Thursday, February 3, 2011

Update on Potential Texas Snow Event

The National Weather Service has converted the Winter Storm Watch for the I-35 Coridor (Austin to San Antonio) to a Winter Weather Advisory (light purple shading on the map above).  The valid time of this evening through Friday morning remains unchanged.  Meanwhile, a Winter Storm Warning is in effect for much of deep South and Southeast Texas, including the Houston, Corpus Christi and Brownsville areas (pink shading on the map above).

Based on the latest observations and computer model data, it looks to me like the I-35 corridor from San Antonio to Austin can expect 1-2 inches of snow tonight and tomorrow morning.  Areas East of I-35 could see 2-3 inches with localized amounts near 4 inches (nearer to the Gulf moisture).

The above matches up pretty well with the HPC computer generated probabilities of 1 inch of snow:

and 2 inches of snow:

One of the problems we often have with winter storms and snow potential here in South Texas is that the ground is typically too warm to allow for significant accumulation.  That won't be the case in this particular event.  The arctic blast that moved through the region Monday night has kept temperatures at or below freezing much of the week, and the top layer of the ground has cooled accordingly.  This will allow for greater potential of snow accumulation across the region.

Along the coast, including the Houston area and Corpus Christi, the event may begin as sleet and/or freezing rain this afternoon or evening, with some ice accumulation possible.

The storm system that will be responsible for the precipitation is turning Northeast across Mexico this morning.  Flurries or very light snow will begin across south Texas later this afternoon, and increase overnight into early Friday morning.  According to the model guidance, the best chance of accumulating snow would take place between 3am and 6am CST near the I-35 corridor, then between 6am CST and Noon further East.

We'll continue to monitor the system as it progresses today and post updates as warranted.

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