Isaias to bring flooding rains, strong winds Tuesday

  • Isaias will impact New Jersey beginning late Monday night through Tuesday evening
  • Flooding rains, strong winds, and coastal flooding and beach erosion are all likely
  • Short duration, high impact event

Tropical Isaias is churning northeast along the East Coast, just 100 miles offshore from the Georgia and South Carolina border. Isaias is now a strong tropical storm with sustained winds of 70 mph. A brief window remains for potential strengthening to hurricane status before it makes landfall Monday evening between Charleston and Myrtle Beach.

Isaias, a small, compact tropical system will then accelerate northward, with the storm center essentially traveling I-95 up the East Coast from the southern mid-Atlantic into New England. This puts New Jersey directly in the path of the storm center, which will rake across the state Tuesday morning and afternoon. Being a small storm, and moving quickly, this will generally be a shorter duration tropical weather event for New Jersey. On the other hand, it is a potent system, as the storm’s speed will allow it to maintain strength as it races northward towards the state.

Tropical storm warnings have now been issued by the National Weather Service for every county in New Jersey. We will see a myriad of tropical storm conditions, which will be quite varied depending on the exact location throughout the state. The expected track directly over New Jersey, coupled with upper level jet stream dynamics, will result in western counties receiving more rainfall than those along the coast. Counties bordering the Delaware River as well as Morris and western portions of Passaic and Somerset Counties should expect 2 to 5 inches of rainfall on Tuesday, with 1 to 3 inches falling elsewhere across the state.

The strongest winds will be present in the reverse scenario, with coastal zones and locations lying to the immediate east of Isaias’s path taking the brunt. Expect sustained tropical storm force winds — greater than 39 mph — along the coastline, including the Delaware Bay, with tropical storm force gusts inland.

Coastal flooding is a third concern. Waves of 10 to 15 feet will pound New Jersey beaches, exacerbated by the spring tide due to Monday’s full moon phase. Gale force southeasterly winds will bring moderate coastal flooding, especially to south or southeast facing bays and inlets. An isolated tornado cannot be ruled out anywhere in the state, with the greater chances being on the eastern flank of Isaias.

Rain will begin as rain showers and isolated thunderstorms in western portions of the state as early as pre-dawn Tuesday, when initial moisture from Isaias interacts with an upper-level trough and surface cold front across the Ohio Valley. The precipitation directly associated with Isaias arrives mid-Tuesday morning and spreads south to north by midday. Early afternoon will be the peak of tropical storm conditions. Conditions will improve as the afternoon progresses, and we might even see some peeks of sun as it sets Tuesday evening.

A Tropical Storm Fay affected New Jersey two weeks ago, bringing several inches of rain and tropical storm force gusts. Residents of New Jersey should expect Isaias to perform as a Fay redux, with a bit more strength and slightly worse conditions. Power outages are possible, particularly in locations that have seen above average rain fall in the last couple of weeks. Namely, that would be the Route 18 corridor, the Musconetcong River Valley in Warren County, and portions of southern Cumberland and Atlantic Counties.

Flooding rains and strong winds are the recipe for downed trees and power outages, which is a particular concern when all trees are in full leaf as they are now. All residents should make sure important items are secured or brought inside, and coastal residents should prepare for a moderate flooding event. It is in our favor that Isaias will be moving with speed up the coast, and tropical storm conditions should be felt for just about 8 hours or so. Still, preparedness is always in your favor.