Updated 800am CT – Wednesday / 3 September 2014
…. Slim Rain Chances Today with Little Change in Our Local Weather Pattern ….
…. Tropical Cyclone Dolly Ashore and Weakening over Eastern Mexico ….
On this Wednesday morning…. high pressure is centered over the lower Mississippi valley and the southeastern USA with a low pressure trough over west Texas. Weakening tropical cyclone Dolly continues to move further ashore onto the east coast of Mexico well south of Brownsville. As a result of this surface weather pattern, our local surface winds are east southeasterly.
In the upper levels of the atmosphere… a rather zonal.. that is, west to east.. upper level wind pattern continues over the northern and central USA with an upper air low pressure disturbance moving through the westerly wind flow over eastern Washington. Upper level high pressure.. acting like a lid on the atmosphere.. covers the southern USA from Georgia westward across Texas and then into the southwestern USA. 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 relatively light and variable at 10 to 20 mph.
Tropical cyclone Dolly has moved ashore overnight into eastern Mexico. The upper level high pressure area, over the southern USA, continues to steer this tropical system westward into the mountains of Mexico. The system continues to be far enough south of the area.. and the upper level high pressure above us is strong enough.. that there will be minimal effects locally.
Meanwhile, afternoon heat will combine with available low level moisture and limited atmospheric instability (the upper level high above is very stable!!) to give us isolated to widely scattered afternoon and early evening rain showers and thunderstorms over the area this afternoon into this evening.
For the balance of the seven day forecast period.. tomorrow into early next week.. it looks dry with a typical summer weather pattern prevailing. A cold front is forecast is move southward into north Texas by Saturday into Sunday but the front is expected, at this point, to remain north of our local area.
Regarding my forecast, my local forecast confidence: My forecast confidence is high through tonight (reference any precipitation timing and amounts)… then high to very high tomorrow (I’m a little concerned I may have to add minimal afternoon rain chances). Thursday night and beyond in the seven day forecast period, my confidence is very high.
Have a good Wednesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel