Vermont, New York Get Surprise Downpours, Flood Threat Dramatically Worsens

Chaos in Barre, Vermont after a May, 2011 flash flood.
There's some risk we could see scenes like this again this weekend.

Much more rain fell across northern New York and the northern half of Vermont overnight, and this sets the stage for a real flood threat.

The threat is even higher than I had been expecting earlier this week.

Last night's torrential rains, amounted to two to three inches, locally even a little more from the St. Lawrence Valley of New York, across Lake Champlain and the northern half of Vermont.

Burlington got 2.16 inches of rain and Colchester piled up 2.71 inches.

By the way, June rainfall in Burlington has so far amounted to 6.79 inches. If we don't get a drop of rain today, it'll still be the seventh wettest June on record.

Flood warnings were issued across a stripe of northern Vermont, along and roughly 30 miles either side of a line from Burlington to a little south of St. Johnsbury.

There's been no major flooding in that zone, but there is high water, washouts and that kind of thing.

Mainstem rivers are already getting into the act, too. There's a flood warning for the Winooski River at Waterbury. Today's flooding won't be as bad as during Tropical Storm Irene, when the Winooski flooded most of downtown Waterbury.

But low spots, and low roads are going to go underwater. Flooding will cover fields and damage crops downstream to Richmond, and possibly all the way down to the famed vegetable farms in Burlington's Intervale.

The rain was temporarily waning early this morning and the flood warnings will have probably been dropped, at least for awhile across northern Vermont by the time you read this. With the exception of the Winooski River flood warning, which will probably remain in effect most of the day, even if we don't get much more rain.

However, this flood event is only just beginning.

A flash flood watch is up across northern New York, the northern half of Vermont, northern New Hampshire and western Maine through Saturday night.

The warm front that caused the torrential rains last night is lifting toward Quebec and we'll get firmly entrenched in the warm, very humid air today.

Disturbances riding along a front to our west will fire up plenty of showers and thunderstorms this afternoon and evening, and some will of course have torrential rain.  Even as I write this at 7 a.m. Friday, heavy downpours were lurking in western New York, heading east.

Here's how high the risk is: It would only take about an inch of rain in an hour to cause a flash flood. Some of the thunderstorms today and even more numerous ones Saturday and Saturday night could easily drop two inches of rain in an hour.

Flash flooding in Richmond,  Vermont in June, 2013. This
kind of thing could easily happen again today, and
especially Saturday in Vermont. 

And some locations that are unlucky enough to get repeated storms could get three to five inches of rain between now and Saturday night.

We get flash flood watches fairly often, but this to me is the most precarious situation since the big spring and summer floods of 2011.

Some of today's storms could also be severe, with strong gusty winds. NOAA's Storm Prediction Center has Vermont in part of a broad zone of a slight severe storm risk today.

The storms will subside tonight, but there's still a chance of locally heavy downpours overnight.

For what it's worth, one weather model has a band of heavy rain lingering for several hours across northern Vermont this evening. That might or might not actually happen, but it's something to watch.

Saturday afternoon and night is looking even more dangerous. The cold front to our west will be closer, and the thunderstorms will be much more numerous Saturday than they will be today.

Even worse, the air will be even more humid than today, providing the fuel for even more torrential rains. And some of those storms could be severe, with gusty winds.

Not only is flash flooding a threat, but some of the bigger rivers in the North Country could flood. We already mentioned today's flood warning on the Winooski.

I wouldn't be surprised if the Winooski flooded again by Saturday, along with other rivers like the Ausable in New York, and Vermont's Lamoille, Mississquoi and Mad rivers. This all depends, of course, on how widespread and heavy the rain is.

So heads up. It's going to be a rough weekend. The threat of flooding is pretty damn high. We could get lucky and not get so many storms, but I'm not holding my breath. This could be one for the record books.

New England Storm Forecast Update: Damn Tricky Business Here

The National Weather Service in South Burlington,
Vermont has taken an initial stab at forecasting
how much snow is coming, but this map is
BIG Time subject to change. (Click on the image to
make it bigger and easier to read.)  

Up here in Vermont, the National Weather Service in South Burlington has this evening opted to hold off on upgrading a winter storm watch for Sunday night and Monday into a warning.

They have good reason to be hesitant. This storm has a super high forecast bust potential. Vermonters hoping for a good dump of snow better not start celebrating yet.

There's still a very good chance of four to 10 inches of snow in Vermont, but there are a lot of complicating factors.

