Updated 915am CT – Wednesday / 29 July 2015
.. A Dry and Stable Weather Pattern Continues ..
.. Rain and Thunderstorm Chances Continue for Friday and Saturday ..
On this Wednesday…. a trough.. or line.. of low pressure extends southwestward from a surface low over northern Oklahoma and southern Kansas into southwest Texas. Within this trough.. a cold front extends southwestward from southern Kansas into northwest Texas /west of Wichita Falls/ to near Midland then west southwestward to south of El Paso. Surface high pressure is over the Gulf of Mexico. As a result of this surface weather pattern, our local surface winds are southerly.
In the upper levels of the atmosphere.. an upper level high pressure area.. acting like a “lid” on the atmosphere.. is centered from New Mexico eastward into Texas. An upper level low pressure trough extends southwestward from Canada /south southwest of Hudson Bay/ into Minnesota. As a result, our upper air winds at about 18,500 feet, are light and variable.
As we’ve seen over the last few weeks, a typical summer weather pattern continues with a moist and tropical air mass holding across the area.
The upper level high pressure area will continue overhead of our area through tomorrow with high temperatures near 100 degrees along the IH35 corridor.
By late tomorrow night and into the upcoming weekend, the upper level high pressure.. and the “lid” effect it has on the atmosphere.. will retreat westward more over the southwestern USA and the four corners region. As this occurs and we find ourselves east of the high pressure area, we’ll see a more pronounced northerly wind aloft along with a slightly more unstable atmosphere. A weakening cold front.. supported by this more northerly wind aloft.. will move southeastward into northern Texas before pulling up stationary just to the north and northeast of the Austin area. Given the forecast instability as well as increased low level moisture, I will call for widely scattered rain showers and thunderstorms for the Friday through the weekend time period. With the increased cloud cover, daytime high temperatures will be down a few degrees as well.
Beyond the weekend, upper level high pressure appears to rebuild over the area with rain chances dropping from the forecast.
Have a good Wednesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel