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FXUS06 KWBC 302056
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST THU NOVEMBER 30 2023
6-10 DAY OUTLOOK FOR DEC 06 - 10 2023
THE GEFS, CANADIAN, AND ECMWF ENSEMBLE MEANS ARE IN GOOD AGREEMENT THAT THE 6
TO 10 DAY PERIOD STARTS WITH AN AMPLIFIED 500-HPA TROUGH EXTENDING FROM ALASKA
SOUTHWARD INTO THE NORTHEASTERN NORTH PACIFIC, A MODERATELY AMPLIFIED MID-LEVEL
RIDGE EXTENDING FROM THE INTERMOUNTAIN WEST AND DESERT SOUTHWEST TO THE
MISSISSIPPI VALLEY, AND A MODERATELY AMPLIFIED MID-LEVEL TROUGH PUSHING FROM
THE EASTERN CONTIGUOUS U.S. (CONUS) INTO THE ATLANTIC OCEAN. GUIDANCE GENERALLY
SHOWS THESE FEATURES TO BE PROGRESSIVE, MOVING EASTWARD, AND DEAMPLIFYING
DURING THE FIRST HALF OF THE PERIOD. THE RESULT IS A PROGRESSIVE PATTERN OF
WEAKLY- TO MODERATELY-AMPLIFIED FEATURES THAT TRACK STEADILY ACROSS THE CONUS,
RESULTING IN A RELATIVELY ZONAL MEAN PATTERN. MORE PERSISTENT MID-LEVEL
FEATURES ARE PRESENT AT HIGHER LATITUDES, WITH A HIGHLY-AMPLIFIED 500-HPA RIDGE
BUILDING NEAR THE WESTERN BERING SEA, AND MODERATELY ABOVE-NORMAL MID-LEVEL
HEIGHTS CENTERED OVER NORTHERN CANADA.
AS THE NORTH PACIFIC MID-LEVEL TROUGH TRACKS EASTWARD INTO THE PACIFIC
NORTHWEST, ENHANCED PACIFIC FLOW IS LIKELY TO EXTEND ACROSS A LARGE PART OF THE
CONUS, FAVORING ABOVE-NORMAL PRECIPITATION ACROSS THE NORTHWESTERN QUARTER OF
THE COUNTRY AND INTO THE NORTHERN GREAT PLAINS. THE BEST CHANCES FOR
ABOVE-NORMAL PRECIPITATION COVER PORTIONS OF THE NORTHWEST BETWEEN THE PACIFIC
COAST AND THE CASCADES, WHERE ODDS EXCEED 50 PERCENT.
WITH MILD PACIFIC AIR COVERING MUCH OF THE NATION, ABOVE-NORMAL TEMPERATURES
ARE FAVORED OVER MOST OF THE CONUS FROM THE OHIO, TENNESSEE, AND LOWER
MISSISSIPPI VALLEYS WESTWARD TO THE PACIFIC COAST. STRONG DOWNSLOPING SURFACE
FLOW RESULTS IN ABOVE-NORMAL TEMPERATURE PROBABILITIES EXCEEDING 80 PERCENT
ACROSS THE NORTHERN AND CENTRAL GREAT PLAINS. FORECAST CONFIDENCE IN THE
TEMPERATURE OUTLOOK IS CONSIDERABLY LOWER IN THE EASTERN CONUS DUE TO HIGHLY
INCONSISTENT GUIDANCE REGARDING THE EVOLUTION OF A POTENTIAL SURFACE LOW
PRESSURE SYSTEM IN THE WESTERN NORTH ATLANTIC EARLY IN THE PERIOD, THE STRENGTH
OF COLD AIR ADVECTION IN ITS WAKE, AND HOW QUICKLY THE ASSOCIATED MID-LEVEL
TROUGH MOVES AWAY FROM THE EAST COAST. THE 6-10 DAY OUTLOOK LEANS WARMER THAN
YESTERDAY IN THIS REGION, RESTRICTING ENHANCED CHANCES FOR SUBNORMAL
TEMPERATURES TO COASTAL NEW ENGLAND AND THE FLORIDA PENINSULA. THE EUROPEAN
ENSEMBLE MEAN HOLDS NEAR- TO BELOW-NORMAL 500-HPA HEIGHTS OVER THE EASTERN
CONUS LONGER THAN THE GEFS AND CANADIAN ENSEMBLE MEANS, BUT GIVEN THE EXPECTED
PROGRESSIVE NATURE OF THE PATTERN, THE GEFS AND CANADIAN ENSEMBLE SOLUTIONS ARE
PREFERRED. THIS WOULD HAVE PRECIPITATION MOVING OUT OF THE EASTERN CONUS BEFORE
DAY 6 (DECEMBER 6), WITH SLIGHTLY ABOVE-NORMAL MID-LEVEL HEIGHTS AND MILDER AIR
PUSHING INTO THE EASTERN CONUS BY DAY 8 (DECEMBER 8).
