Lake-Effect Snow in New York, November 2 to 3, 2020

Name: Lake-Effect Snow in New York, November 2 to 3, 2020
Start: 2020-11-02T16:00
End: 2020-11-03T00:00
Location: New York

November 2 to 3, 2020 · NWS BUF · 2 events in 2 counties and zones

Water Vapor Imagery showed a well-defined trough cutting across the Ottawa Valley. The surface low was positioned in the vicinity of James Bay.

Where it happened

Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS BUF wrote it up.

Water Vapor Imagery showed a well-defined trough cutting across the Ottawa Valley. The surface low was positioned in the vicinity of James Bay. This surface low was 996 hPa and remained steady state through most of the event. Temperatures over the lake were near -9C at 850 hPa but warmed to around -3 or -4C by the end of the event. A heavy band of lake effect snow developed east of Lake Ontario with favorable instability and moisture within the dendritic snow growth zone. Plenty of over-lake instability was in place with lake equilibrium levels rising above 15,000 ft. This amount of extreme instability resulted in some thunder and lightning. Another trough dropped across Lake Ontario during the event, pushing the lake snows southward toward the southeast end of the lake. Selected snowfall totals for the event included 13 inches in Constableville, 8.2 inches near Redfield, 8 inches in Highmarket, and 7.8 inches in Osceola.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Buffalo, NY wrote its last area forecast discussion before the first event at Nov 2, 2:56 PM EST, 1 hour 4 minutes earlier.

Area forecast discussion, Nov 2, 2:56 PM EST, 1 hour 4 minutes before

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Hazardous weather outlook, Nov 2, 6:47 AM EST, 9 hours 13 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

2 lake-effect snow. Local standard time, as filed.

Lake-Effect Snow, Lewis

When: November 2, 4:00 PM EST to November 3, 12:00 AM EST
Where: Lewis forecast zone
Reported by: COOP Observer
Coordinates: 43.785, -75.449 (the zone’s center; the record gives no point)

Lake-Effect Snow, Oswego

When: November 2, 4:00 PM EST to November 3, 12:00 AM EST
Where: Oswego forecast zone
Reported by: COOP Observer
Coordinates: 43.464, -76.209 (the zone’s center; the record gives no point)

What these are

Lake-Effect Snow: Heavy snow in bands downwind of a large lake as cold air crosses warmer water.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in New York in 2020 Every state in 2020 This day in weather history Warnings in New York, November 2020

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 930472, 930473.