444
FXUS02 KWNH 010638
PREEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
237 AM EDT TUE JUL 1 2025
VALID 12Z FRI JUL 04 2025 - 12Z TUE JUL 08 2025
...HEAVY RAIN/FLASH FLOODING THREATS FOR BOTH FLORIDA AND THE
NORTH-CENTRAL PLAINS/UPPER MIDWEST THROUGH FRIDAY/SATURDAY...
..HOLIDAY WEEKEND CENTRAL-EASTERN U.S. HAZARDOUS HEAT THREAT
..PATTERN OVERVIEW
AMPLIFIED UPPER TROUGHING OVER THE NORTHEAST WILL LIFT OUT OVER THE
UPCOMING HOLIDAY WEEKEND AS MULTIPLE PACIFIC SYSTEM ENERGIES DIG
INTO A WEST COAST MEAN UPPER TROUGH POSITION THAT LINGERS INTO
NEXT WEEK. IN BETWEEN, A BUILDING UPPER RIDGE WILL SPREAD A THREAT
FOR HAZARDOUS HEAT ACROSS THE CENTRAL TO EASTERN U.S. THIS HOLIDAY
WEEKEND INTO EARLY NEXT WEEK. MEANWHILE, A CONTINUED SERIES OF
STRONG TO SEVERE CONVECTION FORCING AND LOCAL HEAVY RAIN FUELING
IMPULSES AND FRONTS WILL MEANWHILE PROGRESS OVERTOP/INTO THE RIDGE
FROM THE NORTH-CENTRAL U.S. TO THE MIDWEST/EAST. AN ACTIVE TROPICS
FAVORS LINGERING MOISTURE OVER THE SOUTHERN HIGH PLAINS INTO THE
FOURTH AND A MULTI-DAY FLORIDA PENINSULA HEAVY RAIN PATTERN FUELED
BY TROPIPCAL MOISTURE THAT MAY ALSO FEED UP INTO THE GULF COAST.
...GUIDANCE/PREDICTABILITY ASSESSMENT
THE WPC MEDIUM RANGE PRODUCT SUITE WAS DERIVED FROM A BROAD BLEND
OF MODEL AND ENSEMBLE GUIDANCE ALONG WITH WPC CONINUITY AND THE
NATIONAL BLEND OF MODELS AND AIFS. FORECAST SPREAD AND UNCERTAINTY
INCREASE OVER TIME WITHIN AVERAGE SEASONAL NORMS, LENDING MAJORITY
BLEND GUIDANCE WEIGHTING TRANSITION FROM THE MODELS FRIDAY/SATURDAY
TO THE ENSEMBLES SUNDAY TO NEXT TUESDAY. THE BLEND TENDS TO SMOOTH
FORECAST VARIANCES AS CONSISTENT WITH FEATURE PREDICTABILITY.
..WEATHER/HAZARDS HIGHLIGHTS
THUNDERSTORMS WITH DEEP MOISTURE AND INSTABILITY WILL SUPPORT HEAVY
CONVECTIVE DOWNPOURS ALONG/SOUTH OF A LINGERING FLORIDA FRONT INTO
THE WEEKEND. WPC EXCESSIVE RAINFALL OUTLOOK (ERO) MARGINAL RISK
AREAS ARE IN PLACE FOR DAY 4/FRIDAY AND DAY 5/SATURDAY IN A REGION
WITH PRECURSOR HEAVY RAINS AND ANOMALOUS GULF TROPICAL MOISTURE.
LATEST GUIDANCE HAS BACKED OFF ON EXPLICIT QPF DESPITE A FAVORABLE
PATTERN FEEDING OFF THE EASTERN GULF AS BEING LOOKS AT BY THE NHC.
MONSOONAL MOISTURE WITH SOME CONNECTION TO CURRENT EASTERN PACIFIC
HURRICANE FLOSSIE AND SOME GULF MOISTURE FROM RECENT BARRY MAY
BOOST RAIN POTENTIAL THAT MAY LINGER INTO FRIDAY OVER THE BIG
BEND AND VICINITY WHERE AN ERO MARGINAL RISK AREA IS DEPICTED.
PERIODIC AFTERNOON AND NOCTURNAL STRONG TO SEVERE STORMS/MCS
ACTIVITY OFFER HEAVY RAIN/RUNOFF POTENTIAL TO FOCUS OVER THE NORTH-
CENTRAL PLAINS AND UPPER MIDWEST LATE WEEK INTO SATURDAY AS UPPER
TROUGH/IMPULSE ENERGIES WORK OVER THE NORTHERN PERIPHERY OF THE
MAIN CENTRAL U.S. UPPER RIDGE AS MOISTURE/INSTABILITY POOLS NEAR
WAVY PASSING AND DRAPING FRONTS. WPC ERO MARGINAL RISK AREAS HAVE
BEEN INTRODUCED FOR DAY 4/FRIDAY AND DAY 5/SATURDAY. WEEKEND TO
EARLY NEXT WEEK ACTIVITY WITH UPPER SYSTEM/FRONTAL PROGRESSIONS
THEN WORKS OVER THE CENTRAL MIDWEST/GREAT LAKES AND THE NORTHEAST
WHILE CONTINUED ACTIVITY REFIRES BACK TO THE NORTH-CENTRAL STATES
NEAR THE TRAILING AND WAVY FRONTAL ZONE WITH UNCERTAIN LOCAL FOCUS.
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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