BELOW-NORMAL PRECIPITATION IS FAVORED FOR THE NORTHEAST, WITH ANY SURFACE STORM
SYSTEM MOVING AWAY FROM THE CONUS WHILE THE MID-LEVEL RIDGE MOVES EASTWARD FROM
THE PLAINS, RESULTING IN ANTICYCLONIC MID-LEVEL FLOW AND BUILDING 500-HPA
HEIGHTS. BELOW-NORMAL PRECIPITATION IS ALSO FAVORED FOR MOST OF THE SOUTHERN
TIER OF THE NATION, REACHING AS FAR NORTH AS THE CENTRAL GREAT PLAINS, BASED ON
MODEL CONSENSUS OF A MEAN NORTHERLY SURFACE FLOW EAST AND SOUTH OF A HIGH
PRESSURE SYSTEM OVER THE CENTRAL ROCKIES. AREAS FROM SOUTHERN TEXAS EASTWARD
ACROSS THE CENTRAL GULF COAST ARE AN EXCEPTION, AS ENSEMBLE MEANS SHOW THE
REMNANT OF THE NORTH PACIFIC MID-LEVEL TROUGH DIVING SOUTHEASTWARD INTO THE
SOUTHERN ROCKIES LATE IN THE PERIOD. THIS WOULD TRIGGER SURFACE LOW PRESSURE
DEVELOPMENT OVER OR NEAR THE WESTERN GULF OF MEXICO, ADVECTING ANOMALOUSLY
MOIST AIR AND PRECIPITATION INTO THE REGION ON DAYS 9 AND 10 (DECEMBER 9-10).
TOOLS FAVOR A SLIGHT LEAN TOWARDS ABOVE-NORMAL PRECIPITATION IN DEEP SOUTH
TEXAS, BUT TOOLS ARE LESS CONSISTENT FARTHER NORTH AND EAST, SO NEITHER
ABNORMALLY DRY NOR WET WEATHER IS FAVORED FROM THE LOWER BIG BEND EASTWARD
THROUGH SOUTHERN PARTS OF THE LOWER MISSISSIPPI VALLEY.
MODEL SOLUTIONS FEATURE A STRENGTHENING RIDGE OVER THE ALEUTIANS WHICH IS
LIKELY TO RESULT IN BELOW-NORMAL TEMPERATURES ACROSS MUCH OF SOUTHWESTERN
ALASKA. NEAR TO ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE REMAINDER
OF ALASKA WITH MODEST ONSHORE FLOW. THE RIDGE OVER THE ALEUTIANS FAVORS
BELOW-NORMAL PRECIPITATION FOR PARTS OF SOUTHWESTERN ALASKA, WHILE ABOVE-NORMAL
PRECIPITATION IS MORE LIKELY ACROSS EASTERN ALASKA DUE TO AN EASTERN GULF OF
ALASKA TROUGH AND A MEAN SURFACE LOW PRESSURE SYSTEM IN THE NORTH PACIFIC OCEAN
NEAR THE MAINLAND.
THE 6-10 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS FOR HAWAII ARE BASED ON THE
CONSOLIDATION TOOL. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR THE ENTIRE
HAWAIIAN ISLAND CHAIN, ESPECIALLY FROM WESTERN PARTS OF THE BIG ISLAND TO
EASTERN OAHU, WHERE ODDS FOR ABOVE-NORMAL TEMPERATURES EXCEED 50 PERCENT. NEAR
NORMAL PRECIPITATION IS FAVORED THROUGHOUT THE STATE.
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 GFS SUPERENSEMBLE MEAN CENTERED
ON DAY 8, 15% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 15%
OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT AMONG THE TOOLS ON TEMPERATURE AND PRECIPITATION PATTERNS, TEMPERED
BY INCONSISTENCIES REGARDING THE TIMING AND EVOLUTION OF SOME FEATURES INHERENT
TO A PROGRESSIVE FLOW PATTERN WITH RELATIVELY WEAK MID-LEVEL SYSTEMS,
PARTICULARLY ALONG THE GULF COAST.
8-14 DAY OUTLOOK FOR DEC 08 - 14 2023
THE GEFS, ECMWF, AND CANADIAN ENSEMBLE MEANS HAVE TRENDED TOWARDS A BUILDING
RIDGE OVER THE ALEUTIANS DURING WEEK-2 AND THE PERSISTENCE OF
MODERATELY-ELEVATED 500-HPA HEIGHTS ACROSS FAR NORTHERN CANADA. AT LOWER
LATITUDES, GUIDANCE SHOWS THE LONGWAVE PATTERN REMAINING PROGRESSIVE. THE RIDGE
UPSTREAM OVER THE ALEUTIANS COULD EVENTUALLY LEAD TO STRENGTHENING ARCTIC HIGH
PRESSURE AT THE HIGH LATITUDES OF WESTERN NORTH AMERICA. THIS EVOLVING PATTERN
WILL HAVE TO BE CLOSELY MONITORED FOR A POTENTIAL PATTERN CHANGE BEYOND THE
WEEK-2 PERIOD. THE TEMPERATURE OUTLOOK, VALID FOR DECEMBER 8 TO 14, CONTINUES
TO FAVOR ABOVE-NORMAL TEMPERATURES FOR NEARLY ALL OF THE CONUS DUE TO A ZONAL
MID-LEVEL PATTERN FLOODING THE CONUS WITH MILD PACIFIC AIR. THE ONLY EXCEPTION
IS IN THE NORTHWESTERN CONUS, WHERE COOLER AIR FROM NORTHWESTERN NORTH AMERICA
MAY BEGIN TO MOVE IN LATE IN THE PERIOD. .
