Severe Thunderstorm Watch Sunday Afternoon & Evening for the Finger Lakes

Father’s Day Severe Thunderstorm Threat

The first part of the day Sunday will be sunny, hot, and humid. Temperatures will approach or exceeed 90 degrees for much of the Finger Lakes and heat index values will range through the 90s.

A cold front to the west will be poised to sweep the heat away, but not until after the potential for some strong thunderstorms.

There are two primary questions that will determine how robust the severe threat is today.

First, will storms remain disorganized clusters of cells or develop into a well organized linear system? Second, how far east will the severe threat extend once the sun sets?

Storm Organization

Despite all of the heat and humidty at the surface, the atmosphere will only be moderately primed for thunderstorm growth this afternoon.

This is due to the presence of warm air throughout the low and mid levels of the atmosphere.

The presence of cold air aloft is important to storm development because it provides a contrast in temperature and, subsequently, air density that favors the rapid upward movement thunderstorms need.

The warm air aloft today could be a significant deterent in the ability of the storms to organize, though some models do still show signs of a squall line.

Should a line of storms develop, the overall threat for severe weather, especially damaging winds and hail, would increase.

Storm Timing

Thunderstorms are expected to develop over western New York during the later afternoon hours. These storms should enter the Finger Lakes by dinner time and will push east as the sun sets.

Strong thunderstorms should persist for a couple hours after sunset, but eventually, they will weaken.

For the eastern Finger Lakes, exactly how quickly they dissipate will have a major impact on the severe threat for these areas.

Generally speaking, the further west, the greater the chance for severe weather up to about Keuka Lake. West of there, the threat is fairly consistent.

Severe Thunderstorm Risks

The main threat from today’s thunderstorms could end up being torrential downpours and flash flooding.

The National Weather Service in Buffalo has already issued some flash flood watches for the western Finger Lakes, and the Binghamton office is watching the situation closely for the easter Finger Lakes.

Multiple thunderstorms could develop and move repeatedly over the same areas this evening. Even just two storms could bring a single locale 1-3 inches of rain in a short time.

Especially over the Genesee Valley, where heavy rain fell Thursday, this could lead to areas of flash flooding.

Damaging wind will be the other primary threat, especially if a line of storms is able to develop. Given the uncertainty in that occurring, the wind threat is currently set between low and moderate.

There is a lesser chance for hail and just a minimal tornado threat.

Storm Updates Today

I will continue to monitor the storm situation this afternoon and evening. i will post most of my updates on Twitter. For convenience, and for those who are not on Twitter, I have embedded my feed and the radar below. Simply return to the post throughout the day and scroll to the bottom for the latest updates.