Active Vermont Weather Week: Downpours, Thunder, Sharp Cold Fronts and Snow?

Like in a scene from "The Mist," a fast moving wall
of fog quickly swept into St. Albans, Vermont Sunday
evening amid a day of shifting weather, clouds,
showers and brief downpours

 We had another sort of weird weather day on Sunday with a wide mix of weather in Vermont.

That'll set the tone for the rest of the week with some locally torrential rain today, thunderstorms, too, followed by a sharp, stormy cold front later in the week, cold north winds, and --  Yep! hate to say it, a real possibility of a little snow.   

Before you panic, any snow would be limited to elevations above 3,000 feet, so most of us need not worry. 

Let's take things piece by piece.

On Sunday, a cold front settled southward into Vermont and stalled. That lead to two afternoon weather regimes. North of Route 2, by afternoon anyway, it was a bit chilly, ,damp and definitely rainy. 

South of Route 2 it was cloudy, humid with scattered showers. 

Since there seemed to be some pretty good energy in the disturbances riding along the front, there was some convection, too, which led to locally  heavy downpours.  And some odd weather moments.

As I noted on Twitter last evening, here in St. Albans, it felt for a time like I was in the Steve King horror book and movie "The Mist."

After hours of calm wind and drizzle, suddenly we had a gush of wind from the west and a wall of dense fog swept in. Luckily, I didn't notice any big scary man eating creatures in the mist, so I guess we're good. 

Rainfall was light in southern Vermont Sunday but amounted to up to an inch far north. My unofficial rain gauge in St. Albans, Vermont had collected 0.9 inches by 8 a.m. today.

All this sets the stage for today. 

MONDAY

The latest rainfall map from the National Weather Service
office in South Burlington. One to two inches of 
additional rain is due through 8 a.m Tuesday, with
locally higher amounts 

That front is still stalled across us, and a pretty decent storm is moving west to east along the front. Already, early this morning, there have been scattered, brief, sporadic downpours. Already, a batch of thunderstorms was moving across northern New York toward Vermont as of 9 am. 

The rain, showers and scattered downpours will increase as we go through the day. 

Updated forecasts have reduced the risk of flooding from today's rains but have not entirely erased that risk. 

Most of Vermont should see another inch or two of rain today. That's good news, as we're still trying to recover from a summer drought. 

But a few areas could receive some repeated downpours, much like last Tuesday. Which means it's possible a few towns could see rainfall totals in the three to four inch range.

Since the ground is wetter than last week, it won't be quite as efficient at soaking up that much rain in a short amount of time. So if that heavy rain develops anywhere, there could be a few pockets here and there of flash flooding. 

Any flooding that does develop shouldn't be too widespread. Today's rains should make main stem rivers like the Winooski, Lamoille, Missisquoi and Otter Creek rise by two to four feet, says the National Weather Service in South Burlington. 

Since  these rivers were running low before the onset of rain on Sunday, those rising river levels shouldn't cause any flooding problems.  Overall, NOAA's national Weather Prediction Center has the core of today's heaviest rains over Vermont, with all of the Green Mountain State, along with adjacent portions of New Hampshire, New York and Massachusetts under a slight risk of flash flooding today and this evening. 

That's level two of five alert levels. It means the risk of spotty flash flooding. 

NOAA's Weather Prediction Center has Vermont
bullseyed under a slight risk of flash flooding today.
The risk is for local instances of high water in spots
where downpours are especially persistent

Tomorrow will be much quieter. Cool. Mostly cloudy, some showers around, nothing too wild. 

NEXT COLD FRONT

On Wednesday, we'll be ramping up for the next system. As clouds increase, you'll notice it getting somewhat warmer and vaguely humid. That'll be the first sign of a powerful autumn cold front heading our way.

Out in western New York, the front will arrive early enough in the day to produce some late season, severe thunderstorms. 

The band of showers and storms will get here late in the day and at night. Because of the late timing, severe thunderstorms seem unlikely at this point. However, we're still in line for some gusty evening and night time storms.

Thunderstorms at night are pretty rare in September, but in this case it looks like we might get them.  We could get up to an inch of additional rainfall. Since these storms will be moving right along, they won't linger long enough to set off anything worse than minor street flooding and ponding on roads.

Get your woolies out on Thursday. A north wind will blast in. It'll be mostly cloudy and temperatures will fall through the 50s during the day. Up in the mountains, above 3,000 feet, we could see the first light snows of the season Thursday evening and night. 

After that, we'll need to watch for frost in the cold air that will linger Friday and into the weekend.