Cold Air Bring Signs Of Spring, But Winter To Win Out For Now

Shower clouds billowed upward Sunday as warm March
sun caused updrafts into chilly air aloft, forming
numerous, but scattered showers of rain, snow and graupel.

 It was subtle, but it was there. 

The sky on Sunday bore signs of spring, even as temperatures began to drop as wintry air approached New England.  

It was in the clouds. Cold air had moved in aloft.  At the same time, as we head toward spring, the sun is getting stronger and stronger.  That sun was able to heat up what is snow-free ground in many areas of Vermont. 

This, in turn caused updrafts that hit the chilly air a few thousand feet overhead. That forced the updraft to condense into sort of those billowy clouds you see in the summer. 

It wasn't pure spring. Some of those billowy clouds yielded snow and graupel mixed with the rain, so they weren't exactly pleasant summertime showers.  

Still, Sunday was a welcome change of sorts. During the heart of winter, the sun is usually too weak to cause much in the way of updrafts, so clouds more often than not have that bland, flat overcast look. In the spring and summer the sky begins to look more interesting, as it did Sunday. 

So, spring!

Maybe not so fast. On top of the wintry showers these clouds produced, their gust fronts caused by the downdrafts in these tall clouds, would chill the air abruptly. Sunshine and relative warmth would disappear into instant chill whenever and wherever these showers showers arrived Sunday.  

OUTLOOK

The forecast still calls for more winter than spring for the next week or so. Spring, despite the signs we saw Sunday, is on hold.

Today, we'll probably see similar weather to Sunday, with those convective clouds and scattered rain, snow and graupel showers. They might be fewer and further between than Sunday. Between now and Tuesday morning, a few inches of snow might pile up in the central and northern Green Mountains. 

The next little system coming in Wednesday looks like it will have a little more oomph that previous forecasts told us. It will by no means be a big storm, but it'll be responsible for yet another few inches of snow in the mountains, and a dusting to a couple inches down in the valleys. 

It'll stay cold through the weekend, with the chilliest days being Thursday and Sunday.  Many of us won't make it above freezing those two days. 

Meanwhile, we a look forward to the prettier skies of later spring and summer. 

As we go further into spring and into summer, the contrast between the heated air near the ground and colder air aloft will grow. On some days, anyway. 

By summer, the mini-billowy, vertical clouds you saw Sunday will grow into those tall thunderstorms that occasionally create torrential downpours, lightning strikes and strong wind gusts. In contrast to the mini-me showers we had Sunday. 

Thunderstorms are perversely my favorite kind of weather. Sunday's clouds happily told me the season of lightning is coming soon.  I'll just have to bundle up and wait, at least during this week.  

Slight Uptick In Rain Hope In Vermont, But Comes With A Bit Of A Price

A fast moving gusty, quick downpour approaching
South Burlington late Sunday afternoon. A sign
that summer thunderstorm season is approaching.

 Yesterday in this here blog thingy, I whined about the lack of rain in the Green Mountain State (except in far southern Vermont). And I whined that precious little rain was coming anytime soon.

I've still got that whine, at least a little bit, but at least there is now hope for at least some rain this week, especially in northern Vermont.  

The price we'll pay is a potentially lousy, cold Wednesday afternoon and evening. 

Before I get into that, a couple interesting things happened in Vermont for us weather geeks yesterday and last night. 

First of all, I'll have to say I was taken by surprise by a broken line of gusty showers that swept southward through the northern half of Vermont late yesterday afternoon and evening. 

It was a sign that summer thunderstorm season was finally approaching. I didn't notice any lightning with these showers, but they had all the other elements of a thunderstorm: Gusty winds of up to 30 mph, brief downpours in a few spots, and even a shelf cloud to herald the arrival of these brief storms. 

Most places didn't get much rain out of them, but anything helps. 

Video of this Welcome-to-summer convective shower is at the bottom of the post. Love that kind of weather. 

Satellite view of what I call the "smoke front" over
southern Quebec late Sunday afternoon. Milky stuff
is smoke from Alberta, whiter clouds over northern
Vermont are showers just ahead of a cold front
that you can see abruptly clearing the air 
over southern Quebec. 

Those showers were ahead of a cold front, that I will also call a smoke front.  As had been forecast, quite a bit of smoke from those big Alberta wildfires hazed up the skies for a good part of Sunday. 

Overnight, a cold front swept south, and that dramatically cleared the skies. 

You could see on satellite images last evening a sharp cutoff between smoke and no smoke over far southern Quebec. It was pretty striking. 

The cold front prompted frost advisories for this morning over much of northern Vermont, but temperatures were near freezing in only the coldest hollows. So that's good. 

Now on to some rain hopes. Sort of.

UPCOMING

Today and tomorrow will be dry and sunny, so that hasn't changed. It'll be kind of cool today, with highs in the 60s this afternoon and 70s on Tuesday.

Now, remember that sharp cold front that came through last Tuesday that led to the hard freeze in Vermont during the middle of last week? Of course you do. 

Something very similar is forecast to happen this Wednesday. Before you panic, we're not expecting anything as damaging or cold as last week's freeze.

What does seem to be happening is that the upcoming strong cold front is now looking like it will have more moisture to work with as it comes through. 

This all means the northern half of Vermont could get a decent half inch of rain out of this. Not spectacular, but helpful. 

The price we'll pay is it will turn pretty nasty cold for May again.  The current forecast has temperatures crashing from the upper 60s  down to around 50 in the afternoon, with cold rains. 

Showers will continue into Wednesday night, and could actually mix with snow in the higher elevations. Pretty late, for snow if it happens, but not unprecedented.

We will have to watch out for frost Thursday and/or Friday morning but it still looks like it will not be nearly as cold as last week.  So if any frost does come our way, it won't be destructive, like last week.

The computer forecasting models, meanwhile, are still struggling with what kind of weather we'll see during the Memorial Day weekend. 

Some feature an upper level low swirling nearby most of the weekend, which would keep us on the cool side with light showers and clouds. Others push this thing off to our east, which would mean more sunshine and seasonably warm temperatures in the 70s.

It's too soon to believe any forecast for the holiday weekend. We'll just have to stay tuned.

Video: The first decent convective shower of the warm season approaches and arrives in South Burlington, Vermont with a shelf cloud, some gusts to 30 mph and a brief downpour. Click on this link to view, or click on the image below if you see it to watch it: