605pm CT – Sunday / 8 January 2012

…. Upper Level Low Pressure Storm System Poised to Move Across Texas ….
…. Beneficial Rainfall Event Expected over the Next 36 Hours ….

On this Sunday evening, a strong eastward moving upper air low pressure storm system is located
over northern Mexico.. southeastern Arizona and southwestern New Mexico west of El Paso. You
can see this system clearly by examining water vapor satellite imagery through this link:
http://www.atmo.arizona.edu/products/wximagery/500mbwv.html

As the system approaches, abundant atmospheric moisture has moved into place across Texas.
It should be noted that a warm front is situated in the Texas coastal plains with gulf moisture riding
back northwestward over the front in a typical overrunning pattern. With the upper air low pressure
storm system slated to move from west to east overhead later tonight into Monday,  I expect
widespread rain.. rain showers and even isolated thunderstorms across the area. Given the colder
vertical temperature profile of the passing upper level low, some small hail could fall from the stronger
thunderstorms late tonight through tomorrow.

Current NWS rainfall guidance suggests, in general, one to two inches of rain across the area over
the next 36 hours or so. This will be a very beneficial rainfall event with very limited, mainly urban and
street flooding, impacts expected. NWS rainfall forecast data (1 to 5 day forecast) can be found at:
http://www.hpc.ncep.noaa.gov/medr/95ewbg.gif

The upper level low pressure system will complete its move across the area by later tomorrow night with
rain chances decreasing. Skies will rapidly clear by sunrise into midday on Tuesday.

Please note that we are expecting a stronger cold frontal passage.. no precipitation expected.. in the
early morning hours (predawn) on Thursday. Outlying areas will likely see overnight freezes later this
week as colder surface high pressure builds into Texas from the Rockies.

Have a good week ahead,
Troy