Wednesday Vermont Storm Update And Nicholas

Best chances of severe storms Wednesday look to be in
the yellow zone. Marginal risk in dark green. Graphic
is from the National Weather Service in South 
Burlington, using data from NOAA's Storm
Prediction Center.

We're still looking at just one day over the next week or more in which we here in Vermont could have some tricky weather.  

That's tomorrow.  

The forecast still calls for the risk of some strong to severe storms, especially in southern and eastern Vermont. 

You know the drill: Some storms might have damaging winds, torrential downpours could set off a local flash flood or two, and the lightning will be dangerous.

You know this part of the drill, too: Southern Vermont will be the real target, while northern Vermont, especially the northwest, escapes the weather to an extent. 

The best chance of severe storms for now looks to be south and east of a roughly Rutland to St. Johnsbury line. Still, there could be a few isolated instances of strong winds in central and even northern Vermont. In this area. NOAA"s Storm Prediction Center has at least a slight risk of severe storms Wednesday afternoon and evening.

The Storm Prediction Center has been toying with the idea of boosting the risk level of severe weather to "enhanced," which is level 3 in a 5 point risk scale. But due to some uncertainty in the forecast, they're keeping it at slight risk for now. That's level 2 in the 5 point risk scale.

As a warm front comes through tonight, you might be awakened by the sound of rain on the roof and maybe a few rumbles of thunder. Nothing severe with that batch of showers and storms, though. 

When you get up tomorrow morning, the air will have a more humid feel to it. That'll set us up for the storms as a cold front slowly comes in from northern New York.

Up in northwest Vermont, lots of clouds will hold down instability, and the best upper air support for strong storms will be to the south. So, there could be some downpours, some lightning, maybe just a little wind up in the that neck of woods.

The morning and early afternoon will feature at least some sun in southern Vermont, which will help to make the atmosphere more unstable.  That means it'll be easier to form strong updrafts that give rise to those towering thunderstorm clouds. 

Stronger winds aloft will help maintain the storms.  When the upper level winds aren't very strong, the towering thunderstorm clouds remain more or less vertical.  That means the warm moist updraft with thunderstorms gets mixed up with the cold downdraft with the storm's rain, and the overall storm falls apart. It's too disorganized.

If there's strong wind aloft, the big towers of the thunderstorms are tilted. That means the warm, wet updraft that sustains the thunderstorm stays on one side of big towering cloud, while the cold, gusty downpours stay out ahead of the updraft, and doesn't interfere with it.   The updrafts and downdrafts don't get mixed up with each other, so the storm can sustain itself and get stronger.  

That's the kind of deal southern Vermont faces tomorrow. It's a pretty typical setup for strong to severe thunderstorms. 

Those strong upper level winds will also change direction with height. That could cause some storms to rotate. Which in some cases can actually spin up a tornado.  The Storm Prediction Center has a very low, but not zero risk of a couple tornadoes in southeastern Vermont, southern New Hampshire and southern Maine Wednesday.

But the main threat will be damaging straight line winds with the storms.

After all that goes by, we stay in some benign, warm weather for several days at least.  There could be a couple showers Saturday, but nothing widespread. Temperatures on many afternoons over the next week will flirt with a summery 80 degrees.

NICHOLAS

Tropical Storm Nicholas managed to increase to hurricane status for a short time overnight just before making landfall in Texas.  Top winds at landfall were 75 mph.

But as we mentioned yesterday, wind isn't the big problem here.  There was a fair bit of storm surge flooding overnight.  Most of the streets in downtown Galveston, Texas were under water from the surge that came in from the Gulf of Mexico, and there is storm surge damage throughout the mid-Texas coast.

Nicholas is forecast to more or less stall over 
Louisiana, which will unleash another disaster
on the state, this time devastating floods.

The even bigger problem is the torrential rain falling on the upper Texas coast and moving into Louisiana. They're still forecasting up to 20 inches of rain. 

Video from Live Storms Media from the Texas Coast last night showed an incredible amount of water pouring from the skies on top of the storm surge.  

Nicholas will diminish to a tropical depression, but will nearly stall over Louisiana this week. That will unleash tremendous amounts of rain on the storm-beleaguered state, and they will have another big disaster on their hands, this time from flooding. 

Even though the wind wasn't extreme, more than a half million people are without power in Houston, surrounding areas and into Louisiana. That doesn't include the people in Louisiana still without electricity from Hurricane Ida a few weeks ago.

The United States really seems to be a target for hurricanes and tropical storms this year. So far, eight such storms have hit the U.S.  

After Nicholas, there's nothing in the next couple of days that is threatening the United States, but there's still plenty of time left in hurricane season for more to hit.