567
FXUS06 KWBC 231903
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU MAY 23 2024
6-10 DAY OUTLOOK FOR MAY 29 - JUN 02, 2024
AN AMPLIFIED MID-LEVEL HEIGHT PATTERN IS FORECAST ACROSS THE CONUS AT THE
OUTSET OF THE PERIOD. TROUGHING IS PREDICTED ACROSS THE NORTHEASTERN CONUS WITH
ANOMALOUS RIDGING OVER PARTS OF THE WESTERN AND CENTRAL CONUS. ANOTHER WEAK
TROUGH IS FORECAST ACROSS WESTERN CANADA EXTENDING INTO PARTS OF THE NORTHWEST.
THESE FEATURES ARE FORECAST TO BREAK DOWN BY THE END OF THE PERIOD, RESULTING
IN A MORE ZONAL MID-LEVEL FLOW PATTERN ACROSS THE CONUS BY DAY-10. FOLLOWING A
GENERALLY WEAK MID-LEVEL FLOW PATTERN AT THE BEGINNING OF THE PERIOD ACROSS
ALASKA, TROUGHING AND A CLOSED MID-LEVEL LOW ARE FORECAST TO DEVELOP ACROSS THE
BERING SEA AND SOUTHWESTERN ALASKA. TODAY’S MANUAL 500-HPA HEIGHT BLEND DEPICTS
NEAR- TO BELOW-NORMAL HEIGHTS FOR MOST OF THE EASTERN CONUS. SLIGHTLY
ABOVE-NORMAL HEIGHTS ARE FAVORED FOR MUCH OF THE WESTERN AND CENTRAL CONUS,
ALONG WITH MAINLAND AND SOUTHEAST ALASKA. NEAR-NORMAL HEIGHTS ARE INDICATED
OVER THE ALEUTIANS DUE TO GREATER INFLUENCE FROM THE DEVELOPING TROUGH.
NEAR-NORMAL HEIGHTS ARE FORECAST ACROSS THE HAWAIIAN ISLANDS, WITH TROUGHING IN
THE VICINITY OF THE STATE FORECAST TO GRADUALLY WEAKEN.
TROUGHING FAVORS INCREASED PROBABILITIES OF BELOW-NORMAL TEMPERATURES ACROSS
PORTIONS OF THE OHIO AND TENNESSEE VALLEYS, MID-ATLANTIC, AND NORTHEAST.
ENHANCED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS
NORTHERN NEW ENGLAND AND CLOSER TO THE GULF COAST AND SOUTHEAST, UNDERNEATH
WEAKER HEIGHT ANOMALIES AND CONSISTENT WITH THE GEFS AND ECMWF REFORECAST
TOOLS. INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER MUCH OF
THE WEST DUE TO PREDICTED RIDGING AND INCREASED PACIFIC FLOW, WITH BELOW-NORMAL
TEMPERATURES FAVORED ACROSS PARTS OF THE PACIFIC NORTHWEST DUE TO THE INFLUENCE
FROM POTENTIAL WEAK TROUGHING IN THE VICINITY. ABOVE-NORMAL TEMPERATURE CHANCES
ARE INCREASED OVER PARTS OF NORTHERN AND CENTRAL MAINLAND ALASKA, WHILE
BELOW-NORMAL TEMPERATURE PROBABILITIES ARE INCREASED OVER SOUTHERN ALASKA,
INCLUDING PARTS OF THE ALEUTIANS AND SOUTHEAST ALASKA. NEAR-NORMAL TEMPERATURES
ARE FORECAST OVER MOST OF HAWAII, WITH ABOVE-NORMAL TEMPERATURES SLIGHTLY
FAVORED ACROSS SOUTHERN PARTS OF THE BIG ISLAND GIVEN THE PREDICTED WEAKENING
OF THE TROUGH.
