Can We Ease Northern Vermont Drought Without Flooding Out Southern Vermont

A torrential downpour in South Burlington on Wednesday.
The heaviest rain with Wednesday's storms partly
missed far northern Vermont, which most needs the rain.

We're into that time of year now when we're gradually transitioning out of the normal summer pattern of hit and miss showers and thunderstorms into one where we sometimes get larger areas of rain.

Meanwhile, Vermont is in a weird spot with water needs.  There was too much rain in southern Vermont this summer, and not enough in northern parts of the state. 

 All of northern Vermont within about 30 or 40 miles of the Canadian border are still stubbornly in moderate drought, says the U.S. Drought monitor.

I can sort of confirm that here in St. Albans. We've had some needed rain lately.   But digging through the tough clay soil here two days ago, I found things moist in the top two inches or so of soil, then it was still dusty underneath that.

Also the "Woof River" as we call it here, a tiny stream that runs by our house, is still dry, as it has been since June. 

The drought might or might not continue, but with the normal change in weather patterns, we can hope that northern areas get better rains without flooding out soggy southern Vermont. No guarantees, but here's typical autumn scenarios, from worst to best for southern areas of the state.

DYING HURRICANES

Not a great option for southern Vermont.  Former tropical storms and hurricanes can drop a tremendous amount of rain in the autumn.  Problem is, they usually come up from the south, and can drop their heaviest downpours over southern Vermont.  That would lead to flood problems, but if the rains get far enough north, they can alleviate drought near the Canadian border.

NOR'EASTERS

These coastal storms become more and more common especially as you get toward late autumn. Again, not as great for southern Vermont as they tend to drop more rain there. But if they come inland far enough, northern areas can share in the bounty, too.

Of course, nor'easters can often draw down cold air from Canada and can result in early season snowstorms. 

GREAT LAKES BOMBS

This is a great option for northern Vermont, but can come at a steep price for those who live near the Great Lakes or even northern Plains. 

In the autumn, especially when you get into October and November, storms moving northward from the Midwest into the Great Lakes often "bomb out." They get energy from the still relatively warm Great Lakes and become monster, strong storms.

These can be really, really bad. This type of storm caused the famous "Wreck Of The Edmund Fitzgerald" in 1975, and a November, 2013 example created a large Illinois tornado outbreak that killed 11 people and caused $1.6 billion in damage.

Cold fronts associated with these storms often slow down when they reach the eastern Great Lakes and the east coast. Lots of moisture can ride up along these fronts and cause heavy rain.  Or, a storm can form along one of these slow cold fronts. That sometimes prolongs and intensifies the rains over Vermont.

If we get a few of those storms, that would help

FRIENDLY SOUTHWEST WINDS 

If we get into a long lasting or frequent pattern of a jet stream coming at Vermont from the southwest, that would be a great scenario, especially for northern parts of the state.

That would lead to frequent storms with rain practically every other day.  Each individual storm probably wouldn't drop much rain, but the frequency of these storms would add up. A few of these storms could also scoop up some moisture from the Gulf of Mexico, enhancing the rainfall.

We've sort of been in this pattern for a few days and it looks like it might continue for a few more, so more shower chances are coming. This has helped northern Vermont a little in the past week, and might continue to do so. 

BAD SCENARIOS

Here's two weather patterns common in the autumn which would make the northern Vermont drought persist or even get worse

What I might call a ridge roadblock sometimes sets up in the autumn, in which a strong upper level ridge sets up over southeastern Canada. That would give us delightful Indian Summer weather, with abnormally warm temperatures and lots of sunshine. But it would also deflect storms away from us.  This set up would also tend to steer hurricanes into the southeastern United States instead of recurving harmlessly out in the open Atlantic Ocean

Another common scenario is a deep dip in the jet stream over us or just to the east. That would make it cold here, and deflect wet, juicy storms off to our south and east. We'd be left with almost worthless cold, light rain showers or gusty snow flurries.  And also lousy weather for outdoor fall fun.

I don't really trust long range forecasts, but for what it's worth, many of the predictions I've seen call for warmer than average temperatures. These forecasts are also undecided on whether we'll be wet or dry for the rest of the autumn. 

Again, for what it's worth, the U.S. Drought Monitor is optimistic.  They're predicting we'll get enough rain in the coming weeks and months so that they can remove the drought designation for northern Vermont.