551
FXUS06 KWBC 201903
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON MAY 20 2024
6-10 DAY OUTLOOK FOR MAY 26 - 30 2024
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE PREDICTED 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 GEFS, ECMWF, AND CANADIAN MODELS DUE TO RECENT MODEL
SKILL. THE RESULTANT MANUAL BLEND FEATURES NEGATIVE 500-HPA HEIGHT ANOMALIES
AND A WEAK TROUGH OVER PARTS OF THE NORTHERN PLAINS, THE UPPER MISSISSIPPI
VALLEY, AND THE UPPER GREAT LAKES. RIDGING AND POSITIVE HEIGHT ANOMALIES ARE
FORECAST OVER MUCH OF THE WESTERN, NORTHEASTERN, AND SOUTHERN TIER OF THE
CONTIGUOUS U.S. (CONUS). MID-LEVEL RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS ARE
FORECAST OVER THE ALEUTIANS, WHILE A TROUGH IS DEPICTED OVER THE EASTERN GULF
OF ALASKA EXTENDING SOUTHWARD OFF THE WEST COAST. A WEAK MID-LEVEL TROUGH IS
ANTICIPATED OVER THE HAWAIIAN ISLANDS.
MID-LEVEL TROUGHING OFF THE WEST COAST FAVORS BELOW-NORMAL TEMPERATURES OVER
PARTS OF WESTERN WASHINGTON, NORTHWESTERN OREGON, AND SOUTHWESTERN CALIFORNIA.
ENHANCED CHANCES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES ARE PREDICTED OVER THE
REMAINDER OF THE CONUS DUE TO SUBTROPICAL RIDGING AND GENERALLY ABOVE-NORMAL
500-HPA HEIGHT ANOMALIES, SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE
FORECAST TOOLS. PROBABILITIES FAVORING ABOVE NORMAL TEMPERATURES EXCEED 70% FOR
PORTIONS OF SOUTH TEXAS AND FLORIDA. ABOVE-NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER PARTS OF NORTHERN ALASKA, WHILE BELOW-NORMAL TEMPERATURES ARE
FAVORED IN PORTIONS OF SOUTHWESTERN AND SOUTHEASTERN ALASKA, CONSISTENT WITH
MOST TEMPERATURE GUIDANCE. IN HAWAII, BELOW-NORMAL TEMPERATURE PROBABILITIES
ARE FAVORED UNDERNEATH WEAK TROUGHING AND NEGATIVE HEIGHT ANOMALIES.
THE SUBTROPICAL RIDGE FAVORS BELOW-NORMAL PRECIPITATION OVER MUCH OF THE
WESTERN CONUS, EXCEPT FOR PORTIONS OF NORTHWESTERN WASHINGTON WHERE
ABOVE-NORMAL PRECIPITATION IS INDICATED DUE TO A TROUGH PREDICTED OVER THE WEST
COAST. IN CONTRAST, NEAR- TO ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE
INCREASED OVER THE REMAINDER OF THE CONUS DUE TO SOUTHERLY RETURN FLOW
ASSOCIATED WITH MEAN SURFACE HIGH PRESSURE OVER THE SOUTHEAST AND THE MID-LEVEL
TROUGH EXPECTED TO LINGER IN THE REGION THROUGH MUCH OF THE PERIOD, AND
SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION FORECAST TOOLS. ABOVE NORMAL
PRECIPITATION CHANCES ARE ELEVATED OVER MOST OF ALASKA SUPPORTED BY MOST OF THE
DYNAMICAL PRECIPITATION FORECAST TOOLS. IN HAWAII, ANOMALOUSLY WET CONDITIONS
STATEWIDE ARE LIKELY IN ADVANCE OF A 500-HPA TROUGH.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% 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
GOOD AGREEMENT AMONG MODEL SOLUTIONS AND FORECAST TEMPERATURE AND PRECIPITATION
TOOLS.
