Updated 935am Wednesday / 7 March 2012
…. Clouds Continue As Upper Level Low Pressure Approaches from the West ….
…. Rain Showers and Thunderstorms Due Thursday into Friday and Friday Night ….
…. 1 to 3 Inches of Rain Still Possible Mid/Late Week into the Weekend ….
On this Wednesday… surface high pressure is situated off the east coast of the USA with a deepening trough.. or line.. of surface low pressure.. and an associated cold front.. extending southward from Minnesota into Colorado and the desert southwest. As a result of this surface pressure pattern, a southerly 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 from the northern plains into the desert southwest with a closed area of low pressure over southern Nevada and western Arizona. As a result of this pressure pattern, the upper air winds are moderate to strong southwesterly across Texas.
Clouds continue as a strong southerly surface wind flow continues. We’ve seen.. as expected.. some patchy light rain and rain showers today.
As the upper level low continues to approaches us from the west and an associated cold front also approaches the area by late tomorrow night, atmospheric lift and instability is already increasing. As a result, rain shower and thunderstorm chances will be increasing by over the next 12 to 24 hours. While the threat of severe weather for us looks limited (and more to the areas to our north and northeast), current forecast guidance suggests one to three inches of rain (with some isolated heavier totals to our northeast) could fall locally before the cold front moves east of the area and washes out over the weekend and precipitation chances begin to taper off.
A drier and more stable weather pattern will develop by later Sunday into Sunday night with partial clearing expected to continue into the new week.
My forecast confidence through the remainder of the week and through next weekend is medium with rain timing/chances and the exact timing of the cold front tomorrow night contributing to the forecast uncertainty.
For Austin and south central Texas… tonight will see a mostly cloudy sky with widely scattered to scattered rain showers. Low 60s. For tomorrow, a cloudy sky with scattered rain showers and a few thunderstorms by afternoon. Highs in the 70s. Southerly winds will continue over the next 24 hours.
Have a good Wednesday night and Thursday…
Meteorologist Troy Kimmel