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FXUS06 KWBC 171902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON APRIL 17 2023
6-10 DAY OUTLOOK FOR APR 23 - 27 2023
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED AMPLIFIED
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING
THE 6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE
ENSEMBLE MEANS FROM THE GFS, ECMWF, AND CANADIAN MODEL ENSEMBLES DUE TO RECENT
MODEL SKILL. THE RESULTANT MANUAL BLEND FEATURES ANOMALOUS MID-LEVEL TROUGHING
AND ASSOCIATED NEGATIVE 500-HPA HEIGHT ANOMALIES OVER ALASKA EXTENDING
SOUTHEASTWARD TO THE NORTHEAST PACIFIC. DOWNSTREAM WEAK ANOMALOUS RIDGING IS
FORECAST OVER THE WESTERN CONTIGUOUS U.S. (CONUS), WHILE AN ANOMALOUS TROUGH IS
SITUATED OVER THE EASTERN CONUS DURING THE 6-10 DAY PERIOD IN MODEL SOLUTIONS.
ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES ARE FAVORED OVER PARTS OF THE
GREAT PLAINS AND EASTERN HALF OF THE CONUS UNDER THE PREDICTED ANOMALOUS
MID-LEVEL TROUGH AND BELOW-NORMAL 500-HPA HEIGHT. ENHANCED PROBABILITIES OF
ABOVE-NORMAL TEMPERATURES EXCEEDING 80% ARE DEPICTED OVER PARTS OF THE OHIO AND
TENNESSEE VALLEY. PREDICTED WEAK MID-LEVEL ANOMALOUS RIDGING SUPPORTS NEAR- TO
ABOVE-NORMAL TEMPERATURES OVER MUCH OF THE WESTERN CONUS, EXCEPT FOR WESTERN
WASHINGTON, WESTERN OREGON, AND NORTHEASTERN MONTANA WHERE BELOW-NORMAL
TEMPERATURES ARE INDICATED. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR ALASKA
UNDER BELOW NORMAL 500-HPA HEIGHTS AND NORTHWESTERLY FLOW ALOFT, SUPPORTED BY
MOST OF THE DYNAMICAL TEMPERATURE FORECAST TOOLS.
TROUGHING OVER THE NORTHEAST PACIFIC FAVORS ABOVE-NORMAL PRECIPITATION OVER
NORTHERN CALIFORNIA, THE PACIFIC NORTHWEST, AND PARTS OF THE NORTHERN GREAT
BASIN AND THE NORTHERN ROCKIES. ODDS ALSO TILT TOWARDS ABOVE-NORMAL
PRECIPITATION FOR PORTIONS OF THE NORTHEAST, THE FLORIDA PENINSULA, AND
SOUTHERN TEXAS, WHILE NEAR-TO BELOW-NORMAL PRECIPITATION IS LIKELY OVER THE
REMAINDER OF THE CONUS, SUPPORTED BY MOST PRECIPITATION FORECAST TOOLS. SURFACE
LOW PRESSURE OVER THE GULF OF ALASKA IS PREDICTED BY MODEL GUIDANCE, RESULTING
IN ENHANCED PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION FOR MUCH OF SOUTHERN
ALASKA, WHILE BELOW-NORMAL PRECIPITATION IS FAVORED OVER NORTHWESTERN MAINLAND
ALASKA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 30% 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, DUE TO
MODEL AGREEMENT ON AN AMPLIFIED 500-HPA PATTERN ACROSS MUCH OF THE FORECAST
DOMAIN.
8-14 DAY OUTLOOK FOR APR 25 - MAY 01, 2023
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT AN EVOLVING 500-HPA
CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS. ANOMALOUS
MID-LEVEL TROUGHING WITH BELOW-NORMAL 500-HPA HEIGHTS IS SITUATED OVER THE
BERING SEA AND ALASKA, IN ENSEMBLE MEAN SOLUTIONS FROM THE GEFS, ECMWF AND
CANADIAN MODELS. AN ANOMALOUS 500-HPA TROUGH WITH BELOW NORMAL 500-HPA IS
PREDICTED OVER THE EASTERN CONUS, WHILE WEAK RIDGING AND WEAK 500-HPA HEIGHT
ANOMALIES ARE FORECAST OVER THE WESTERN CONUS.
