Updated 800am CT – Thursday / 09 October 2014
…. South Southeasterly Surface Winds Continue with Higher Humidity ….
…. A More Unsettled Air Mass Friday through the Weekend As a Weak Cold Front Moves In ….
…. A Strong Cold Front Sweeps Across Texas Early Monday ….
On this Thursday morning…. a trough.. or line.. of surface low pressure extends southward from a low pressure area over southeastern Colorado into eastern New Mexico and southwest Texas. High pressure.. to our east.. is located over the eastern USA. As a result of this surface weather pattern, our local surface winds are southerly.
In the upper levels of the atmosphere… a broad and deep trough of low pressure is situated southward from Hudson Bay through the northeastern USA. A eastward moving upper air low pressure disturbance is over Arizona. Upper level high pressure.. acting like a lid on the atmosphere.. extends from northern Mexico across south Texas and the western Gulf of Mexico. As a result of this pattern, the upper level winds over south central Texas and the Austin metro area, about 18,000 feet above the ground, are westerly less than 20 mph.
Low level moisture has increased across our area of Texas; at the same time, the atmosphere has become a bit more unstable. This is evidenced by patchy light rain and drizzle from the northward moving low level cloud deck this morning.
By tomorrow through the weekend.. some remnant mid and upper air moisture from the Pacific Ocean will combine with available atmospheric instability.. low level gulf moisture as well as the approaching upper level low pressure disturbance to give us increased rain shower and thunderstorm chances. Current indications are that we would see widely scattered to scattered precipitation. With the upper air disturbance approaching, a surface cold front will try to move down into the area by late Saturday into Saturday night with it getting into our area before washing out and returning back northward as a warm front by late Saturday night into early Sunday.
By late Sunday into Monday, as the main part of the upper air disturbance moves across Texas, a strong cold front will surge southeastward through Texas with perhaps the best rain shower and thunderstorm chances of the seven day forecast. Guidance suggests that the cold front will arrive in our local area sometime between 5am and 9am Monday. Drier.. much drier and slightly cooler air will overtake the state of Texas.
The latest rainfall guidance from the NWS suggests that we will see upwards to 1/2 to 1 inch of rain between now and Tuesday.
Regarding my forecast, my local forecast confidence: My forecast confidence is high to very high today. By Friday into the weekend and Monday, my confidence falls to medium in regards to precipitation occurrence and timing, precipitation amounts as well as the timing of the cold front early next week.
Have a good Thursday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel