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FXUS06 KWBC 052030
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 05 2023
6-10 DAY OUTLOOK FOR DEC 11 - 15 2023
TODAY’S ENSEMBLE MEAN MODEL SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE
500-HPA MEAN FLOW PATTERN ACROSS NORTH AMERICA AND ADJACENT OCEANIC AREAS
DURING THE 6-10 DAY FORECAST PERIOD. ANOMALY CORRELATION SCORES FOR THE PAST 60
DAYS DO NOT SIGNIFICANTLY FAVOR ONE MODEL OVER ANOTHER, HENCE THE MANUAL HEIGHT
BLEND IS COMPOSED OF NEARLY EQUAL WEIGHTS OF THE 00Z RUNS OF THE GFS, ECMWF,
AND CANADIAN ENSEMBLE MEANS. THE MANUAL HEIGHT BLEND DEPICTS MID-LEVEL RIDGING
AND ABOVE NORMAL 500-HPA HEIGHTS OVER FAR EASTERN SIBERIA, AND MID-LEVEL
TROUGHING AND MODESTLY BELOW NORMAL 500-HPA HEIGHTS OVER MOST OF ALASKA. A
BROAD RIDGE AND ABOVE NORMAL 500-HPA HEIGHTS ARE PREDICTED NEAR THE WEST COAST
OF NORTH AMERICA. THIS RIDGE IS FORECAST TO BE SIGNIFICANTLY MORE AMPLIFIED
THAN IT WAS YESTERDAY ON THE MANUAL HEIGHT BLEND. DOWNSTREAM, OVER MUCH OF THE
CENTRAL AND EASTERN CONTIGUOUS U.S. (CONUS), THE MANUAL HEIGHT BLEND DEPICTS AN
ANOMALOUS MID-LEVEL TROUGH OVER THE GREAT LAKES REGION, OHIO VALLEY, AND
NORTHEAST.
THE 6-10 DAY TEMPERATURE OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES OVER
CALIFORNIA, SOUTHWESTERN PORTIONS OF OREGON AND UTAH, AND MOST OF NEVADA AND
ARIZONA. PROBABILITIES FAVORING ABOVE NORMAL TEMPERATURES EXCEED 60% OVER PARTS
OF COASTAL SOUTHERN CALIFORNIA. ODDS ALSO FAVOR ABOVE NORMAL TEMPERATURES OVER
THE VICINITY OF THE DAKOTAS, THE NORTHEAST, AND SOUTHERN FLORIDA. ALL OF THESE
FAVORED AREAS OF RELATIVE WARMTH ARE SUPPORTED BY THE CONSOLIDATION AND
AUTOMATED TEMPERATURE TOOLS. ODDS FAVOR BELOW NORMAL TEMPERATURES FROM CENTRAL
NEW MEXICO EASTWARD ACROSS THE SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND
PARTS OF THE SOUTHEAST. THIS IS ALSO SUPPORTED BY THE CONSOLIDATION AND
AUTOMATED TEMPERATURE TOOLS. NEAR NORMAL TEMPERATURES ARE FAVORED FOR REMAINING
AREAS OF THE CONUS, WHICH ENCOMPASS A LARGE FRACTION OF THE LOWER 48 STATES.
THIS INCLUDES PORTIONS OF THE NORTHERN INTERMOUNTAIN REGION AND CENTRAL
ROCKIES, WHERE PRE-EXISTING SNOW COVER FAVORS RADIATIONAL COOLING AND THE
OVERALL REDUCTION OF TEMPERATURES. BELOW NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER WESTERN ALASKA, DUE TO A MID-LEVEL TROUGH AND WIDESPREAD
NORTHERLY FLOW PREDICTED OVER THE AREA. WITH THE MORE AMPLIFIED MID-LEVEL RIDGE
NOW PREDICTED OVER THE WEST COAST OF NORTH AMERICA IN TODAY’S MODEL RUNS, THERE
IS A TILT IN THE ODDS TOWARDS ABOVE NORMAL TEMPERATURES ACROSS SOUTHEASTERN
ALASKA. FOR HAWAII, RELATIVELY WARM SEA-SURFACE TEMPERATURES AND A VERY WEAK
MID-LEVEL HEIGHT ANOMALY PATTERN FAVOR ABOVE NORMAL TEMPERATURES FOR THE
ISLANDS, SUPPORTED BY THE ERF-CON TEMPERATURE TOOL.
