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FXUS06 KWBC 192007
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST TUE DECEMBER 19 2023
6-10 DAY OUTLOOK FOR DEC 25 - 29 2023
TODAY’S GEFS, CMCE, AND ECMWF SOLUTIONS OF THE 500-HPA ANOMALY FIELD DEPICT
DEEP TROUGHING OVER THE NORTH PACIFIC, WEAK NEGATIVE HEIGHT ANOMALIES OVER THE
SOUTH-CENTRAL AND SOUTHEASTERN CONTIGUOUS U.S. (CONUS), AND EXPANSIVE POSITIVE
HEIGHT ANOMALIES COVERING MUCH OF THE NORTHERN CONUS AND ALMOST ALL OF CANADA.
THIS SETUP FAVORS ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE CONUS AND
ABOVE-NORMAL PRECIPITATION FOR THE WEST COAST AND MOST OF THE LOWER 48 EAST OF
THE ROCKIES.
WITH POSITIVE HEIGHT ANOMALIES OVER CANADA CONFINING COLDER AIR TO HIGHER
LATITUDES, ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE CONUS,
ESPECIALLY FOR THE GREAT LAKES REGION WHERE PROBABILITIES EXCEED 80%. PACIFIC
AIR MOVING INTO THE WEST COAST FAVORS CLOUDIER CONDITIONS AND MODERATED
TEMPERATURES, PARTICULARLY FOR THE DESERT SOUTHWEST WHERE NEAR-NORMAL
TEMPERATURES ARE MOST LIKELY. RIDGING OVER CANADA AND TROUGHING OVER THE NORTH
PACIFIC FAVORS A SPLIT FORECAST FOR ALASKA, WITH BELOW (ABOVE)-NORMAL
TEMPERATURES INDICATED FOR WESTERN (EASTERN) PORTIONS OF THE STATE. MOST OF
HAWAII CONTINUES TO TILT TOWARDS ABOVE-NORMAL TEMPERATURES, ALTHOUGH
NEAR-NORMAL TEMPERATURES ARE FAVORED TO MOVE INTO SOUTHEASTERN PORTIONS OF THE
BIG ISLAND.
DEEP TROUGHING OVER THE NORTH PACIFIC AND A SECONDARY TROUGH OVER THE EASTERN
CONUS RESULTS IN A FAIRLY WET PATTERN FOR MUCH OF THE LOWER 48. PROBABILITIES
FOR ABOVE-NORMAL PRECIPITATION ARE HIGHEST FOR FLORIDA (>60%), AND ENHANCED
PROBABILITIES EXTEND UP THE EAST COAST. ABOVE-NORMAL PRECIPITATION IS ALSO
FAVORED FOR THE WEST COAST, PARTICULARLY FOR NORTHERN CALIFORNIA, BUT
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION DO NOT EXTEND VERY FAR INTO THE
GREAT BASIN, WHICH ALONG WITH ROCKIES AND PORTIONS OF THE NORTHERN PLAINS, TILT
TOWARDS BELOW-NORMAL PRECIPITATION. SOUTHERLY FLOW OFF THE NORTH PACIFIC TILTS
MOST OF ALASKA TOWARDS ABOVE-NORMAL PRECIPITATION,WHILE NEAR-NORMAL
PRECIPITATION IS MOST LIKELY FOR WESTERN PORTIONS OF THE STATE. BELOW-NORMAL
PRECIPITATION IS FAVORED FOR THE HAWAIIAN ISLANDS, SUPPORTED BY THE ERF-CON
HAWAII TOOL.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 34% 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: ABOVE AVERAGE, 4 OUT OF 5, WITH
VERY GOOD AGREEMENT AMONG ENSEMBLE MODELS AND FORECAST TOOLS, OFFSET BY LARGE
SHIFTS IN PRECIPITATION GUIDANCE RELATIVE TO YESTERDAY.
8-14 DAY OUTLOOK FOR DEC 27, 2023 - JAN 02, 2024
THE WEEK-2 FORECAST PERIOD FEATURES A SIMILAR SYNOPTIC PICTURE TO WHAT IS SEEN
IN THE 6-10 DAY PERIOD. MODEL 500-HPA HEIGHT ANOMALIES ARE MOSTLY DIMINISHED
RELATIVE TO THE EARLY PERIOD, ALTHOUGH MODEL SOLUTIONS FAVOR A SLIGHT DEEPENING
OF THE TROUGHING OVER THE SOUTHEAST U.S. AND A WEAKER TROUGH OVER THE NORTH
PACIFIC. THIS FAVORS CONTINUED ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE CONUS,
AND ABOVE-NORMAL PRECIPITATION FOR BOTH COASTS.
