Monday, December 27, 2010

New Year's Eve Storm Update

Right now, it is COLD outside, but that will be changing. Warm air will start moving in from the south and as that warm air moves over the cold air, we will start seeing rain develop on Wednesday. I think we will warm up enough for it to be all rain, but I can't rule out some BRIEF sleet at the onset Tuesday night into Wednesday morning. The bulk of this type of rain (overruning rain) will fall on Wednesday, although showers are still in the forecast for Thursday as warm air continues to move in from the south. At this point, I'm eyeballing Friday. It's a big day for people. Many will be heading out to New Year's Eve Parties and the weather will impact your day and night... whether it is severe or not. So, let's talk about it.

First, the temperatures are going to be warm! Look at the map for midday on Friday:
The "circle" in the northern part of Missouri is the surface LOW. It has a counter-clockwise spin and typically draws in warm air, ahead of the low at the surface. In the map above the 12Z GFS has the mid 60s into Arkansas and I believe that if we see some breaks in the clouds, 70s will be possible in the state. In addition, the dewpoints appear to be in the 55-65 range. Typically, we need dewpoints over 55 to have the "juice" to support strong storms. This appears to be in place on Friday.

Now, let's talk about other variables. We appear to have some upper-level support and shear to support  strong storms, but overall instability could be lacking. Below is the CAPE map. More or less, this is the fuel to get the storms to build:
Notice, the greatest instability is down to our south. I'm not saying this is not enough to spark some strong storms, but the greatest CAPE stays well south it appears by the GFS... and other models. There is a chance that the GFS is not playing this up as high as it could go, but we'll watch it.

This next map is the lifted index map. Pretty much, thunder/lightning is possible in areas with negative numbers (colored areas). It's not that cut and dry, but it's a good starting point. Notice, we do run the risk of at least hearing some thunder from nature's own New Year's Eve Fireworks!
Models are not agreeing on what happens after this storm system, but I think most of the precipitation is gone by New Year's Day. We'll see though...

Maps provided by my friends at

Stay tuned,

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