Updated 915am CT – Tuesday / 17 March 2015
.. First of Two Upper Air Low Pressure Storm Systems Crosses Tonight ..
.. Second Weather System Passes Late Thursday into Saturday ..
.. Rain and Thunderstorm Chances on the Increase ..
.. Two or More Inches of Rainfall Possible ..
On this Tuesday morning…. surface high pressure is located over the northwestern Gulf of Mexico and south Texas. A southeastward moving cold front extends from eastern Missouri into northwestern Oklahoma and northern Texas panhandle then northwestward into northeastern New Mexico and central Colorado. As a result of this surface weather pattern, our local surface winds are light southerly.
In the upper levels of the atmosphere.. a ridge.. or line.. of upper air high pressure extends north northwestward from the Gulf of Mexico northward into western Louisiana. A strong upper level low pressure disturbance is over western Mexico. As a result, our upper air winds at about 18,500 feet are south southwesterly at 15 to 25 mph.
The upper level low pressure area.. over western Mexico.. is already creating a more moist and slightly more unstable air mass with precipitation spreading northeastward across the Rio Grande River at mid morning.
The upper air disturbance will move across the area by tonight into tomorrow producing dynamic atmospheric lift and will result in excellent chances of rain and thunderstorms later today into tonight and tomorrow. The latest manual and computer guidance continues the high rain chances with the latest NWS forecast rainfall amounts locally are showing around 1 1/2 inches, I would not be surprised with isolated heavier amounts.
Another strong upper level disturbance combined with a southeastward moving weak cold front will result in renewed rain and thunderstorm chances by late Thursday into Friday through Saturday with the clouds and rain chances extending into the weekend. Another inch or two of rain is possible with this weather system as it passes overhead.
Temperatures will be at or slightly above average over the next few days with temperatures cooling a bit to below average by late Thursday through Friday before returning to near average by next weekend.
Regarding my forecast, my local forecast confidence: My forecast confidence is medium to high through the week and into the weekend. The main questions will be the exact probability for rain as well as precipitation timing and amounts.
Have a good Tuesday….
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel