Saturday Update; Tuesday Cloud Analysis

finger lakes weather forecast update saturday july 17 2021 flooding
Confidence is increasing for hazardous weather on Saturday, including potentially significant flash flooding and severe thunderstorms, possibly including tornadoes.

Saturday Update

Flash Flood Watches are now in place for the entire region, starting tonight and continuing into Saturday night. As I mentioned in my post this morning…there will be two rounds of rain, one tonight, and then a second with thunderstorms tomorrow.
The Weather Prediction Center has upgraded the southeastern Finger Lakes to a MODERATE (level 3 of 4) risk for flash flooding tomorrow. This upgrade represents increased confidence in flash flooding occurring and a greater probability of significant flash flooding.
On the severe weather side of things…I continue to be concerned with the possibility of severe weather in the area, and especially the southeastern FLX (same area as the greatest flood risk, generally speaking). Damaging winds are the greatest threat, but I am concerned about a tornado threat as well.
In all, not much has changed from my thinking in the blog post I issued this morning, except for an increase in confidence that hazardous conditions are likely.
I will be updating throughout the day tomorrow, starting with a morning blog post, and following up with live updates through the afternoon. These live updates will give you the absolutely latest information, warnings, and expert analysis.

Tuesday Storm Report

I had intended to do a full blog post on Tuesday’s storms and the pictures circulating Facebook. However, given the seriousness of tomorrow’s event and wanting to get the word out about that first and foremost, I’ll just add a few things here as a footnote.
The cloud pictures attached here, which have been circulating Facebook and resulting in speculation of a tornado. Indeed, the top-left picture does *look* tornadic…but after a lot of research and seeing other pictures, it is *not* a tornado.
Basically, as warm air is ingested into the storm, the temperature drops and the dewpoint rises, leading to new cloud formation. Oftentimes, this is seen as wispy “scud” clouds. Other times, the cloud base lowers into a wall cloud.
What was witnessed in these pictures is a combination of scud coming up into the cloud and assisting in the formation of a small wall cloud. Wall clouds are not uncommon, but they can sometimes start to rotate and form tornadoes. This storm was a small, weak cell that had no indications of becoming that mature.
Furthermore, this storm cloud was photographed around 4 PM. It is *not* related to the widespread damage that occurred in Dresden, which was from a separate storm about four hours later.
Regarding the damage in Dresden, based on many eye-witness reports, photos, and video, I find *no evidence* for a tornado. Straight-line damaging winds were responsible for the damage. This is an important reminder that damaging winds inside thunderstorms can cause damage on par with a weak tornado.

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Follow Meteorologist Drew Montreuil:
Meteorologist Drew Montreuil has been forecasting the weather in the Finger Lakes region since 2006 and has degrees in meteorology from SUNY Oswego (B.S. with Honors) and Cornell (M.S.). Drew and his wife have four young boys. When not working or playing with the boys, he is probably out for a run through the countryside.

6 Responses

  1. Valerie

    Drew, thanks for addressing the recent storm. Although I was in Auburn, I believe I saw very similar clouds during our latest severe thunderstorm on Thursday. I was afraid I was seeing funnel clouds, but they weren’t rotating from what I could discern, so I figured they had to be scud clouds. Still, they were kinda scary looking when illuminated by lightning flashes. With the threat of high winds and all the lightning, I decided to keep away from the windows and stay downstairs in case we needed to shelter in the basement.

  2. Carol Chaplin

    I am scheduled to travel from Manhattan by bus tomorrow back to Ithaca by around 6:30pm. (Saturday) Based on what you know now, would you recommend postponing this trip by a day? Thanks.

    • Meteorologist Drew Montreuil

      Hi Carol. If it isn’t inconvenient, it never hurts to play the safe route. That being said, if staying is a big problem…there may be some rough weather at times, but you would probably be OK on a bus…really comes down to personal preference and your situation.

      • Carol

        Thanks Drew. Staying put another day. Appreciate your response.

  3. Michael Nash

    Thanks, Drew. Exceptional job as always.


    • Meteorologist Drew Montreuil

      Thanks, Michael!