Vermont: Follow The Bouncing Temperatures; Air And Water

Irises in my St. Albans, Vermont gardens seemed to enjoy
the sunshine and change to cooler temperatures last evening

 That was quite a change in the air yesterday, wasn't it?

After a few days of record and near record heat, Sunday dawned warm and humid and summerlike.

That didn't last, did it? 

The cold front that blew through in the morning and afternoon was accompanied by some strong-ish gusts, falling temperatures, but sadly, little rain. Most of us received a tenth of an inch or less, so the dry, dry year we've been enduring continues. 

It wasn't just the air temperature that fell dramatically. So did the water temperature on Lake Champlain. 

The summery warmth of the past few days was accompanied by light winds.  That lack of wind kept water from deeper in the lake from rising to the surface through wave action.  The heat and the strong May sun had water temperatures in Lake Champlain go all the way into the 60s, which is way warm for this time of year. 

The sudden gusts of north winds Sunday - gusting to 40 mph over the lake - created what the National Weather Service in South Burlington is calling a very impressive upwelling event on Lake Champlain. 

What that means is those strong wind gusts displaced water which allowed cooler water down below to come up to the lake's surface. The lake water temperature was 66 degrees at 11:30 a.m. Sunday on the lake at Burlington moments before the cold front arrived.

By 11:30 p.m. last night, the water temperature was down to 48 degrees.

Air temperatures plummeted last night as well, and frost was reported this morning in a few places well away from Lake Champlain. The lowest temperatures I saw so far this morning were in the notorious cold spots. Island Pond was 30 degrees and Saranac Lake, New York was down to 28 degrees. The Banana Belt Champlain Valley was in the low 40s

This temperatures aren't all that unusual for this time of year, but it's been so summery lately it seems odd. 

Temperatures will continue to bounce all over the place the rest of this week.

Today is going to be late spring perfection with plenty of sun and temperatures rebounding really, really fast to the low 70s.

Readings will trend upward again Tuesday, reaching 80 degrees or so. By Wednesday it's back to summer, with temperatures up in the 80s with a fair amount of humidity around. 

Then another cold front comes in, dropping temperatures late week to levels probably even cooler than last night. 

Frost could be a worry again Thursday night.  Temperatures Thursday and Friday might not get past 60 degrees in many areas. 

Then it warms up again over the weekend. Up and down, up and down.

The only consistency is the lack of rain.  While the midweek cold front will cause quite a drop in temperature, rainfall with the front looks like it will be unimpressive. I suppose a few places that get bullseyed by a decent thunderstorm could get a quarter inch of rain or more, but otherwise, this will be another relatively dry cold front. 

The drought goes on. 

The dry conditions are probably helping make the temperatures a little more extreme, both on the warm and cold side. If the soil is wet, it leaches moisture into the air, and that moisture tends to prevent hots from getting too hot and colds from getting too cold. 

The lack of soil moisture now is probably allowing sunshine to boost afternoon temperatures to slightly higher levels than they otherwise would be.  The same issue is helping to create cooler nights than we'd otherwise have, as long as the night in question is clear and calm,  like it was last night. 

This phenomenon is why deserts tend to get so hot in the afternoon and still manage to get chilly at night.  We're not exactly a desert here in the Green Mountain State, but droughts are not only bad for crops, they can make us uncomfortably hot or cold, too.