663
FXUS06 KWBC 252008
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 25 2024
6-10 DAY OUTLOOK FOR DEC 01 - 05 2024
TODAY’S MODEL SOLUTIONS FROM THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS FOR
500-HPA HEIGHTS AND ANOMALIES ALL DEPICT A LOW FREQUENCY WAVE TRAIN PATTERN
OVER NORTH AMERICA DURING THE 6-10 DAY PERIOD AVERAGE, WITH RIDGING FORECAST
OVER THE WEST COAST AND TROUGHING OVER THE EASTERN CONTIGUOUS U.S. (CONUS).
MODELS ARE IN GOOD AGREEMENT WITH REGARD TO BOTH THE POSITION AND AMPLITUDE OF
THESE FEATURES, INCREASING FORECAST CONFIDENCE.
A STRONG COLD FRONT AND AN ASSOCIATED COLD AIRMASS ARE FAVORED TO MOVE OVER THE
CONUS EAST OF THE ROCKIES DURING THE WEEK-1 PERIOD, RESULTING IN A STRONG TILT
TOWARDS BELOW-NORMAL TEMPERATURES, ESPECIALLY EAST OF THE MISSISSIPPI RIVER
WHERE PROBABILITIES GREATER THAN AT LEAST 50% ARE ALMOST UNIVERSAL AND
EXCEEDING 80% FOR THE MID-ATLANTIC AND ADJACENT REGIONS. MEANWHILE, AMPLIFIED
RIDGING OVER THE WEST COAST FAVORS ABOVE-NORMAL TEMPERATURES ROUGHLY FROM THE
ROCKIES WESTWARD PARTICULARLY FOR MUCH OF CALIFORNIA AND THE DESERT SOUTHWEST
WHERE PROBABILITIES EXCEED 50%. WIDESPREAD POSITIVE HEIGHT ANOMALIES OVER
EASTERN SIBERIA AND THE BERING SEA FAVOR BELOW-NORMAL TEMPERATURES FOR MUCH OF
MAINLAND ALASKA, WHILE STRONG ONSHORE FLOW OFF THE GULF OF ALASKA TILTS THE
ODDS TOWARD ABOVE-NORMAL TEMPERATURES FOR THE PANHANDLE. ABOVE-NORMAL
TEMPERATURES ARE ALSO FAVORED FOR HAWAII, CONSISTENT WITH MODEL GUIDANCE.
MODEL SOLUTIONS OF THE RIDGE OVER THE WEST COAST DEPICT A VERY HIGH AMPLITUDE
FEATURE WITH POSITIVE HEIGHT ANOMALIES EXTENDING WELL NORTH OF THE U.S.-CANADA
BORDER, LIMITING PACIFIC MOISTURE FLUXES INTO THE CONTINENT AND FAVORING
BELOW-NORMAL PRECIPITATION FOR MUCH OF THE LOWER 48. ODDS ARE HIGHEST FOR
NORTHERN CALIFORNIA AND EXTENDING INTO THE GREAT BASIN WHERE PROBABILITIES
EXCEED 50%. EASTERLY RETURN FLOW IS DEPICTED OVER THE GULF OF MEXICO, TILTING
THE ODDS TOWARD ABOVE-NORMAL PRECIPITATION FOR PORTIONS OF THE SOUTHERN PLAINS.
ALTHOUGH A STRONG RIDGE IS FAVORED OVER THE WEST COAST, THE POTENTIAL FOR AN
ALBERTA-TYPE CLIPPER SYSTEM SLIGHTLY FAVORS ABOVE-NORMAL PRECIPITATION FOR
PORTIONS OF THE NORTHERN PLAINS. STRONG ONSHORE FLOW INTO SOUTHEASTERN ALASKA
FAVORS ABOVE-NORMAL PRECIPITATION FOR THE PANHANDLE AND THE SOUTHEASTERN
MAINLAND, WHILE THE WESTERN AND NORTHERN PORTIONS TILT TOWARDS BELOW-NORMAL
PRECIPITATION UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. GUIDANCE IS MIXED WITH
REGARD TO PRECIPITATION OVER HAWAII, SO NEAR-NORMAL PRECIPITATION IS FAVORED
FOR THE ISLANDS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 34% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 33% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: VERY HIGH, 5 OUT OF 5, WITH STRONG
AGREEMENT AMONG FORECAST MODELS ACROSS VARIABLES.
8-14 DAY OUTLOOK FOR DEC 03 - 09 2024
MODEL ENSEMBLES FAVOR A PERSISTENCE OF THE SYNOPTIC PATTERN FROM THE 6-10 DAY
PERIOD. LIKE THE EARLY PERIOD, THE WEEK-2 500-HPA MANUAL HEIGHT BLEND FEATURES
AMPLIFIED RIDGING OVER THE WEST COAST AND A BROAD TROUGH OVER THE EASTERN CONUS
AND NORTH ATLANTIC. THE WEEK-2 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE ALSO
VERY SIMILAR TO THE 6-10 PERIOD, ONCE AGAIN WITH HIGH FORECAST CONFIDENCE DUE
TO BOTH THE PERSISTENT PATTERN AS WELL AS GOOD MODEL AGREEMENT.
CONTINUED POSITIVE 500-HPA HEIGHT ANOMALIES OVER WESTERN NORTH AMERICA CONTINUE
TO FAVOR ABOVE-NORMAL TEMPERATURES FOR THE CONUS WEST OF THE ROCKIES. CHANCES
OF ABOVE-NORMAL TEMPERATURES ARE INCREASED FROM THE EARLIER FORECAST PERIOD,
WITH AT LEAST 50% CHANCES FAVORED WEST OF THE ROCKIES. THE TROUGH OVER THE
EASTERN CONUS DEPICTED OVER THE EASTERN CONUS DURING THE 6-10 DAY PERIOD IS
FAVORED TO WEAKEN SOMEWHAT, SLIGHTLY REDUCING CHANCES OF BELOW-NORMAL
TEMPERATURES FOR THE EASTERN HALF OF THE COUNTRY. PROBABILITIES REMAIN ABOVE
70% FOR MUCH OF THE MID-ATLANTIC AND NEIGHBORING REGIONS WHERE COLD AIR IS
FAVORED TO LINGER THROUGHOUT THE PERIOD. WITH CONTINUED ONSHORE FLOW OFF THE
GULF OF ALASKA, CHANCES OF ABOVE-NORMAL TEMPERATURES CONTINUE OVER SOUTHEASTERN
ALASKA AND ARE FAVORED TO SPREAD FURTHER INTO THE MAINLAND, POTENTIALLY
REACHING AS FAR AS THE ALASKAN INTERIOR. PORTIONS OF WESTERN AND NORTHERN
ALASKA CONTINUE TO TILT TOWARDS BELOW-NORMAL TEMPERATURES UNDER THE CONTINUED
INFLUENCE OF RIDGING OVER EASTERN SIBERIA. PERSISTENCE IS ALSO THE PREFERRED
SOLUTION FOR THE HAWAIIAN ISLANDS, WITH THE WHOLE STATE FAVORED FOR
ABOVE-NORMAL TEMPERATURES.
CONTINUED AMPLIFIED RIDGING OVER THE WESTERN CONUS FAVORS BELOW-NORMAL
PRECIPITATION TO PERSIST FOR MUCH OF THE LOWER 48 THROUGH WEEK-2. CHANCES ARE
SLIGHTLY REDUCED OVER THE CENTRAL PLAINS AND INTO THE OHIO VALLEY AND
MID-ATLANTIC BUT REMAIN ABOVE 50% FOR MUCH OF NORTHERN CALIFORNIA AND THE GREAT
BASIN. CONTINUED RETURN FLOW OFF THE GULF OF MEXICO KEEPS PORTIONS OF THE
SOUTHERN PLAINS TILTING TOWARDS ABOVE-NORMAL PRECIPITATION, WHILE ALBERTA
CLIPPERS REMAIN A POSSIBILITY ALONG THE U.S.-CANADA BORDER, TILTING THE ODDS
SLIGHTLY TOWARD ABOVE-NORMAL PRECIPITATION FOR PORTIONS OF THE NORTHERN PLAINS.
AS ONSHORE FLOW CONTINUES OFF THE GULF OF ALASKA THE TILT TOWARDS ABOVE-NORMAL
PRECIPITATION IS FAVORED TO SPREAD FURTHER INTO THE MAINLAND COVERING MOST OF
THE STATE, EXCEPT ALONG THE WESTERN COAST WHERE NEAR-NORMAL PRECIPITATION IS
INDICATED. NEAR-NORMAL PRECIPITATION IS ALSO FAVORED FOR THE HAWAIIAN ISLANDS
WHERE MODEL GUIDANCE CONTINUES TO BE MIXED.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 34% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 33% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, WITH
GOOD AGREEMENT AMONG FORECAST MODELS ACROSS VARIABLES, OFFSET BY DIFFERENCES IN
DEPICTED AMPLITUDE OF SYNOPTIC FEATURES AND WEAKER ANOMALIES DURING THE
FORECAST PERIOD
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
DECEMBER 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:
19631113 - 19611127 - 19731111 - 19811209 - 19661201
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:
19631114 - 19611127 - 19801202 - 19731110 - 19651115
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 01 - 05 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B NRN CALIF A B
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A B E MONTANA B N WYOMING A B
UTAH A B ARIZONA A N COLORADO A B
NEW MEXICO A B N DAKOTA B A S DAKOTA B N
NEBRASKA B B KANSAS B B OKLAHOMA B B
N TEXAS B A S TEXAS B A W TEXAS N N
MINNESOTA B N IOWA B B MISSOURI B B
ARKANSAS B B LOUISIANA B A WISCONSIN B B
ILLINOIS B B MISSISSIPPI B B MICHIGAN B N
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B 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 B S CAROLINA B B GEORGIA B B
FL PNHDL B B FL PENIN B B AK N SLOPE B B
AK ALEUTIAN B B AK WESTERN B B AK INT BSN B N
AK S INT B A AK SO COAST N A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 03 - 09 2024
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 B NEVADA A B
W MONTANA A A E MONTANA A A WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A A W TEXAS A B
MINNESOTA B N IOWA B B MISSOURI B B
ARKANSAS B B LOUISIANA B N WISCONSIN B N
ILLINOIS B B MISSISSIPPI B N MICHIGAN B N
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B 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 B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B N AK INT BSN N 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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