I'll make one thing clear:
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| Expected rainfall with Debby. One to two inches expected in most of eastern Vermont, with two to four inches northwest and mountains. Note that this is a broad brush map. Locally higher amounts could be embedded in some areas. |
But - fingers and toes crossed big time - this is looking less like the wholesale new big disaster for Vermont than it did two or three days ago.
OVERALL TRENDS/NEWS
Forecast trends continue to keep remnant Debby zipping by and heading to Canada really quickly, which would limit the time the storm has to dump torrential downpours. And while those downpours are likely in at least part of Vermont, the biggest focus for them should be in the Adirondacks.
Not that I want that to happen. I'd hate to see the kind of destruction in New York that we saw in Vermont earlier this summer. But Vermont can sure live without another big flood, too.
NOAA's Weather Prediction Center still has almost all of Vermont in a moderate risk zone for flooding with this. That's level 3 of 4 on the risk scale and definitely a sign of potential trouble. That said. it's possible that moderate risk in Vermont might be trimmed back later today in some areas if relatively happy forecast trends continue. We shall see!
We're not completely out of the woods, of course. As mentioned, we're going to get some pretty stiff downpours. And there's still a few question marks regarding the exact track of what will be former Debby.
For now, the National Weather Service in South Burlington is confident enough about heavy rain in the Adirondacks to issue a flood watch there. No flood watch is in Vermont, at least not yet. There's some high resolution data that was just coming in early this morning they wisely want to take a look at first before making any decisions on whether to hoist any flood watches in the Green Mountain State.
I notice flood-spooked Vermonters are taking no chances, which is a smart move. The city of Barre, repeatedly hit hard by recent floods, is making sandbags available for residents and businesses.
Let's walk you through what meteorologists think will unfold as this thing goes by. As you're reading, remember, the forecast is subject to change. The paths of tropical storms and former tropical storms can be really unpredictable.
TODAY
Another nice one as the humidity remains low and bright sunshine bathes the state. At least for awhile. You'll notice increasing high cloudiness this afternoon, as what will be former Debby begins its charge toward us.
It'll be a seasonably warm day with highs in the 77 to 83 degree range most valleys
TONIGHT
The burst of high humidity that tropical systems always bring along with them will ooze quickly in, turning the night from refreshing to muggy by morning. This blast of humidity will trigger a band of rain with a few embedded heavy downpours and thunderstorms.
This won't be enough to trigger any flooding, but could prime the pump for flooding that might come with later bursts of downpours from Debby.
FRIDAY
It's going to be kind of a weird, tropical day. That band of initial rain will move out. You'll notice the oppressive, awful humidity we had through most of July and the opening days of August will be back. Don't worry, this outbreak of air you can wear will be brief.
Especially on the Vermont side of Lake Champlain, there could be fairly long periods during the day with no rain at all. Or, there will be fitful, quick hitting showers that might not amount to all that much.
At first.
But especially if we see a fair number of breaks in the clouds, that could destabilize the air and trigger some torrential thunderstorms. We'll have to watch those for the risk of any isolated instances of afternoon and evening local flash floods. There won't be anything widespread, if anything at all, but it will be worth watching.
FRIDAY NIGHT
The heart of the storm, and when the greatest risk of flash flooding might happen. The steady, heavy rain should continue all night in the Adirondacks. Debby is actually using Vermont as sort of a meet up spot with a cold front coming in from the west.
The two will team up to come through Vermont probably with a band of heavy downpours. (Latest projections from the National Hurricane Center has the center of former Tropical Storm Debby about over Morrisville at 2 a.m. Saturday).
The band of storms will be moving fairly fast, but since the rain will come down so hard, in many cases on already sopping wet soil, the risk of flash flooding goes up. Note that nighttime flash floods are dangerous, as they're hard to see and you might be sleeping when warnings go up. Have a way to wake up to warnings if you live in a flood-prone area.
There's cautious optimism on main rivers like the Mad, Winooski and Lamoille, and the Otter Creek. All those waterways will have sharp rises, but so far, only minor flooding at worst is in the forecast. That could change if rainfall amounts and patterns change from what is now in the forecast, but for now, again, fingers crossed.
There might also be a problem with wind in spots overnight Friday. Even though former Debby will be rather weak by the time it gets here, there will still be a fair amount of energy with it. Strong winds aloft could mix down to the surface overnight. That's especially true perhaps along the western slopes of the Green Mountains and maybe the Champlain Valley.
We won't have any ferocious windstorms like we did this past January, but gusty winds hitting trees on soggy, unstable soil could topple a few of them, causing some scattered power outages.
SATURDAY AND BEYOND
The remnants of Debbie should quickly scoot away, so most of the day should be rain-free. We'll need to watch how high main rivers get during the day, but as noted, I think we might be OK. We could really end up with a nice summer day on Saturday.
Beyond that, a weak dip in the jet stream might promote scattered showers and rumbles of thunder, mixed with periods of sun Sunday through Tuesday. The showers will be light and widely scattered, and pose no flood threat.
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