Denville and the rest of Morris County are under a Severe Thunderstorm Watch until 8 p.m. Tuesday, July 28, 2026, after the National Weather Service office in Mount Holly issued Severe Thunderstorm Watch 525 at 12:52 p.m.
The watch covers 15 New Jersey counties, including Morris, Sussex, Warren, Hunterdon, Somerset and Middlesex, along with 10 Pennsylvania counties and New Castle County in Delaware. A watch means conditions are favorable for damaging storms, not that severe weather is already happening. A warning means it is time to take cover.
Storms moving through the region Tuesday afternoon have already triggered severe thunderstorm warnings across western Morris County, with wind gusts up to 60 mph indicated on radar. Wharton, Mount Arlington, Netcong, Stanhope and Chester were among the areas covered. Gusts that strong are enough to bring down tree limbs and power lines.
Rain is the bigger concern into Wednesday. A Flood Watch remains in effect for Morris County through Wednesday evening. Forecasters say rainfall rates of 1 to 3 inches per hour are possible, with storm totals of 2 to 5 inches and locally higher amounts. A second round of heavy rain is expected Wednesday afternoon and into the evening.
That kind of rainfall can push creeks, streams and low lying roads past their banks quickly. Drivers should never attempt to cross a flooded roadway, and residents in flood prone spots near the Rockaway River and Indian Lake should be ready to move to higher ground.
Denville residents can track live watches and warnings through the National Weather Service Mount Holly office and should keep a charged phone and a backup light source handy in case of outages. Power outages can be reported to JCP&L at 1-888-544-4877.
