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FXUS06 KWBC 222003
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED NOVEMBER 22 2023
6-10 DAY OUTLOOK FOR NOV 28 - DEC 02, 2023
THERE IS BETTER AGREEMENT IN THE DYNAMICAL MODELS REGARDING A PATTERN
TRANSITION FORECAST TO OCCUR DURING THE 6-10 DAY PERIOD. INITIALLY, ANOMALOUS
TROUGHING IS FAVORED ACROSS THE EASTERN CONUS WITH RIDGING ACROSS THE WEST.
BOTH THE 0Z GEFS AND ECMWF ENSEMBLES DEPICT TROUGHING AMPLIFYING ACROSS THE
EASTERN PACIFIC AND WESTERN NORTH AMERICA LATER IN THE PERIOD, WITH A SLIGHTLY
QUICKER TRANSITION INDICATED IN THE GEFS. TROUGHING OVER THE EAST IS FORECAST
TO GRADUALLY WEAKEN TOWARD DAY-10, WITH POSITIVE HEIGHT ANOMALIES BEGINNING TO
DEVELOP ACROSS CENTRAL NORTH AMERICA. FOR THE 6-10 DAY PERIOD AS A WHOLE,
TODAY’S MANUAL 500-HPA HEIGHT BLEND DEPICTS THE LARGEST NEGATIVE HEIGHT
ANOMALIES ACROSS THE EASTERN CONUS (-120 METERS OVER NEW ENGLAND), WITH NEAR-
TO SLIGHTLY BELOW-NORMAL HEIGHTS EXTENDING THROUGH THE SOUTHERN TIER INTO THE
SOUTHWEST. ABOVE-NORMAL HEIGHTS ARE INDICATED ACROSS THE NORTHWEST CONUS AND
SOUTHEAST ALASKA GIVEN THE RIDGING FAVORED EARLY IN THE PERIOD. BELOW-NORMAL
HEIGHTS ARE FORECAST ACROSS MAINLAND ALASKA AND THE ALEUTIANS AS TROUGHING
INCREASES ACROSS THE BERING SEA. TROUGHING FORECAST EARLY IN THE PERIOD NEAR
HAWAII IS FORECAST TO WEAKEN, RESULTING IN NEAR- TO SLIGHTLY BELOW-NORMAL
HEIGHTS.
NOVEMBER IS FORECAST TO END ON THE COLDER SIDE ACROSS MOST OF THE EASTERN CONUS
WITH MOST AREAS HAVING INCREASED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES,
WITH THE EXCEPTION OF THE SOUTHERN FLORIDA PENINSULA WHERE ABOVE-NORMAL
TEMPERATURE PROBABILITIES ARE ELEVATED TO THE SOUTH OF THE FRONTAL BOUNDARY.
THE LARGEST PROBABILITIES FOR BELOW-NORMAL TEMPERATURES (GREATER THAN 70
PERCENT) ARE PREDICTED ACROSS THE OHIO VALLEY, MID-ATLANTIC, AND NORTHEAST,
WHERE AVERAGE TEMPERATURES 5 TO 10 DEG F BELOW-NORMAL ARE POSSIBLE BASED ON THE
UNCALIBRATED 0Z GEFS AND ECMWF ENSEMBLES. WHILE BELOW-NORMAL TEMPERATURES ARE
ALSO FORECAST ACROSS THE WEST, SOME MODERATION IS POSSIBLE TOWARD THE END OF
THE PERIOD, WITH THE ECMWF REFORECAST TOOL BEING QUITE ROBUST WITH ELEVATED
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES DEPICTED ACROSS THE WEST COAST, AND
EXTENDING ACROSS THE NORTHERN ROCKIES AND PLAINS. THE GEFS REFORECAST TOOL HAS
ALSO INCREASED ABOVE-NORMAL TEMPERATURE PROBABILITIES ACROSS THE NORTHERN
ROCKIES AND PLAINS COMPARED TO YESTERDAY. HOWEVER, A STRONGER SIGNAL FOR
BELOW-NORMAL TEMPERATURES STILL EXISTS IN THE UNCALIBRATED GUIDANCE, FAVORING
WEAKER ABOVE-NORMAL TEMPERATURE PROBABILITIES AND COVERAGE IN TODAY’S FORECAST.
ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE FAVORED ACROSS PARTS OF CALIFORNIA,
THE PACIFIC NORTHWEST, AND THE NORTHERN ROCKIES AND PLAINS, WITH BELOW-NORMAL
TEMPERATURES REMAINING FAVORED ACROSS MUCH OF THE FOUR CORNERS REGION AND
SOUTH-CENTRAL STATES. SOUTHERLY MID-LEVEL FLOW ACROSS ALASKA FAVORS ELEVATED
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE STATE. A TRANSITION TO
SLIGHTLY ABOVE-NORMAL TEMPERATURES IS FORECAST ACROSS SOUTHERN HAWAII, WITH
NEAR-NORMAL TEMPERATURES FAVORED ACROSS PUUWAI, KAUAI, AND MOST OF OAHU.
THE OVERALL HEIGHT PATTERN GENERALLY FAVORS A MORE SUPPRESSED STORM TRACK
ACROSS THE CONUS LEADING TO INCREASED PROBABILITIES OF BELOW-NORMAL
PRECIPITATION OVER MUCH OF THE NORTHERN TWO-THIRDS OF THE CONUS, WITH THE
LARGEST PROBABILITIES (GREATER THAN 50 PERCENT) FORECAST OVER THE OHIO VALLEY
TIED TO TELECONNECTION ANALYSIS WITH THE NEGATIVE HEIGHT ANOMALY CENTER OVER
NEW ENGLAND AND SURFACE HIGH PRESSURE PREDICTED ACROSS THE REGION. ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE ELEVATED ACROSS THE SOUTHERN TIER, SUPPORTED BY
THE GEFS AND ECMWF REFORECAST TOOLS, AND CONSISTENT WITH EL NINO CLIMATOLOGY.
TODAY’S GEFS REFORECAST TOOL INDICATES A GREATER NORTHWARD PUSH OF ELEVATED
ABOVE-NORMAL PRECIPITATION PROBABILITIES INTO THE SOUTHEAST COMPARED TO THE
ECMWF, WITH THE ADDED UNCERTAINTY RESULTING IN MORE NEAR-NORMAL PRECIPITATION
FORECAST RELATIVE TO YESTERDAY. MODELS ARE IN GOOD AGREEMENT REGARDING STRONG
SOUTHERLY FLOW ACROSS ALASKA RESULTING IN ELEVATED PROBABILITIES OF
ABOVE-NORMAL PRECIPITATION ACROSS THE STATE. A SLIGHT TILT TOWARDS ELEVATED
ABOVE-NORMAL PRECIPITATION PROBABILITIES IS INDICATED FOR THE HAWAIIAN ISLANDS,
IN PROXIMITY TO A MID-LEVEL TROUGH FORECAST EARLY IN THE PERIOD.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 8, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY'S OPERATIONAL 0Z ECMWF 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: AVERAGE, 3 OUT OF 5, DUE TO
GENERALLY GOOD TOOL AGREEMENT REGARDING THE TEMPERATURE AND PRECIPITATION
OUTPUTS, BUT WITH ADDED UNCERTAINTY REGARDING A TRANSITIONAL PATTERN LATER IN
THE PERIOD.
