Updated  Friday / 17 February 2012

…. Clouds and Rain Chances Continues as Major Storm System Moves Across Area ….
…. NWS Issued Flash Flood Watch Along and East of IH35 Corridor ….
…. Clouds Break Late Saturday Into Sunday; Clouds Pick Up Again Next Week ….

On this Friday… a stationary front extends from northern Florida westward through the northern Gulf of Mexico into south Texas between Corpus Christi and Brownsville.  Surface high pressure area is located over western Kentucky. As a result of this surface pressure pattern, a east northeasterly surface wind is blowing across our area.

In the upper levels of the atmosphere… a deep trough.. or line.. of upper air low pressure is located over the southwestern USA and northern Mexico with the center of the upper air low over extreme northern Mexico just south of the southwestern corner of New Mexico and southeastern corner of Arizona. Within this broad low pressure counterclockwise circulation, disturbances are rotating (like spokes on a bicycle wheel) northeastward through Texas. As a result of this pressure pattern, the upper air winds are strong southwesterly across Texas and our local area.

Over the next 24 hours, the main upper air low pressure storm system will move east northeastward overhead of our local area. The cold front, that came through the area on Wednesday afternoon and is over the northwestern Gulf of Mexico now, will try to return into the area in advance of the upper air storm system but will not make it this far northward. However, abundant moisture is streaming northward from the Gulf and northeastward from the Pacific Ocean and is “overrunning” the cooler air at the surface over our area. The passing upper air disturbance will trigger the development of a surface low and cold front well to our southeast in the vicinity of the old frontal boundary over south Texas and the northwestern Gulf of Mexico. Between now and Saturday morning, the heaviest rain and strongest thunderstorms will be to our southeast down mainly along and southeast of the IH10 corridor. Nevertheless, beneficial rains will fall across our area with rainfall generally an inch or less over the hill country… 1 to 2 inches along the IH35 corridor and 2 or more inches in our southeastern most areas.

As that surface low moves eastward across the northern Gulf (and away from us), high pressure will build into the area from the north and rain chances will drop and a more stable atmosphere will return by late Saturday through Sunday. As a result, sunshine will increase as we wrap up the weekend.

Clouds will increase again as yet another weather system.. in a progressive (quick moving) series of disturbances.. affects Texas by late Monday and Tuesday. Rain chances look limited at this point. A cold front will swiftly sweep through our area in the wake of the upper air disturbance on Tuesday.

High pressure will settle southeastward into the area with a dry and stable weather pattern for the middle into the latter part of next week.

My forecast confidence through this weekend is still high to very high. My confidence for the forecast for early next week is medium (with rain chances/cold frontal passage time being issues) with my forecast confidence rising back to high for Wednesday and Thursday next week.

For Austin and south central Texas… tonight will see rain showers and thunderstorms with heavy rain possible mainly in areas to our southeast. Lows in the 50s with a northeasterly wind. For tomorrow, rain showers and thunderstorms in the morning will decrease by afternoon. Highs in the 50s to near 60 with a northerly wind.

Have a good Friday night and Saturday…
Meteorologist Troy Kimmel