FLASH FLOOD EMERGENCIES ISSUED FOR FAIRFIELD AND NEW HAVEN COUNTIES UNTIL 12:30 AM…CATASTROPHIC URBAN FLOODING IS POSSIBLE…FLASH FLOOD WARNINGS ISSUED FOR LITCHFIELD, HARTFORD, TOLLAND AND WINDHAM COUNTIES…

Posted 9/1/2021

EXWU0062 - Full Weather Report

At 11:00 PM radar showed a large cluster of thunderstorms over southwestern Connecticut moving into New Haven county at this time. This large cluster contains extremely heavy rainfall with rainfall rates of 2” – 5” inches per hour. Catastrophic urban flooding may occur in several towns and cities in Fairfield and New Haven counties during the next 90 minutes. A tornado watch remains in effect until 1:00 AM for southern Connecticut. Flash Flood Warnings have been issued for Litchfield, Hartford, Tolland and Windham counties.

Small streams and rivers in southwestern CT (e.g. the Rippowam River in Stamford) are rising very rapidly and are well above flood stage in Fairfield county. Stamford has reported vehicles stranded in deep water on city roads. Other small streams and rivers across the state are also starting to rise rapidly.

Overnight: Heavy rain is expected between now and 3:00 AM across most of the state with rainfall rates of 1” – 2” per hour at times. Periods of extremely heavy rain (rainfall rates of 2” – 5” per hour) are possible in heavier showers or thunderstorms especially in southern CT. Major to Catastrophic urban flooding is expected with multiple road and bridge washouts. Widespread moderate to major small stream flooding and some moderate river flooding is also likely. 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 by 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” with isolated amounts up to 10”.

The Department of Emergency Services and Public Protection, Division of Emergency Management and Homeland Security will continue to closely monitor this serious flooding threat.

Connecticut State Division of Emergency Management and Homeland Security