Tuesday, July 15, 2014

From Maine To Virginia, Severe Storms and Floods Today

Lightning hits near the U.S. Capitol Monday. 
That big dip in the jet stream over the Midwest, call it the Polar Vortex if you want, or loathe the term - either way, it's causing some real havoc. And will cause havoc today.

Today, expect severe storms and floods in the Northeast and forest fires, heat and drought from the West Coast all the way to northwestern Canada.

The problem is, the jet stream forms a big, deep "U" with the bottom of the "U" right in the middle of the country.

The left side of the "U" has hot, dry air pumping up the West Coast and way, way up all the way into northwestern Canada. In that entire region, the weather pattern is worsening drought, and encouraging forest fires, some of them huge and epic, to continue to spread and intensify.

On the East Coast, the right side of that "U" the pattern is bringing up very humid, unstable air from the south, causing repeated rounds of severe thunderstorms and flash flooding.

In the Midwest, an autumnal chill settled in over the past few days, interrupting summer, but at least the cold isn't particularly destructive.

On Monday, there were also damaging thunderstorms from Kansas to Illinois to Tennessee ahead of the cold front introducing the chilly air in the Midwest. Those areas should be calmer today.

Since this pattern hasn't moved much in the past few days, the western heat and the eastern wetness  haven't gotten out of our hair. The longer it lasts, the worse it gets.    
From @timbutz70 via Twitter, a menacing storm
moves through Maryland Monday.  

The big dip in the jet stream does show signs of flattening out in the next few days and that will calm the weather some.

But in the meantime, the Northeast can expect another destructive day of damaging wind gusts in thunderstorms, a tornado or two, and a lot more flash flooding.

According to the NOAA Storm Prediction Center, the best chances of severe thunderstorms extend from central Vermont and central New Hampshire on down the East Coast to North Carolina.

In that zone, some storms this afternoon and evening will cause huge, scary, tree smashing wind gusts, maybe an isolated tornado, a few pockets of large hail and dangerous lightning.

If that wasn't bad enough, the rain from these storms will become torrential again. In some spots, the dreaded "training storms" might get going. That's when storms line up like boxcars on a railroad track and repeatedly go over the same spot, causing inches and inches of rain in narrow bands and creating intense flash floods.    
Colorado got into the act Monday. From@JermeyDanMoore
via Twitter, the aftermath of a hailstorm in Berthoud, Co.  

It's really hard to guess where, and even if, these training storms will set up much in advance, so I don't know where the worst flash flooding will be today.

The biggest potential for flash floods goes from Maine, through New Hampshire, into southern New England, southern New York State, and on down through New Jersey into the Mid-Atlantic states.

Those areas have already had a lot of rain. Which means the ground is soaked, and it won't take all that big a downpour to cause flash flooding

Further west in most of Vermont, especially the northwestern half, and in northern New York, there is a chance of flash flooding, but the rain might not be as intense. Plus, those areas haven't had as much rain over the past couple of months as points south and east so the chances of flooding aren't as great.

Finally, finally, the zone of heaviest rain with this weather pattern will shift off the coast tomorrow, and things will dry out. At least for now.

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