Early Afternoon Vermont Flood Update: Western Vermont/NY Getting Most Of It for Now

Weather radar was really lit up, especially in New York and
northwestern Vermont as of 1 p.m. or so. Expect the heavy 
rain to continue focusing on New York, but some of it
will spread further in Vermont, raising flash flood
threats in the Green Mountain State as well. 

UPDATE: 2 PM

Tornado watch just issued for Vermont from Addison and Windsor counties south until 10 p.m. tonight.

PREVIOUS DISCUSSION

So far today, rainfall continued to exceed expectations a little bit, so wary meteorological eyes continue to watch what happens with the remnants of Tropical Storm Debby in Vermont through this evening. 

The good news is there's been a relative lull in rainfall in the eastern half of Vermont, which means rivers that were starting to rise sharply have stabilized. A flood warning that was in effect for the area around St. Johnsbury, Lyndonville and Barton has expired. They're not entirely out of the woods, as more heavy rain is due there later, but at least there's a break.

Western Vermont, especially the immediate Champlain Valley and in through most of Franklin County in the northwest, along with New York State, has been and is seeing the bulk of the rain as of 1 p.m.

A flood warning went up around Essex, New York and on across the lake around Vergennes, Ferrisburgh and Charlotte as a particularly intense blast of rain went through that neck of the woods at mid-morning. 

Another, more serious looking flood warning just went up after 12 noon for a region on either side of the northern portion of Lake Champlain. In Vermont, this is in northwest Chittenden County, Franklin and Grand Isle counties. Basically from Colchester north. Up to 2.5 inches of rain has already fallen there. Up to another 2.5 inches of rain could fall, so that could be really serious.

I see that Plattsburgh, New York had already gotten a storm total of two inches of rain as of 1 p.m, and it was still raining pretty hard there. 

So far the only report of trouble with this is about three or four inches of water on Interstate 89, a little north of Exit 16 in Colchester 

 Northern New York got no real break from the heavy rain, so that's where the most serious concern for flooding is right now. There's already a huge area of flash flood warnings in southwestern New York centered around Binghamton. That torrential rain seems destined to head toward the Adirondacks and St. Lawrence Valley later today.

Rainfall rates this afternoon over in New York could be one to two inches per hour. Some places in the Adirondacks could get five inches of rain. With the steep terrain over there, flash flooding could get pretty scary.

We'll also have to watch and see whether that concentrated area of rain clips far northwestern Vermont later, because of all the rain that's fallen there. For the rest of Vermont, we still have to worry some about flash floods, especially when the heaviest rain gets here in the late afternoon and early evening. 

As the center of former Tropical Storm Debby draws nearer this afternoon, we'll have to be on the look out for embedded thunderstorms, a few of which might contain damaging winds. 

The thunderstorm risk for western Vermont from Burlington south has been upgraded from level 1 marginal risk  to level 2 slight risk, which suggests there could be more than just isolated trouble with today's storms. 

In this western Vermont slight risk, there's a 5 percent chance of a tornado within 25 miles of a given point. Yeah, that's low odds to be sure, but more than we usually see in Vermont. There's a decent chance of a quick spinup, but of course that's far from guaranteed. If a spinup happens, it could come at dusk or after dark, making such an event that bit more dangerous. 

That said, rainfall patterns have been transitioning from a steady if sometimes heavy rain to more cellular type things. That means heavy showers and thunderstorms. With this new regime this afternoon and evening, the rainfall might be less constant and include some breaks, but when the rain does come, it will often be ferocious. 

Winds should really pick up in western Vermont especially today as the circulation of former Debby comes closer. We still expect winds to gust to 50 mph in a few spots. This is just regular winds, outside any severe thunderstorms. So power outages are a decent bet here and there. 

Since we're not entering the heart of the storm danger period - lasting from now into the evening - stay weather aware and pay attention for  any flood or severe storm warnings that might be issued over then next several hours.