UPDATE:  Wednesday, Sept. 1, 7:25 p.m. — The NWS has upgraded the Wilton area to a flash flood warning.

ORIGINAL STORY:  Wednesday, Sept. 1, 6:50 p.m. — The National Weather Service has issued a Tornado Watch in effect until 1 a.m. on Thursday, Sept. 2 for Wilton and the surrounding Fairfield County.

In addition to Fairfield County, the tornado watch has been issued for Middlesex, New Haven and New London counties also.

New Jersey counties under the tornado watch include Bergen, Essex, Hudson, Passaic and Union. The watch includes nine counties in southeast New York:  Bronx, Kings (Brooklyn), Nassau, New York (Manhattan), Queens, Richmond (Staten Island), Rockland, Suffolk and Westchester.

Significant Flooding Possible

A flood watch also remains in effect for the entire state of Connecticut. The National Weather Service warns that “significant flooding is likely overnight” due to remnant rains from former hurricane Ida.

Police Chief John Lynch said that his department will continue monitoring for flooding, downed trees and any outages.

According to the NWS, Wilton is at possible risk for severe thunderstorms. The latest model runs are showing southern Connecticut with the most rainfall (6-8 inches with isolated spots up to 10 inches) and northern CT with slightly less rainfall (3-6 inches). However, all towns should be prepared to closely monitor their known flood prone areas tonight. Here’s a detailed forecast based on the latest models.

Wednesday Evening: Bands of heavy rain will return from the west by 7 p.m. and spread across the rest of the state by 9 p.m. Some embedded thunderstorms can also be expected to move across the state. Rainfall rates of 1-2 inches per hour can be expected especially in southern CT by 9 p.m. Moderate urban flooding is expected.

Overnight: Heavy rain is expected between 9 p.m. and 3 a.m. across most of the state with rainfall rates of 1-2 inches at times. Brief periods of extremely heavy rain (3-4 inches per hour) are possible in thunderstorms especially in southern CT. Major urban flooding is expected with multiple road and some bridge washouts. Widespread moderate-to-major small stream flooding and some moderate river flooding is also possible. Basement flooding is also likely. There is a 5% chance of an isolated tornado in any thunderstorms that develop especially in southern CT. All towns should closely monitor known flood prone areas overnight.

Thursday Morning: The rain is expected to taper off from west to east around daybreak. Urban and small stream flooding is expected to subside by mid-morning. River flooding may continue into Thursday afternoon and evening. Total rainfall is forecast to range from 4-8 inches with isolated amounts up to 10 inches.