642
FXUS06 KWBC 272002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST MON NOVEMBER 27 2023
6-10 DAY OUTLOOK FOR DEC 03 - 07 2023
THE GEFS, CANADIAN, AND ECMWF ENSEMBLE MEANS ARE IN GOOD AGREEMENT DEPICTING A
DEEP 500-HPA TROUGH OVER THE NORTHEASTERN PACIFIC WITH ENHANCED PACIFIC FLOW
THROUGHOUT MUCH OF NORTH AMERICA. ALTHOUGH THE GEFS PREDICTS A NEGATIVE ARCTIC
OSCILLATION (AO) DURING THE NEXT TEN DAYS WHICH TYPICALLY CORRELATES WITH BELOW
NORMAL TEMPERATURE ACROSS THE CENTRAL AND EASTERN CONTIGUOUS (CONUS), THE
ENHANCED AND PERSISTENT PACIFIC FLOW ARE LIKELY TO RESULT IN ABOVE-NORMAL
TEMPERATURES THROUGHOUT MOST OF THE LOWER 48 STATES. AN EXCEPTION IS THE FOUR
CORNERS REGION WHERE A MID-LEVEL TROUGH CROSSES THIS REGION ON DAY 6 AND THEN
SURFACE HIGH PRESSURE MAY PROMOTE LOW-LEVEL INVERSIONS AND ANOMALOUSLY COLD
MORNINGS. THE LARGEST ABOVE-NORMAL TEMPERATURE PROBABILITIES (ABOVE 70 PERCENT)
ARE FORECAST ACROSS THE NORTHERN GREAT PLAINS CONSISTENT WITH THE REFORECAST
TOOLS.
THE DEEP TROUGH OVER THE NORTHEASTERN PACIFIC AND STRONG ONSHORE FLOW SUPPORTS
RELATIVELY LARGE ABOVE-NORMAL PRECIPITATION PROBABILITIES ACROSS THE PACIFIC
NORTHWEST, NORTHERN CALIFORNIA, AND NORTHERN INTERMOUNTAIN WEST. THE GEFS,
CANADIAN, AND ECMWF ENSEMBLE MEANS DEPICT 5-DAY PRECIPITATION AMOUNTS EXCEEDING
4 INCHES (LIQUID EQUIVALENT) FOR WESTERN PARTS OF OREGON AND WASHINGTON. ON
DAYS 6 AND 7 (DECEMBER 3-4), A LOW PRESSURE SYSTEM AND TRAILING FRONT ARE
FORECAST TO PROGRESS THROUGH THE EASTERN CONUS WHERE ABOVE-NORMAL PRECIPITATION
IS FAVORED. ELSEWHERE, ACROSS THE CENTRAL AND SOUTHWESTERN CONUS, A MEAN
500-HPA RIDGE AND REFORECAST TOOLS SUPPORT INCREASED BELOW-NORMAL PRECIPITATION
PROBABILITIES.
MODEL SOLUTIONS FEATURE ANOMALOUS 500-HPA TROUGHING OVER ALASKA AND A MEAN
SURFACE LOW ACROSS THE GULF OF ALASKA. THIS PATTERN FAVORS ABOVE-NORMAL
PRECIPITATION FOR SOUTHEASTERN ALASKA AND THE REFORECAST TOOLS ALSO DEPICT
SLIGHTLY ELEVATED ABOVE-NORMAL PRECIPITATION PROBABILITIES FOR EXTREME
NORTHWESTERN ALASKA. THE 6-10 DAY TEMPERATURE OUTLOOK ACROSS ALASKA WAS BASED
MOSTLY ON THE CONSOLIDATION TOOL WHICH FAVORS NEAR TO ABOVE-NORMAL
TEMPERATURES. THE 6-10 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR HAWAII
ARE ALSO BASED ON THE CONSOLIDATION TOOL. ABOVE-NORMAL TEMPERATURES ARE FAVORED
FOR THE ENTIRE HAWAIIAN ISLAND CHAIN AND A SLIGHT TILT TOWARD BELOW-NORMAL
PRECIPITATION IS INDICATED FOR THE BIG ISLAND.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 40% 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, DUE TO
GOOD AGREEMENT AND CONTINUITY AMONG THE ENSEMBLE MEANS.
