NYC Emergency Management Issues Weather Alert for Heavy Rain and Thunderstorms for August 20th

August 19, 2026

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NYC EMERGENCY MANAGEMENT ISSUES WEATHER ALERT FOR HEAVY RAIN AND THUNDERSTORMS FOR THURSDAY, AUGUST 20

Heavy Downpours Could Produce Localized Flash Flooding During the Afternoon and Evening

NEW YORK - New York City Emergency Management (NYCEM) has issued a Weather Alert for Thursday, August 20. According to the National Weather Service (NWS), showers and thunderstorms are expected to move through the area Thursday afternoon and evening, with locally heavy downpours that could produce isolated to scattered flash flooding.

Scattered showers are expected to begin late Thursday morning, with the bulk of the widespread showers and embedded thunderstorms expected between approximately 2 p.m. and 8 p.m. The heaviest rainfall is currently expected between 5 p.m. and 8 p.m., which could affect the evening commute. NYCEM has activated the City's Flash Flood Emergency Plan and is coordinating with the NWS and City agencies to monitor conditions and prepare for potential impacts.

"New Yorkers should prepare for heavy rain and thunderstorms Thursday afternoon and evening, particularly during the evening commute," said Mayor Zohran Kwame Mamdani. "We have activated our Flash Flood Emergency Plan, and agencies are taking steps now to ready the city. New Yorkers should prepare too: stay alert, avoid flooded areas, text NOTIFYNYC to 692-692, and as always, look out for your neighbors."

"Thursday's storms could produce very heavy rain over a short period of time, and even localized flooding can quickly create dangerous conditions," said NYCEM Commissioner Christina Farrell. "The greatest concern is during the late afternoon and evening, so give yourself extra time to travel and do not enter flooded streets, subway stations, or other low-lying areas. If you live in a basement apartment, pay close attention to conditions and be prepared to move to a safer location if flooding develops."

The NWS Weather Prediction Center has placed New York City in a Slight Risk (Level 2 of 4) for excessive rainfall on Thursday. This carries the potential for isolated to scattered flash flooding.

Current forecasts call for approximately 0.75 inches to just over 1 inch of rain across New York City, with higher totals possible in localized areas. Higher rainfall amounts are currently more likely across southern portions of the city.

Brief rainfall rates of 1 to 2 inches per hour are possible in stronger thunderstorms. However, the showers and thunderstorms are expected to move steadily through the area rather than repeatedly pass over the same locations, limiting the duration of the heaviest rainfall.

Localized rainfall totals of approximately 1.5 to 1.75 inches are possible in areas that receive heavier downpours. Higher amounts cannot be ruled out in a low-probability scenario.

The greatest risk for heavy rainfall and localized flash flooding is expected during the late afternoon and evening, including the evening commute. Showers and thunderstorms should begin to taper off after approximately 8 p.m., with generally dry conditions expected after midnight Thursday night into Friday morning.

New Yorkers should take the following precautions:

• Allow extra time for travel on Thursday afternoon and during the evening commute
• .Avoid flooded streets, rooms, subway stations, and other flooded areas. Never drive, bike, or walk through floodwater. Water may be deeper than it appears and can hide submerged hazards, openings, debris, and electrical dangers.
• If you live in a basement apartment or other below-grade space, stay alert to changing conditions and be prepared to move to a higher floor or another safer location before flooding begins.
• Do not wait for water to enter your home before acting if conditions are worsening.
• If a Flash Flood Warning or other emergency instruction is issued for your area, follow official guidance immediately.
• Keep phones, medical equipment, and other essential devices charged.
• Check on family, friends, neighbors, older adults, and people who may need additional assistance before and during the storm.
• Call 911 if you are in immediate danger.

Forecast conditions remain dependent on the timing and placement of the heaviest showers and thunderstorms. Localized areas that experience stronger storms could receive significantly more rainfall than surrounding neighborhoods over a short period.

NYC Emergency Management will continue to coordinate with the NWS and City agencies as conditions evolve.

New Yorkers can find preparedness recommendations and guidance for excessive rainfall, flash flooding, thunderstorms, and other hazards at nyc.gov/beready, including steps to take before, during, and after an emergency.

New Yorkers should stay informed through official sources. Subscribe to Notify NYC for free emergency alerts by texting NOTIFYNYC to 692-692. New Yorkers who live in basement apartments can sign up for a basement alert and choose to receive alerts by phone. To enroll in these additional alert options, visit nyc.gov/notify.

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