THE CONTINUED POSITIVE HEIGHT ANOMALIES OVER CANADA FAVOR A PERSISTENCE OF
ABOVE-NORMAL TEMPERATURES FOR MOST OF THE CONUS. THE HIGHEST PROBABILITIES
(>70%) ARE OVER THE UPPER MIDWEST AND NORTHERN PLAINS, SHIFTED SLIGHTLY
WESTWARD RELATIVE TO THE 6-10 DAY PERIOD. FALLING 500-HPA HEIGHTS OVER THE
SOUTHEAST U.S. INCREASE NORTHERLY FLOW INTO THE GULF COAST, RESULTING IN A
SLIGHT TILT TOWARDS BELOW-NORMAL TEMPERATURES FOR THAT REGION. THE SYNOPTIC
FLOW OVER ALASKA IS MOSTLY UNCHANGED FROM THE 6-10 DAY PERIOD, SO THE
WEST-EAST, BELOW-ABOVE NORMAL PATTERN FOR TEMPERATURES CONTINUES INTO WEEK-2.
FOR HAWAII, COOLER TEMPERATURES ARE FAVORED FOR THE SOUTHEASTERN PORTION OF THE
BIG ISLAND, WHILE THE NORTHWESTERN PART AND THE REST OF THE ISLANDS TILT
TOWARDS ABOVE-NORMAL TEMPERATURES.
ALTHOUGH MODEL SOLUTIONS FAVOR A WEAKENING OF THE TROUGH OVER THE NORTH PACIFIC
DURING WEEK-2, PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION FOR THE WEST COAST
REMAIN AT SIMILAR LEVELS TO THE 6-10 DAY PERIOD AND EXPAND SLIGHTLY EASTWARD AS
POSITIVE HEIGHT ANOMALIES OVER CANADA SHIFT TO THE EAST. THE TROUGH OVER THE
SOUTHEAST U.S. IS ALSO FAVORED TO SHIFT EASTWARD, RESULTING IN A WEAKER TILT
TOWARDS ABOVE-NORMAL PRECIPITATION FOR THE EAST COAST AND AN EASTWARD SHIFT IN
THE AREA FAVORED FOR BELOW-NORMAL PRECIPITATION TO COVER MOST OF THE GREAT
PLAINS, THE MISSISSIPPI, TENNESSEE, AND OHIO VALLEYS AS WELL AS PORTIONS OF
ALABAMA AND GEORGIA. ALASKA CONTINUES TO TILT TOWARD ABOVE-NORMAL PRECIPITATION
FOR MUCH OF THE STATE WITH CONTINUED MOIST ONSHORE FLOW OFF THE GULF OF ALASKA,
WHILE THE ERF-CON CONTINUES TO INDICATE BELOW-NORMAL PRECIPITATION FOR HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 34% 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 ON SYNOPTIC PATTERN AMONG DYNAMICAL MODELS, OFFSET BY WEAK
ANOMALIES AND PROBABILITIES FROM PRECIPITATION FORECAST TOOLS.
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 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:
19571214 - 19901210 - 19791202 - 19841207 - 19651207
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:
19571213 - 19901210 - 19841206 - 19571208 - 19911212
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 25 - 29 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A B NEVADA A A
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA N B COLORADO A B
NEW MEXICO N B N DAKOTA A B S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A N
N TEXAS A N S TEXAS N A W TEXAS N N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A 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 A
AK ALEUTIAN B N AK WESTERN B N 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 DEC 27, 2023 - JAN 02, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A N NEVADA A A
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A A ARIZONA A A COLORADO A N
NEW MEXICO A N N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A N OKLAHOMA A N
N TEXAS N N S TEXAS N N W TEXAS A N
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS N B LOUISIANA B N WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA N N NEW YORK A N
VERMONT A N NEW HAMP A A MAINE A N
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A N
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA N A GEORGIA N N
FL PNHDL B A FL PENIN B A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN A N
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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