Troy Kimmel Weather

Forecasting Austin and South Central Texas Weather Since 1984

TK’s Special Briefing….

Austin / Travis County and South Central Texas Winter Weather Update #1 (Corrected to include Lee County)
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
725am CT – Thursday / 23 January 2014

… Winter Storm Watch Replaced by Winter Weather Advisory for:
Travis (Metro Austin), Hays, Caldwell, Bastrop, Lee, Milam, Bell, Fayette Counties effective 6pm today until noon Friday…
Williamson, Burnet and Blanco Counties effective at noon today until noon Friday…

… Little Change in My Forecast Thought …

A southward moving series of cold fronts.. the leading edge of much colder arctic air.. has now advanced
southward into Texas. Locally, temperatures.. currently in the 40s to near 50.. will continue to slowly fall into
the 30s later today to near and then to below freezing after sunset tonight and continue below freezing until midday
Friday. At the same time, a series of west-to-east moving upper air disturbances will be moving overhead
later today through tonight and into tomorrow.. essentially riding up and over the much colder surface air.

As a result, light “overrunning” precipitation will develop over our local area during the late morning into midday
hours today and continue through tonight before ending with the departure of the upper air disturbances
by the midday Friday. Of course, as previously mentioned, the key to this forecast and the forecast precipitation
type over the next 24 hours will be surface and upper air temperature profiles and actually how cold the atmosphere..
at the surface and aloft.. gets over the next 24 hours.

At this point, I still think that most of the precipitation.. rather light in nature.. would be in frozen form (snow
and sleet) with patchy freezing rain possible and mainly in the 8/9pm tonight to 10am time period tomorrow.
Given this and the fact that we could see liquid equivalent precipitation amounts.. over the next 24 hours.. of
up to one to two tenths of an inch (0.10-0.20″), it still seems possible that some areas of south central Texas
and the adjacent Texas Hill Country could see up to 1/2 to 1 inch of snow/sleet accumulations. This would cause
hazardous driving conditions locally in the evening into nighttime hours tonight and through the morning and
midday hours tomorrow (Friday).

Please note a couple of things..
(1) As I mention every time we encounter this type of winter weather episode.. the difficulty in
forecasting winter precipitation types at 30 degrees north latitude (the Austin area).  A relatively thin
warmer than expected layer of temperatures aloft could easily cause this to be more of a freezing rain
event (ice).. just as a layer of much drier air aloft than expected can reduce the amount of precipitation
that reaches the surface.
(2) At this time, I think the transition to frozen/freezing precipitation will not occur until about sunset or
just thereafter tonight. If the air gets colder quicker than what I’m thinking, it could result in the deterioration
of weather conditions earlier (this afternoon). Let’s monitor for this slim possibility as well.

I will continue to monitor this situation carefully and will issue another updates as necessary.

An important note… winter weather (storm) reports will be essential later today through tonight and into
tomorrow. The NWS/Austin-San Antonio depends upon those ground truth reports.. you are welcome to
submit those reports of snow, sleet and icing (and amounts, times of occurrence, exact location by cross
streets) by going directly to their storm submission webpage at

http://www.srh.noaa.gov/StormReport/SubmitReport.php?site=EWX

tk