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FXUS06 KWBC 261902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED APRIL 26 2023
6-10 DAY OUTLOOK FOR MAY 02 - 06 2023
THE SYNOPTIC PATTERN AS DEPICTED BY THE ENSEMBLE MEANS FROM THE GFS, ECMWF, AND
CANADIAN MODELS SHOW THE 500-HPA HEIGHTS AND ANOMALIES FOR THE 6-10 DAY PERIOD
WITH AN AMPLIFIED PATTERN OVER NORTH AMERICA. THERE IS LIKELY TO BE TROUGHING
OVER THE WEST COAST AND THE GREAT LAKES AND RIDGING OVER THE ROCKIES AND THE
NORTH PACIFIC. TODAY’S MODEL SOLUTIONS SHOW LARGER HEIGHT ANOMALIES RELATIVE TO
YESTERDAY BUT LITTLE HORIZONTAL MOVEMENT, RESULTING IN A LARGELY PERSISTENT
FORECAST.
WITH DEEP TROUGHING OVER THE GREAT LAKES, BELOW-NORMAL TEMPERATURES ARE FAVORED
FOR MUCH OF THE EASTERN CONTIGUOUS U.S. (CONUS), PARTICULARLY PORTIONS OF THE
UPPER OHIO VALLEY WHERE PROBABILITIES EXCEED 60%. TROUGHING OFF THE WEST COAST
FAVORS BELOW-NORMAL TEMPERATURES FOR MUCH OF CALIFORNIA AND PORTIONS OF
ADJACENT STATES AS WELL. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE
ROCKIES AND GREAT BASIN UNDER ANOMALOUS RIDGING. TROUGHING OVER THE BERING SEA
RESULTS IN MOIST SOUTHWESTERLY FLOW FOR ALASKA, LEADING TO THE POTENTIAL FOR
INCREASED CLOUDINESS AND A TILT TOWARDS BELOW-NORMAL TEMPERATURES FOR
SOUTHWESTERN MAINLAND ALASKA, WHILE NEAR-NORMAL TEMPERATURES ARE FAVORED FOR
THE NORTH SLOPE AND SOUTHEAST ALASKA.
RIDGING OVER THE ROCKIES RESULTS IN A TILT TOWARDS BELOW-NORMAL PRECIPITATION
FOR A BROAD SWATH OF THE CENTRAL AND EASTERN CONUS, WITH THE HIGHEST
PROBABILITIES (>40%) EXTENDING FROM THE NORTHERN PLAINS SOUTHEASTWARD THROUGH
THE UPPER MISSISSIPPI VALLEY. ODDS ALSO TILT TOWARDS BELOW-NORMAL PRECIPITATION
FOR PORTIONS OF THE OHIO VALLEY, THE MID-ATLANTIC, AND THE SOUTHEAST U.S.
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE WESTERN CONUS AND
SOUTHERN PLAINS WITH A MID-LEVEL TROUGH IN PLACE OVER THE WEST COAST THROUGHOUT
THE FORECAST PERIOD, WITH PROBABILITIES EXCEEDING 50% FOR MUCH OF CALIFORNIA
AND NEVADA. ONSHORE FLOW OFF THE NORTH PACIFIC RESULTS IN A TILT TOWARDS
ABOVE-NORMAL PRECIPITATION FOR MUCH OF MAINLAND ALASKA, WHILE NEAR-NORMAL
PRECIPITATION IS MOST LIKELY FOR SOUTHEAST ALASKA.
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, DUE TO
GOOD AGREEMENT AMONG MODEL ENSEMBLES AND FORECAST TOOLS, OFFSET BY DIFFERENCES
AMONG MODELS REGARDING 500-HPA ANOMALOUS FEATURES.
8-14 DAY OUTLOOK FOR MAY 04 - 10 2023
THE SYNOPTIC PATTERN FOR THE 8-14 DAY PERIOD AS DEPICTED IN MODEL ENSEMBLE
SOLUTIONS MAINTAIN 500-HPA HEIGHT ANOMALIESVERY SIMILAR TO WHAT IS SHOWN FOR
THE 6-10 PERIOD, WITH CONTINUED TROUGHING OVER THE WEST COAST AND RIDGING OVER
THE ROCKIES. HOWEVER, THE TROUGH DEPICTED OVER THE GREAT LAKES IN THE EARLIER
PERIOD IS SHIFTED OVER THE NORTH ATLANTIC AND HEIGHT ANOMALIES OVERALL HAVE A
LOWER MAGNITUDE AS THE HIGH AMPLITUDE PATTERN EASES SOMEWHAT. THIS PATTERN
EVOLUTION RESULTS IN TEMPERATURE AND PRECIPITATION FORECASTS FOR THE 8-14 DAY
PERIOD THAT ARE VERY SIMILAR TO THE 6-10 DAY PERIOD, ALTHOUGH WITH LOWER
PROBABILITIES GIVEN A LESS AMPLIFIED FLOW PATTERN.
