Updated 930am CDT Thursday / 13 September 2012
… Good Rain Chances Into the Weekend …
… Beneficial General Rainfall of 1 to 2 Inches Likely Over the Next Few Days …
… Another Cold Front with Chance of Rain Next Tuesday …
On this Thursday… surface high pressure is over the eastern USA. A cold front is moving southeastward from eastern Oklahoma into north and southwestern Texas. As a result of this surface pattern, a southerly surface wind is prevailing across our area.
In the upper levels of the atmosphere, a upper high pressure ridge, acting like a lid on the atmosphere, has weakened over Texas as a trough. or line.. of upper air low pressure continues to move eastward along a line from the northern plains southwestward into New Mexico. As a result of this upper air wind flow, the upper level winds overhead have become more southwesterly and increased.
The cold front.. to our northwest.. will, in combination with the approaching upper air low pressure trough, move across the area through tomorrow and into the weekend. While the surface cold front will move through the area by early tomorrow, the trough.. or line.. of upper air low pressure will lag a bit behind the front with our clouds and rain chances are expected to linger more into the weekend than I thought over the last few days.
The latest computer and manual guidance continues to suggest a beneficial extended wet event. Scattered to numerous rain showers and thunderstorms are beginning now and will continue through tomorrow and tomorrow night into Saturday and Saturday night. NWS rainfall guidance is most recently suggesting that a general 1 to 2″ of rain will fall across our area with the passage of this dynamic weather system. Given the on going drought conditions, this rainfall will be very beneficial and will not create any major problems.
A weak area of surface high pressure will build into the area with slightly cooler and drier conditions as the cold front moves southeast of our area and washes out along the Texas coast by late Sunday. Southerly surface winds will return quickly to the area by late Sunday into Sunday night..
Another cold front will affect the area by next Tuesday midday into afternoon with another chance of rain showers and thunderstorms. Drier air and a little cooler temperatures will follow the passage of the front.
For Austin and south central Texas… tonight will see a cloudy sky with scattered to numerous rain showers and thunderstorms with lows in the 60s to near 70 with a south wind becoming westerly after midnight. For tomorrow, a cloudy sky with scattered to numerous rain showers and thunderstorms with highs in the 80s with a northerly wind.
Have a good Thursday night and Friday…
Meteorologist Troy Kimmel