461
FXUS02 KWBC 260748
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
348 AM EDT SUN APR 26 2026
VALID 12Z WED APR 29 2026 - 12Z SUN MAY 03 2026
...HEAVY RAINFALL/RUNOFF POTENTIAL ACROSS THE SOUTH-CENTRAL U.S.
AND ALSO WITH A NEW ENGLAND COASTAL LOW TO MONITOR FOR
THURSDAY/FRIDAY...
..OVERVIEW
AN INCREASINGLY AMPLIFIED SYNOPTIC PATTERN WILL LEAD TO EPISODES
OF ACTIVE WEATHER ACROSS PARTS OF THE CONUS FOR THE LATTER HALF OF
THE UPCOMING WEEK INTO NEXT WEEKEND. A LOW PRESSURE/FRONTAL SYSTEM
WILL BRING MUCH NEEDED RAIN TO THE EASTERN SEABOARD MID TO LATE
WEEK, WITH COASTAL DEVELOPMENT LEADING TO POTENTIALLY HEAVY RAINS
ACROSS PARTS OF NORTHERN NEW ENGLAND. FARTHER SOUTH, A PACIFIC LOW
EJECTING OUT OF THE DESERT SOUTHWEST WILL SET THE STAGE FOR HEAVY
RAIN FOR THE SOUTH-CENTRAL U.S. TO ROUND OUT THE WORK WEEK.
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL GUIDANCE HAS A RELATIVELY GOOD HANDLE ON THE
SYNOPTIC SCALE THROUGH THE MEDIUM RANGE PERIOD DESPITE INCREASING
MID-LEVEL AMPLIFICATION AND A LIKELY BLOCKING PATTERN MID TO LATE
WEEK INTO NEXT WEEKEND. AS A RESULT, THE WPC PRODUCT SUITE WAS
PRODUCED BY UTILIZING A MULTI-MODEL COMPOSITE BLEND FEATURING
MOSTLY DETERMINISTIC SOLUTIONS EARLY ON THE PERIOD, FOLLOWED BY
INCREASING WEIGHTING OF ECMWF AND GEFS ENSEMBLE MEANS (UP TO 50% BY
DAY 7) TO OFFER STABILITY AND RETAIN CONTINUITY.
..WEATHER/HAZARDS HIGHLIGHTS
A FRONTAL WAVE WILL LAY A COLD FRONT ACROSS THE DEEP SOUTH JUST TO
THE NORTH OF THE GULF COAST ON WEDNESDAY, PROVIDING THE FOCUS FOR
ADDITIONAL AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. SOME OF
THIS ACTIVITY MAY CONTAIN HEAVY RAINFALL RATES GIVEN ADEQUATE
MOISTURE AND INSTABILITY, BUT ANY FLOODING CONCERNS SHOULD REMAIN
LOCALIZED. THUS, A NULL DAY 4/WEDNESDAY ERO IS MAINTAINED WITH THIS
FORECAST UPDATE. THE AFOREMENTIONED FRONTAL WAVE WILL TRACK OFF
THE MID-ATLANTIC COAST WEDNESDAY INTO THURSDAY, SPREADING MUCH
NEEDED RAINFALL TO MUCH OF THE EASTERN U.S. BY THE END OF THE WEEK,
A GROWING SIGNAL FOR DEEPER COASTAL LOW DEVELOPMENT AND ANOMALOUS
LONG-FETCH GULF/ATLANTIC MOISTURE WRAPPING INTO NEW ENGLAND WILL
SUPPORT A HEAVY RAIN THREAT WITH THE POTENTIAL FOR 1-2"+ OF
RAINFALL. WHILE THE SIGNAL FOR HEAVY RAIN IS NOTEWORTHY AND COULD
LEAD TO RUNOFF OR LOCALIZED POOR DRAINAGE FLOODING, RECENT MODERATE
TO SEVERE DROUGHT CONDITIONS SHOULD RENDER MOST OF THE RAIN MORE
BENEFICIAL THAN HAZARDOUS. AS A RESULT, NO DAY 5/THURSDAY ERO WAS
HIGHLIGHTED FOR THE TIME BEING. THE COASTAL LOW WEAKENS AND STALLS
OUT LATER FRIDAY INTO THE WEEKEND, ALLOWING INTENSITY TO WANE BUT
KEEPING CONDITIONS COOL, CLOUDY, AND UNSETTLED. A LITTLE SNOW CAN'T
BE RULED OUT EITHER ACROSS THE HIGHER ELEVATIONS OF NORTHERN NEW
ENGLAND AND THE INTERIOR NORTHEAST.
MEANWHILE, A SOUTHERN STREAM PACIFIC LOW WILL SLOWLY TRACK INLAND
ACROSS SOUTHERN CALIFORNIA, THE SOUTHWEST, AND THE SOUTHERN FOUR
CORNERS STATES WEDNESDAY INTO THURSDAY, SPREADING LIGHT TO MODERATE
LOW ELEVATION RAIN AND HIGHER ELEVATION MOUNTAIN SNOW INTO THE
REGION. AS THIS FEATURE EJECTS EASTWARD INTO THE SOUTHERN PLAINS,
ANOTHER GROWING SIGNAL FOR SIGNIFICANT RAINFALL DEVELOPS AND
EXPANDS/STRENGTHENS OVER THE SOUTH-CENTRAL U.S. THURSDAY INTO
FRIDAY. ANOMALOUS GULF MOISTURE OVERRUNNING A LINGERING FRONTAL
BOUNDARY COMBINED WITH IMPRESSIVE DYNAMICS AND FORCING FROM A
STRONG UPPER JET WILL LEAD TO THE POTENTIAL FOR RAINFALL TOTALS OF
1-3"+ ACROSS THE HEART OF TEXAS. DESPITE QUESTIONS WITH RESPECT TO
THE QUALITY OF INSTABILITY (PARTICULARLY WITH NORTHWARD EXTENT) AND
THE ONGOING DROUGHT CONDITIONS OVER PARTS OF THE REGION, THE HEAVY
RAIN SIGNAL IS CONCERNING ENOUGH TO AT LEAST INTRODUCE A MARGINAL
RISK ERO FOR RUNOFF/ISOLATED FLOODING ISSUES ON DAY 5/THURSDAY.
SUBTLE WAVES ALONG THE FRONTAL ZONE WILL EXPAND THE RAINFALL
FOOTPRINT EASTWARD INTO THE MID-SOUTH AND SOUTHEAST HEADING INTO
THE WEEKEND, WITH ADDITIONAL RISKS OF HEAVY RAIN TO BE MONITORED.
MILLER
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
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