Updated 845am CT Thursday / 5 December 2013
…. Arctic Cold Front Moving Through Texas ….
…. Winter Storm / Ice Storm for Parts of Texas Over Next Few Days ….
On this Thursday morning…. a southward moving strong cold front extends from middle Tennessee southwestward to along the Texas coast then northwestward into a low pressure storm system over New Mexico. As a result of this surface weather pattern, surface winds are gusty northerly across our area in the wake of front.
In the upper levels of the atmosphere… an intense upper level low moving slowly east southeastward over the Dakotas southwestward into California. As a result, the upper level winds over south central Texas and the Austin metro area about 18,000 feet above the ground are now southwesterly 65 to 75 mph.
A massive area of arctic high pressure has surged southward into the western and central USA as the upper level low pressure moves to the east. By later tonight and into Friday into the weekend, the leading edge cold front will move well into the Gulf of Mexico and the arctic air mass will continue overtake much of the lower 48 states.
As the colder surface air moves in, the subtropical jet stream (higher in the atmosphere) off the tropical Pacific, is sending disturbances overhead and has created an overrunning pattern where moisture comes back on top of the colder air. As the upper air disturbances move overhead, they will cause atmospheric lift with periods of precipitation possible back in the colder air. With temperatures expected to be near or even slightly below freezing, especially in the Friday night and Saturday night overnight hours and primarily north of the Austin area, we could see periods of freezing drizzle and freezing rain given the very shallow layer of surface based arctic air. The NWS/Austin-San Antonio has issued a winter weather advisory effective at 12 midnight tonight through noon tomorrow for the IH35 corridor.. including the Austin metro area.. as well as the Texas hill country for possible ice accumulations.
Additional disturbances will keep a chance of precipitation.. both freezing and non-freezing.. for Friday night through Sunday morning across our area.
The unseasonably cold weather pattern will likely persist for a few days with another surge of colder air moving into the area.. mainly reinforcing the colder air place.. by late next Monday into Tuesday. As we look ahead, under a clearing sky, we could see the coldest air of this fall season by Monday night and Tuesday night of next week with hard overnight freezes likely.
Regarding my forecast, my local forecast confidence: Very high forecast confidence through today and tonight.. then dropping to medium tomorrow (whether precipitation type will be rain or freezing rain). For Friday through the weekend, my forecast confidence drops to low to medium with the main questions being the intensity of the cold air along with liquid/freezing precipitation chances. I return to very high forecast confidence for next week.
Have a good Thursday…
Meteorologist Troy Kimmel