weather briefing

Severe Thunderstorms Possible This Afternoon/Early Evening... Decision Support Briefing #1 As of: 6:00 AM May 15, 2018

Current Hazards

What Has Changed? Severe Weather Threat for entire Tri-State Damaging Winds Main Threat This afternoon/Early Evening

Weather Forecast Office

New York, NY

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Presentation Created 5/15/2018 6:51 AM 1

Main Points Hazard

Impacts

Location

Timing

• Downed trees and powerlines, along with isolated structural damage associated with the strongest storms.

Entire Tri-State Region

This afternoon and early this evening

• Isolated flash flooding is possible, especially where multiple storms train over the same area. Rainfall rates of around 1 to 2 inches an hour possible. Rapid flooding of Urban Areas, Low-lying Roads, and Small Streams and Creeks.

Entire Tri-State Region


Large Hail

• Large hail can cause damage to vehicles and other property.

Much of the Lower Hud Valley, NE NJ, and Interior SW CT


Isolated Tornadoes

Isolated tornadoes possible with damage to structures, trees, and powerlines. Power outages possible.

Much of the Lower Hud Valley, NE NJ, and Interior SW CT


Damaging Winds

Flash Flooding


New York, NY




Summary of Greatest Impacts Damaging Winds: Entire Tri-State Region None

Limited

Elevated

Significant

Extreme

Flash Flooding : Entire Tri-State Region None

Limited

Elevated

Significant

Extreme

Large Hail : Much of the Lower Hud Valley, NE NJ, and Interior S CT None

Limited

Elevated

Significant

Extreme

Isolated Tornadoes: Much of the Lower Hud Valley, NE NJ, and Interior S CT None

Limited

Elevated

Significant


New York, NY



Extreme


Severe Weather SPC Convective Outlooks 32 Day 1

Hazards:   

Wind Gusts up to 65 mph Hail up to 1” Weak tornadoes possible

Impacts:  

Localized/Scattered/Widespread downed trees and powerlines Localized/Scattered/Widespread structural damage

Timing and Location: 

Heaviest rain from 4 to 9 pm

Uncertainty:  Impact of Marine Influence from NYC on East.  Exact magnitude of Severe Gusts (could be stronger than 65 mph in places)


New York, NY




Flash Flooding

Hazards:  

Rainfall of 1/2 to 1 inch, with locally higher amounts Rainfall rates of around 1to 2“/hr possible

Impacts:  Day 1 2 3 Excessive Rainfall Outlook



Rapid Flooding of Urban Areas, Low-lying Roads, and Small Streams and Creeks. Isolated Flash Flooding Most Likely over NE NJ/NYC.

Timing: 

Heaviest rain from 3 to 9 pm

Uncertainty: Most likely to see just minor flooding.


New York, NY




Forecast Uncertainty or Scenarios

 Exact impact of Marine Influence will determine how far east and south Severe Threat gets.   Magnitude of wind gusts is uncertain. There is a low end potential for 70-80 mph wind gusts.  Extent of flash flooding – most likely will not occur due to fast moving storms. However if 1+” an hour rates do happen over urban/poor drainage areas, then isolated flash flooding could happen.


New York, NY




Event Summary

 Severe Thunderstorms Possible Across Entire Tri-State This Afternoon/Evening  Main Threat from Damaging Wind Gusts  Lower Threat from Large Hail, Isolated Tornadoes and Flash Flooding  Severe Storms most likely across NE NJ/Lower Hudson Valley/Interior SW CT


New York, NY




Contact and Next Briefing Information This will be the final briefing

Web: http://www.weather.gov/okx/

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Phone (public): 631-924-0517

Twitter: http://www.twitter.com/NWSNewYorkNY

YouTube: https://www.youtube.com/user/NWSNewYor kNY

Disclaimer: The information contained within this briefing is time-sensitive, do not use after 6 PM Tuesday (05/15/18).


New York, NY


