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A January Severe Weather Threat?

7 Jan 2013, 11:15 am

Interesting Early-Middle Of This Week


Hanford, CA Scud Clouds
Hanford, CA Scud Clouds


Above you can see the view from the town of Hanford, California.  Kind of an ominous-looking view, no?  Well – those are just scud clouds, thankfully, which are basically just garbage clouds ejected from a thunderstorm.  They can get wrapped around the outflow of a supercell thunderstorm, however, and hopefully we won’t see too much of that taking place in the next couple of days!

Here is the scenario:

A low pressure center looks to develop over northern Mexico and slide northward into southern Texas over the course of today and tomorrow.  With it will come more warmth, more humidity, and of course: more storm chances.  That may not be a good thing, though.  Some of these types of storms bring with them low-level rotation that could cause supercell thunderstorms, and possibly isolated tornadoes, to form.

Here is the setup, as seen via dewpoint temperatures.  We’ll start with the lack of storms for today, and a brief description of why:


NAM Dewpoints Tonight
NAM Dewpoints Tonight


Look closely at those oranges and yellows on the map.  You can see those right along the warm front (thicker red line drawn onto the map, with little red semi-circles).  Those represent 60 degree dewpoint temperatures.  That is kind of a threshold (it can vary, but this can work as a very basic rule of thumb) for thunderstorm/severe thunderstorm development.  One of the biggest ingredients for storms is moisture, so with dry air you won’t get storms.  You can see the little surge of moisture over the gulf in that picture above trying to build northward.

Well, it does.

Check out the following image, this a forecast for tomorrow evening’s dewpoint temperatures:


NAM Dewpoints Tomorrow
NAM Dewpoints Tomorrow


You can see in the image above that the moisture content has started to build back into the region.  Southern Texas and Louisiana have the largest influx of moisture, and coupled with the region of low pressure building a little bit northward you start to see a chance of thunderstorms building in.

Let’s continue onward.  This time we jump ahead to Wednesday evening’s dewpoints, along with low pressure location.


NAM Dewpoints Wednesday
NAM Dewpoints Wednesday


Notice that big surge of moisture – and if you look closely those winds as well coming in from the Southeast.  Starts to become an interesting set-up.  Not ideal for supercell thunderstorms, but with a limited amount of energy, but a decent amount of twisting in the bottom layers of the atmosphere – you definitely see an enhanced severe storm risk for Wednesday.

Storms are a concern – but rain is as well.  We could see some issues with flooding.  Here is the view of our RPM model’s 3-day rainfall forecast… Notice the highlighted area in eastern Texas:


3 Day Rainfall
3 Day Rainfall


Those purplish/pinkish shaded regions indicate a potential for anywhere from 5 inches of rainfall to closer to 8 or so inches!  Hopefully that doesn’t really happen and it becomes a bit more moderated, but it certainly looks to be a bit soggy, either way.

Also, as an aside… I tweeted that picture from above and got the following post via Facebook about the image:



Pretty cool, huh?  I didn’t even notice that resemblance in the picture!

Stay tuned these next couple of days!

WeatherNation Meteorologist Aaron Shaffer @ashafferWNTV

One response to “A January Severe Weather Threat?

  1. Our local weatherman says we’re in for some cold arctic air on or around the 18th of this month. A warm-up is forecast this week with highs in the 40s by Saturday, but he’s predicting the bottom dropping out and we could be in for wind chills at -30 to -35 degrees. Snow is likely, but he’s thinking it will be to the east of us, namely Ohio. (I’m from northwest Illinois near Davenport, IA.) On his FB posts, he’s saying Accuweather is starting to predict this, too. Not everyone is jumping on board. What’s your take? Please tell me he’s wrong.

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