Sunday, October 25, 2015

Texas Flooding Again After Drought, Flood And Other Drought - Weather Whiplash

This train was derailed by flash flooding near Corsicana, Texas
over the weekend.  
You might have seen on the news Texas is drowning again.

It's been raining hard for the past couple of days in much of the state, and things just kept intensifying during the day Saturday.

A strong trough of low pressure is moving into that area, and there's a big feed of intense moisture coming off the Gulf of Mexico.  That's producing coastal waterspouts, a few tornadoes and southeast Texas, but most importantly, TONS of rain.

Just as importantly, the remnants of Hurricane Patricia moved into northern Mexico, then on out into the Gulf of Mexico, where it has generated a new non-tropical storm.

That low pressure around Texas is tapping into that deep moisture from Patricia's detritus to produce the flash flooding and storms in Texas.

Already, as of early Saturday afternoon, up to 20 inches of rain had drowned an area southeast of Dallas, especially near the community of Corsicana, which was inundated.

This has caused all kinds of intense problems, such as numerous water rescues, a freight train that was washed off the tracks, derailing 46 cars, and prompting flash flood warnings through huge sections of the state.

Another foot or more of rain is expected, especially in the southeastern half of the state. And on into Louisiana. That's going to lead to big trouble.

This storm is yet another example of the kind of extremely heavy rain storms that keep plaguing different parts of the United States and much of the rest of the world. (Remember South Carolina a couple weeks ago?)

This Texas flood is also another example of "weather whiplash" in which conditions go from one extreme to the other. This is also getting more common.

You might remember up until early this year, Texas was in the throes of an intense drought. Towns were running out of water, crops dried up, and wildfires broke out.

Then in May intense rains hit Texas, pretty much erasing most of the drought in just a few days. These torrential rains also caused disastrous flash floods. At least 11 people died in the flooding, and Texas had its wettest month on record.

Just as suddenly, the rain abruptly stopped in early June, and it pretty much didn't rain there again until the past few days.

Crops were dying again. Earlier this month, brush and forest fires consumed at least 64 buildings  outside of Austin, in the Bastrop County pines.

Now the rains are back, big time, and so are the floods.  The same areas of Bastrop County that had devastating fires less than two weeks ago were inundated with flash floods So were large areas of central and southern Texas over the weekend.
Motorists unwisely drive into Dallas floodwaters Friday
The vehicle on the right unsurprisingly stalled.  

The torrential rain was moving into Lousiana Sunday, where flood alerts were in effect.

This year's yo-yo weather in Texas is a pretty dramatic example of weather whiplash, which seems to have become more common.

Scientists are increasingly convinced that global warming is leading to more instances of weather whiplash. 

The thought goes like this: The Arctic is warming up faster than the tropics with global warming. That means the constrast in temperature between the two regions is less. The diminished temperature contrast allows the jet stream to meander in bigger dips toward the midlatitudes, and bigger ridges up toward the Arctic.

The bigger troughs and ridges in the jet stream allows for larger storms, bigger and more intense heat waves and sometimes stronger cold waves.

Plus, these big dips and ridges and such in the jet stream are showing an increasing tendency to "get stuck" in place, prolonging things like intense rains or big heat waves or a series of snowstorms in a particular geographic location.

The translation: Places like Texas get stuck for months in unrelenting drought, then get stuck for days or weeks in torrential rains. South Carolina was in a fairly nasty drought just before the devastating floods a couple weeks ago.

This, of course isn't just happening in Texas. It's happening pretty much everywhere.

Although I get a little leery about pinning a single weather event on global warming, examples of these stuck jet stream patterns resulted in California's brutal drought, the intense winter onslaught of snow and cold in the northeastern United States and southeastern Canada last winter, and the parade of devastating storms in Britain during the winter of 2013-14.

It's impossible to know weeks in advance where exactly these huge stuck jet stream dips and northward bulges will set up. And it's hard to know when weather whiplash will set in. California is a prime candidate for whiplash this winter, as El Nino is widely expected to bring heavy rain and storms to the Golden State in the upcoming months.

But if a number of climate scientists are right, weather whiplash will become more and more the "new normal" for most of us.  

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