339
FXUS02 KWBC 040620
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
220 AM EDT WED JUN 4 2025
VALID 12Z SAT JUN 07 2025 - 12Z WED JUN 11 2025
...HEAVY RAINFALL/FLASH FLOODING THREAT FROM THE SOUTHERN PLAINS
TO THE NORTHEAST INTO THE WEEKEND TO INCLUDE A SOUTHERN PLAINS TO
MID-SOUTH SEVERE WEATHER THREAT...
...HEATWAVE FOR THE INTERIOR NORTHWEST/WEST AND ALSO THE U.S.
SOUTHERN TIER, BUT ESPECIALLY SOUTH TEXAS...
...COMPACT LOW TO LIFT ALONG/OFF THE SOUTHEAST U.S. LATE WEEK
BEING MONITORED BY NHC FOR SUB-TROPICAL DEVELOPMENT...
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST SUITE OF GUIDANCE CONTINUED TRENDING TOWARD A BETTER
CLUSTERED UPPER LEVEL FLOW PATTERN EVOLUTION THROUGH MEDIUM RANGE
TIME SCALES; HOWEVER THERE ARE STILL SOME STRUGGLES WITH DETAILS
FOR INDIVIDUAL SYSTEMS AND THE ASSOCIATED LOCAL WEATHER WEATHER AND
HAZARDS. MAINTAINED CONTINUITY BY UTILIZING A MULTI-MODEL BLEND OF
THE GFS/ECMWF/CANADIAN/UKMET AND GEFS/ECMWF/CANADIAN ENSEMBLE
GUIDANCE ALONG WITH FAVORABLY SUPPORTING GUIDANCE FROM THE 01 UTC
NATIONAL BLEND OF MODELS. THIS BLEND SEEMS TO OFFER A REASONABLE
MIDDLE OF SPECTRUM DEPICTION OF SURFACE SYSTEM AND HAZARD THREATS
CONSISTENT WITH THE MORE PREDICTABLE UPPER FLOW.
..WEATHER/HAZARDS HIGHLIGHTS
A NON-TROPICAL LOW IS EXPECTED TO DEVELOP OFFSHORE THE SOUTHEAST
COAST PRIOR TO THE EXTENDED. THE NATIONAL HURRICANE CENTER IS
MONITORING THIS FEATURE FOR THE POTENTIAL TO TRANSITION INTO A
SUBTROPICAL OR TROPICAL LOW. DEEPEST MOISTURE MAY STAY OFFSHORE
AND UNCERTAINTY IS HIGH, BUT THERE IS A CHANCE OF SOME HEAVIER
RAINFALL ALONG THE COAST.
POOLED MOISTURE ACROSS THE CENTRAL U.S. WILL HELP CONVECTION FIRE
UP ALONG A SLOW-MOVING AND WAVY FRONT THAT WILL STRETCH FROM THE
NORTHEAST AND OHIO VALLEY STATES DOWN TO THE SOUTHERN PLAINS.
LOCALLY ENHANCED RAINFALL WILL BE SUPPORTED THANKS TO STEADY
ADVECTION FROM THE GULF COUPLED WITH SHORTWAVE/JET. CONDITIONS
WILL BE FAVORABLE FOR HOURLY RATES OF 1 INCH/HOUR OR GREATER. WPC
HAS A BROAD MARGINAL RISK SPANNING FROM THE PLAINS TO THE GREAT
LAKES/NORTHEAST INTO THE WEEKEND. WITHIN THE MARGINAL IS A SMALLER
AREA HIGHLIGHTED WITH A SLIGHT RISK OF EXCESSIVE RAINFALL MAINLY
FOR OKLAHOMA, BUT ALSO INTO THE ADJACENT COUNTIES OF ARKANSAS AND
SOUTHWEST MISSOURI. THE SOUTHERN TRAILING TAIL OF THE ELONGATED
BOUNDARY WILL STALL AND WEAKEN OVER THE SOUTHERN PLAINS. DYNAMIC
UPPER CLOSED LOW/TROUGH DIGGING INTO THE NORTH- CENTRAL U.S. FROM
THE WEEKEND INTO EARLY NEXT WEEK WILL SPAWN FRONTO/CYCLO GENESIS,
WITH BAROCLINICITY REJUVENATED MORE BROADLY AGAIN THAT MAY ACT TO
SPREAD HEAVY RAINFALL FOCUS ACROSS THE MID- SOUTH AND TENNESSEE
VALLEY THEN DOWN ACROSS THE MID- ATLANTIC AND THE SOUTH/SOUTHEAST.
SUMMER HEAT WILL BUILD ACROSS THE INTERIOR NORTHWEST/WEST AND INTO
THE DESERT SOUTHWEST WITH ESTABLISHMENT OF MEAN UPPER RIDGING OVER
THE WEEKEND INTO NEXT WEEK. MAXIMUM TEMPERATURES OVER THE INTERIOR
NORTHWEST MAY RANGE UPWARDS TO 20-25F DEGREES ABOVE NORMAL. AREAS
FROM SOUTH TEXAS INTO THE GULF COAST WILL ALSO EXPERIENCE RISING
TEMPERATURES, CRESTING UPWARDS OF 105F BY THE WEEKEND OVER SOUTH
TEXAS TO PUSH HEAT INDEX VALUES DANGEROUSLY UPWARDS TO 110-115F.
PLEASE TAKE HEAT SAFETY PRECAUTIONS SUCH AS INCREASED WATER INTAKE
AND MORE TIME IN AIR CONDITIONED AREAS TO AVOID HEAT EXHAUSTION
AND HEAT STROKE. SEE WEATHER.GOV/HEAT FOR MORE INFORMATION ON
SAFETY TIPS AND RESOURCES.
CAMPBELL/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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