Severe Storms Possible Monday In Vermont/Much Of Northeast

 A rapidly developing storm Saturday just north of St. 
Albans, Vermont. The storm raced east and became strong
over northwestern New Hampshire as it encountered a
better atmosphere to sustain itself.

 Saturday was a close miss in terms of severe thunderstorms around Vermont. 

We were just on the western edge of a zone in which storms really fired up Saturday afternoon.  During much of the afternoon, showers would appear in northeastern New York and race across northern Vermont. 

Some of these attempted to form into powerful thunderstorms, but a punch of dry air several thousand feet above the ground prevented them from getting the necessary fuel. 

Strong winds aloft had the potential to be brought down to the surface if these storms really got going, but the higher level winds were so strong that the storms couldn't organize.

You could watch and see how fast these showers would come and go over us. Conditions for bad storms were more favorable over New Hampshire and Maine, so you could track the showers and weak storms zip across Vermont, the blossom into more dangerous stuff in eastern New England.

One such storm grew into a supercell over eastern Maine which prompted tornado warnings. There was wind damage where that storm occurred, so I'm sure that area will be investigated today to see whether a tornado actually touched down 

After a nice summer day, today, there's another chance at severe weather Monday. I'd say that arguably, tomorrow's chances of severe storms in Vermont are highest so far this summer. That's not saying much, but still means we should be on the lookout.

This time, conditions look like they might come together to cause some bad stuff mostly in Vermont and eastern New York, and points southwestward from there. 

Areas in yellow have the best chance of
seeing severe thunderstorms Monday.

A squirt of very warm, humid air will pop up into our neck of the woods tomorrow. It'll be sticky and under some morning and early afternoon, temperatures will get well into the 80s, with a few spot 90 degree readings possible. 

That'll prime the pump for strong thunderstorms by helping create a lot of instability. 

A cold front will be lurking well to our west by afternoon.  As is often the case with potential severe weather threats in Vermont, something called a pre-frontal trough will come in from the west well ahead of the actual cold front. 

A pre-frontal trough is basically a mini-weather front, an elongated area of low pressure where winds converge. Converging winds help encourage updrafts, and that's where thunderstorms can blossom. 

Strong winds aloft can also encourage budding thunderstorms to turn big and nasty,  and that could easily happen tomorrow. The strongest winds high up in the atmosphere will be further west, and not exactly line up with the pre-frontal trough, so this won't be the perfect set up for severe weather. 

But the upper level winds, combined with the instability and plenty of moisture (unlike Saturday),  seem good enough to put us in the risk zone for severe storms Monday afternoon.  

I don't really have the timing down yet, but anytime between, say 1 p.m. and well into the evening will be the time to watch the skies. 

There's a very low, but not zero chance of a 
tornado Monday. The 5% in the map means
there is a 5% chance of a tornado within
25 miles of any spot in the brown part
of the map on Monday. 

The biggest threat from any severe storms Monday, as is usually the case in Vermont, is strong straight line winds. 

Storms might organize into small lines or segments, which could help produce strong winds.  Hail is another threat.  Most of any hail that does form will be small, but there might be pockets of hail that are enough to cause damage.

With the humid air in place, some of these storms could also produce torrential downpours, which could create abrupt street flooding and some gullywashers here and there. 

Since winds will be changing direction with height tomorrow, there's a chance of a rogue supercell or two to form as well. 

NOAA's Storm Prediction Center gives most of Vermont, along with northern New York, northern New Hampshire and western Maine a very low, but not zero chance of a tornado or two with this.  

The actual cold front will arrive Monday night and very early Tuesday. That will encourage plenty of showers and thunderstorms around Monday night. Those later storms probably won't be severe, but could again produce locally heavy downpours. 

That's good news is we can stand the rain, as I keep saying over and over again this dry year. 

I'm sure the severe weather forecast will go through some adjustments between now and tomorrow morning, so we'll update as we get closer to the event.