426
FXUS06 KWBC 291919
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 29 2024
6-10 DAY OUTLOOK FOR MAY 05 - 09 2024
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON A PERSISTENT LONGWAVE 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, ECENS, AND CANADIAN MODELS DUE TO RECENT MODEL
SKILL. THE RESULTANT MANUAL BLEND FEATURES A 500-HPA TROUGH AND NEGATIVE
500-HPA HEIGHT ANOMALIES OVER THE BERING SEA AND ALASKA DOWN INTO THE EASTERN
PACIFIC ALONG THE WEST COAST. A RIDGE AND ASSOCIATED POSITIVE 500-HPA HEIGHT
ANOMALIES ARE FORECAST OVER THE CENTRAL AND EASTERN CONTIGUOUS U.S. (CONUS),
WHILE A TROUGH IS PREDICTED OVER THE WESTERN ATLANTIC. WEAK TROUGHING WITH
NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FAVORED FOR HAWAII.
MID-LEVEL RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES AS WELL AS SOUTHERLY
SURFACE FLOW FORECAST ACROSS THE CENTRAL AND EASTERN CONUS BRING ELEVATED
CHANCES FOR ABOVE-NORMAL TEMPERATURES FROM THE ROCKIES TO THE EAST COAST. THE
STRONGEST CHANCES ARE FORECAST OVER PARTS OF THE SOUTHERN PLAINS AND THE LOWER
MISSISSIPPI VALLEY WITH PROBABILITIES EXCEEDING 80% IN THIS REGION. ANOMALOUS
MID-LEVEL TROUGHING AND ENHANCED ONSHORE FLOW FAVORS BELOW-NORMAL TEMPERATURES
ACROSS WESTERN THIRD OF THE CONUS. IN ALASKA, BELOW-NORMAL TEMPERATURES ARE
FAVORED OVER WESTERN ALASKA UNDER BELOW-NORMAL 500-HPA HEIGHTS, WHILE
ABOVE-NORMAL TEMPERATURES ARE FORECAST OVER EASTERN ALASKA AND SOUTHEAST
ALASKA, SUPPORTED BY ECMWF CALIBRATED REFORECAST TOOL. IN HAWAII, PROBABILITIES
TILT TOWARD BELOW-NORMAL TEMPERATURES OVER HAWAII, CONSISTENT WITH THE
CONSOLIDATION TOOL.
AN UPSTREAM TROUGH ALONG THE WEST COAST AND ENHANCED ONSHORE FLOW FAVORS
ABOVE-NORMAL PRECIPITATION FROM MUCH OF THE WESTERN CONUS EXTENDING EASTWARD TO
THE NORTHERN AND CENTRAL PLAINS. SURFACE SOUTHERLY FLOW LEADS TO INCREASED
ABOVE-NORMAL PRECIPITATION PROBABILITIES OVER MUCH OF THE CENTRAL AND EASTERN
CONUS, EXCEPT FOR SOUTHERN FLORIDA WHERE BELOW-NORMAL PRECIPITATION IS
INDICATED. BELOW-NORMAL PRECIPITATION IS FORECAST FOR PARTS OF COLORADO, NEW
MEXICO AND WESTERN TEXAS, SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION
FORECAST TOOLS. A 500-HPA TROUGH OVER THE BERING SEA FAVORS ABOVE-NORMAL
PRECIPITATION FOR MUCH OF ALASKA. IN HAWAII, ABOVE-NORMAL PRECIPITATION IS
FAVORED ACROSS MUCH OF HAWAII DUE TO A WEAK TROUGH OVER THE REGION.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED
ON DAY 8, 30% 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 07 - 13 2024
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD MAINTAIN A FAIRLY PERSISTENT
AND LESS AMPLIFIED 500-HPA CIRCULATION PATTERN RELATIVE TO THE 6-10 DAY PERIOD
ACROSS NORTH AMERICA AND THE SURROUNDING REGIONS. DURING WEEK-2, A WEAK RIDGE
IS FORECAST OVER THE SOUTH-CENTRAL CONUS. A TROUGH WITH NEGATIVE ANOMALIES ARE
FORECAST OVER WESTERN ALASKA AND THE ALEUTIANS EXTENDING SOUTHEASTWARD ACROSS
THE EASTERN PACIFIC INTO THE WESTERN CONUS. ANOTHER TROUGH IS PREDICTED OVER
THE NORTHEASTERN CONUS. A WEAK TROUGH WITH SLIGHTLY BELOW-NORMAL 500-HPA
HEIGHTS IS PREDICTED OVER HAWAII.
