Thursday Evening Update: Flood Risk Continues In Vermont/New York With Debby; Rather Weird Weather, Too

Expected rainfall amounts through Saturday with
the remnants of Debby. Less rain is expected in
Vermont than earlier forecasts, which will help prevent
another big flood disaster. But local flash loods
are still a real risk. 

As advertised, clouds increased this afternoon across Vermont and surrounding areas as now ex- Tropical Storm Debby makes its way towards us.  If it isn't raining where you are when you read this, it will soon.  

THE BIG PICTURE

Already, as of 5 p.m. rain had moved into far southern Vermont and in northwestern New York. There were a few heavy downpours embedded with that rain. A sign of things to come. 

The overall forecast for its track, timing and duration hasn't changed much since this morning. The 5 p.m update from the National Hurricane Center actually has it moving a little faster than they predicted this morning. 

This morning, the projection was former Debby would be over northern Vermont as of 2 a.m. Saturday. Now, it's expected to be just north of the northern tip of New Hampshire at that hour.

The faster former Debby moves the better, as it would have less time to dump a bunch of rain on us. 

Heaviest rain is still expected to be across northern New York with this thing with somewhat lighter totals in Vermont. 

The National Weather Service office in South Burlington has updated its flood watches, expanding the watch across all of the northern half of Vermont except the Champlain Valley. 

Although trends have continued to minimize the threat of another mega-flood disaster in the Green Mountain State, instances of flooding, washouts, that kind of thing are still definitely in play. 

That northern Vermont flood watch was put in place largely because areas hard hit by the two other big floods this summer are especially vulnerable to heavy rain. 

The State of Vermont, and towns affected by that flooding hurriedly patched up washed out roads and culverts just to get the roads open. More permanent repairs come later. 

Since a lot of those quick repairs are ad hoc, they're not particularly  resilient against heavy rains. So downpours associated with ex-Debby that in normal times wouldn't be that big a deal are. Ex-Debby might undo a lot of the work that's been done in the past month. 

STEP BY STEP OUTLOOK

Tonight

Overnight, chances are you'll hear the occasional roar of quick downpours on your roof, interspersed with periods of lighter rain or no rain. Overall, radar has rain coming in quicker than I thought, so you might see a shower even before sunset. 

Overnight, rainfall will only amount to maybe a quarter of an inch in southern Vermont, with locally higher amounts. Northern Vermont can expect maybe a half inch to an inch. 

This won't be enough to trigger flooding but will prime the pump for possible flooding later, as I noted this morning. 

Friday/Friday Evening

A weird, tropical day. There might be a lull in the rainfall early in the morning, but it should pick up in the form of numerous showers and thunderstorms in the afternoon.  The day will feel incredibly humid and south winds could get a little gusty with this, too.

 Former Debby is still expected to cross over northwestern Vermont. With tropical storms and former tropical storms thunderstorms tend to develop along and east of the path, with a steady, heavy rain west.

So the steady, heavy rain will mostly stick to New York. 

The more sporadic nature of the numerous showers and storms will make things a bit challenging for forecasters. Areas of flash flooding - and flash flood warnings - won't become apparent until the actual flood is underway, or the flooding is just minutes away.

Though we know that most of us will receive one to two inches of rain, there could be much higher totals in a couple spots if storms hit the same spot over and again.

If we do see any flash flooding with this, the best chance of it hitting are between early afternoon and midnight Friday.

Definitely be ready to hear any flash flood or severe thunderstorm warnings that might be issued tomorrow. It will be an active day and evening .

Some of the storms could end up being severe, with a few reports of damaging gusts definitely possible.  Vermont is now in a marginal risk for severe storms Friday and Friday evening, meaning there could be isolated instances of damage. I do wonder whether that risk level will be upgraded to slight tomorrow, which is a slightly higher risk of severe weather. 

Tropical systems can be prolific tornado producers. There have already been several in the Southeast. There is a low, but not zero chance of a brief spinup with former Debby in Vermont tomorrow and tomorrow evening. Could happen anywhere in the state. If it does happen, the best chance is in southwestern Vermont. 

Outside of those severe storms, winds could gust to 40 mph in spots Friday afternoon and evening. That could be enough to push over a few trees. Remember, wind can uproot trees more easily if the soil is wet and soggy. So expect a few widely scattered power outages, even if no severe thunderstorms develop.

Saturday

Since this ex-Debby thingy will be rocketing by so fast, it now looks like Saturday will be a nice day. Although the chances of serious river flooding in Vermont appears low, we'll have to watch those water levels, especially Saturday morning if the rain we get Friday and Friday evening turns out to be heavier than expected.