8-14 DAY OUTLOOK FOR NOV 30 - DEC 06, 2023
TROUGHING OVER THE EASTERN CONUS IS FORECAST TO WEAKEN DURING WEEK-2 WITH A
TREND TOWARD HIGHER MID-LEVEL HEIGHTS. THE GEFS AND ECMWF ARE NOW IN GOOD
AGREEMENT REGARDING TROUGHING EXTENDING THROUGH ALASKA, THE EASTERN PACIFIC,
AND WEST COAST OF THE CONUS, WITH RIDGING DEVELOPING OVER CENTRAL AND
EAST-CENTRAL NORTH AMERICA. TODAY’S MANUAL 500-HPA HEIGHT BLEND FOR WEEK-2
DEPICTS NEAR-NORMAL HEIGHTS ACROSS THE EASTERN SEABOARD, WITH ABOVE-NORMAL
HEIGHTS FAVORED ACROSS PARTS OF THE UPPER MIDWEST AND NORTHERN PLAINS.
BELOW-NORMAL HEIGHTS ARE PREDICTED ACROSS ALASKA AND MUCH OF THE WESTERN THIRD
OF THE CONUS. NEAR-NORMAL HEIGHTS ARE FAVORED ACROSS HAWAII.
FORECAST TOOLS GENERALLY MAINTAIN ELEVATED PROBABILITIES OF BELOW-NORMAL
TEMPERATURES ACROSS THE EASTERN CONUS, ALTHOUGH PROBABILITIES ARE REDUCED
COMPARED TO THE 6-10 DAY OUTLOOK. SOME GEFS AND ECMWF ENSEMBLE MEMBERS SUGGEST
THE DEVELOPMENT OF A POSITIVE NORTH ATLANTIC OSCILLATION IN EARLY DECEMBER,
WHICH COULD FURTHER ENHANCE THE WARMING TREND AT THE END OF WEEK-2. THE GEFS
AND ECMWF REFORECAST TOOLS BOTH SHOW INCREASED PROBABILITIES FOR ABOVE-NORMAL
TEMPERATURES ACROSS THE WESTERN AND CENTRAL CONUS DURING WEEK-2. HOWEVER,
BELOW-NORMAL TEMPERATURE PROBABILITIES REMAIN ELEVATED IN THE UNCALIBRATED
ECMWF OVER MUCH OF THE INTERIOR WEST AND SOUTH-CENTRAL CONUS. GIVEN THE
UNCERTAINTY IN THE SPEED OF THE PATTERN TRANSITION, ONLY A SLIGHT TILT TOWARD
ABOVE-NORMAL TEMPERATURE PROBABILITIES IS POSTED ACROSS THE FOUR CORNERS AND
PARTS OF THE SOUTHERN PLAINS, WITH HIGHER PROBABILITIES FOR ABOVE-NORMAL
TEMPERATURE PROBABILITIES CLOSER TO THE WEST COAST AND ACROSS PARTS OF THE
NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. NEAR-NORMAL TEMPERATURE
PROBABILITIES ARE INCREASED ACROSS PARTS OF THE LOWER MISSISSIPPI, TENNESSEE,
AND OHIO VALLEYS, AND SOUTHEAST (EXCLUDING FLORIDA WHERE ABOVE-NORMAL
TEMPERATURE PROBABILITIES REMAIN ELEVATED). ENHANCED SOUTHERLY FLOW AHEAD OF
TROUGHING FAVORS A CONTINUATION OF INCREASED NEAR- TO ABOVE-NORMAL TEMPERATURE
PROBABILITIES ACROSS ALASKA. INCREASING MID-LEVEL HEIGHTS NEAR HAWAII FAVOR
ELEVATED ABOVE-NORMAL TEMPERATURE PROBABILITIES ACROSS THE ISLANDS.
