533
FXUS02 KWBC 090700
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT THU MAY 9 2024
VALID 12Z SUN MAY 12 2024 - 12Z THU MAY 16 2024
...EXCESSIVE RAINFALL/FLOODING THREAT FOR THE SOUTHERN PLAINS,
GULF COAST AND SOUTHEAST...
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A
COMPOSITE BLEND OF REAOSNABLY WELL CLUSTERED GUIDANCE FROM THE 18
UTC GFS AND 12 UTC ECMWF/UKMET/CANADIAN FOR SUNDAY AND MONDAY. THIS
SOLUTION IS BROADLY SUPPORTED BY ENSEMBLES AND IS GENERALLY
COMPATIBLE WITH THE NATIONAL BLEND OF MODELS, NEWER 00 UTC CYCLE
GUIDANCE AND WPC CONTINUITY IN A PATTERN WITH SLIGHTLY ABOVE NORMAL
PREDICTABILTY DESPITE LINGERING AND IMPORTANT LOCAL DIFFERENCES
OFFSET BY THE COMPOSITE. FORECAST SPREAD GROWTH PROMPTED A
TRANSITION DAY TUESDAY TO MOSTLY STILL COMPATIBLE 18 UTC GEFS AND
12 UTC ECMWF ENSEMBLE MEAN GUIDANCE INTO NEXT WEDNESDAY AND
THURSDAY AS PREDICTABILTY LOWERS THROUGH NORMAL TO LOWER VALUES.
..WEATHER/HAZARDS HIGHLIGHTS
A GENERAL SPLIT FLOW PATTERN WILL PERSIST OVER THE LOWER 48 STATES
INTO NEXT WEEK. THIS PATTERN WILL BE HIGHLIGHTED BY AN AMPLIFIED
SOUTHERN STREAM UPPER TROUGH SLATED TO EJECT SLOWLY BUT STEADILY EAST-
NORTHEASTWARD FROM THE SOUTHWEST SUNDAY AND THROUGH THE MID-
SOUTH/SOUTH TO OFFSHORE THE MID-ATLANTIC/EAST COAST NEXT THURSDAY.
THIS SYSTEM AND ASSOCIATED LEAD WAVY FRONT WILL INCREASINGLY TAP
AND FEED INLAND A RETURN OF DEEP GULF MOISTURE AND INSTABILITY
UNDER FAVORABLE UPPER TROUGH AND RIGHT ENTRANCE REGION UPPER JET
SUPPORT TO FUEL A POTENTIALLY SIGNIFICANT HEAVY RAINFALL AND
RUNOFF/FLOODING PERIOD. THE WPC DAY 4/SUNDAY EXCESSIVE RAINFALL
OUTLOOK (ERO) DEPICTS A MARGINAL RISK AREA SPREAD SOUTHEASTWARD
FROM SOUTHERN OKLAHOMA AND TEXAS TO THE LOWER MISSISSIPPI VALLEY.
WITHIN THIS, A SLIGHT RISK AREA REMAINS IN PLACE FOR SOUTHEAST
TEXAS GIVEN MOIST SOIL/STREAMFLOW SENSITIVITIES FROM HEAVY RECENT
RAINFALL. THE DAY 5 ERO INTRODUCES ELONGATED MARGINAL AND EMBEDDED
SLIGHT RISK AREAS STRETCHING FROM SOUTHEAST TEXAS THROUGH THE
CENTRAL GULF COAST AND VICINITY. HEAVY RAIN AND A THREAT OF RUNOFF
ISSUES IS ALSO EXPECTED TO SPREAD ACROSS THE SOUTHEAST THROUGH NEXT
MIDWEEK TO MONITOR.
MEANWHILE, SEVERAL AMPLIFIED UPPER TROUGHS AND SURFACE SYSTEMS ARE
SET TO WORK OVER THE NORTHERN TIER OF THE NATION FROM THE
NORTHWEST AND NORTH- CENTRAL U.S. THROUGH THE NORTHEAST AND FOCUS
MAINLY MODEST MOISTURE AND PRECIPITATION.
SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC
MEDIUM RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
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