Stormy Days Like Today, Yesterday Show Why You Shouldn't Go Out On Lake

Possible microburst over Lake Champlain west of Burlington Tuesday.
(Click on the photo to make it bigger and easier to see.). Even if
this wasn't a microburst and even though the storm wasn't severe
when it came ashore in Vermont, this illustrates why you
should not be out on the lake when thunderstorms develop. 

Today in Vermont, we once again have several weather threats,   including strong to severe thunderstorms with locally damaging winds, a lot of lightning, and maybe even localized flooding.

Which is a great reason to stay off of places like Lake Champlain today.

That idea was well illustrated to me yesterday when thunderstorms that were (mostly) not as strong as today's expected weather developed.  

Tuesday's storms developed in the Adirodacks and drifted slowly across Lake Champlain into Vermont. As the photo in this post shows, one storm looked like it got ferocious when it was part way across the lake. There was a possible, dangerous microburst out there.

If the microburst occurred, it didn't last long and faded away before the storm came ashore in and around Burlington. Winds gusted to just 32 mph during the storm at the Burlington International Airport, where the National Weather Service is located. I'd estimate gusts along Burlington's lakeshore were about 40 mph. Windy, but manageable.

So the storm wasn't severe on land, and there were no reports of storm damage anywhere in northern New York and Vermont. I only saw a few twigs and small branches down. No biggie.

But the lake was wild, going from calm to having large waves in an incredibly short period of time. I could see big crashing waves slamming into the Burlington breakwater. Lightning strikes hitting the lake couldn't have helped.

It had been a beautiful, sunny day. Then it wasn't. Which means people on boats should always keep their eyes open for developing storms, know what they look like and head to the docks when they see them forming.

The National Weather Servicie in South Burlington did have a special weather statement on yesterday's storm, which said in part: "If you are on or near Lake Champlain, move to safe shelter now! Do not be caught on the water in a thunderstorm."  Note the exclamation point in that statement.

Last week, two kayakers drowned in Malletts Bay around Colchester during a strong thunderstorm.  I don't know if the storm was directly related, but before the storm it was sunny and hot and calm, and then, suddenly, it wasn't. Were these victims caught unaware as the storm bore down on them?

STORM THREATS TODAY

Areas in yellow have a slight risk of severe storms today.
Darker green is marginal risk. 

Today is going to be a more hazardous day than yesterday, as I've already mentioned. As the NWS in South Burlington, Vermont explains it, the heating of the sun getting through the mostly cloudy skies this morning will be enough to get the air destabilized.  

Wind shear - which is wind shifting and/or changing speeds with height - will be increasing during the peak heating hours. That'll help to develop thunderstorms and organize them.

This organization, in turn could create bands of strong to severe storms. These potentially severe storms are most likely south of Route 2, the NWS says, but could happen anywhere in Vermont.  

NOAA's Storm Prediction Center has the southern two thirds of Vermont in a slight risk zone of severe storms, meaning they expect scattered severe storms, with one or two perhaps becoming intense. Far northern areas are in a marginal risk zone.

The main risk from these storms would be damaging wind gusts, some hail, cloud to ground lightning and heavy downpours. Due to the wind shear above, there is a very, VERY tiny, but still not zero chance of a brief spin up tornado. But don't count on that.

The timing of the worst storms looks like it will be somewhere between mid-afternoon and early evening.

Note that as always only some areas will see damaging thunderstorms. It'll be hit and miss. A classic example was last week, when a severe storm caused widespread damage in places like Swanton, Highgate and Sheldon, while places just a couple miles south suffered absolutely no harm.

Areas north of Route 2 are slightly less at risk of severe storms, but have another problem.  The center of a weak area of low pressure will pass over or near northern New York and far northern Vermont.

Thicker cloud cover there will help tamp down on severe thunderstorms a bit, but this little low pressure area, working with humid air will tend to focus downpours in this region. Although it has been fairly dry in recent weeks, intense downpours can still cause local flooding, such as small streams going nuts, urban street flooding, washouts on steep hills, damaged culverts, that sort of thing.

The National Weather Service's Excessive Rainfall Outlook puts northern zones of Vermont and New York in a slight risk zone for flash flooding.

It'll be somewhat calmer tomorrow as a cold front starts to come through, but there will be scattered showers and thunderstorms around. It's still looking cool for the weekend.