UPDATE (Monday, July 22, 2019; 5:04 pm): The NWS Severe Thunderstorm Warning that had been issued this afternoon, to be in effect over Newtown and other immediate areas until 4:45, has been extended to 5:45 pm.

Additionally, a Flash Flood Warning has now been issued for parts of the tri-state area, including Newtown. This warning will remain in effect until 8 pm. Details below. 

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The National Weather Service (NWS) in Upton NY has issued a Severe Thunderstorm Warning for Fairfield County. The warning will remain in effect until 4:45 pm.

The warning also includes areas of northwestern New Haven County, northern Westchester County in southeastern New York, and Putnam County in southeastern New York.

At 3:55 pm, severe thunderstorms were located along a line extending from near Fahnestock State Park to near Yorktown Heights to Ossining, N.Y., moving east at 35 mph.

The storm has the potential of delivering 60 mph wind gusts. The weather service says areas hit by the storm could “expect damage to trees and power lines.”

Isolated hail to quarter size (1" diameter) is also possible, according to the US NWS New York NY Facebook page.

According to the weather service the severe thunderstorms will be near Mahopac, N.Y., around 4:00 pm; Lake Carmel and Carmel around 4:05 pm; And Mount Kisco and Brewster around 4:10 pm.

The storm is expected to move into Connecticut, reaching New Fairfield around 4:20 pm; Ridgefield and Brookfield around 4:25 pm; Stamford and Danbury around 4:30 pm; Norwalk and New Canaan around 4:45 pm; and  Bridgeport and Shelton around 4:45 pm.

For the safety of all, moving to an interior room on the lowest floor of a building is suggested by the weather service. 

“Intense thunderstorm lines can produce brief tornadoes and widespread significant wind damage,” NWS said as part of this afternoon’s warning. “Although a tornado is not immediately likely, it is best to move to an interior room on the lowest floor of a building. These storms may cause serious injury and significant property damage.

“Torrential rainfall is occurring with these storms, and may lead to flash flooding. Do not drive your vehicle through flooded roadways.”

Flash Flood Warning

At 4:58 pm Monday, NWS issued a Flash Flood Warning for Fairfield County and southwestern New Haven counties in Connecticut. Sections of New York and New Jersey were also covered by the warning, which was in effect until 8 pm. 

At 4:57 pm, Doppler radar indicated thunderstorms producing heavy rain across the warned area. Flash flooding is expected to begin shortly, according to the bulletin.

The weather service asks residents to report flooding to local law enforcement agencies “when you can do so safely.”

A Flash Flood Warning means that flooding is imminent or occurring. 

“If you are in the warned area move to higher ground immediately. Residents living along streams and creeks should take immediate precautions to protect life and property,” the bulletin advises. 

Additional Alerts 

A Flash Flood Watch that includes Newtown was also issued by the weather service this afternoon. That alert, which includes all of Fairfield and New Haven counties, will remain in effect through Tuesday morning. No specific time was issued with the bulletin, released as 2:53 pm Monday afternoon.

According to the weather service: “Rain showers with embedded thunderstorms will develop and move across the area today through early Tuesday. Multiple rounds of thunderstorms and heavy rainfall will be possible. Rainfall  totals of around 1.5 to 2 inches are expected with locally   higher amounts possible.

“Flash flooding will be possible, especially in areas of poor drainage, low-lying areas, and in urban areas. Fast reacting rivers and streams may flood as well,” that alert continued. 

A Flash Flood Watch means that conditions may develop that lead to flash flooding. Flash flooding is a very dangerous situation.

“Monitor later forecasts and be prepared to take action should flash flood warnings be issued,” the weather service suggested. 

The Severe Thunderstorm Warning issued Monday afternoon was an upgrade from a Severe Thunderstorm Watch also issued by NWS on Monday. The watch covers the entire state, and is in effect until 10 pm.