More Needed Rain, And Multifaceted Challenging Vermont Weekend Forecasts

Yesterday we bought the annuals we need to make our pots
planters and window boxes look lovely for the summer.
It's going to be hot, humid work starting this job
over the weekend. 

 We're used to ifs ands or buts in Vermont weather forecasts as the Green Mountain State can be a challenging place to forecast what the heck will come out of the sky, if anything.  

This weekend is a classic case in point, with questions about how hot it will get both days, whether severe thunderstorms manage to pop up later Saturday, and how widespread showers and storms might be on Sunday. 

Prepare for surprises, but also prepare to sweat it out: It's going to be an oppressively warm to hot, and very humid weekend. 

First, though, a quick review of yesterday's little soaker. In northern Vermont, the rain was a little heavier than forecast. Which is a good thing, to keep things well wetted down.  Most of us got a quarter to a half inch of rain, with a few drier spots here and there. 

In Burlington, yesterday's rain brought the month's total so far in May to 2.2 which is right at normal for this date of the month. That's also more rain than fell all of last May, when we had just 1.42 inches. 

Next up, let's untangle the weather for the next few days. Do note that the forecast will almost definitely change one way or another, but this is what it looks like at this point:

TODAY

Today will be a big transition day. It's starting off chilly with partly cloudy to clear skies, with plenty of areas of dense fog. The fog will burn off quickly, and temperatures will zoom up to around 80 degrees by mid to late afternoon. You'll notice humidity starting to creep up as well. 

The question marks for today and this evening are a fairly strong disturbance passing to our south and a weaker one tonight to our north. The southern one will probably set off a few severe thunderstorms in and around Pennsylvania. 

Up here, definitely nothing severe, but some showers of a rumble of thunder could develop overnight because of the two systems. It will end up being muggy overnight, too.  

SATURDAY

Hoo-boy, you're going to be hot. Temperatures in the warmer valleys could easily get to 90 degrees unless more clouds roll in than expected. This hot spell is going to be much more humid than the one last week, so it will feel worse. 

Bad enough for the National Weather Service to hoist Vermont's first heat advisories of this summer season. Those heat advisories are in effect Saturday afternoon and evening in the Champlain Valley and low elevations of southwestern Vermont from about Milton south, and for the lower Connecticut River Valley from about White River Junction south. 

The heat index in the advisory zones will be around 95 degrees. If you're outside the heat advisory zone, it's still going to be uncomfortable.  At this point, the actual high temperature for Burlington Saturday is 92 degrees, which would tie the record for the date. We shall see! 

The forecast for thunderstorms Saturday hasn't changed much from the CAPE vs cap discussion I had yesterday.

CAPE, the potential for storms in the atmosphere will be really high, but you need a trigger for storms, and a way for them to get going. A layer of warm air aloft - which is the cap - will tend to prevent the towering updrafts that lead to thunderstorms. 

NOAA's Storm Prediction Center is maintaining a slight
risk for severe thunderstorms  - level 2 of 5 alert levels
for us on Sunday

However, the air tomorrow will be volatile with the CAPE. If any updrafts break the cap, chances are the updraft would quickly become a strong to severe thunderstorm.  As it looks now, any storms that form late tomorrow afternoon or evening will be few and far between so that most of us will be unaffected. But if one forms near year, watch out, it could be a doozy.

NOAA's Storm Prediction Center has us in a marginal risk zone for severe storms Saturday, the lowest level of alert in a five point scale. 

Saturday night will be stuffy with just a chance of a lingering storm. 

SUNDAY

Everything on Sunday depends on the timing of a cold front, how many clouds are out ahead of it, and how hot it gets.

We know Sunday will be quite humid.  If there's some sun, as currently expected, we'd get up into the upper 80s.

With the cold front approaching there's a decent shot of thunderstorms in the afternoon or evening, and some could be severe. 

How extensive the storms will be will depend on a few factors. If most of the day is cloudy, that would minimize instability and reduce the chances of severe weather. 

If we have a period of sunshine in the late morning to early and mid afternoon that would increase the chance of severe weather. 

We'll know more details as we get closer. For now, NOAA's Storm Prediction Center has us in a slight risk zone for severe storms. 

MONDAY

Blessedly much. much cooler and much, much less humid.