICAL
MODEL FORECAST TOOLS.
NEAR TO BELOW NORMAL PRECIPITATION IS FAVORED FOR THE WESTERN CONUS, UNDER
POSITIVE 500-HPA HEIGHT ANOMALIES RIDGING FORECAST OVER THE REGION. ODDS TILT
TOWARD BELOW-NORMAL PRECIPITATION IN SOUTHERN TEXAS, SOUTHERN FLORIDA
PENINSULA, AND PARTS OF THE GREAT LAKES REGION, WHILE NEAR- TO ABOVE-NORMAL
PRECIPITATION IS FAVORED OVER THE REMAINDER OF THE CENTRAL AND EASTERN CONUS,
SUPPORTED BY THE PRECIPITATION CONSOLIDATION TOOL. IN ALASKA, AN ACTIVE STORM
TRACK IS PREDICTED TO PERSIST, FAVORING INCREASED CHANCES OF NEAR- TO
ABOVE-NORMAL PRECIPITATION FOR MOST OF THE STATE.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 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 30% 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, DUE TO
GOOD AGREEMENT AMONG MODEL ENSEMBLES ON THE PERSISTENT SYNOPTIC PATTERN, OFFSET
BY WEAKER ANOMALIES REDUCING FORECAST CONFIDENCE.
FORECASTER: LUKE H
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 21.
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:
20070918 - 19610918 - 20050914 - 19900828 - 19900904
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:
20070917 - 19900827 - 20050914 - 19610917 - 19900903
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 10 - 14 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A B
SRN CALIF A B IDAHO A N NEVADA A B
W MONTANA A N E MONTANA A A WYOMING A A
UTAH A N ARIZONA A B COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA N A
NEBRASKA N A KANSAS N A OKLAHOMA A A
N TEXAS A A S TEXAS A N W TEXAS A A
MINNESOTA N N IOWA N A MISSOURI N A
ARKANSAS A A LOUISIANA A N WISCONSIN B N
ILLINOIS B N MISSISSIPPI A N MICHIGAN B B
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA A N NEW YORK B A
VERMONT B A NEW HAMP N A MAINE N A
MASS N A CONN B A RHODE IS N A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA N A S CAROLINA N A GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N
AK S INT N A AK SO COAST N A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 12 - 18 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF N N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A A
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A N W TEXAS A A
MINNESOTA A N IOWA N N MISSOURI N A
ARKANSAS A A LOUISIANA A N WISCONSIN N N
ILLINOIS N N MISSISSIPPI A A MICHIGAN N N
INDIANA B N OHIO B N KENTUCKY B A
TENNESSEE N A ALABAMA A N 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 A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA N A GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N
AK S INT N A AK SO COAST N 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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