THE 6-10 DAY PRECIPITATION OUTLOOK FAVORS BELOW NORMAL PRECIPITATION FOR MOST
OF THE LOWER 48 STATES, ASSOCIATED WITH WIDESPREAD NORTHWESTERLY AND WESTERLY
MID-LEVEL FLOW. THIS IS CONSISTENT WITH REFORECAST-CALIBRATED PRECIPITATION
FROM THE THREE ENSEMBLE MEANS. RELATIVELY SMALL-SCALE AREAS OF FAVORED ABOVE
NORMAL PRECIPITATION ARE DEPICTED OVER MAINE, FLORIDA, AND MUCH OF TEXAS. FOR
MOST OF ALASKA, ABOVE NORMAL PRECIPITATION CHANCES ARE ENHANCED, DUE TO THE
PROXIMITY OF A MID-LEVEL TROUGH OVER THE WESTERN PART OF THE STATE, AND AN
AMPLIFYING RIDGE OVER THE SOUTHEASTERN PART OF THE STATE. THIS OVERALL PATTERN
IS CONDUCIVE TO WIDESPREAD ONSHORE FLOW ACROSS ALASKA. WELL TO THE SOUTH, NEAR
NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE HAWAIIAN ISLANDS, WITH THE
EXCEPTION OF THE SOUTHERN PORTION OF THE BIG ISLAND WHERE THERE IS A SLIGHT
TILT TOWARDS BELOW NORMAL PRECIPITATION. THIS IS CONSISTENT WITH THE
AUTO-PRECIPITATION AND ERF-CON PRECIPITATION TOOLS.
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 ON A SCALE OF
1-5, BASED ON FAIRLY GOOD AGREEMENT AMONG THE VARIOUS 500-HPA HEIGHT MODELS,
AND THE SURFACE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR DEC 13 - 19 2023
TODAY’S 00Z ENSEMBLE MEAN SOLUTIONS FROM THE GFS, ECMWF, AND CANADIAN DYNAMICAL
MODELS ARE IN GOOD AGREEMENT ON THE PREDICTED LARGE-SCALE 500-HPA HEIGHT
PATTERN ACROSS THE FORECAST DOMAIN. THESE SOLUTIONS DEPICT A BROAD ANOMALOUS
RIDGE OVER MOST OF THE CONUS, AND A SMALLER-SCALE ANOMALOUS RIDGE IN THE
GENERAL VICINITY OF 35N-40N/160W-165W (NORTH-NORTHWEST OF THE HAWAIIAN
ISLANDS). NEGATIVE 500-HPA HEIGHT ANOMALIES ARE INDICATED OVER ALASKA, THE GULF
OF ALASKA, AND THE NORTHERN HALF OF CANADA. SOUTHERN STREAM ENERGY IS PREDICTED
TO MOVE INTO CALIFORNIA AND THE SOUTHWEST DURING WEEK-2, INCREASING THE
LIKELIHOOD FOR CLOUD COVER AND PRECIPITATION.
THE 8-14 DAY TEMPERATURE OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES ACROSS
APPROXIMATELY THE NORTHERN HALF TO TWO-THIRDS OF THE CONUS, ASSOCIATED WITH
MID-LEVEL ANOMALOUS RIDGING. THIS IS GENERALLY CONSISTENT WITH THE
REFORECAST-CALIBRATED TEMPERATURE TOOLS FROM THE VARIOUS ENSEMBLE MEANS.
HOWEVER, THERE IS HARDLY ANY STATISTICAL SUPPORT FOR FAVORED ABOVE NORMAL
TEMPERATURES ACROSS THE FAR SOUTHERN PORTIONS OF THE WEST, WHICH IS WHY THE
OUTLOOK FOR THAT REGION WAS LEFT AS FAVORING NEAR NORMAL. ABOVE NORMAL
TEMPERATURE CHANCES ARE ELEVATED OVER MOST OF FLORIDA. IN SOUTHEAST ALASKA,
ABOVE NORMAL TEMPERATURES ARE FAVORED, IN PROXIMITY TO A MID-LEVEL RIDGE. FOR
APPROXIMATELY THE WESTERN HALF OF ALASKA, ODDS TILT TOWARDS BELOW NORMAL
TEMPERATURES DUE TO THE PROXIMITY OF A MID-LEVEL TROUGH AND BELOW NORMAL
500-HPA HEIGHTS. AS WAS THE CASE YESTERDAY, THE MID-LEVEL TROUGH PREDICTED OVER
MUCH OF ALASKA IS FORECAST TO BE DEEPER DURING WEEK-2 THAN DURING THE EARLIER
6-10 DAY PERIOD. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE HAWAIIAN
ISLANDS, CONSISTENT WITH ERF-CON AND AUTOMATED TEMPERATURE GUIDANCE.
