573
FXUS06 KWBC 281902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI APRIL 28 2023
6-10 DAY OUTLOOK FOR MAY 04 - 08 2023
THE MID-LEVEL, 500 HPA, HEIGHT PATTERN REMAINS AMPLIFIED ACROSS NORTH AMERICA
DURING THE 6-10 DAY PERIOD AS DEPICTED BY THE GEFS, ECMWF, AND CANADIAN MODELS.
MID-LEVEL TROUGHING IS FAVORED ALONG THE WEST COAST STRETCHING UP INTO ALASKA
AND ALSO IN THE EASTERN THIRD OF THE CONTIGUOUS UNITED STATES (CONUS) DURING
THE PERIOD. RIDGING REMAINS FAVORED ACROSS THE NORTH-CENTRAL CONUS AND NORTH
PACIFIC NEAR THE ALEUTIAN ISLANDS.
WITH TROUGHING AND NORTHERLY FLOW ACROSS MUCH OF THE EASTERN CONUS,
BELOW-NORMAL TEMPERATURES REMAIN FAVORED, WITH PROBABILITIES EXCEEDING 50% IN
PARTS OF THE MID-ATLANTIC AND NORTHEAST. 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 INTO THE SOUTHERN PLAINS UNDER POSITIVE 500-HPA HEIGHT
ANOMALIES. TROUGHING IN THE BERING SEAS RESULTS IN SOUTH-WESTERLY FLOW FOR MUCH
OF ALASKA LEADING TO BELOW-NORMAL TEMPERATURES BEING FAVORED FOR MUCH OF
MAINLAND ALASKA DUE TO INCREASED CLOUDINESS. NEAR-NORMAL TEMPERATURES ARE MOST
LIKELY FOR THE NORTH SLOPE AND SOUTHEAST ALASKA.
ABOVE-NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE WEST COAST AHEAD OF A
MID-LEVEL TROUGH. THE HIGHEST CHANCES ARE IN CALIFORNIA WHERE CLIMATOLOGIES
CONTINUE TO FALL QUICKLY, SO ANY PRECIPITATION THAT FALLS INCREASES CHANCES FOR
ABOVE-NORMAL PRECIPITATION. BELOW-NORMAL PRECIPITATION IS FAVORED IN PARTS OF
THE NORTHERN PLAINS, UPPER AND MIDDLE-MISSISSIPPI VALLEY AND GREAT LAKES WHERE
NORTHERLY FLOW IS FAVORED AHEAD OF RIDING ACROSS THE ROCKIES AND BEHIND THE
TROUGHING ALONG THE EAST COAST. ALONG THE GULF COAST, REFORECAST TOOLS INDICATE
HIGHER CHANCES FOR ABOVE-NORMAL PRECIPITATION, RELATIVE TO YESTERDAY, DUE TO A
MORE NORTHERLY TRACK OF THE SOUTHERN JET. IN ALASKA, MUCH OF THE STATE IS
FAVORED TO SEE NEAR-NORMAL PRECIPITATION WITH A SLIGHTLY WETTER SIGNAL FROM THE
RAW ENSEMBLE GUIDANCE BUT SLIGHTLY DRIER AMONG THE REFORECAST TOOLS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 33% OF TODAY'S 6Z 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 NORMAL, 5 OUT 5. VERY GOOD
AGREEMENT WITH GOOD CONSISTENCY BETWEEN TOOLS AND PRIOR FORECASTS.
8-14 DAY OUTLOOK FOR MAY 06 - 12 2023
THE WEEK-2 MEAN 500-HPA HEIGHT PATTERN REMAINS VERY SIMILAR TO THE MEAN 6-10
DAY PATTERN, AS DEPICTED BY MODEL GUIDANCE. NEGATIVE 500-HPA HEIGHTS REMAINS
OVER THE WEST COAST AND MUCH OF THE EASTERN THIRD OF THE CONUS. MEANWHILE,
MID-LEVEL RIDGING PERSISTS ACROSS THE ROCKIES AND NORTH-CENTRAL CONUS. THE
TROUGH ACROSS THE EASTERN CONUS IS FORECAST TO PROGRESS INTO THE ATLANTIC BY
THE END OF THE PERIOD, DECREASING 500-HPA ANOMALIES FOR THE PERIOD AS A WHOLE
IN THE EASTERN CONUS.
AS THE EASTERN TROUGH SHIFTS FROM THE NORTHEAST TO OVER THE NORTH ATLANTIC,
TEMPERATURES MAY MODERATE ACROSS THE GREAT LAKES BUT BELOW-NORMAL TEMPERATURES
REMAIN FAVORED FOR MUCH OF THE SOUTHEASTERN QUADRANT OF THE CONUS, WITH
PROBABILITIES EXCEEDING 50% FOR PORTIONS OF THE SOUTHEAST. 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 NORTHERN AND CENTRAL 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 60% IN PART DUE TO DECLINING CLIMATOLOGIES. FURTHER
INLAND, SOME LINGERING MOISTURE MAY INTERACT WITH WEAK RETURN FLOW FROM THE
GULF OF MEXICO; THIS LEADS TO SLIGHT CHANCES FOR ABOVE-NORMAL PRECIPITATION IN
PARTS OF THE SOUTHERN AND CENTRAL PLAINS. HOWEVER, THE STRENGTHENING RIDGE OVER
THE GREAT PLAINS RESULTS IN INCREASING PROBABILITIES FOR BELOW-NORMAL
PRECIPITATION OVER MUCH OF THE EASTERN CONUS. ONE EXCEPTION TO THIS ARE THE
SOUTHERN ATLANTIC STATES AND GULF COAST WHERE NEAR-NORMAL PRECIPITATION IS
FAVORED. CONTINUED SOUTH WESTERLY FLOW ALOFT OVER MAINLAND ALASKA FAVORS A
CONTINUED TILT TOWARDS NEAR TO 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: 40% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 20% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: FORECASTER CONFIDENCE: ABOVE
NORMAL, 4 OUT 5. GOOD AGREEMENT AND CONSISTENCY BETWEEN TOOLS AND PRIOR
FORECASTS OFFSET BY EASTERN TROUGH SHIFTING OFFSHORE BY THE END OF THE PERIOD.
FORECASTER: RYAN BOLT
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:
19540505 - 19510409 - 19730427 - 20080503 - 19990413
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:
19510410 - 19540504 - 19730427 - 20080505 - 19990413
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 04 - 08 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N 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 N WYOMING A A
UTAH N A ARIZONA B N COLORADO A A
NEW MEXICO N N N DAKOTA A B S DAKOTA A B
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A A W TEXAS A A
MINNESOTA N B IOWA N B MISSOURI N N
ARKANSAS N N LOUISIANA N N WISCONSIN N B
ILLINOIS B B MISSISSIPPI N N MICHIGAN B B
INDIANA B B OHIO B B 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 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 N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 06 - 12 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 A A E MONTANA A A WYOMING A N
UTAH N N ARIZONA B N COLORADO N N
NEW MEXICO N N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS N N OKLAHOMA N N
N TEXAS N N S TEXAS N A W TEXAS N N
MINNESOTA A B IOWA N B MISSOURI B B
ARKANSAS B N LOUISIANA B N WISCONSIN N B
ILLINOIS B B MISSISSIPPI B N MICHIGAN N B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B N NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS N B CONN N B RHODE IS N B
PENN N B NEW JERSEY N B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B A FL PENIN B A AK N SLOPE N A
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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