DURING WEEK-2, PRECIPITATION CHANCES ARE FORECAST TO INCREASE ACROSS THE
WESTERN CONUS GIVEN THE INCREASED TROUGHING. A LARGE CHANGE IS NOTED IN THE
UNCALIBRATED ECMWF REGARDING INCREASED PRECIPITATION ALONG THE WEST COAST, WITH
TOTALS AND ABOVE-NORMAL PRECIPITATION PROBABILITIES FALLING MORE IN LINE WITH
THE GEFS. ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED TO ABOVE 40
PERCENT ACROSS MUCH OF THE PACIFIC NORTHWEST, CENTRAL AND NORTHERN CALIFORNIA,
AND WESTERN NEVADA, WITH A SMALL AREA OF PROBABILITIES GREATER THAN 50 PERCENT
HIGHLIGHTED OVER NORTHERN CALIFORNIA. SOME CONSIDERATION WAS GIVEN TO EXPANDING
THIS GREATER THAN 50 PERCENT AREA NORTHWARD TO OREGON AND WASHINGTON BUT HELD
OFF GIVEN THE HIGHER CLIMATOLOGY IN THESE REGIONS, AND THE STRONGEST DAILY
PRECIPITATION SIGNALS IN THE ECMWF ENSEMBLE NOT EMERGING UNTIL DAY-10.
DOWNSTREAM ACROSS THE REMAINDER OF THE CONUS, INCREASING PACIFIC FLOW AND A
LESS AMPLIFIED PATTERN FAVOR ELEVATED PROBABILITIES OF ABOVE-NORMAL
PRECIPITATION EXPANDING NORTHWARD COMPARED TO THE 6-10 DAY PERIOD, WITH A
SLIGHT TILT TOWARD ELEVATED PROBABILITIES FOR BELOW-NORMAL PRECIPITATION
REMAINING ACROSS THE NORTHERN TIER. INCREASED SOUTHERLY ONSHORE FLOW ACROSS
ALASKA SUPPORTS ELEVATED CHANCES OF NEAR- TO ABOVE-NORMAL PRECIPITATION OVER
THE STATE. PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE INCREASED OVER
HAWAII AS WELL, CONSISTENT WITH THE UNCALIBRATED GEFS AND ECMWF ENSEMBLES.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 10% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO BETTER
MODEL AGREEMENT REGARDING THE MID-LEVEL PATTERN COMPARED TO YESTERDAY, BUT WITH
INCREASING UNCERTAINTY RELATED TO A TRANSITIONAL PATTERN, AND CONTINUED DAY TO
DAY CHANGES SEEN IN THE FORECAST TOOLS.
FORECASTER: THOMAS COLLOW
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:
19591130 - 19691127 - 20021121 - 19631130 - 19541122
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:
19591129 - 20021122 - 19621101 - 19541121 - 20061205
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 28 - DEC 02, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF N A IDAHO N B NEVADA N B
W MONTANA A B E MONTANA A B WYOMING B B
UTAH B B ARIZONA B A COLORADO B B
NEW MEXICO B A N DAKOTA A B S DAKOTA A B
NEBRASKA N B KANSAS B B OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N B IOWA N B MISSOURI B B
ARKANSAS B N LOUISIANA B A WISCONSIN B B
ILLINOIS B B MISSISSIPPI B N MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B N NEW YORK B B
VERMONT B B NEW HAMP B B MAINE B B
MASS B B CONN B B RHODE IS B B
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B N S CAROLINA B N GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 30 - DEC 06, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF N A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A B WYOMING A N
UTAH A A ARIZONA A A COLORADO A N
NEW MEXICO A A N DAKOTA A B S DAKOTA A B
NEBRASKA A N KANSAS A A OKLAHOMA A A
N TEXAS N A S TEXAS N A W TEXAS A A
MINNESOTA A B IOWA A N MISSOURI A A
ARKANSAS A A LOUISIANA N A WISCONSIN A N
ILLINOIS A N MISSISSIPPI N A MICHIGAN A B
INDIANA A N OHIO N N KENTUCKY N A
TENNESSEE N A ALABAMA N A NEW YORK B N
VERMONT B N NEW HAMP B N MAINE B B
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA N N
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA N A
FL PNHDL N A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN A N AK WESTERN A N AK INT BSN A A
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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