Severe Storm Risk Is Still Iffy In Vermont Today. Rain And Much Cooler Weather Tomorrow Is NOT Iffy

A severe thunderstorm over Lake Champlain in July, 2023.
Severe storms are possible in Vermont today, if
the right factors come together. We won't know until
shortly before the storms develop. 

 We're starting the day really mild, especially in the Champlain Valley, where temperatures were in the low 60s at dawn.

Such warm temperatures to start the day might make you feel like that risk of severe storms today will come true. After all, summer-like temperatures equal summer-like storms, right?

Well, maybe.

Meteorologists are not much closer to figuring out today's severe weather risk than they were yesterday. 

As the National Weather Service in South Burlington said in their overnight forecast discussion, we're reduced to "nowcasting," which means we'll only know whether any severe weather looms just hours or even less than an hour before they actually hit. If they hit. 

NOAA's Storm Prediction Center still has northern New York and northern New England under a marginal risk of severe weather today. That's level one of five, the lowest alert level. The SPC is also sort of into "nowcasting" with this, saying they'll upgrade to a level 2 slight risk if later forecasts increase the amount of instability in the air 

For Vermont, the marginal risk covers the entire state except areas right along the Massachusetts border. 

One limiting factor might be what was going on just after dawn today.  Light rain showers were over the Champlain Valley, and somewhat more substantial showers were in central New York, heading east towards us. 

NOAA's Storm Prediction Center has for now
kept a marginal risk of severe storms over norther
New England (dark green shading). I the risk
of storms seems to increase later this morning,
it'll go to level 2 slightly risk, like what you
see over Arkansas in this map. 

Showers and clouds this morning would tend to suppress instability, and that would more or less squash severe storm potential.  If skies clear up by early afternoon, we could maintain the instability and fire up the storms.  

The amount of moisture in the air is another key factor. Some forecasts show slightly higher humidity today than what was thought yesterday,  which is good if you want storms. 

But other forecasts mix drier air from aloft down to the surface this afternoon, which would lower the humidity. Pick your poison, I guess.

The wind situation thousands of feet overhead are great if severe storms are your thing. If storms can get going, they have the chance of "grabbing" pieces of that high speed air and bringing it to the surface as damaging wind gusts. 

Whether these storms develop depends on whether an approaching cold front can team up with enough instability from sunshine to allow thunderstorms to erupt. If, by noon it's nice and sunny out, we have a  good chance of some good storms to fire up. If it's cloudy and showery, you can't necessarily kiss the severe storms goodbye, but the chances of them actually happening get pretty low
. 

NOAA says if we do see severe storms today, they'll take the form of either what they call bowing echoes or brief supercells. 

Bowing echoes are short lines of thunderstorms. If you look at a bowing echo on radar, the line of storms is shaped like a backwards "C"  The front part of that backwards "C" that sticks out ahead of the rest of the line of thunderstorms is where you'd see those damaging wind gusts. 

Or, we could see some brief, or what NOAA calls transient supercells. It makes it sound like those poor supercells are unhoused. What they really mean is the supercells wouldn't last as long as they usually do. Midwestern supercells can last for many hours. In this case, not so much. 

Still, those "transient" supercells can cause damaging winds and maybe some hail.  Since supercells tend to spin, we'd still have a very, very, very, low risk of a brief tornado. A low risk but not no risk. 

If we do get those rambunctious thunderstorms, they'll come through between about 1 and 6 p.m. today. 

Overall, most of Vermont will not see severe storms today. If we get any damaging winds from the storms, it would be in just a few spots. But we don't know which spots yet, so keep an ear to weather radio or reliable weather forecasting sources like the National Weather  Service or the local TV meteorologists for updates. 

Other than the storms, today will be breezy to windy, especially in the Champlain Valley. Most of us will get well into the 70s before the showers or storms arrive. 

TONIGHT/TOMORROW

Meteorologists aren't sure about today's thunderstorms, but they are sure we're going to get pretty damned wet overnight tonight and tomorrow

Today's shower and thunderstorms will evolve into a steady rain tonight which should pretty much continue through Wednesday. It's looking like a nice soaker, which we need. 

Total rainfall today through tomorrow night looks like it'll amount to more than inch across most of Vermont. Some areas of central Vermont, especially in and near the Green Mountains, could close in on two inches. 

Aside from brief, torrential downpours if thunderstorms develop today, the rain will come down at a slow enough pace that means we shouldn't see any flooding. Rivers will rise and become turbulent, of course, so kayaking in them is probably a bad idea for a couple or few days. 

The weather misery index of Wednesday is really high, though. With the steady, day-long rain, temperatures should only hold near 50 degrees, except maybe somewhat warmer than that in far southern Vermont. 

AFTER TOMORROW

We still have another round in which we spend several days with below normal temperatures and a risk of showers at almost any time. Aside from tomorrow, it won't be as cold as it was last weekend, with highs most days in the mid 50s to low 60s.  Sunday might actually be a little warmer, getting into the near-normal 60s. 

This pattern still looks like it will hold more or less in place through at least May 18 or so.  Most of the showers between Thursday and May 18 are looking very much on the light side, at least so far. That means it's actually good that Wednesday will be so miserable and rainy.