Austin / Travis County and South Central Texas Weather Update #15
Prepared by UT University/Incident Meteorologist Troy Kimmel
845am CT – Saturday / 18 April 2015
…. “Slight” Risk of Severe Thunderstorms Late This Afternoon into Tonight ….
Outlooks prepared by meteorologists at the NWS/Storm Prediction Center
continue to indicate the possibility of severe thunderstorms areawide later today
and tonight with a “SLIGHT” risk posted for our IH35 corridor counties of
Williamson.. Travis and Hays…
The latest short range high resolution computer models (HRRR and Texas Tech
WRF) suggests that we’ll see initial thunderstorm development, in response to next
strong upper level disturbance and associated surface trough/weak front, during the
afternoon into evening hours. While the Texas Tech models are more bullish and suggest
some pre-trough/pre-frontal scattered strong thunderstorms developing in areas immediately
to our west and southwest as early as 2pm, the main push is in the 3 to 4 pm hour this
afternoon in a north south line from Wichita Falls southward to Abilene and Del Rio
with the line of thunderstorms forecast to progress eastward to the Austin metro area
and the IH35 corridor by mid to late evening. Both models show all precipitation and
any threat of severe weather to the east of the IH35 corridor by 11pm to 12 midnight
tonight.
As we go into our Saturday morning, our atmosphere has become more stable
as a result of being “worked over” by the thunderstorms late yesterday afternoon
and nighttime hours. How efficiently we’re able to destabilize our environment today
into tonight in advance of the next strong upper air low pressure disturbance is going
to be an important key as it regards the extent of (severe) thunderstorm development
later today into tonight. If we can’t destabilize the atmosphere efficiently today, this
event will not be as significant. If we are able to create some breaks in the overcast
and get a bit more significant surface heating, the severe weather risk will increase.
Current NWS/Weather Prediction Center rainfall forecast guidance confirms the
fairly progressive movement of this system through the area with most areas expected
to receive 1/2 to 3/4 inch of rain or less with this passing system later today into
tonight. As a result, other than very localized low water crossing flooding as well as
some brief urban flooding effects, I do not expect flooding to be a big issue.
Remember.. with the risk of severe thunderstorms comes the threat of large hail,
up to an inch in diameter or larger, along with straight line thunderstorm winds
gusts to 58 mph or higher and even isolated tornadoes. Frequent deadly
cloud-to-ground lightning will occur around any thunderstorms as well.
Let’s remain weather aware today and listen for the latest information from the
National Weather Service..
I will continue to monitor… tk