Major flooding ahead for the northeast

Two rounds of heavy rainfall will affect the northeast tonight through Wednesday.

A strong subtropical jet is shifting east into the Gulf of Mexico, deepening an upper level trough. Surface low pressure is ejecting out of the central Plains into the Ohio Valley, while secondary low pressure has begun to develop in the southeast. A frontal boundary extending north from the low will be the focus for heavy rain tomorrow as a high-PWAT airmass advects north on the low level jet. Totals of 1.5 to 2.5 inches region-wide can be expected through Monday night.

The second round comes as the secondary low turns up the east coast. The upper level trough will close off and capture the surface low, stalling it south of Long Island on Tuesday. In accordance, the low level jet will continue to transport moisture from the Atlantic, and provide a focus for lift over New England. By Wednesday morning, a dry slot working up from the south will shut off the rain across most of the region save a few left over showers. Totals for the entire event will range between 4 and 7 inches, with the axis of heaviest rainfall from New York City through Worcester where upwards of 8 inches is not out of the question. Most of the region is still recovering from major flooding just a week ago. Water levels are still high for most streams, and the soil is saturated. This has the makings of a major flood event for the region.