A MID-LEVEL TROUGH AND NEGATIVE 500-HPA HEIGHT ANOMALIES SUPPORTS SLIGHTLY
ELEVATED BELOW-NORMAL TEMPERATURE PROBABILITIES FOR THE NORTHWESTERN CONUS.
ELEVATED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE FORECAST OVER MUCH OF
THE CENTRAL AND EASTERN CONUS DUE TO THE FORECAST RIDGING, ABOVE-NORMAL 500-HPA
HEIGHTS AND SURFACE SOUTHERLY FLOW OVER THE REGION, AND SUPPORTED BY MOST
DYNAMIC TEMPERATURE FORECAST TOOLS. IN ALASKA, BELOW-NORMAL TEMPERATURES REMAIN
FAVORED ACROSS THE WESTERN MAINLAND, WHILE ABOVE-NORMAL TEMPERATURES ARE
FORECAST OVER EASTERN ALASKA AND SOUTHEAST ALASKA, CONSISTENT WITH THE ERF
CONSOLIDATION TOOL. IN HAWAII, SLIGHTLY BELOW-NORMAL TEMPERATURES ARE FAVORED
UNDER A WEAK TROUGH AND WEAK BELOW-NORMAL 500-HPA HEIGHTS.
THE WEEK-2 PRECIPITATION FORECAST IS SIMILAR TO THE 6-10 DAY FORECAST WITH A
LARGE AREA OF SLIGHTLY ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS
MUCH OF THE WESTERN CONUS, NORTHERN TIER AND EASTERN CONUS IN CONJUNCTION WITH
THE TROUGHING ACROSS THE WEST COAST AND SOUTHERLY RETURN FLOW ASSOCIATED WITH
MEAN SURFACE HIGH PRESSURE OVER THE WESTERN ATLANTIC. BELOW-NORMAL
PRECIPITATION IS LIKELY OVER PORTIONS OF WESTERN TEXAS, NEW MEXICO, ARIZONA,
AND PARTS OF THE GULF COAST, SUPPORTED BY MOST TEMPERATURE FORECAST TOOLS. A
500-HPA TROUGH OVER THE ALEUTIANS SUPPORTS INCREASED NEAR- TO ABOVE-NORMAL
PRECIPITATION PROBABILITIES NEARLY STATEWIDE FOR ALASKA. NEAR- TO ABOVE-NORMAL
PRECIPITATION IS ALSO FORECAST OVER HAWAII, CONSISTENT WITH THE CONSOLIDATION
TOOL
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF TODAY'S GFS SUPERENSEMBLE MEAN
CENTERED ON DAY 11, 45% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY
11, AND 25% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
MODEL AGREEMENT ON THE LONGWAVE PATTERN OFFSET BY INCREASING FORECAST
UNCERTAINTY ACROSS THE EASTERN CONUS.
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 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:
19570421 - 19730416 - 19680412 - 20010421 - 19860426
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:
19900422 - 19860426 - 20020413 - 19730417 - 19680415
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 05 - 09 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO B A NEVADA B A
W MONTANA B A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A B
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN A A
ILLINOIS A 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 N 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 A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 07 - 13 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF N N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA N A WYOMING N N
UTAH N A ARIZONA N N COLORADO A N
NEW MEXICO A N N DAKOTA N A S DAKOTA N A
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA N A IOWA A A MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A A
VERMONT N A NEW HAMP N A MAINE N A
MASS N A CONN N A RHODE IS N 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 N FL PENIN A B AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B N AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A 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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page