Troy Kimmel Weather

Forecasting Austin and South Central Texas Weather Since 1984

TK’s Special Briefings…. (735am CT-Mon/11May2015)

by

Austin / Travis County and South Central Texas Weather Update #9
Prepared by UT University/Incident Meteorologist Troy Kimmel
735am CT – Monday / 11 May 2015

…. No Big Changes in Severe Weather/Rainfall Risk ….
– “Slight” risk of severe thunderstorms with larger hail and strong
straight line thunderstorm winds being the primary risk

–  7 Day Rainfall Forecast Amounts Reduced Slightly to 4 to 6 Inch Range ….
http://www.wpc.ncep.noaa.gov/medr/97ewbg.gif?1431000446

…. Severe Thunderstorm Watch Continues Until 11am ….
LINK… http://www.spc.noaa.gov/products/watch/ww0163.html

…. NWS/Storm Prediction Center Mesoscale Discussion Issued ….
LINK… http://www.spc.noaa.gov/products/md/md0605.html

MESOSCALE DISCUSSION 0605
NWS STORM PREDICTION CENTER NORMAN OK
0704 AM CDT MON MAY 11 2015

AREAS AFFECTED...S-CNTRL TX EWD INTO SERN TX

CONCERNING...SEVERE THUNDERSTORM WATCH 163...

VALID 111204Z - 111300Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 163
CONTINUES.

SUMMARY...A FAIRLY ISOLATED LARGE-HAIL RISK WILL CONTINUE ACROSS
S-CNTRL TX THROUGH MID MORNING WHILE A SHORTER-TERM THREAT FOR ISOLD
LARGE HAIL/LOCALIZED WIND DAMAGE EXISTS ACROSS SERN TX.

DISCUSSION...SUBJECTIVE SURFACE MESOANALYSIS/RADAR COMPOSITE SHOW AN
EXTENSIVE QLCS FROM THE LOWER MS VALLEY SWWD INTO SERN TX WITH RICH
BOUNDARY-LAYER MOISTURE /LOWER 70S DEWPOINTS/ LOCATED TO THE E AND S
OF THE ONGOING STORMS.  THE QLCS HAS LARGELY BECOME ORIENTED WSW-ENE
WITH THE MEAN WIND LARGELY PARALLEL TO THE LEADING GUST FRONT.  A
REDUCED WINDOW OF OPPORTUNITY APPEARS TO EXIST FOR EMBRYONIC STORMS
TO DEVELOP AND MATURE AHEAD OF THE LINE OVER SERN TX GIVEN THE
DISSIPATION OF EARLIER WARM SECTOR CONFLUENCE ZONES.  LOW-LEVEL
SHEAR SAMPLED BY 88D VAD DATA IS BECOMING MORE MARGINAL AND THIS
TREND SHOULD CONTINUE THROUGH THE MORNING.  AS A RESULT...IT APPEARS
THERE IS ONLY A SHORT-TERM RISK FOR EMBEDDED HP SUPERCELLS CAPABLE
OF WATER-LOADED DOWNDRAFTS YIELDING A LOCALIZED WIND DAMAGE RISK AND
LARGE HAIL.  FARTHER W OVER THE SRN HILL COUNTRY INTO SRN PORTIONS
OF THE EDWARDS PLATEAU...A FEW STORMS WILL PROBABLY CONTINUE TO POSE
AN ISOLD THREAT FOR LARGE HAIL GIVEN A MORE FAVORABLE MODE AND A
PRISTINE FEED OF STEEP MID-LEVEL LAPSE RATES OFF THE MEXICAN
PLATEAU.

..SMITH.. 05/11/2015

…. Quick Look at Hi-Res Short Range Guidance for the Day Ahead ….
 Remembering that computer model prediction is only a guidance tool, the latest guidance
does suggests the possibility of more rain showers and thunderstorms.. in a east to west
line.. to continue over our area over the next few hours before another larger cluster of
rain showers and thunderstorms develops to our west and southest by mid and late afternoon.

tk