Gearing Up For A Rough Weather Night In Vermont, As Floods, Winter Storms, Severe Weather Hit Swaths Of Nation

Just one example of the flooding risk in Vermont from 
tonight's rains.  The Otter Creek at Center Rutland is
forecast to crest Friday at moderate flood stage, and
just one foot lower than major flood. 

 As expected today has been a wicked, active weather day in many locations east of the Mississippi River in the United States, and in parts of southeastern Canada.  

Here in Vermont, as of late afternoon we were still waiting for the main show to begin, but it's certainly on its way. We weren't expecting much action until tonight anyway, more on that in a bit. 

As of 4 p.m. tornadoes were beginning to spin in and around Mississippi,  and a nasty winter storm extended from Kansas City to Detroit. 

The main issue with this storm though, is its moisture supply, heavy rain and flooding. Flash flood and flood warnings cover a huge area from southern Missouri, on through parts of Illinois, Kentucky, Indiana, Ohio, western New York and Ontario Canada. As you go north into Michigan, New York and Ontario, ice jams on rivers are added to the mix.

This is all due to a pretty wild moisture feed for this time of year. It's essentially atmospheric river coming from the Gulf of Mexico. The air is pretty much as wet as it's ever been for February, and that has been unleashing some hefty downpours. 

WHAT'S IN IT FOR US?

Here in Vermont, we've only had light rain so far today, and most of that has been confined to areas along and north of Route 2. The rain was starting to fill in a little more as darkness approached, and it will be quite a rainy night.  Or the first part of tonight, anyway, depending upon where you are. 

Flooding

The light rain today prevented northern Vermont from achieving record high temperatures, but the humidity is quite high for this time of year. I've noticed the snow in my yard in St. Albans, Vermont has been melting astonishingly fast this afternoon. That's happening pretty much everywhere in the Green Mountain State, and that is helping to prime the pump for some flooding trouble. 

The unusually wet air will really unleash the rains for awhile tonight, with most places in Vermont expecting over an inch of rain or melted ice and snow. It will be mostly rain for the bulk of the region. 

(I'll get into an ice update in a bit)

This rain, and the snowmelt, has prompted the National Weather Service and the USGS to up their flood forecasts for overnight and Friday. 

Snow was melting off of my St. Albans, Vermont yard
rapidly late this afternoon, but there was still a decent
amount left, More melting will contribute to runoff ad
a flood risk overnight and Friday 

The Otter Creek at Center Rutland is forecast to peak Friday at just one foot below major flood stage. The Mad River at Moretown is also predicted to go into moderate flood, at 2.6 feet above flood stage. The Winooski River at Essex Junction is probably going to go to 1.8 feet above flood stage.

This clearly isn't an Irene-level flood scenario but it's disruptive enough. The usual low-lying roads that flood in the spring probably won't be passable tomorrow.  There will probably be other, smaller waterways that flood, too.

Flooding is harder to see at night, so be careful driving. Don't drive through flooded roads, especially not now. It's dangerous enough in the summer. In the winter, you also have very cold water, which means you'll be paralyzed by the cold water if you fall in, and there will be much less time to rescue you before you drown. 

Ice Jams

Ice jams are the wild card tonight.  Ice jams are what would cause the most sudden, most dire problems, especially if they form in the wrong place. 

Once an ice jam forms, water will quickly back up behind them, essentially causing a frigid flash flood. I would deem ice jams likely tonight. We just don't know where. These jams were already starting to form in rivers like the Ausable in the Adirondacks.  

We've heard reports of the solid ice on Vermont rivers beginning to creak and move late this afternoon. As runoff increases and water rises, it won't take much to set this off. The risk of ice jams starts about now and continues through Friday, even after temperatures crash to well below freezing levels.

Freezing Rain/Sleet

Speaking of crashing temperatures, the forecast hasn't changed much regarding mixed precipitation and ice in the Champlain Valley.

Once the main part of the storm approaches, a shallow north wind will bring subfreezing air later tonight to the lowest elevations. Meanwhile, warm, wet south winds will continue aloft. 

The National Weather Service in South Burlington says at some point late tonight or early tomorrow morning, predictions are for temperatures to be around 27 degrees at elevations of around 1,500 near the Champlain Valley but near 44 degrees at 3,500 feet, a little below the highest summits of the Green Mountains.  

The National Weather Service in South Burlington is thankfully
still forecasting less than a tenth of an inch of ice 
accumulation overnight in northwestern Vermont. That
would spare us from much tree or power line damage

There's a recipe for freezing rain if I ever saw one. It's still unclear what proportion of the stuff coming out of the sky will be freezing rain and how much will be sleet. But it will be a mess, that's for sure. That fun little nightmare should start a little before midnight. 

 

It's still looking like the ice accumulation won't be enough to bring down much in the way of branches and power lines so that's good. Let's hope that forecast holds.  

 In this type of situation, the shallow cold air has trouble making the leap over the Green Mountains, so places along and east of the Green Mountains will only  have a brief period of mixed precipitation when the full force of the sharp cold front comes through before dawn. 

Not much snow will fall at the tail end of this, We're just a little too far east. New York's St. Lawrence Valley is expecting a bunch. But the heaviest snow will fall over the northwest corner of Vermont early tomorrow, and that will only amount to three inches or so. Everyone else gets less, unless we have some weird overnight surprise. 

Flash Freeze

It will be well below freezing by dawn in all but southeastern Vermont, so the forecast from this morning holds. Any water and schmutz will freeze solid, and be difficult to remove from roads, sidewalks, driveways and cars. 

The full force of the cold air will probably hit before dawn for many of us, so at least the flash freeze won't be taking people by surprise as they drive to work.  The damage will have been done for most people by the time the commute starts.

Gusty winds

Once the cold front comes through, we'll have a nice blast of strong northwest winds. Most places are prone to gusts to at least 30 mph.  Southern Vermont is still under a wind advisory as winds could gust to over 50 mph, bringing down scattered branches and power lines early tomorrow. 

Overall, this will be the most challenging storm so far this year, with multiple risks and worries. It won't go down into the annals of history as one of the Worst Storms Ever, but it does need to be taken seriously.