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED OVER NORTHERN NEW
ENGLAND DUE TO THE LINGERING IMPACTS FROM A SURFACE LOW FORECAST EARLY IN THE
PERIOD. ENHANCED NORTHWESTERLY MID-LEVEL FLOW AND SURFACE HIGH PRESSURE ON THE
BACKSIDE OF THE DEPARTING TOUGH IN THE EAST FAVOR ENHANCED CHANCES FOR
BELOW-NORMAL PRECIPITATION ACROSS PARTS OF THE EASTERN CONUS, EXTENDING TO THE
CENTRAL GULF COAST. SOUTHERLY RETURN FLOW AROUND THE SURFACE HIGH FAVORS
ENHANCED CHANCES OF ABOVE-NORMAL PRECIPITATION ACROSS PORTIONS OF THE GREAT
PLAINS AND MISSISSIPPI VALLEY, SUPPORTED BY THE ECMWF AND GEFS REFORECAST
TOOLS. BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ELEVATED OVER MUCH OF THE
WESTERN CONUS UNDERNEATH A RELATIVELY WEAK MID-LEVEL FLOW PATTERN, EXCEPT FOR
PORTIONS OF THE PACIFIC NORTHWEST WHERE NEAR- TO ABOVE-NORMAL PRECIPITATION
CHANCES ARE INCREASED DUE TO GREATER INFLUENCE FROM TROUGHING OVER WESTERN
CANADA. ABOVE-NORMAL PRECIPITATION CHANCES ARE ELEVATED OVER MOST OF ALASKA DUE
TO THE TREND TOWARD MORE TROUGHING OVER THE BERING SEA LATE, SUPPORTED BY MOST
OF THE DYNAMICAL PRECIPITATION FORECAST TOOLS. IN HAWAII, NEAR- TO ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE INCREASED AHEAD OF WEAKENING TROUGHING.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY'S OPERATIONAL 0Z ECMWF 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 THE FORECAST TOOLS, OFFSET BY DECREASING AMPLIFICATION
TOWARD THE END OF THE PERIOD.
8-14 DAY OUTLOOK FOR MAY 31 - JUN 06, 2024
A TRANSITIONAL MID-LEVEL HEIGHT PATTERN IS PREDICTED ACROSS THE CONUS DURING
WEEK-2. ALTHOUGH THE PERIOD MAY BEGIN WITH SOME HINTS OF LINGERING TROUGHING
(RIDGING) ACROSS THE EASTERN (CENTRAL) CONUS, THE OVERALL PATTERN IS FORECAST
TO BECOME MORE ZONAL. BY THE END OF THE PERIOD, THE 0Z GEFS, ECMWF, AND
CANADIAN ENSEMBLES DEPICT EXPANDING RIDGING AND POSITIVE 500-HPA HEIGHT
ANOMALIES OVER MUCH OF THE CONUS. HOWEVER, HIGH LATITUDE BLOCKING ACROSS THE
NORTH ATLANTIC MAY FAVOR A CONTINUED WEAKNESS AND CLOSER TO NORMAL HEIGHTS
ACROSS PARTS OF THE EAST. A POTENT TROUGH IS FORECAST TO MOVE SLOWLY ACROSS THE
ALEUTIANS AND SOUTHWESTERN ALASKA. THE WEEK-2 MANUAL 500-HPA HEIGHT BLEND
DEPICTS SLIGHTLY ABOVE-NORMAL 500-HPA HEIGHTS ACROSS MUCH OF THE CONUS.
BELOW-NORMAL HEIGHTS ARE PREDICTED ACROSS THE ALEUTIANS AND SOUTHWESTERN
MAINLAND ALASKA, WITH NEAR-NORMAL HEIGHTS FORECAST OVER THE REST OF THE STATE.
NEAR- TO ABOVE-NORMAL HEIGHTS ARE FORECAST OVER HAWAII.
THE TRANSITION TO A MORE ZONAL MID-LEVEL FLOW PATTERN FAVORS ELEVATED
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR MOST OF THE CONUS, WITH THE
HIGHEST PROBABILITIES (GREATER THAN 60 PERCENT) HIGHLIGHTED ACROSS PORTIONS OF
SOUTHERN TEXAS AND FLORIDA. TELECONNECTION ANALYSIS WITH THE POSITIVE HEIGHT
ANOMALY CENTER IN THE NORTH ATLANTIC FAVORS INCREASED CHANCES OF RELATIVELY
COOLER CONDITIONS ALONG THE EASTERN SEABOARD, AND THEREFORE NEAR-NORMAL
TEMPERATURES ARE FAVORED OVER PORTIONS OF THE MID-ATLANTIC AND NORTHEAST
DESPITE THE WARMER ECMWF GUIDANCE. BELOW-NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER SOUTHERN PORTIONS OF ALASKA, WITH ABOVE-NORMAL TEMPERATURE
CHANCES ENHANCED OVER THE NORTHERN AND CENTRAL MAINLAND. NEAR- TO ABOVE-NORMAL
TEMPERATURES ARE FORECAST ACROSS HAWAII, CONSISTENT WITH THE CONSOLIDATED
FORECAST TOOL.
INCREASED PROBABILITIES FOR BELOW-NORMAL PRECIPITATION ARE FAVORED ACROSS
PORTIONS OF THE LOWER MISSISSIPPI VALLEY, SOUTHEASTERN TEXAS, AND THE SOUTHEAST
UNDERNEATH SURFACE HIGH PRESSURE. INTERMITTENT FRONTAL ACTIVITY AND RETURN FLOW
FROM THE SOUTH FAVORS ELEVATED CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS
MUCH OF THE CENTRAL CONUS AND INTO PORTIONS OF THE OHIO VALLEY, GREAT LAKES,
AND INTERIOR NORTHEAST. WEAKLY POSITIVE MID-LEVEL HEIGHT ANOMALIES FAVOR A
SLIGHT TILT TOWARD ELEVATED BELOW-NORMAL PRECIPITATION PROBABILITIES ACROSS THE
INTERIOR WEST, WITH INCREASING ONSHORE FLOW LEADING TO SLIGHTLY ABOVE-NORMAL
PRECIPITATION CHANCES ALONG THE WEST COAST. TROUGHING PREDICTED ACROSS
SOUTHWESTERN ALASKA FAVORS ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION
ACROSS MOST OF THE STATE. NEAR- TO BELOW-NORMAL PRECIPITATION IS FORECAST
ACROSS HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 50% 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
CONTINUED GOOD AGREEMENT AMONG THE FORECAST TOOLS, OFFSET BY DECREASING
PREDICTABILITY AS THE MID-LEVEL PATTERN BECOMES MORE ZONAL.
FORECASTER: THOMAS COLLOW
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:
19990601 - 20030507 - 19620602 - 19980514 - 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:
19990604 - 20030507 - 19890517 - 19620527 - 19660515
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 29 - JUN 02, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON N B NRN CALIF A B
SRN CALIF A B IDAHO N B NEVADA A B
W MONTANA N N E MONTANA A A WYOMING A N
UTAH A B ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI N A
ARKANSAS A A LOUISIANA A N WISCONSIN N A
ILLINOIS N N MISSISSIPPI A B MICHIGAN N N
INDIANA B N OHIO B N KENTUCKY B B
TENNESSEE B B ALABAMA A B NEW YORK B N
VERMONT N N NEW HAMP N N MAINE A A
MASS N N CONN N N RHODE IS N N
PENN B N NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA N B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A A
AK S INT B A AK SO COAST B A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 31 - JUN 06, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF N N IDAHO A B NEVADA A N
W MONTANA A B E MONTANA A B WYOMING A N
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO A A N DAKOTA A N S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A B W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A N
ILLINOIS A N MISSISSIPPI A B MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK N N
VERMONT N N NEW HAMP N N MAINE A N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA A N S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN A A AK INT BSN A A
AK S INT N 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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