SLIGHTLY-INCREASED ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE FORECAST ACROSS
A LARGE PART OF THE NATION, BUT ODDS EXCEED 40 PERCENT ONLY IN PARTS OF THE
NORTHERN HIGH PLAINS AND ALONG THE GULF COAST. DYNAMIC AND RE-CALIBRATED MODEL
GUIDANCE FAVORS UNUSUALLY WET WEATHER MOST CONSISTENTLY IN EASTERN PARTS OF
WYOMING AND SOME ADJACENT AREAS WHILE THE CANADIAN, EUROPEAN, AND GEFS ENSEMBLE
MEANS ALL SHOW THE POTENTIAL FOR ENHANCED SOUTHERLY FLOW FROM THE GULF OF
MEXICO BRINGING ABOVE-NORMAL PRECIPITATION TO AREAS ALONG THE GULF COAST.
ENHANCED ODDS FOR BELOW-NORMAL PRECIPITATION IN THE CONUS ARE LIMITED TO PARTS
OF THE SOUTHWEST, AND DO NOT EXCEED 40 PERCENT.
DOWNSTREAM OF THE AMPLIFIED RIDGE AXIS, BELOW-NORMAL PRECIPITATION IS FAVORED
FOR SOUTHWESTERN ALASKA AND THE ALASKA PENINSULA. BASED ON A CONSENSUS OF THE
TOOLS, SLIGHTLY ELEVATED ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE FORECAST
ACROSS MUCH OF EASTERN AND NORTHERN ALASKA UNDER SUBNORMAL 500-HPA HEIGHT
DOWNSTREAM FROM THE AMPLIFIED ALEUTIAN RIDGE. NORTH TO NORTHEAST SURFACE FLOW
SUPPORTS INCREASED BELOW-NORMAL TEMPERATURE PROBABILITIES ACROSS MOST OF THE
MAINLAND EXCEPT THE FAR NORTHERN TIER, WITH ODDS TOPPING 50 PERCENT IN
SOUTHWESTERN PARTS OF THE MAINLAND AND THE ADJACENT ALEUTIANS.
THE WEEK-2 TEMPERATURE OUTLOOK FOR HAWAII IS BASED ON THE CONSOLIDATION TOOL
AND FAVORS WARMER THAN NORMAL CONDITIONS ACROSS THE STATE, PARTICULARLY FROM
THE NORTHERN BIG ISLAND THROUGH OAHU, WHERE ODDS EXCEED 50 PERCENT. INCREASED
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE FORECAST FOR WESTERN HAWAII WHICH
MAY BE RELATED TO THE MJO SHIFTING EAST FROM THE INDIAN OCEAN TO THE
WEST-CENTRAL PACIFIC DURING THE NEXT TWO WEEKS, BUT THE SIGNAL HAS WEAKENED
RELATIVE TO YESTERDAY FARTHER EAST ACROSS MOLOKAI, MAUI, HAWAII ISLANDS, AND
ADJACENT AREAS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 45% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S GFS SUPERENSEMBLE MEAN
CENTERED ON DAY 11, 15% 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 DECENT
AGREEMENT AMONG THE VARIOUS TEMPERATURE AND PRECIPITATION TOOLS OFFSET BY
UNCERTAINTIES INHERENT TO THE EXPECTED PROGRESSIVE, TRANSIENT PATTERN OVER THE
CONUS.
FORECASTER: RICH TINKER
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:
19881214 - 20001120 - 19891120 - 19571202 - 19851214
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:
19891119 - 20001119 - 19881213 - 19571202 - 19761122
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 06 - 10 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 A B COLORADO A N
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A B MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A B
TENNESSEE A B ALABAMA N B NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS B B CONN B B RHODE IS B B
PENN N B NEW JERSEY N B W VIRGINIA A B
MARYLAND N B DELAWARE N B VIRGINIA N B
N CAROLINA N B S CAROLINA N B GEORGIA N B
FL PNHDL N B FL PENIN B B AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B N AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 08 - 14 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO N N NEVADA A N
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A N ARIZONA A B COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
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 N ALABAMA A A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A N CONN A N RHODE IS A N
PENN A A NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B N
AK S INT B N AK SO COAST B N AK PNHDL B N
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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