GUIDANCE FROM THE DYNAMICAL MODELS, REFORECAST TOOLS, AND OTHER TOOLS INDICATE
ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES OVER THE EASTERN CONUS DUE TO A
PREDICTED ANOMALOUS TROUGH WITH BELOW NORMAL 500-HPA HEIGHTS OVER THE REGION.
MEANWHILE, ENHANCED PROBABILITIES OF NEAR- TO ABOVE-NORMAL TEMPERATURES ARE
FAVORED OVER MUCH OF THE WESTERN CONUS (EXCEPT FOR THE WEST COAST WHERE
BELOW-NORMAL TEMPERATURES ARE INDICATED) UNDER PREDICTED WEAK ANOMALOUS
RIDGING. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF ALASKA UNDER BELOW
NORMAL 500-HPA HEIGHTS AND NORTHWESTERLY FLOW ALOFT, WITH THE EXCEPTION OF THE
ALASKA PANHANDLE WHERE NEAR-NORMAL TEMPERATURES ARE MOST LIKELY UNDER ANOMALOUS
SOUTHERLY FLOW.
ANOMALOUS TROUGHING IS FORECAST TO BUILD OVER THE EASTERN CONUS DURING THE 8-14
DAY PERIOD, RESULTING IN A TILT TOWARDS ABOVE-NORMAL PRECIPITATION OVER MOST OF
THE SOUTHEASTERN CONUS. ABOVE-NORMAL PRECIPITATION IS FAVORED OVER NORTHERN
CALIFORNIA AND THE CENTRAL CONUS, WHILE BELOW-NORMAL PRECIPITATION IS LIKELY
OVER NORTHERN ARIZONA, THE UPPER AND MIDDLE MISSISSIPPI VALLEY, THE OHIO VALLEY
AND UPPER GREAT LAKES REGION, CONSISTENT WITH THE GEFS AND ECMWF PRECIPITATION
REFORECAST TOOLS. CONTINUED SURFACE LOW PRESSURE OVER THE GULF OF ALASKA IS
FAVORED BY MODEL GUIDANCE, RESULTING IN ELEVATED PROBABILITIES FOR NEAR- TO
ABOVE-NORMAL PRECIPITATION FOR MUCH OF ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 30% 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, DUE TO
MODEL AGREEMENT ON AN AMPLIFIED 500-HPA PATTERN ACROSS MUCH OF THE FORECAST
DOMAIN.
FORECASTER: LUKE H
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
APRIL 20.
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:
19620430 - 19550412 - 19520331 - 19790412 - 19860427
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:
19620430 - 19880403 - 19520402 - 19550412 - 19860428
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR APR 23 - 27 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF N A
SRN CALIF A N IDAHO N A NEVADA A N
W MONTANA N A E MONTANA B N WYOMING N N
UTAH A B ARIZONA A B COLORADO A N
NEW MEXICO A B N DAKOTA B N S DAKOTA B N
NEBRASKA B N KANSAS B N OKLAHOMA B N
N TEXAS B N S TEXAS B N W TEXAS B B
MINNESOTA B N IOWA B N MISSOURI B N
ARKANSAS B N LOUISIANA B N WISCONSIN B N
ILLINOIS B N MISSISSIPPI B N MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B N NEW YORK B N
VERMONT B N NEW HAMP B N MAINE N N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE B N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B N
AK S INT B A AK SO COAST B A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR APR 25 - MAY 01, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON N N NRN CALIF N N
SRN CALIF B N IDAHO A N NEVADA N N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA N N S DAKOTA N N
NEBRASKA N N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA B N IOWA B N MISSOURI B N
ARKANSAS B N LOUISIANA B N WISCONSIN B N
ILLINOIS B N MISSISSIPPI B N MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N 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 N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN N N AK N SLOPE B N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B N
AK S INT B A AK SO COAST B A AK PNHDL N 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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