THE 8-14 DAY PRECIPITATION OUTLOOK FAVORS ABOVE NORMAL PRECIPITATION OVER
CALIFORNIA AND ADJACENT PARTS OF NEVADA. PREDICTED SURFACE HIGH PRESSURE OVER
THE SOUTHEAST LEADS TO MOIST, EASTERLY FLOW AND INCREASED CHANCES OF ABOVE
NORMAL PRECIPITATION FOR FLORIDA AND NEIGHBORING PARTS OF THE SOUTHERN ATLANTIC
COAST. RETURN FLOW AROUND THIS SURFACE ANTICYCLONE TILTS THE ODDS TOWARDS ABOVE
NORMAL PRECIPITATION FOR MUCH OF THE SOUTHERN AND CENTRAL PLAINS, ASSOCIATED
WITH AN EXPECTED INCREASE IN LOW-LEVEL GULF MOISTURE. BELOW NORMAL
PRECIPITATION IS FAVORED FROM THE NORTHERN INTERMOUNTAIN REGION AND NORTHERN
HALF OF THE ROCKIES EASTWARD ACROSS THE NORTHERN PLAINS, UPPER MISSISSIPPI
VALLEY, GREAT LAKES REGION, OHIO AND TENNESSEE VALLEYS, MOST OF THE
APPALACHIANS, AND THE ATLANTIC COASTAL PLAIN FROM MAINE TO THE DELMARVA
PENINSULA. THIS IS SUPPORTED BY THE AUTO-PRECIPITATION AND CONSOLIDATED
PRECIPITATION TOOLS. THIS IS ALSO CONSISTENT WITH PREDICTED WIDESPREAD
ANOMALOUS MID-LEVEL RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES. THE WEEK-2
PRECIPITATION OUTLOOK FOR ALASKA FAVORS NEAR NORMAL PRECIPITATION CHANCES
ACROSS FAR WESTERN PORTIONS OF ALASKA, AND ABOVE NORMAL PRECIPITATION CHANCES
ELSEWHERE, ASSOCIATED WITH A SIGNIFICANT MID-LEVEL TROUGH, BELOW NORMAL 500-HPA
HEIGHTS, AND CYCLONIC CURVATURE. NEAR NORMAL PRECIPITATION CHANCES ARE FAVORED
ACROSS MOST OF HAWAII, BASED ON A COMPROMISE BETWEEN THE ERF-CON PRECIPITATION
GUIDANCE AND THE AUTO-PRECIPITATION TOOL.
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 ON A SCALE OF
1-5, BASED ON FAIRLY GOOD AGREEMENT BETWEEN THE ENSEMBLE MEAN 500-HPA HEIGHT
FORECASTS, OFFSET BY SOME DISAGREEMENTS IN THE SURFACE TOOLS.
FORECASTER: ANTHONY A
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:
20031214 - 19601118 - 19811202 - 19881128 - 19591121
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:
19531125 - 19681119 - 20031215 - 19811202 - 19591120
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 11 - 15 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N B OREGON N B NRN CALIF A B
SRN CALIF A B IDAHO N B NEVADA A B
W MONTANA N B E MONTANA N B WYOMING N B
UTAH N B ARIZONA A B COLORADO N B
NEW MEXICO N B N DAKOTA A B S DAKOTA A B
NEBRASKA N B KANSAS N N OKLAHOMA N N
N TEXAS B B S TEXAS B A W TEXAS B N
MINNESOTA N B IOWA N B MISSOURI N B
ARKANSAS N B LOUISIANA B B WISCONSIN N B
ILLINOIS N B MISSISSIPPI B B MICHIGAN N B
INDIANA N B OHIO N B KENTUCKY N B
TENNESSEE N B ALABAMA B B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A A
MASS A N CONN A N RHODE IS A N
PENN N B NEW JERSEY A N W VIRGINIA N B
MARYLAND N N DELAWARE N N VIRGINIA N B
N CAROLINA N N S CAROLINA N B GEORGIA N B
FL PNHDL B N FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN N A
AK S INT N A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 13 - 19 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 A B NEVADA A N
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A N ARIZONA N N COLORADO A N
NEW MEXICO N 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 N A
MINNESOTA A B IOWA A N MISSOURI A A
ARKANSAS A N LOUISIANA N N WISCONSIN A B
ILLINOIS A N MISSISSIPPI N N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE N B ALABAMA N N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A B W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA N B
N CAROLINA N N S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B N AK INT BSN N A
AK S INT N A AK SO COAST B 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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