Updated 930am CDT Wednesday / 26 September 2012
A Dry and Stable Weather Pattern Continues For Now …
More Unsettled with Increased Clouds/Rain Chances Late Week and Weekend …
Heavier.. Beneficial Rainfall Due Later Friday through Saturday …
On this Wednesday… a high pressure area is located over the southeastern USA and another over the southern Rockies. A low pressure area is over south southwestern Kansas with a trough.. or line.. of low surface pressure southwestward fro the surface low into west Texas and eastern New Mexico. As a result of this surface pattern, a southerly surface wind prevails across our area.
In the upper levels of the atmosphere, the ridge of upper air high pressure that has been overhead is being suppressed to the south of the area now with an east southeastward upper level low pressure area over eastern Utah. As a result of this upper air wind flow, our upper level winds are light to moderate westerly.
Southerly surface winds continue across our area with patchy fog and morning low cloudiness and patchy fog prevailing with an otherwise partly cloudy sky. This pattern will continue through tomorrow and tomorrow night.
By Friday, the upper air low pressure disturbance.. to our northwest.. will slowly pass from west to east to our north and will combine with available moisture (including tropical moisture from the Pacific Ocean) to produce increased clouds and widely scattered to scattered rain showers and thunderstorms.. particularly Friday night into Saturday.. as it creates atmospheric lift overhead. Due to the slow forward movement of the system, current guidance is now suggesting a heavier and more beneficial rainfall with upwards of 1 to 3 inches of rain for the late Friday and Friday night through Sunday morning time frame.
As the upper air low pressure disturbance passes, a weak surface cold front will slowly pass through the area during the day on Saturday. By Sunday and Sunday night into early next week, a slightly cooler and drier air mass will take hold in a more stable airmass.
For Austin and south central Texas… tonight will see a partly cloudy sky with low clouds developing after 10pm. Lows in the in the 70s with a south southeasterly wind. For tomorrow, it’ll be partly cloudy after some morning low clouds and patchy fog with highs around 90 with a southerly wind.
Have a good Wednesday night and Thursday…
Meteorologist Troy Kimmel