Significant Winter Storm

Decision Support Briefing #4 Current Hazards

As of: 5:00 AM Mar 21, 2018

What Has Changed?

Snowfall amounts increased for most of

the Tri-State

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 Main Points
Hazard Impacts Location Timing
• 10-18” possible for NYC, NE NJ, much
of Long Island, portions of Lower
Hudson Valley and southern CT. Entire Tri-State Region
Heavy • 6-12” across n Orange County, Putnam Today and tonight
Snow County, and forks of Long Island. Highest Accumulations
• Snowfall rates of 1-3”/hr under snow bands
• This afternoon and tonight.
• Near white-out conditions at times.

• 20 to 30 MPH with gusts to 45 mph,

isolated gusts to 50 mph on the Twin Entire Tri-State Region
Strong Forks. Late morning through this
Winds • Widespread power outages possible. Strongest gusts closest evening
• Widespread downed trees and power to the coast
lines possible.

• Minor to moderate coastal

Coastal flooding. Vulnerable locales along
During times of high tide
• Inundation of 1 to 3 ft above NY/NJ Harbor, Jamaica
Impacts ground in vulnerable areas. Bay, S and E Bays of LI, today and tonight
• Localized dune erosion. and LI Sound

• Wind gusts up to 55 KT on the

ocean.
Nearshore and coastal Late morning through this
Marine • 35 to 45 KT on all other waters.
• Seas of 11-16 ft on the Ocean
ocean waters evening
and 3-7 ft on LI Sound.

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 Summary of Greatest Impacts

Heavy Snow: Entire Tri-State Region

None Limited Elevated Significant Extreme

Strong Winds: NYC Metro, LI, Coastal CT and Westchester

None Limited Elevated Significant Extreme

Coastal Impacts: Vulnerable locales along NY/NJ Harbor,

Jamaica Bay, S and E Bays of LI, and W/E LI Sound
None Limited Elevated Significant Extreme

Marine: Nearshore Waters

None Limited Elevated Significant Extreme

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 Heavy snow
Hazards:
 Snowfall of 10-18” for NYC, NE NJ,
much of Long Island, portions of the
Lower Hudson Valley and southern CT.
 6-12” across Orange, Putnam and the
Forks of Long Island.
 Near white-out conditions at times.
 1-3” per hour at times.

Impacts:
 Widespread downed trees, tree limbs
and powerlines possible.
 Difficult/Impossible travel.

Timing:
 Heaviest snow late morning through
around midnight.

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 Heavy snow

More Sleet and/or low

weaker/farther to S and E

Less Sleet and/or low

stronger/farther to N and W

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 Coastal Flooding

Coastal Flood Hazards and

Impacts:
 Minor to Moderate coastal flooding.
 Inundation of 1 to 2 ft above ground
in vulnerable areas.
 2-3 ft above ground for south
shore of western Long Island
tonight.

Shoreline Hazard and Impacts:

 Localized dune erosion.

Timing:
 During times of high tide today and
tonight.

*Coastal Flood Watch for tonight for south shore Bays of NYC and Western Long
Island
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 Onset Onset
Approximate Time Time

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 Approximate Ending Time

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 Forecast Uncertainties

 The location and timing of heaviest snowfall.

 The temperatures, especially during the day time.

 How much mixing with sleet, if any, occurs?

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 Event Summary
 Accumulating heavy, wet snow and gusty winds could cause
widespread power outages and widespread tree damage.

 Near blizzard conditions possible across NYC, Nassau County, SW

CT and portions of NE NJ and the Lower Hudson Valley.

 Snowfall rates 1 to 3” per hour, late this morning through around

midnight.

 Hazardous travel possible developing by around midday and becoming

nearly impossible for the afternoon and evening commute.

 Minor to moderate coastal impacts with the high tides today and tonight.

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 Contact and Next Briefing Information

This will be the final briefing

Facebook:
Web: http://www.facebook.com/NWSNewYorkNY
http://www.weather.gov/okx/

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

Phone (public):
YouTube:
631-924-0517
https://www.youtube.com/user/NWSNewYor
kNY

Disclaimer: The information contained within this briefing is

time-sensitive, do not use after 5 PM Wednesday (03/21/18).

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