138
FXUS02 KWBC 251945
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
345 PM EDT SAT APR 25 2026
VALID 12Z TUE APR 28 2026 - 12Z SAT MAY 02 2026
...HEAVY RAIN/RUNOFF AND SEVERE WEATHER THREATS FROM THE ARKLATEX
TO THE TENNESSEE VALLEY TUESDAY MAY BE FOLLOWED BY ADDITIONAL HEAVY
RAINFALL/RUNOFF POTENTIAL ACROSS THE SOUTH-CENTRAL U.S. AND ALSO
WITH A NEW ENGLAND COASTAL LOW TO MONITOR FOR THURSDAY/FRIDAY...
..GUIDANCE/PREDICTABILITY ASSESSMENT
LATEST GUIDANCE CLUSTERING AND PREDICTABILITY SEEMS ABOVE AVERAGE
WITH THE MID-LARGER SCALE PATTERN EVOLUTION AND OVERALL MAIN
SYSTEM TIMINGS AND THREATS FOCUS THROUGH MUCH OF UPCOMING MEDIUM-
RANGE TIME SCALES. A FAVORED MULTI-MODEL AND ENSEMBLE MEAN BLEND
SHOULD ALSO ACT TO MITIGATE WIDE-RANGING/LINGERING SMALLER SCALE
VARIANCES AS CONSISTENT WITH INDIVIDUAL FEATURE PREDICTABILITY.
THIS SOLUTION AND THREAT MESSAGING HAS GOOD WPC CONTINUITY AND
REMAINS GENERALLY IN LINE WITH THE NATIONAL BLEND OF MODELS (NBM).
..WEATHER/HAZARDS HIGHLIGHTS
A TRAILING COLD FRONT IN THE WAKE OF STRONG/WINDY LOW PRESSURE
SYSTEM ADVANCING THROUGH THE GREAT LAKES INTO SOUTHERN CANADA WILL
SLIDE TO THE SOUTH AND EAST ON TUESDAY, BRINGING A ORGANIZED
SHOWERS AND THUNDERSTORMS TO THE EASTERN U.S.. A WAVE OF LOW
PRESSURE DEVELOPING NEAR/AHEAD OF THE TAIL END OF THE FRONT WITH
SOUTHERN STREAM ENERGY EJECTION WILL BECOME THE GREATER FOCUS FOR
ANOTHER ROUND OF HEAVY RAIN AND POSSIBLE SEVERE WEATHER ON TUESDAY
FROM THE ARKLATEX TO THE TENNESSEE VALLEY. SIGNIFICANT MOISTURE AND
INSTABILITY POOLING ALONG THE BOUNDARY AND FRONTAL WAVE WILL
LIKELY LEAD TO CLUSTERS OF STRONG THUNDERSTORMS WITH HIGH RAINFALL
RATES, SUPPORTING THE POTENTIAL FOR ISOLATED INSTANCES OF FLASH
FLOODING. A MARGINAL RISK ERO REMAINS IN PLACE FOR DAY 4/TUESDAY AS
A RESULT. ADDITIONAL SHOWERS AND STORMS LIKELY LINGER ALONG AND
JUST NORTH OF THE GULF COAST AND ALSO NORTHWARD ALONG THE FRONT
OVER THE EAST ON DAY 5/WEDNESDAY, BUT ANY FLOODING RISK SHOULD BE
FAIRLY LOCALIZED GIVEN STEADY PROGRESSION. THE MAIN FRONTAL WAVE
TRACKS TO THE EASTERN SEABOARD WEDNESDAY INTO THURSDAY, SPREADING
MUCH NEEDED ENHANCED RAINFALL INTO THE MID-ATLANTIC AND NORTHEAST.
A BIT OF SNOW ISN'T RULED OUT WITH THIS ACTIVITY FOR PARTS OF THE
HIGHER ELEVATIONS OF NORTHERN NEW ENGLAND AND THE INTERIOR
NORTHEAST. THERE IS A GROWING SIGNAL SUPPORTING DEEPER COASTAL
CYCLOGENESIS THURSDAY-SATURDAY WITH WRAPPING/WINDY LONG-FETCH
GULF/ATLANTIC MOISTURE INFLOW/IVT INTO NEW ENGLAND. SLOWED
PATTERN/SYSTEM MOTION OFFERS CUMULATIVE HEAVY RAIN/RUNOFF ISSUES.
MEANWHILE FAR UPSTREAM, A SOUTHERN STREAM PACIFIC LOW WILL SLOWLY
ADVANCE INLAND ACROSS SOUTHERN CALIFORNIA, THE SOUTHWEST, AND THE
FOUR CORNERS STATES INTO THURSDAY, SPREADING LIGHT TO MODERATE LOW
ELEVATION RAIN AND HIGHER ELEVATION MOUNTAIN SNOW INTO THE REGION.
AS THIS FEATURE CONTINUES EASTWARD, THERE IS A GROWING SIGNAL FOR
SIGNIFICANT RAINFALL/RUNOFF ISSUES TO DEVELOP AND EXPAND/INTENSIFY
OVER THE SOUTH-CENTRAL U.S. THURSDAY INTO FRIDAY AS LEAD GULF
RETURN FLOW INTERSECTS AND OVERRUNS A LINGERING FRONTAL ZONE, WITH
WAVY EASTWARD PROGRESSION OVER THE SOUTH/SOUTHEAST ON SATURDAY.
MILLER/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, EXCESSIVE RAINFALL OUTLOOK, WINTER WEATHER OUTLOOK PROBABILITIES, HEAT INDICES AND KEY MESSAGES ARE AT:
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
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page