Updated  130pm CDT Monday / 2 April 2012

…. Overnight Weather System Temporarily Stabilizes the Atmosphere ….
…. Upper Level Low Pressure Storm and Rain Chances Still On Tonight into Tuesday …
…. Storm System Passes by Mid Week With Sunshine Returning by Late Week ….

On this Monday… a large area of surface low pressure cover the central and southern US plains states. A cold front extends southward from a surface low over southeastern South Dakota southwestward to another surface low over the Texas and Oklahoma panhandles southward into southwest Texas and the Big Bend region. High pressure is over Florida and the eastern Gulf of Mexico. As a result, a southerly surface wind is blowing across our area of Texas.

In the upper levels of the atmosphere, a strong closed area of upper level low pressure is moving slowly east southeastward over the New Mexico/Arizona border region. As a result of the upper air wind flow, upper level winds are southwesterly across our area of Texas.

A passing upper level disturbance.. to our south.. has temporarily left our air mass more stable and, as a result, we’re seeing a lot more sunshine today than I thought we would.
With the southerly surface wind continuing across our area, abundant moisture continues to flow northward with late night and early morning low cloudiness.

As the upper level low out west moves east southeastward and then turns more northeasterly into west Texas over the next 24 hours, our atmosphere will quickly become increasingly unstable and dynamic atmospheric lift will increase as upper air disturbances move through the area in the broad counterclockwise flow around the upper air low.

Scattered rain showers and thunderstorms will develop and move into the area by later tonight and continue through Tuesday before decreasing quickly tomorrow evening. Although the strongest storms will likely remain north of our area.. some of the stronger thunderstorms could be borderline severe with larger hail and strong straightline thunderstorm wind gusts being the main threats. At this point, given the expected relatively fast forward motion of thunderstorms, flooding should not be a problem with NWS national rainfall amount guidance showing between 1/4 and 3/4 inch locally through tomorrow evening.

As the upper level low moves northeastward by mid and late week, a weak cold front will drop southeastward across the area by midday tomorrow. In its wake, a drier and more stable weather pattern with decreased clouds and rain chances is expected Wednesday through late week and into next weekend.

My forecast confidence over the next seven days is high to very high.

For Austin and south central Texas… tonight will see scattered rain showers and thunderstorms develop. Lows in the 60s to near 70. Southerly wind will prevail. For  tomorrow, it’ll be cloudy with scattered rain showers and thunderstorms decreasing by late in the day. Highs in the 80s with south southwesterly winds continuing.

Have a good Monday night and Tuesday…
Meteorologist Troy Kimmel