Preliminary Forecasts
Issued by NWS
Issued by NWS
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 $$