Updated  130pm Thursday / 2 February 2012

…. Upper Air Low Pressure Storm System and Cold Front Late Friday / Friday Night ….
…. Rain and Thunderstorm Chances Increase by Late Tonight into Early Friday ….
…. Cooler Temperatures with Some Clearing Due by the Weekend ….

On this Thursday… a cold front extends west southwestward from northern Alabama into northern Louisiana where it becomes a stationary front and extends southwestward over south central Texas and then westward into southwest Texas. As a result of this surface pressure pattern, a light and variable or southerly surface wind is blowing across our area.

In the upper levels of the atmosphere… a deepening upper air low pressure disturbance is located over the four corners region. As a result of this pressure pattern, the upper air winds over our area of Texas are moderate southwesterly.

A weak cold front has slipped south of the Austin area in the early morning hours today. This front, however, is transitioning to a warm front which will move northward later today into tonight as the upper level low pressure area to the west approaches. A moist air mass will pick back up over the area in the wake of the warm front over our area. By later tonight into early Friday, low clouds along with patchy fog and drizzle is possible.

The second stronger cold front.. in combination with the strong upper air low pressure disturbance.. is due by later Friday through Friday night with scattered to numerous rain showers and thunderstorms. Rain chances will actually begin late tonight and peak Friday into Friday night before ending by sunrise on Saturday night. The latest guidance suggests that upwards of 1 inch rainfall expected.

Surface high pressure.. behind Friday’s cold front..  will move settle southward in the wake of the front with cooler temperatures area wide into the weekend into early next week with a mostly clear to partly cloudy sky being the main feature of our weekend weather.

My forecast confidence today through tomorrow and through tomorrow night is high to very high. My forecast confidence for the weekend through the first half of next week is medium (due to the possibility of more cloudiness and even slim rain chances as suggested by some models as weak upper air disturbances move west-to-east across the area).

For Austin and south central Texas… tonight will see low clouds picking up with some drizzle and fog picking up after midnight. Widely scattered rain showers and isolated thunderstorms are possible. Lows in the 60s with a southerly wind. For tomorrow, a mostly cloudy sky with an increasing chance of rain showers and thunderstorms. Highs in the 70s with southerly wind.

Have a good Thursday night and Friday…
Meteorologist Troy Kimmel