A very slow moving weather system will bring soaking rains to the Mid Atlantic today, with flooding rains becoming more and more likely over a wider area as the afternoon continues. A cold front moving into the region today will very slowly progress south through the end of the week, with several areas of low pressure developing and tracking along it.
The heaviest area of rain and thunderstorms has formed right along the I-95 corridor near Philadelphia and eastern New Jersey. With a hot, humid, and extremely moist airmass in place, the ingredients have set the stage for heavy rain. Upper level winds and steering currents are week, which means showers and storms that do form won’t move far. With heavy rain falling over the same places, flash flooding is likely.
With a lack of wind at higher levels of the atmosphere, thunderstorms that blossom probably won’t produce tornadoes. However, as storms grow taller in the weak-sheer environment, they could create severe downbursts of damaging winds in isolated areas.
Beyond the threat of downbursts, heavy rainfall and flash flooding remain the biggest concerns. The National Weather Service is warning people to “turn around, don’t drown; never drive through flood waters” as the threat of flooding increases under the heavy rain area.