Updated 845am CDT Wednesday / 11 September 2013
…. Slim Thunderstorm Chances Linger Through This Afternoon and Evening ….
…. An Otherwise Typical Late Summer Weather Pattern Continues ….
…. Watching Disturbed Tropical Weather over the Yucatan Peninsula ….
On this Wednesday morning…. surface high pressure continues over the southeastern USA with another high pressure area is to our distant west northwest over the Great Salt Lake basin. A trough.. or line.. low pressure area extends from south southeastern Colorado into eastern New Mexico. As a result of this surface weather pattern, surface winds are south southeasterly over our area.
In the upper levels of the atmosphere… a strong upper level high pressure area has continued to settle southward into the Tennessee Valley region. Being on the south southwest side of the upper air high, winds over south central Texas and the Austin metro area about 18,000 feet above the ground are southeasterly 10 to 20 mph.
Atmospheric moisture will continue today to combine with daytime heating and atmospheric instability to produce isolated to widely scattered rain shower and thunderstorm development. Frequent cloud to ground lightning and gusty winds may accompany the thunderstorms that do develop.
By tomorrow into the weekend, I expect that the upper level high pressure area will build back into our area with increased sunshine and rain chances dropping from the forecast. Temperatures will continue to be at or above average.
By Sunday into next week, a slightly more unstable air mass will move northwestward into Texas from the Gulf of Mexico and I will introduce a very slim rain chance beginning Sunday. These local rain chances will be tied to the development and future movement of the developing tropical system over the Yucatan Peninsula. According to meteorologists at the NWS/National Hurricane Center, there is a fairly high chance that a tropical cyclone (the next name on the list.. Ingrid) will develop over the southwestern and western Gulf of Mexico by Friday and the weekend. I continue to think that anything that does ultimately develop will be steered more westward toward Mexico than northwestward toward Texas and, as a result, I am not going overboard on the rain chances and any effects locally.
Regarding my forecast, my local forecast confidence: High to very high forecast confidence through Saturday.. then a low to medium confidence Sunday into next week with the developing tropical cyclone (its future movement and intensity) over the Gulf throwing much uncertainty into my forecast.
Have a good Wednesday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel