Updated  930am CDT Wednesday / 28 March 2012

…. Better Chances of Rain Showers and Thunderstorms Beginning Tomorrow ….
…. More Clouds with Limited Sunshine Over the Day or So ….
…. A Cold Front Due on Monday with a Chance of Rain Showers / Thunderstorms  ….

On this Wednesday… a broad area of surface low pressure is over the western parts of the south central states with a trough.. or line.. of surface low pressure extending southward from a low pressure area over the northern Texas and Oklahoma panhandles into southwest Texas. A cold front extends from eastern Kansas into the low pressure area then westward into northeastern New Mexico and southern Colorado. Surface high pressure area is off the southeastern USA coast over the western Atlantic Ocean. As a result, a southerly surface wind is blowing across our area of Texas.

In the upper levels of the atmosphere, a rather broad counterclockwise rotating upper level trough.. or line.. of upper air low pressure  is located along the western coast of the USA. Within the flow aloft, upper air disturbances are over the Rio Grande plains of Texas (near Del Rio) with another stronger disturbance over the Baja Peninsula and adjacent eastern Pacific Ocean areas. As a result of the upper air wind flow, upper level winds are west southwesterly across our area of Texas.

With the south southeasterly surface wind across our area, abundant moisture has returned to the area. Clouds will keep sunshine more limited over the next few days.

The upper air disturbance.. currently over the Baja Peninsula.. will approach the area by tomorrow into Friday resulting in scattered rain showers and thunderstorms. The main rain chances appear late in the afternoon Thursday into Thursday night and into the predawn hours Friday. Current NWS rainfall guidance suggests that upwards of 1/2 to 1 inch of rain could fall across parts of the area especially in westernmost areas (hill country areas).

Once the upper air disturbances weakens and moves out of the area, a more stable weather pattern will return by the weekend with rain chances dropping from the forecast with much more sunshine expected.

A southeastward moving cold front is forecast into the area by early Monday. The front will pass through the area with widely scattered to scattered rain showers and thunderstorms and partial clearing and slightly cooler temperatures Monday night into Tuesday.

My forecast confidence over the next couple of days is medium to high with the timing of rain chances for Thursday and Friday being the primary consideration. My confidence will increase again to high to very high for the weekend. By early next week, my forecast confidence decreases again to medium with the cold front on Monday.

For Austin and south central Texas… tonight will see a cloudy sky. Lows in the 60s. Southerly wind will prevail. For  tomorrow, a mostly cloudy sky will prevail with scattered rain showers and thunderstorms. Highs in the 70s to near 80 with southerly winds.

Have a good Wednesday night and Thursday…
Meteorologist Troy Kimmel