Updated 845am CST Monday / 11 November 2013
…. A Strong Cold Front Moves Through Tonight Into Tomorrow ….
…. A More Unsettled Period with Rain Chances Late Week into Weekend ….
On this Monday morning…. a ridge.. or line.. of surface high pressure extends from Virginia southwestward into Arkansas and east Texas. A strong cold front extends from the southern Great Lakes into Kansas and then northwestward as a stationary front into northern Colorado and Wyoming and western Montana. A trough.. or line.. of low pressure is deepening and extending southwestward from Kansas into far west Texas and New Mexico. As a result of this surface weather pattern, surface winds are light easterly over our area.
In the upper levels of the atmosphere… a deepening trough.. or line.. of upper air low pressure extends south southwestward across the eastern 2/3rds of the USA. Another strong upper level low is off the northwest coast of the USA. As a result of the overall upper level wind flow, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are west northwesterly 20 to 30 mph.
As the upper air trough deepens over the eastern half of the country and our upper level winds become more northwesterly and increase with speed, the cold front to our distant north will race southward across Texas. Since the surface winds have had a hard time becoming southeasterly (with the slow departure of the surface high to our east and northeast) and moisture return has been very meager, we will not see much of a rain chance with the front as it moves across the local area around sunrise tomorrow. A few sprinkles are possible but that’s about it with only trace rainfall amounts, if any, expected.
Much cooler temperatures.. in fact, the coldest of the fall season so far.. and clearing skies are expected by late in the day tomorrow into tomorrow night. With winds lightening up, it is very likely that early morning temperatures on Wednesday and Thursday mornings, assuming a clear sky, will fall to near the freezing mark especially in outlying and low lying areas. Guidance does suggest the return of some high level clouds by Thursday morning; if this materializes, temperatures would not be as cold.
NWS offices around our area are talking about the possibility of issuing frost/freeze warnings so we need to monitor the latest information from them.
As the strong surface high moves eastward by the end of the week and as another low pressure storm system gathers over the western USA, we’ll see a fairly rapid return to warmer temperatures and clouds. Rain chances even show up with the clouds and warmer temperatures by as early as late Friday night through our upcoming weekend.
Regarding my forecast, my local forecast confidence: High to very forecast confidence through the middle and latter part of the week with a moderate forecast confidence for next weekend (regarding rain chances).
Have a good Monday…
Meteorologist Troy Kimmel
Contact me:
tkimmel@austin.utexas.edu
http://www.facebook.com/troykimmel