The National Weather Service forecast discussion is illuminating as to why the entire staff in South Burlington will be bald by Monday because they're pulling their hair out over this one.

Here are the problems:

1. Temperatures will be margional for snow, especially during the first part of the storm. It looks like many areas will start off as rain. But will the precipitation change over to snow as soon as the heavier precipitation comes in?

If not, who gets rain, and which areas stay cold enough for snow?  The higher elevations, of course, would be more apt to get snow, but what about the Champlain Valley? The valleys around Rutland?
How far do you have to go east of the Green Mountains before you encounter mostly rain?

A degree or two off in the forecast for any layer of the atmosphere, not just the surface, and current forecasts would be wrong.

2. Where will the heaviest precipitation be? There's a sharp cutoff expected between heavy snow or rain to the east, and very light precipitation to the west. Right now, it looks like the heaviest precipitation will be from the Champlain Valley east.

Even if forecasters are off by as little as 20 miles as to how far west the heavy precipitation will get, some areas will miss out on the heavy snow, or, in the case of eastern New York, unexpectedly get dumped on.

By the way, a 20 mile error in this regard is practically inevitable at this point.

3. These kinds of storms often form what is called a deformation zone, which is an area of heavier precipitation on the western edge of a storm that stays put for a few hours. Will a deformation zone set up? If so where?

4. Will mountains block the moisture feed in some areas? That's especially a risk west of the Green Mountains and even more so in Vermonts Northeast Kingdom, where New Hampshire's White Mountains could block the moisture.

You can see why Vermont is still under an uncertain winter storm watch. Who the hell knows what this storm is going to do?

The going forecast now, definitely subject to change, calls for about a foot of snow in the high-ish elevations in far north central Vermont, especially around Jay Peak.

Northwestern Vermont, especially areas at least five miles east of Lake Champlain, are pegged to get 6 to 10 inches of snow.

The Champlain Valley south of Franklin County, and central Vermont are up for four to eight inches.

Southwestern Vermont would get 1 to 4 inches of snow, and only an inch or two will come down in the Connecticut River Valley south of St. Johnsbury

As I noted, this snow forecast is BIG TIME subject to change.

By the way, things are just as uncertain in northern New Hampshire. They might get a big snowstorm, they migh not.

Down in Massachusetts, the NFL Patriots vs. Indiana Colts game, scheduled to start at 6:40 p.m. Sunday, promises to be a really unpleasant slog in the weather department.

Rain could come down pretty hard, and temperatures will only be in the low 40s. There's even a chance of thunder. However, there's still a chance the heaviest weather could wait until after the Patriots game. We'll wait and see on that one.

After the storm, the weather looks very easy to forecast, at least by comparison. It'll be a little colder than normal through most of next week, with just chances of light snow here an there across northern New England

Southeastern U.S. Under The Winter Storm Gun Again

Last month, the city of Atlanta had its End of The World moment when a couple inches of snow, combined with a panicked, "We've got to close the schools and get everyone home from work NOW" mentality caused enormous traffic jams that had people trapped on the roads for as long as 20 hours.

The Atlanta GA snow/traffic nightmare in January.
There's another winter storm watch up for
Atlanta. If a storm materializes, we'll see
if they do better this time.  

Well, guess what? There's a winter storm watch up again for Atlanta. This time it's for Monday afternoon into Tuesday.

It's still VERY unclear if the storm will be bad, or just turn out to be mostly rain for Atlanta. It's right on the edge.

But it will be very interesting to see how they handle another winter storm, if it arrives.

We hope practice makes perfect.

This Atlanta storm question is part of another round of snowy, icy weather that will stretch over the next few days from Louisiana to the Carolinas. So we'll hear about problems down that way for a few days.

By the standards of the people of the north, like me here in Vermont, the storm won't be that bad. But despite the frequency of southern storms this winter, the South is still not equipped for, or used to winter storms.

By the way, we here in northern New England won't see much in the way of storminess. We might get a dusting or an inch or two of snow tonight and Monday morning from a weak system passing by.

It'll be cold midweek with subzero lows before it warms up again to near normal February highs in the upper 20s or low 30s by the end of the week.

Some type of storm system might come through New England at the end of the week. It's hard to say how intense it will be, but early indications suggest it will be just light snow in Vermont and surrounding areas on Friday.

Long range forecasts like that are notoriously iffy, so we'll have better forecasts for the Friday system by about midweek.