Austin / Travis County and South Central Texas Weather Update #5
Prepared by Incident Meteorologist Troy Kimmel (www.troykimmelweather.com)
415pm CST – Saturday / 23 November 2013
.. Weather Update #5 ..
…. Large Winter Storm Expected to Develop Across Texas / Southern Plains ….
…. Winter Storm Warnings Go In Effect for the Hill Country at 6pm Tonight and
then for the Austin area/IH35 Corridor at 2pm Sunday ….
…. System Slower Moving With Wintry Weather Lingering Monday Night into Tuesday ….
NWS watches/advisories/warnings (as of 4pm today) by issuing NWS office:
NWS/Austin-San Antonio:
WINTER WEATHER ADVISORY for the Texas Hill Country.. including Blanco, Burnet,
Gillespie and Llano Counties.. until 6pm this evening.
WINTER STORM WARNING for the Texas Hill Country.. including Blanco, Burnet, Gillespie
and Llano counties.. in effect from 6pm this evening until 12 noon Monday (ice accumulations
less than 1/4 inch).
WINTER STORM WARNING for IH35 Corridor / the Austin Metro Area, including
Travis, Williamson and Hays counties.. valid from 2pm Sunday through 12 noon Monday
(ice accumulations less than 1/4 inch).
NWS/San Angelo:
WINTER WEATHER ADVISORY for Mason County continues until 6pm today.
WINTER STORM WARNING for Mason County in effect from 6pm today until 6am
Monday (up to 1 inch ice/sleet/snow accumulations).
NWS/Fort Worth:
WINTER STORM WARNING for all of the DFW Metroplex goes into effect at 6am Sunday
morning and continues until 12 noon Monday (up to 1 inch ice/sleet/snow accumulations).
WINTER STORM WARNING for Bell and IH35 counties northward through Waco, including
Killeen, Belton and Temple, goes into effect at 12 noon Sunday and continuing through 12 noon
Monday (up to 1 inch ice/sleet/snow accumulations).
Temperatures have risen into the upper 30s and lower 40s across the area as a cold modified
arctic air mass continues to build into the area. Above the layer of surface based cold air,
southerly and southwesterly winds are bringing moisture northward and overrunning it over the
colder surface air. Over the next 48 hour period, a series of upper air low pressure disturbances
will move across the area (west to east) creating atmospheric lift and keeping us in clouds and
precipitation chances.
On this Saturday afternoon, there are three very critical issue that will determine who gets frozen..
freezing or liquid precipitation as this winter storm moves across the southern plains over the next
two days. Those considerations.. (1) how cold the surface air is becoming and will become Sunday
into Monday, (2) the depth or “thickness” of the surface based cold air – this is an important complex
factor in determining winter precipitation types, where it occurs – and, (3) the exact track of the
dynamic upper level low pressure storm system as it moves eastward across the area. Please note
that a difference of as little as 20 or 30 miles in the actual track of the system can have profound
effect on who gets just a cold rain, who gets freezing rain, who gets sleet and who gets snow.
Even though it’s warmed a little more in the Austin area than I thought it would this afternoon, I
still do not believe that the numerical forecast models have a good handle on the forecast temperatures.
There is reinforcing arctic air coming southward through the plains and it will continue southward into
Texas tonight into Sunday. Today, when compared with tomorrow and Monday, may see the warmest
temperatures of this episode as the cold air is reinforced. I continue to be concerned that this developing
winter storm.. particularly the passage of the major upper level low Sunday into Monday and Monday
night.. will give us problems into the Austin metro area and the IH35 corridor. As mentioned
yesterday, please understand that precipitation is not the question here.. it will occur. Temperatures,
throughout the atmosphere, are the question (see critical issues above) and my thinking continues to be, at
this point, is that surface temperatures may fall to freezing or even slightly below freezing Sunday night
into Monday morning (especially west through north of Austin). In addition, it now appears that clouds and
precipitation will linger into Monday night and early Tuesday, with problems continuing or redeveloping
again Monday night into Tuesday. Please note that the models are forecasting 1/2 to 1 inch of rain (or
liquid water equivalent) over most of our area between 12 noon Sunday and Tuesday morning.. so you
can understand that, where freezing temperatures are present, real problems could be the result.
I urge you to remain in close touch with the latest forecasts and the latest NWS watches/advisories
and/or warnings that are expanded and/or issued over the next few days as the effects of this
potential winter storm across Texas become more focused.
I’ll continue to keep you informed… tk
tk
—
Updated 355pm CT – Sat/23Nov2013
Quick Update… from NWS Austin-San Antonio…
WINTER STORM WARNING FROM 2 PM SUNDAY TO NOON CST MONDAY FOR THE FOLLOWING COUNTIES: COMAL...HAYS...TRAVIS...WILLIAMSON. WINTER STORM WARNING FROM 6 PM THIS EVENING TO NOON CST MONDAY FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE. WINTER WEATHER ADVISORY UNTIL 6 PM CST THIS EVENING FOR THE FOLLOWING COUNTIES: BANDERA...BLANCO...BURNET...EDWARDS... GILLESPIE...KENDALL...KERR...LLANO...REAL...VAL VERDE.
My update will be issued shortly…tk