Winter Storm Warning
Decision Support Briefing #2
As of: 5:00 AM Mar 20, 2018
What Has Changed?
Winter Storm Warning now in effect for all
areas except eastern Suffolk County.
Winter Storm Watch remains in effect for
eastern Suffolk County.
Weather Forecast Office Presentation Created
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Main Points
Hazard Impacts Location Timing
• Snowfall of 12-15” possible for
NYC, NE NJ, Lower Hudson Valley
and southwestern CT.
Heavy • 4-9” for LI and southeastern CT. Wednesday into Wednesday
Snow • Snowfall rates of 1-2”/hr possible Entire Tri-State Region night
Wed afternoon and evening.
• Visibilities of 1/4 miles or less at
times.
• 20 to 30 MPH with gusts to 45
Strong mph.
• Scattered Power Outages. NYC Metro, LI, Coastal
Tonight into Wednesday night
Winds • Scattered downed trees and CT and Westchester
power lines.
• Minor to moderate coastal
Coastal flooding. Vulnerable locales along
During times of high tide
• Inundation of 2 to 3 ft above NY/NJ Harbor, Jamaica
Impacts ground in vulnerable areas. Bay, S and E Bays of LI, Wednesday
• Localized dune erosion. and W/E LI Sound
• Wind gusts up to 55 KT on the
ocean.
Late tonight through
Marine • 35 to 45 KT on all other waters. Nearshore Waters
• Seas of 12-17 ft on the Ocean
Wednesday night
and 3-6 ft on LI Sound.
Weather Forecast Office Presentation Created
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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
Heavy Snow: Entire Tri-State Region
None Limited Elevated Significant Extreme
Weather Forecast Office Presentation Created
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Heavy snow
Hazards:
Snowfall of 12-15” possible for NYC,
NE NJ, Lower Hudson Valley and
southwestern CT
4-9” for LI and southeastern CT.
Visibilites ¼ mi or less at times
Impacts:
Scattered downed trees, tree limbs and
powerlines.
Difficult/Impossible travel.
Timing:
Heaviest snow Wed afternoon to
evening.
Weather Forecast Office Presentation Created
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Forecast Uncertainty or Scenarios
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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.
Shoreline Hazard and Impacts:
Localized dune erosion.
Timing:
During times of high tide around
mid-day Wednesday.
Weather Forecast Office Presentation Created
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Forecast Uncertainty or Scenarios
There are still uncertainties with the exact track and strength of the
storm.
A track farther to the north and west could result in more rain and
sleet over LI and coastal CT and heavier snow totals elsewhere.
A track farther to the south and east could reduce accumulations
from NYC on N and W and increase accumulations for LI and S CT.
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Event Summary
2 rounds of precipitation.
A light wintry mix tonight mainly impacting S portion of the Tri-State.
Snow likely becoming heavy Wednesday afternoon, with significant
impacts to the Wednesday afternoon rush hour probable.
Heavy, wet snow and gusty winds could cause power outages.
Minor to moderate coastal impacts with Wednesday high tide.
Weather Forecast Office Presentation Created
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