Updated 845am CDT Tuesday / 29 October 2013
…. A Moist Air Mass in Place Across the Area ….
…. A Strong Upper Air Storm System / Cold Front to Move Overhead ….
…. A Round of Rain Showers and Thunderstorms as System Passes ….
On this Tuesday morning…. a surface high pressure area is over the southeastern USA with a cold front extending westward from the Ohio Valley into Kansas southward into the Texas panhandle then northwestward into Colorado. A trough.. or line.. of low pressure extends south southwestward from a surface low along the cold front over northwestern Texas into southwest Texas. As a result of this surface weather pattern, surface winds are south southeasterly across our area.
In the upper levels of the atmosphere… a eastward moving strong upper level low pressure area is over northeastern Nevada. As a result, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are southwesterly at 30 to 40 mph.
A warmer than normal moist weather pattern continues across south central Texas as a south southeasterly surface wind persists across the area.
As the upper low out west moves eastward by tonight into tomorrow, the inflow of moisture from the south and southeast is increasing as is atmospheric instability and lift. As a result, we’ll see rain shower and thunderstorm chances increase by late tonight and especially later tomorrow into tomorrow night and Thursday. Some periods of heavier rain are possible.. especially Wednesday night into Thursday.. as the upper air system, moves by to our distant north. Current NWS guidance suggests than upwards of 1 to 3 inches of rain could fall over our area tomorrow into early Thursday.. isolated heavier totals are certainly possible.
As the upper system passes, an associated cold front will be allowed to drop through the area by late Thursday afternoon into Thursday night (slightly delayed from yesterdays forecast) with high pressure.. cooler and drier air.. and clearing skies taking hold late week through the weekend.
Regarding my forecast, my local forecast confidence: High forecast confidence through Thursday (some break in the clouds and exact timing of rain chances being the confidence reducing factors) then very high confidence for Thursday night and Friday through the weekend.
Have a good Tuesday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel