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FXUS06 KWBC 241903
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 24 2023
6-10 DAY OUTLOOK FOR APR 30 - MAY 04, 2023
THE GFS, ECMWF, AND CANADIAN ENSEMBLE MEANS ARE IN FAIRLY GOOD AGREEMENT ON THE
PREDICTED BROAD-SCALE FEATURES OF THE 500-HPA CIRCULATION OVER THE VICINITY OF
NORTH AMERICA DURING THE 6-10 DAY FORECAST PERIOD. HOWEVER, A NEW DEVELOPMENT
OVER THE CENTRAL AND EASTERN PACIFIC IS NOW COMPLICATING THE PICTURE. STARTING
UPSTREAM OVER THE BERING SEA, AN AMPLIFIED TROUGH IS FORECAST BY THE VARIOUS
ENSEMBLES. A BRIEF INTENSIFICATION OF THIS FEATURE CONTRIBUTES TOWARD THE
DOWNSTREAM DEVELOPMENT OF A RIDGE OVER THE EAST-CENTRAL PACIFIC, AND A TROUGH
OVER THE FAR EASTERN PACIFIC. COMPARED WITH PREVIOUS MODEL RUNS, TWO LONG WAVES
(RATHER THAN ONE) ARE FORECAST DOWNSTREAM OF THE BERING SEA TROUGH, OVER THE
EAST-CENTRAL AND EASTERN PACIFIC, WITH NARROWER WAVELENGTHS. MEANWHILE, OVER
THE CONTIGUOUS U.S. (CONUS), TODAY’S ENSEMBLE MEANS CONTINUE TO FORECAST A
RIDGE OVER THE WEST, AND A TROUGH OVER THE EAST. THE NORTHERN PORTION OF THIS
RIDGE IS PREDICTED TO OVERSPREAD EASTERN AND CENTRAL ALASKA.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM THE HIGH PLAINS REGION WESTWARD TO
NEAR THE PACIFIC COAST, ASSOCIATED WITH THE PREDICTED 500-HPA RIDGE AND NEAR TO
ABOVE-NORMAL MID-TROPOSPHERIC HEIGHTS. THE NORTHWESTERN PORTION OF THIS RIDGE
ELEVATES PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES OVER EASTERN ALASKA.
BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE CENTRAL AND EASTERN
CONUS, ASSOCIATED WITH THE AMPLIFIED 500-HPA TROUGH AND BELOW-NORMAL
MID-TROPOSPHERIC HEIGHTS. ENHANCED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES
ARE ALSO INDICATED ACROSS SOUTHWESTERN ALASKA, IN PROXIMITY TO THE BERING SEA
TROUGH.
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF ALASKA EAST OF THE BERING
SEA TROUGH WITH SOUTHERLY, ONSHORE FLOW. ABOVE-NORMAL PRECIPITATION IS ALSO
FAVORED OVER THE EASTERN GREAT LAKES REGION, NORTHEAST, MID-ATLANTIC, THE
FLORIDA PENINSULA, AND SOUTHERN AND WESTERN PORTIONS OF THE SOUTHERN PLAINS.
THE ENHANCED PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE GENERALLY EAST
AND SOUTH OF THE EASTERN CONUS TROUGH, WITH A MEAN BAROCLINIC ZONE EXPECTED TO
EXTEND NORTHWESTWARD FROM THE GULF OF MEXICO TO THE SOUTHERN AND CENTRAL HIGH
PLAINS. WEST OF THE CONTINENTAL DIVIDE, ABOVE-NORMAL PRECIPITATION IS ALSO
FAVORED FOR MOST AREAS DUE TO A TROUGH APPROACHING FROM THE EASTERN PACIFIC.
BELOW-NORMAL PRECIPITATION IS FAVORED FROM THE NORTHERN PLAINS SOUTHEASTWARD TO
THE INTERIOR EASTERN GULF COAST AND SOUTHERN ATLANTIC COAST REGIONS. THIS IS
DUE TO THE DRIER NORTHWESTERLY FLOW ANTICIPATED BEHIND THE EASTERN TROUGH.
BELOW-NORMAL PRECIPITATION IS ALSO FAVORED OVER PARTS OF SOUTHEAST ALASKA,
ASSOCIATED WITH A MID-LEVEL RIDGE.
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: NEAR-AVERAGE, 3 ON A SCALE FROM
1-5, BASED ON GOOD AGREEMENT AMONG THE VARIOUS ENSEMBLE MEANS ON THE 500-HPA
CIRCULATION PATTERN, BUT OFFSET BY THE EXPECTED INCREASE IN WAVENUMBER UPSTREAM
OVER THE EAST-CENTRAL AND EASTERN PACIFIC.
8-14 DAY OUTLOOK FOR MAY 02 - 08 2023
THE GFS AND ECMWF ENSEMBLE MEANS PREDICT THE BERING SEA TROUGH WILL WEAKEN
DURING WEEK-2. DOWNSTREAM, A PRONOUNCED SPLIT-FLOW PATTERN IS EXPECTED TO SET
UP, WITH A RIDGE OVER WESTERN CANADA AND MOST OF ALASKA, AND A TROUGH NEAR THE
WEST COAST OF THE CONUS. RIDGING IS EXPECTED TO EXTEND FROM THE SOUTHERN PLAINS
TO THE NORTHERN HIGH PLAINS, WITH BROAD CYCLONIC FLOW ACROSS MOST OF THE
EASTERN HALF OF THE CONUS. THE CANADIAN ENSEMBLE MEAN DIFFERS IN THAT IT
PREDICTS PHASING OF THE NORTHERN AND SOUTHERN STREAMS, WITH NO SPLIT FLOW
CONFIGURATION.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM THE NORTH-CENTRAL ROCKIES
SOUTHEASTWARD ACROSS MOST OF THE HIGH PLAINS TO THE TEXAS COAST, SOUTHERN
FLORIDA, AND EASTERN AND NORTHERN PORTIONS OF ALASKA. THIS IS ATTRIBUTED TO
MID-LEVEL RIDGING AND NEAR TO ABOVE-NORMAL 500-HPA HEIGHTS. THE ANOMALOUS
WARMTH FAVORED OVER SOUTHERN FLORIDA IS PREDICTED TO BE AHEAD (SOUTH) OF THE
AVERAGE LOCATION OF THE COLD FRONT ASSOCIATED WITH THE MID-LEVEL TROUGH.
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE ELEVATED FOR THE EASTERN
DAKOTAS AND MOST OF THE MISSISSIPPI VALLEY TO NEAR THE EASTERN SEABOARD
ASSOCIATED WITH A BROAD 500-HPA TROUGH. BELOW-NORMAL TEMPERATURES ARE ALSO
FAVORED FOR THE PARTS OF THE WESTERN CONUS NEAR THE WEST COAST, AND
SOUTHWESTERN ALASKA, DUE TO MID-LEVEL TROUGHS PREDICTED IN THOSE AREAS.
ABOVE-NORMAL PRECIPITATION IS FAVORED FROM MOST OF THE GREAT PLAINS WESTWARD TO
NEAR THE PACIFIC COAST, COINCIDENT WITH AND AHEAD OF THE MID-LEVEL TROUGH
PREDICTED NEAR THE WEST COAST OF THE CONUS. ACROSS THE SOUTHERN FLANK OF THE
TROUGH ANTICIPATED NEAR THE EAST COAST, ABOVE-NORMAL PRECIPITATION IS ALSO
FAVORED ACROSS THE GULF COAST REGION. SOUTHERLY, ONSHORE FLOW EAST OF THE
BERING SEA TROUGH IS EXPECTED TO ELEVATE PROBABILITIES OF ABOVE-NORMAL
PRECIPITATION FOR MOST OF ALASKA, THE EXCEPTION BEING THE SOUTHERN PORTIONS OF
SOUTHEAST ALASKA, WHERE BELOW-NORMAL PRECIPITATION IS INDICATED. THERE ARE
ENHANCED ODDS FOR BELOW-NORMAL PRECIPITATION TO THE REAR OF THE MEAN TROUGH
AXIS LOCATED JUST OFF THE EASTERN SEABOARD. THIS INCLUDES THE UPPER GREAT LAKES
REGION AND ILLINOIS EASTWARD TO THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND
COASTS.
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: BELOW-NORMAL, 2 ON A SCALE OF 1-5,
BASED ON FAIRLY GOOD MODEL AGREEMENT, OFFSET BY DIFFERENCES AMONG THE
TEMPERATURE AND PRECIPITATION 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 MAY
18.
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:
19960430 - 19790412 - 20050429 - 19530408 - 19660411
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:
19960430 - 19530408 - 19790412 - 20080430 - 20090419
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR APR 30 - MAY 04, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA N N WYOMING A A
UTAH A A ARIZONA A N COLORADO A A
NEW MEXICO A A N DAKOTA B N S DAKOTA B N
NEBRASKA B N KANSAS B N OKLAHOMA B N
N TEXAS B N S TEXAS B A W TEXAS N A
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 A
VERMONT B A NEW HAMP B A MAINE N A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE N A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL A N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 02 - 08 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO N A NEVADA B A
W MONTANA N A E MONTANA N A WYOMING A A
UTAH N A ARIZONA B A COLORADO A A
NEW MEXICO A A N DAKOTA B N S DAKOTA N N
NEBRASKA N A KANSAS A A OKLAHOMA A N
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA B N IOWA B N MISSOURI B N
ARKANSAS B N LOUISIANA N 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 N N AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST N A AK PNHDL A B
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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