Austin / Travis County and South Central Texas Weather Update #2
Prepared by UT University/Incident Meteorologist Troy Kimmel
205pm CT – Sunday / 28 May 2017
.. Authority NWS/Storm Prediction Center ..
Mesoscale Discussion 0901 NWS Storm Prediction Center Norman OK 0134 PM CDT Sun May 28 2017 Areas affected...Central Texas Concerning...Severe potential...Watch likely Valid 281834Z - 281930Z Probability of Watch Issuance...80 percent SUMMARY...A severe weather watch seems probable at some point late this afternoon and evening, perhaps as early as 20-21Z. DISCUSSION...Objective analysis indicates that insolation within a boundary layer characterized by high moisture content (lower/mid 70s F surface dew points) is contributing to strong/extreme CAPE on the order of 4000+ J/kg across much of the region, including the Interstate 35 corridor between San Antonio and Waco. Mid-level inhibition beneath warm elevated mixed layer air does still appear considerable, particularly given weak, or at least unclear, mid/upper forcing for ascent. An area of enhanced ascent contributing to deepening mid-level based convection near the Interstate 20 corridor, west of the Dallas/Fort Worth metroplex, may remain displaced to the north of an area of sustained enhanced low-level convergence near the Waco area. This is near the intersection of a surface front that extends southwestward into the Rio Grande Valley, to the west of Del Rio, and the western flank of composite outflow from extensive overnight convection, now advancing into the north central Gulf Coast. However, the latest Rapid Refresh suggests that additional surface heating, coupled with subtle mid-level height falls on the southern fringe of the westerlies, may be sufficient to support the initiation of thunderstorms as early as 20-21Z. Once this does occur, intensification likely will be very rapid, and deep layer shear appears sufficient for the evolution of supercell structures with large hail and perhaps an isolated tornado, in addition to strong downbursts accompanied by potentially damaging surface gusts. ..Kerr/Hart.. 05/28/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...HGX...FWD...EWX...SJT... LAT...LON 30359938 31149852 31689787 31949702 31599588 30929570 30419690 29639779 29409830 29329912 30359938