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FXUS06 KWBC 301902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE APRIL 30 2024
6-10 DAY OUTLOOK FOR MAY 06 - 10 2024
MODEL SOLUTIONS DEPICT AN AMPLIFIED LONGWAVE PATTERN FOR THIS TIME OF YEAR WITH
A 500-HPA TROUGH EXTENDING FROM ALASKA TO THE WESTERN CONTIGUOUS U.S. (CONUS)
AND A DOWNSTREAM RIDGE OVER THE EASTERN CONUS. POSITIVE 500-HPA HEIGHT
ANOMALIES COUPLED WITH SOUTHERLY SURFACE FLOW FAVORS ABOVE-NORMAL TEMPERATURES
ACROSS THE CENTRAL TO SOUTHERN GREAT PLAINS, MISSISSIPPI VALLEY, AND EASTERN
CONUS. BELOW-NORMAL TEMPERATURES ARE MORE LIKELY FOR MUCH OF THE WESTERN CONUS
DUE TO THE AMPLIFIED TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES.
AN AMPLIFIED MID-LEVEL TROUGH IS FORECAST TO SHIFT EAST FROM THE WEST COAST TO
THE ROCKIES BY THE GEFS AND ECMWF ENSEMBLE MEANS FROM DAYS 6 TO 10. THIS
EVOLVING LONGWAVE PATTERN SUPPORTS INCREASED ABOVE-NORMAL PRECIPITATION
PROBABILITIES FROM NORTHERN CALIFORNIA AND THE PACIFIC NORTHWEST EAST TO THE
NORTHERN GREAT PLAINS AND UPPER MISSISSIPPI VALLEY. PROBABILITIES DECREASE
FARTHER TO THE EAST AS REFORECAST TOOLS (WET) DIFFER FROM THE ANALOG TOOL (DRY)
DERIVED FROM THE MANUAL 500-HPA HEIGHT BLEND. TODAY’S 6-10 DAY PRECIPITATION
OUTLOOK TRENDED DRIER ACROSS THE SOUTHERN TIER OF THE CONUS AS A SUBTROPICAL
RIDGE IS EXPECTED TO STRENGTHEN BY DAY 8.
A 500-HPA TROUGH FAVORS ABOVE-NORMAL PRECIPITATION FOR MUCH OF ALASKA. BASED ON
THE ANALOG TOOL ALONG WITH THE PREFERRED GEFS AND ECMWF REFORECAST TOOLS,
BELOW-NORMAL TEMPERATURES ARE FAVORED FOR WESTERN MAINLAND ALASKA WITH A SLIGHT
LEAN TOWARDS ABOVE-NORMAL TEMPERATURES LIMITED TO INTERIOR EASTERN ALASKA.
BASED ON THE GEFS AND ECMWF ENSEMBLE MEANS, PROBABILITIES FOR BELOW-NORMAL
TEMPERATURES AND ABOVE-NORMAL PRECIPITATION ARE SLIGHTLY ELEVATED FOR MUCH OF
HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 50% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, AND 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: FORECAST CONFIDENCE: ABOVE
AVERAGE, 4 OUT OF 5, DUE TO AN AMPLIFIED LONGWAVE PATTERN AND GOOD AGREEMENT
AMONG MOST OF THE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR MAY 08 - 14 2024
THE 0Z GEFS AND 0Z ECMWF ENSEMBLE MEANS ARE IN REASONABLY GOOD AGREEMENT WITH A
LONGWAVE TROUGH SHIFTING EASTWARD FROM THE WESTERN TO CENTRAL CONUS DURING THE
SECOND WEEK OF MAY. THE 0Z CANADIAN ENSEMBLE MEAN FAVORS A MORE PERSISTENT
LONGWAVE PATTERN WITH A CONTINUATION OF THE MID-LEVEL TROUGH CLOSER TO THE WEST
COAST. SINCE THE 0Z CANADIAN ENSEMBLE MEAN IS AN OUTLIER, ITS SOLUTION WAS NOT
INCLUDED IN THE MANUAL 500-HPA HEIGHT BLEND. IF THE MID-LATITUDE FLOW PATTERN
BECOMES MORE PROGRESSIVE BY MID-MAY, THEN A TROUGH MAY BE REPLACED BY MORE
RIDGING ALONG THE WEST COAST. THE 0Z GEFS AND 0Z ECMWF ENSEMBLE MEANS AGREE ON
A STRONGER THAN NORMAL SUBTROPICAL RIDGE OVER TEXAS, THE GULF OF MEXICO, AND
FLORIDA.
THE HIGHEST FORECAST CONFIDENCE IN THE WEEK-2 TEMPERATURE OUTLOOK EXISTS ALONG
THE EAST AND GULF COASTS WHERE ABOVE-NORMAL TEMPERATURES ARE FAVORED. THE EAST
COAST IS FORECAST TO BE ON THE WARM SIDE OF A TROUGH AXIS, WHILE THE STRONG
SUBTROPICAL RIDGE LIKELY RESULTS IN ABOVE-NORMAL TEMPERATURES ALONG AND INLAND
OF THE GULF COAST. A VARIABLE TEMPERATURE PATTERN IS EXPECTED ACROSS THE
NORTH-CENTRAL (COOLING TREND) AND WESTERN CONUS (WARMING TREND) WHICH LOWERS
FORECAST CONFIDENCE FOR THESE AREAS.
ALONG AND DOWNSTREAM OF A 500-HPA TROUGH AXIS, ABOVE-NORMAL PRECIPITATION
PROBABILITIES ARE ELEVATED FROM THE GREAT BASIN AND ROCKIES EASTWARD TO THE
MIDWEST AND NORTHEAST. PROBABILITIES ARE TEMPERED DUE TO UNCERTAINTY ON WHERE
THE HEAVIEST CONVECTIVE RAINFALL OCCURS. THE OUTLOOK HEDGED TOWARDS THE DRIER
ANALOG TOOL ACROSS THE SOUTHEAST. DUE TO A PREDICTED ROBUST SUBTROPICAL RIDGE,
BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS THE FLORIDA PENINSULA. COMPARED TO
THE 6-10 DAY OUTLOOK, A DRIER PATTERN IS EXPECTED ALONG THE WEST COAST AS THE
LONGWAVE TROUGH AXIS SHIFTS WELL INLAND AND 500-HPA HEIGHTS INCREASE OVER THE
NORTHEASTERN PACIFIC.
A BROAD 500-HPA TROUGH OVER THE BERING SEA AND WESTERN MAINLAND ALASKA SUPPORTS
INCREASED ABOVE-NORMAL PRECIPITATION PROBABILITIES NEARLY STATEWIDE FOR ALASKA.
COOLER-THAN-NORMAL TEMPERATURES ARE FAVORED FOR A MAJORITY OF ALASKA WITH
WIDESPREAD CLOUDINESS AND ENHANCED PRECIPITATION FORECAST.
BASED ON THE GEFS AND ECMWF ENSEMBLE MEANS, PROBABILITIES FOR BELOW-NORMAL
TEMPERATURES ARE SLIGHTLY ELEVATED FOR HAWAII. THE GEFS ENSEMBLE MEAN SUPPORTS
AN INCREASED CHANCE OF ABOVE-NORMAL PRECIPITATION FOR MOST OF THE STATE EXCEPT
FOR THE BIG ISLAND WHERE NEAR NORMAL PRECIPITATION IS FORECAST.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 50% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, AND 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: FORECAST CONFIDENCE: BELOW
AVERAGE, 2 OUT OF 5, DUE TO AN EXPECTED VARIABLE TEMPERATURE PATTERN ACROSS THE
WESTERN AND NORTH-CENTRAL CONUS AND WEAK SIGNALS AMONG THE PRECIPITATION TOOLS.
FORECASTER: BRAD PUGH
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
16.
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:
19730417 - 19860426 - 20020414 - 19900423 - 19550414
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:
20020414 - 19900424 - 19550413 - 19730418 - 19860426
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 06 - 10 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B N ARIZONA B N COLORADO A N
NEW MEXICO A B N DAKOTA N A S DAKOTA N A
NEBRASKA A A KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N 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 N S CAROLINA A N GEORGIA A N
FL PNHDL A B FL PENIN A B AK N SLOPE B A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN N A
AK S INT N A AK SO COAST B A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 08 - 14 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON B N NRN CALIF N N
SRN CALIF B N IDAHO B A NEVADA B N
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B A ARIZONA B N COLORADO B A
NEW MEXICO N N N DAKOTA N A S DAKOTA N A
NEBRASKA N A KANSAS N N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA N A IOWA N A MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN N A
ILLINOIS A A MISSISSIPPI A N MICHIGAN N A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A B AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A 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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