Southern Plains’ Next Big Storm

It’s funny how the atmosphere works.  Data from the mid-and-upper atmosphere, as well as from the surface, are a privilege to have these days.  Understanding the dynamics and thermodynamics of the atmosphere is very important in what happens at the surface.  I decided not to forecast for the Rio Grande Valley for the next 3 days, mostly just to change things up.  This blog will be about then next winter storm in store for the Southern Plains between Tuesday morning through Wednesday night.

THE SETUP:

In order to get a sense of what will occur, we must look at what’s happening right now, on all levels of the atmosphere, up to the main event.

An area of low pressure at the surface, on the coast of British Columbia, Canada,  will be the main generator for this storm over the next 3 or 4 days.  This low is forecast to move south and east, and will be over MT and WY by Monday afternoon and evening.  There is also an arctic high, producing bitterly cold temperatures for Canada, that will drive southward into the Northern Plains and eventually the Central Plains by Tuesday afternoon and Southern Plains by Wednesday morning.

 

Figure 1. Surface map

A mid-level high (at 500mb), with a fairly amplified ridge over the western coast will stay put over the next few days.  This will allow the flow aloft to stay the same, until a shortwave trough digs south from Canada.  The Southern Plains will be near the base of a trough that develops from this shortwave around the time the surface low is in the area.  This will enhance lift, and increase chances of precipitation.

THE MAIN EVENT:

Focusing strictly on the Southern Plains, this event will start affecting the region beginning early Tuesday morning.

Moderate snow will begin falling in N.E. CO, W. KS, and S.W. NE by Tuesday morning as the temperature and pressure gradients become increasingly stronger.  The surface low will be enhanced from lee troughing as it moves southward along the foothills of the Rockies.

Figure 2. Surface map on Tuesday morning showing a strong pressure/temperature gradient.

By Tuesday evening, the surface low will begin to move southward.  The Panhandle of TX, N.E. NM, S.W. CO, KS, and N.W. OK will be receiving a moderate amount of snow, with some sleet and freezing drizzle possible in OK for the start, as the arctic high pressure quickly drops temperatures into the teens and 20s.

Wednesday looks to be like the most active day for this winter storm.  On Wednesday afternoon, an upper-level shortwave trough interacts with the surface low, intensifying the snowfall for Central OK, South-central OK, S.E. OK, N. TX, and N.E. TX.   There is also abundant divergence in the upper-levels and a nice area of max vorticity in N. TX at 500mb that will also help intensify snowfall for the area.  A well defined, straight jet streak at 250mb that points from S.E. OK toward the Northeast U.S. defines this area of divergences over N. TX and S. OK.  Models are a bit different as far as total amounts of snow right now, but it is possible for some parts of OK to receive up to 10″+ of snow!

Figure 3. Vorticity at 500mb predicted at 18Z Wed. (2/9/2011) from GFS. Notice the max in N. TX.

Figure 4. Probabilities of snowfall amounts >4 inches made by HPC 3 days out.

Figure 5. Forecast Sounding from 00Z GFS valid 12Z Wednesday.

By Wednesday night, with weak support aloft, this winter storm looks to be ending. However, some parts of LA have a possibility of seeing some freezing rain and drizzle by Wednesday night/Thursday morning.

CONCLUSION:

This winter storm may not throw a punch for 2/3 of the nation like that last one, but it will sure come darn close for the Southern Plains.  Central OK may receive up to 10″ of snow, and southeast OK could receive even more! These totals are subject to change, of course, but looking 3 days out, this will affect citizens all over the Southern Plains, especially OK and TX.  After just going through blizzard conditions from a winter system not even a week ago, yet another round awaits.  This is not only rare for the South, but virtually unheard of during La Niña.

About Brian

University of Oklahoma graduate with a degree in Meteorology. Follow me on Twitter: @WeatherInformer
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