8-14 DAY OUTLOOK FOR DEC 05 - 11 2023
THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS WEAKEN THE TROUGH OVER THE
NORTHEASTERN PACIFIC, WHILE A TRANSITION TO A MORE ZONAL FLOW PATTERN OCCURS
ACROSS THE CONUS. THE CANADIAN ENSEMBLE MEAN IS THE FASTEST WITH BUILDING A
500-HPA RIDGE OVER THE NORTHEASTERN PACIFIC AND NORTHWESTERN NORTH AMERICA LATE
IN WEEK-2 WITH THE SOUTHERN STREAM BECOMING MORE ACTIVE. SINCE THE CANADIAN
ENSEMBLE MEAN HAS THE HIGHEST ANOMALY CORRELATION SCORE AT 500-HPA DURING THE
PAST 60 DAYS AND ITS EVOLVING LONGWAVE PATTERN IS MORE CONSISTENT WITH EL NIñO,
THE CANADIAN ENSEMBLE MEAN WAS GIVEN THE MOST WEIGHT IN CREATING THE MANUAL
500-HPA HEIGHT BLEND. GIVEN THE STRONG PACIFIC FLOW LEADING INTO WEEK-2,
ABOVE-NORMAL TEMPERATURES REMAIN THE MOST LIKELY OUTCOME THROUGHOUT MOST OF THE
CONUS, ESPECIALLY THE NORTHERN AND CENTRAL GREAT PLAINS. ALTHOUGH THE
REFORECAST TOOLS ARE IN GOOD AGREEMENT FOR ABOVE-NORMAL TEMPERATURES ACROSS THE
EASTERN CONUS, FORECAST CONFIDENCE IS LOW AS A BLOCKING RIDGE AT THE HIGHER
LATITUDES OVER THE DAVIS STRAIT AND GREENLAND COULD BRING AN INCREASING CHANCE
OF ANOMALOUS COLD BY MID-DECEMBER. THE ANALOG TOOL DERIVED FROM THE MANUAL
500-HPA HEIGHT BLEND FEATURES INCREASED BELOW-NORMAL TEMPERATURE PROBABILITIES
ACROSS THE SOUTHEAST. THEREFORE, THE WEEK-2 TEMPERATURE OUTLOOK HEDGED COLDER
FROM THE AUTOMATED TOOL AND NEAR NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF
THE SOUTHEAST.
ENHANCED ONSHORE FLOW IS EXPECTED TO PERSIST INTO EARLY WEEK-2 WHICH INCREASES
THE CHANCES OF ABOVE-NORMAL PRECIPITATION ACROSS THE PACIFIC NORTHWEST, GREAT
BASIN, AND NORTHERN CALIFORNIA. ELSEWHERE ACROSS THE CONUS, PRECIPITATION TOOLS
DEPICT EITHER ARE WEAK OR DIFFER WHICH LED TO A LARGE COVERAGE NEAR NORMAL
PRECIPITATION BEING FAVORED. BASED ON THE REFORECAST TOOLS AND SUPPORT FROM THE
ANALOG TOOL, BELOW-NORMAL PRECIPITATION IS MOST LIKELY FROM SOUTHERN CALIFORNIA
AND THE SOUTHWEST EAST TO THE PARTS OF THE GREAT PLAINS AND MIDDLE MISSISSIPPI
VALLEY. CYCLONIC FLOW AND A PREDICTED LOW PRESSURE SYSTEM AT THE BEGINNING OF
WEEK-2 SLIGHTLY ELEVATE PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ACROSS
MUCH OF NEW ENGLAND. THE RETURN OF A MORE ACTIVE SOUTHERN STREAM LATER IN
WEEK-2 FAVORS ABOVE-NORMAL PRECIPITATION FOR SOUTHERN TEXAS AND THE FLORIDA
PENINSULA.
SIMILAR TO THE PACIFIC NORTHWEST, ENHANCED ONSHORE FLOW EARLY IN WEEK-2 FAVORS
ABOVE-NORMAL PRECIPITATION FOR SOUTHEASTERN ALASKA. A SLIGHT LEAN TOWARDS
ABOVE-NORMAL TEMPERATURES ACCOMPANIES MOST OF THE FAVORED ABOVE-NORMAL
PRECIPITATION AREAS. THE CONSOLIDATION TOOL SUPPORTS INCREASED CHANCES FOR
BELOW-NORMAL TEMPERATURES ACROSS PARTS OF SOUTHWESTERN ALASKA.
THE WEEK-2 TEMPERATURE OUTLOOK FOR HAWAII IS BASED ON THE CONSOLIDATION TOOL
AND FAVORS WARMER THAN NORMAL CONDITIONS ACROSS THE STATE. INCREASED
BELOW-NORMAL PRECIPITATION PROBABILITIES ARE FORECAST FOR THE BIG ISLAND OF
HAWAII, BUT NEAR NORMAL PRECIPITATION IS FAVORED FOR THE REMAINDER OF THE
HAWAIIAN ISLANDS. THE MJO IS FORECAST TO SHIFT FROM THE INDIAN OCEAN TO THE
WEST-CENTRAL PACIFIC LATER DURING WEEK-2 WHICH MAY OFFSET THE TYPICAL DRYNESS
ASSOCIATED WITH EL NIñO.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 40% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO
INCREASING UNCERTAINTY IN THE TEMPERATURE OUTLOOK FOR THE SOUTHEAST AND WEAK OR
CONFLICTING SIGNALS AMONG THE PRECIPITATION TOOLS.
FORECASTER: BRAD PUGH
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
DECEMBER 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:
20071122 - 20021206 - 20061203 - 19931107 - 19761129
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:
19791109 - 20071121 - 19931107 - 19761129 - 20021205
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 03 - 07 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A B IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A N ARIZONA N B COLORADO A B
NEW MEXICO B B N DAKOTA A N S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS N N W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A A WISCONSIN A N
ILLINOIS A B MISSISSIPPI A A MICHIGAN A N
INDIANA A N OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N
AK S INT N N AK SO COAST N N AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 05 - 11 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A B IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A N WYOMING A N
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A N S DAKOTA A N
NEBRASKA A B 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 A B
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A N NEW YORK A N
VERMONT A N NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA N N GEORGIA N N
FL PNHDL N N FL PENIN N A AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N N AK INT BSN N N
AK S INT N N AK SO COAST N N 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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