Updated 800am CT – Wednesday / 17 December 2014
…. Storm System Approaching with Increased Rain and Thunderstorm Chances ….
…. Drier Weather for the Weekend ….
On this Wednesday morning…. a cold front extends southeastward from a low pressure area over the eastern Great Lakes and the St. Lawrence River valley into the Atlantic Ocean then southwestward across central Florida where it changes into a stationary front through the central Gulf of Mexico and into northern Mexico well south of Brownsville. High pressure.. behind the front.. is over the northern Mississippi Valley southward into Louisiana and Mississippi. As a result of this surface weather pattern, our local surface winds are easterly.
In the upper levels of the atmosphere.. an upper level low pressure area is located over the southeastern Great Lakes. Another strong low pressure disturbance is over southern California with a trough.. or line.. of upper air low pressure extending south southeastward into Mexico. As a result, our upper air winds at about 18,500 feet are west southwesterly 35 to 45 mph.
Clouds and rain chances have returned as another upper level low pressure storm system approaches the area through the end of the week. As the system moves overhead, we’ll see a better chance of rain.. rain showers and thunderstorms over the coming days. As the system departs on Friday, another surface cold front will move through with a high pressure area once again building in with drier and more stable air with abundant sunshine by the weekend.
Longer range guidance has become less bullish regarding the next upper air low pressure storm system for early next week. As a result, we’ll see clouds and rain chances return by Monday with partial clearing due by Tuesday. This guidance still suggests some potential for colder air to arrive in the area after Christmas Day.
Regarding my forecast, my local forecast confidence: My forecast confidence is medium to high through Friday with rainfall timing and amounts being the question. My forecast confidence rises back to very high for Friday night through next weekend. For Monday and beyond next week, my forecast confidence is very low.
Have a good Wednesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel