431
FXUS02 KWBC 281857
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
257 PM EDT SAT JUN 28 2025
VALID 12Z TUE JUL 01 2025 - 12Z SAT JUL 05 2025
..GUIDANCE/PREDICTABILITY ASSESSMENT
THE LATEST MODEL AND ENSEMBLE GUIDANCE CONTINUES TO SHOW
RELATIVELY GOOD AGREEMENT ON THE OVERALL LARGE SCALE VERY
SUMMERTIME-LIKE PATTERN FOR THE MEDIUM RANGE TIME FRAME. THERE ARE
SOME MINOR SMALL SCALE DETAIL DIFFERENCES, MUCH OF WHICH WILL TAKE
UNTIL THE SHORT RANGE TO RESOLVE ANYWAYS, BUT ALSO DOES NOT HAVE
MUCH IMPACT ON SENSIBLE WEATHER AT THIS POINT. TO NOTE THOUGH, THE
GFS WAS FASTER WITH THE TROUGH AS IT EXITS THE EAST LATE WEEK AND A
BIT DIFFERENT WITH ENERGY DISTRIBUTION ACROSS THE WEST. THE WPC
FORECAST FOR TODAY USED A BLEND OF THE NON- GFS BLEND EARLY IN THE
PERIOD, TRANSITIONING TOWARDS A 50/50 BLEND OF THE ECMWF/CMC WITH
THE ENSEMBLE MEANS. OVERALL, THIS MAINTAINED GOOD CONTINUITY WITH
THE PREVIOUS WPC FORECAST.
..WEATHER/HAZARDS HIGHLIGHTS
ORGANIZED THUNDERSTORMS WITH FAVORABLE MOISTURE/INSTABILITY WILL
BRING LOCALLY HEAVY CONVECTIVE DOWNPOURS AHEAD OF AN UPPER TROUGH
AND A WELL DEFINED SUMMER SURFACE FRONTAL BOUNDARY TO PROGRESS INTO
THE EAST AND SOUTH/SOUTHEAST BY TUESDAY AND INTO LATE NEXT WEEK.
AN ELONGATED WPC DAY 4/TUESDAY EXCESSIVE RAINFALL OUTLOOK (ERO)
MARGINAL RISK AREA REMAINS FROM THE NORTHEAST/MID-ATLANTIC BACK
THROUGH THE APPALACHIANS AND BROADLY ACROSS THE SOUTH. AN ERO
MARGINAL RISK AREA IS ALSO HIGHLIGHTED FOR DAY 5/WEDNESDAY WITH
FOCUS ACROSS THE SOUTHEAST. ONE AREA OF FOCUS FOR SOME HEAVIER RAIN
IS ACROSS THE CENTRAL TO EASTERN GULF COAST REGION. AREAS WILL DRY
OUT AND MODERATE TO THE NORTH POST-FRONTAL, BUT ACTIVITY WILL
LINGER ALONG/AHEAD AS THE FRONT SLOWS AND SLOWLY LOSES INFLUENCE
ACROSS THE SOUTH/SOUTHEAST INTO LATE NEXT WEEK. EVEN BEFORE THE
FRONT NEARS, MOIST SCATTERED THUNDERSTORMS ARE LIKELY FARTHER SOUTH
IN THE BROAD WARM SECTOR AS WELL. THERE WILL INITIALLY BE LESS
FORCING FOR ORGANIZATION AND SUSTAINING OF STORMS DEEPER DOWN
ACROSS THE SOUTHERN TIER AWAY FROM THE UPPER JET, BUT INSTABILITY
COULD ALLOW FOR HEAVY RAIN RATES THAT MAY CAUSE LOCALIZED FLASH
FLOODING, AS LIKELY DEPENDENT ON SMALLER SCALE BOUNDARIES.
MONSOONAL MOISTURE WITH SOME CONNECTION TO POSSIBLE PACIFIC
TROPICAL DEVELOPMENT IS LIKELY TO INCREASE NEXT WEEK IN THE
SOUTHERN ROCKIES/HIGH PLAINS WITH SOUTHERLY FLOW UNDER THE UPPER
RIDGE, THUS INCREASING COVERAGE OF RAIN AMOUNTS IN STORMS. MARGINAL
RISKS REMAIN PLANNED THERE FOR DAY 4/TUESDAY AND ALSO FOR SOUTHERN
ARIZONA INTO DAY 5/WEDNESDAY. AREAS LIKE THE SACRAMENTO MOUNTAINS,
WHERE THE STEEP TERRAIN AND BURN SCARS CAUSE THE AREA TO BE
PARTICULARLY SENSITIVE TO RAIN AND MOST VULNERABLE TO POTENTIAL
FLASH FLOODING, ESPECIALLY WITH WET ANTECEDENT CONDITIONS THERE.
ELSEWHERE, AFTERNOON AND NOCTURNAL STORM CLUSTERS MAY DEVELOP FROM
THE NORTHERN ROCKIES TUESDAY ONWARD ACROSS THE NORTHERN PLAINS AND
UPPER MIDWEST WEDNESDAY INTO FRIDAY AS MOISTURE/INSTABILITY POOL
ALONG/OVERTOP A RETREATING FRONT. A DAY 5/WEDNESDAY WPC ERO
MARGINAL RISK AREA CONTINUES GIVEN POTENTIAL FOR TRAINING OF THESE
STRONG TO SEVERE CELLS.
SANTORELLI/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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