Thursday Severe Thunderstorm Outlook

Isolated to scattered severe thunderstorms are likely this afternoon and evening with all modes of severe weather possible.

Summary

• Two potential periods/areas of severe weather
  • First in the mid to late afternoon in the northeastern FLX into the Mohawk Valley
  • Second in the late afternoon and early evening, mainly across the northern FLX
• All modes of severe weather possible. In order of probability from most to least likely: Damaging winds, large hail, a tornado or two
• Rather than a widespread event, isolated corridors of severe weather is expected
• Severe weather watches and warnings are highly likely for parts of the area

Details

A lack of rainfall this morning has reduced one potential inhibitor for thunderstorm development today. The set up still has uncertainty, but confidence is higher this morning than it was last night that at least some severe weather will occur.

There will be two things to watch for today.

First, during the mid to late afternoon, there is a potential for a few isolated supercell type thunderstorms to rapidly develop over the northeastern Finger Lakes, especially Cayuga and Onondaga counties. This development is less certain and may happen further northeast or not at all. Any of these storms that do develop will carry a threat for damaging winds, large hail, and possibly a tornado.

Second will be a line of showers and storms ahead of the cold front which will develop over western New York late in the afternoon and track east-northeast across the area into the early evening. Within this line, there may be some embedded supercell structures and/or small bowing segments pushed forward by strong winds. The areas from Dansville to Penn Yan/Geneva to Auburn and Syracuse seems most at risk for isolated corridors of damaging winds, hail and perhaps a tornado.

The entire line is not likely to be severe, but only isolated parts within the line. How far south the severe potential in this line extends is uncertain, but the overall threat for severe weather is lower across the Southern Tier.

Once this later line of rain and storms passes through, the severe threat will drop off to pretty much zero.

I expect a severe thunderstorm watch to be issued this afternoon, with a small chance that a tornado watch will be issued instead. Several severe thunderstorm warnings and a tornado warning or two also seem likely across Upstate New York, though not necessarily exactly in the Finger Lakes region for the tornado warning.

As a reminder, a WATCH is issued for a long time over a large area to indicate that severe thunderstorms or tornadoes may be possible. A WARNING is issued for a short time and a small area to address current, ongoing severe weather that is indicated by radar or being reported. Watches mean be vigilant… warnings demand immediate action.

At a minimum, all severe weather warnings are automatically posted to the FLX Weather homepage and will show up in this post as well. As necessary, I will also add in my commentary directly into those automatic updates. I will also likely have a couple other updates through the day, which will show up in the same feed as the warnings on the homepage and in this post.

I do not anticipate needing to transition to a live blog format, but will continue to monitor the situation in case a more widespread, substantial threat develops that needs my extra attention and analysis beyond the automatic updates.

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