8-14 DAY OUTLOOK FOR MAY 28 - JUN 03, 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY CONSISTENT
500-HPA CIRCULATION PATTERN RELATIVE TO THE 6-10 DAY PERIOD ACROSS NORTH
AMERICA AND THE SURROUNDING REGIONS. DURING WEEK-2, POSITIVE 500-HPA HEIGHT
ANOMALIES PERSIST OVER THE NORTH PACIFIC AND OVER MUCH OF THE CONUS. A TROUGH
IS PREDICTED ALONG THE WEST COAST. FOR ALASKA, WEAK ANOMALOUS TROUGHING IS
INDICATED OVER THE BERING SEA, WITH MID-LEVEL RIDGING AND POSITIVE HEIGHT
ANOMALIES DOMINATING THE REMAINDER OF THE STATE. A WEAK TROUGH WITH
BELOW-NORMAL 500-HPA HEIGHTS CONTINUES TO BE FORECAST NORTHWEST OF HAWAII.
NEAR- TO ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE CONUS DUE TO
SUBTROPICAL RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS PREDICTED ACROSS THE
COUNTRY, EXCEPT FOR PARTS OF THE NORTHWEST, THE MIDDLE AND LOWER MISSISSIPPI
VALLEY, THE OHIO VALLEY, AND THE TENNESSEE VALLEY, AND ALIGNS WELL WITH THE
OVERALL SYNOPTIC PATTERN. IN ALASKA, BELOW NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER THE SOUTHERN PORTIONS OF THE STATE, WITH ABOVE NORMAL
TEMPERATURE CHANCES ENHANCED OVER NORTHERN PARTS OF THE STATE. IN HAWAII, NEAR-
TO BELOW-NORMAL TEMPERATURES ARE LIKELY OVER THE STATE DUE TO THE WEAK
BELOW-NORMAL 500-HPA HEIGHTS.
ENHANCED CHANCES FOR BELOW-NORMAL PRECIPITATION ARE FAVORED OVER MUCH OF THE
WESTERN CONUS EXCEPT FOR PORTIONS OF THE PACIFIC NORTHWEST WHERE ABOVE-NORMAL
PRECIPITATION IS INDICATED IN ASSOCIATION WITH A TROUGH PREDICTED ALONG THE
WEST COAST. ABOVE-NORMAL PRECIPITATION IS ALSO FORECAST OVER SOUTH-CENTRAL AND
SOUTHEASTERN CONUS AND ACROSS THE EASTERN SEABOARD, CONSISTENT WITH THE
CONSOLIDATION AND AUTO PRECIPITATION TOOLS. ABOVE-NORMAL PRECIPITATION IS
FAVORED OVER ALASKA, SUPPORTED BY MOST OF THE PRECIPITATION FORECAST TOOLS. FOR
HAWAII, PREDOMINANTLY WET CONDITIONS ARE FAVORED RELATIVE TO NORMAL WITH THE
SAME GENERAL SYNOPTIC FEATURES IN PLACE AS WAS THE CASE WITH THE 6-10 DAY
OUTLOOK.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% 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, WITH
GOOD RUN-TO-RUN CONTINUITY AMONG FORECAST MODELS, OFFSET BY DIFFERENCES BETWEEN
MODELS REGARDING STRENGTH AND POSITION OF VARIOUS SYNOPTIC FEATURES.
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
JUNE 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:
19620603 - 19860511 - 19990601 - 19660517 - 19890518
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:
19620602 - 19860511 - 19890517 - 19990601 - 19660516
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 26 - 30 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON N B NRN CALIF N B
SRN CALIF N N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA N N WYOMING N B
UTAH A B ARIZONA N N COLORADO N N
NEW MEXICO A A N DAKOTA N N S DAKOTA N N
NEBRASKA N N KANSAS N A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA N A IOWA N A MISSOURI N A
ARKANSAS A A LOUISIANA A A WISCONSIN N A
ILLINOIS N A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN B N AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 28 - JUN 03, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N N NRN CALIF N B
SRN CALIF N N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A A
NEW MEXICO A A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS N A OKLAHOMA N A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A N IOWA N N MISSOURI N N
ARKANSAS N A LOUISIANA A A WISCONSIN N N
ILLINOIS N N MISSISSIPPI A A MICHIGAN N N
INDIANA N N OHIO N N KENTUCKY N N
TENNESSEE N N ALABAMA N A NEW YORK N A
VERMONT N A NEW HAMP N A MAINE A A
MASS N A CONN N A RHODE IS N A
PENN N A NEW JERSEY N A W VIRGINIA N N
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN N A
AK S INT B N AK SO COAST B N AK PNHDL B 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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