AS THE EASTERN TROUGH SHIFTS FROM THE GREAT LAKES TO OVER THE NORTH ATLANTIC,
TEMPERATURES WILL MODERATE BUT BELOW-NORMAL TEMPERATURES REMAIN FAVORED FOR
MUCH OF THE EASTERN CONUS, WITH PROBABILITIES EXCEEDING 50% FOR PORTIONS OF THE
APPALACHIANS AND OHIO VALLEY. BELOW-NORMAL TEMPERATURES CONTINUE TO BE MOST
LIKELY FOR CALIFORNIA, MUCH OF NEVADA AND ARIZONA, AND ADJACENT AREAS AS
TROUGHING CONTINUES OVER THE WEST COAST. THE PERSISTENT ANOMALOUS RIDGE OVER
THE ROCKIES RESULTS IN A TILT TOWARDS ABOVE-NORMAL TEMPERATURES FOR THE
NORTHERN AND CENTRAL ROCKIES AS WELL AS MUCH OF THE GREAT PLAINS. ONGOING
SOUTHWESTERLY FLOW OFF THE BERING SEA FAVORS CONTINUED CLOUDINESS AND
PRECIPITATION RESULTING IN BELOW-NORMAL TEMPERATURES FOR SOUTHWESTERN MAINLAND
ALASKA.
THE PERSISTENT MID-LEVEL TROUGH OVER THE WEST COAST FAVORS ABOVE-NORMAL
PRECIPITATION FOR MUCH OF THE WESTERN CONUS, ESPECIALLY FOR CENTRAL CALIFORNIA,
WHERE PROBABILITIES EXCEED 50%. AS WEEK-2 PROGRESSES SURFACE HIGH PRESSURE
BUILDS NEAR BERMUDA, SETTING UP MOIST SOUTHEASTERLY FLOW AND A TILT TOWARDS
ABOVE-NORMAL PRECIPITATION FOR THE GULF COAST AND PORTIONS OF THE SOUTHERN AND
CENTRAL PLAINS. MEANWHILE, AS THE EASTERN TROUGH AXIS MOVES FROM THE GREAT
LAKES TO THE NORTH ATLANTIC, THE AREA FAVORED FOR BELOW-NORMAL PRECIPITATION
SHIFTS FROM THE NORTHERN PLAINS AND MISSISSIPPI VALLEY TO THE GREAT LAKES.
CONTINUED SOUTHWESTERLY FLOW ALOFT OVER MAINLAND ALASKA FAVORS A CONTINUED TILT
TOWARDS ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE STATE, EXCEPT FOR SOUTHEAST
ALASKA, WHERE BELOW-NORMAL PRECIPITATION IS FAVORED.
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: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG MODEL ENSEMBLES ON THE SYNOPTIC PATTERN, OFFSET BY WEAK
ANOMALIES REDUCING FORECAST CONFIDENCE.
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 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:
20080502 - 19510412 - 19540507 - 19790412 - 19960429
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:
20080502 - 19540507 - 19510411 - 19790411 - 19860410
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 02 - 06 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON N A NRN CALIF B A
SRN CALIF B A IDAHO A A NEVADA N A
W MONTANA A A E MONTANA A B WYOMING A A
UTAH A A ARIZONA B A COLORADO A A
NEW MEXICO N A N DAKOTA N B S DAKOTA N B
NEBRASKA A B KANSAS A N OKLAHOMA N N
N TEXAS N N S TEXAS N A W TEXAS A A
MINNESOTA N B IOWA N B MISSOURI N B
ARKANSAS N N LOUISIANA N N WISCONSIN B B
ILLINOIS B B MISSISSIPPI B N MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B N NEW YORK B N
VERMONT B N NEW HAMP B A MAINE N A
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B B
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B N FL PENIN N N AK N SLOPE N A
AK ALEUTIAN N A AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 04 - 10 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO A A NEVADA B A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH N A ARIZONA B A COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA A N
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA N N IOWA N N MISSOURI N N
ARKANSAS B A LOUISIANA N A WISCONSIN B N
ILLINOIS B N MISSISSIPPI B A MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B A 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 N A FL PENIN A N AK N SLOPE N N
AK ALEUTIAN N A AK WESTERN B A 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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