Sunday, December 18, 2011

Update on Major Christmas Week Storm...

The latest water vapor satellite image above shows the center of a strong area of low pressure in the middle and upper-levels of the atmosphere near the California/Mexico border this morning.  This system is forecast to lift out toward the  East/Northeast over the next 24-48 hours, and will bring a variety of weather conditions to the southern and central Plains...and beyond.

A variety of watches and/or warnings are already in effect for portions of the southwest, southern and central Plains ahead of this system for tonight (Western end) into Monday night and/or Tuesday (eastern end):

The greatest threat to the Blizzard and Winter Storm Watch areas above will come on Monday into Monday night the way it appears right now.  Residents inside of the green Blizzard Watch areas will have the highest combination of heavy snow and strong, gusty winds, which are likely to result in white-out to near white-out conditions at times on Monday afternoon, evening and into Monday Night.  Travel is highly discouraged in these areas.

The latest run of the GFS computer forecast model is calling for a bullseye of 5-7 inch snowfall by 6pm CST on Monday over the Oklahoma and extreme northern Texas panhandle:

Here is the same model projection valid at 6am CST on Tuesday morning.  By this time, the model is forecasting a widespread swath of 9-12 inch snow depth from the extreme northern Texas panhandle across most of the Oklahoma panhandle, extreme southeast Colorado and much of southwestern Kansas:

The system is currently forecast to undergo significant weakening once it tracks into the Midwest on Tuesday and Wednesday.  Accumulating snow is likely from southern and eastern Iowa into at least portions of central and northern Illinois, however at this time the models are suggesting that amounts will average less than 2 inches in most of this region.  Here is the GFS computer model snow depth forecast valid 6pm CST on Tuesday, which illustrates what I was just describing (inside the red circled region on the image):

Folks living in the red circled region on the above image will want to monitor the progress of the system over the next few days should any change in track and/or intensity become apparent.  We should know more about this aspect of the system on Monday.

Meanwhile, out ahead of the system where temperatures will remain above freezing, a widespread heavy rain event still appears likely on Monday and into at least early Tuesday.  Localized amounts of 2-4 inches of rain will be possible, especially in and near the purple and lighter blue shaded areas on the image below:

Some of the thunderstorms that form across central and eastern Texas on Monday afternoon or evening may become strong to locally severe.  This threat will be greatest in southcentral and southeastern portions of the state, including the Austin/San Antonio Metro areas, as well as Houston later into Monday evening or night.

Hail up to 1 inch diameter and strong, possibly damaging wind gusts will be the primary threats with any severe thunderstorms that form in the above areas on Monday.  An isolated tornado also cannot be ruled out.

If you live in the areas forecast to be impacted by winter weather, rain, or severe weather early this week, please remain alert and monitor local media and other trusted sources for the latest forecasts, statements, watches and warnings regarding the upcoming storm system.

If you enjoy reading 'The Original Weather Blog', please be sure to "like" our facebook page!

No comments: