Troy Kimmel Weather

Forecasting Austin and South Central Texas Weather Since 1984

Special Briefings

TK’s Special Briefing…. (822pm CT-Sat/18Apr2015)

by

Austin / Travis County and South Central Texas Weather Update #20
Prepared by UT University/Incident Meteorologist Troy Kimmel
821pm CT – Saturday / 18 April 2015

…. Authority / NWS Austin-San Antonio ….

SEVERE THUNDERSTORM WARNING FOR BLANCO COUNTY AND
NW HAYS COUNTY UNTIL 845PM…

Radar and warning polygon at 819pm:
alert map

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
818 PM CDT SAT APR 18 2015

THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN HAYS COUNTY IN SOUTH CENTRAL TEXAS...
  BLANCO COUNTY IN SOUTH CENTRAL TEXAS...

* UNTIL 845 PM CDT

* AT 817 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR JOHNSON
  CITY...OR 11 MILES SOUTHWEST OF ROUND MOUNTAIN...MOVING EAST AT 45
  MPH.

  HAZARD...60 MPH WIND GUSTS AND QUARTER SIZE HAIL. 

  SOURCE...RADAR INDICATED. 

  IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE 
           TO ROOFS...SIDING AND TREES. 

* LOCATIONS IMPACTED INCLUDE...
  ROUND MOUNTAIN...JOHNSON CITY...SANDY...CYPRESS MILL...ROCKY
  CREEK...PAYTON...HENLY AND PEDERNALES FALLS STATE PARK.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

Continuing to monitor.. tk

--

TK’s Special Briefing…. (652pm CT-Sat/18Apr2015)

by

Austin / Travis County and South Central Texas Weather Update #19
Prepared by UT University/Incident Meteorologist Troy Kimmel
652pm CT – Saturday / 18 April 2015

…. NWS/Storm Prediction Center Issues Mesoscale Discussion ….
MD 366 graphic
Link: http://www.spc.noaa.gov/products/md/md0366.html

MESOSCALE DISCUSSION 0366
NWS STORM PREDICTION CENTER NORMAN OK
0640 PM CDT SAT APR 18 2015

AREAS AFFECTED…PORTIONS OF TEXAS

CONCERNING…SEVERE THUNDERSTORM WATCH 72…76…

VALID 182340Z – 190115Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
72…76…CONTINUES.

SUMMARY…AN EVOLVING MESOSCALE CONVECTIVE SYSTEM WILL CONTINUE
SPREADING EWD ACROSS PORTIONS OF CNTRL TX…WITH DMGG WIND GUSTS AND
SVR HAIL EXPECTED.

DISCUSSION…CONVECTION HAS CONGEALED INTO A FORWARD-PROPAGATING MCS
ACROSS PARTS OF CNTRL TX AND WILL CONTINUE SPREADING EWD TOWARD THE
INTERSTATE 35 CORRIDOR INCLUDING THE DFW METROPLEX AND WACO. STEEP
TROPOSPHERIC LAPSE RATES SUPPORTING 1500-2000 J/KG OF MLCAPE COUPLED
WITH 30-45 KT OF DEEP SHEAR ORIENTED LARGELY ORTHOGONAL TO THE
LEADING CONVECTIVE LINE WILL CONTINUE TO SUPPORT SVR WIND/HAIL. THE
LARGE HAIL POTENTIAL MAY BE SOMEWHAT GREATER WITH TRAILING SUPERCELL
STRUCTURES ON THE SRN FLANK OF THE EVOLVING COLD POOL AND FARTHER S
WITH MORE DISCRETE CONVECTION ACROSS PARTS OF THE EDWARDS PLATEAU
AND TX HILL COUNTRY. IN THE WAKE OF CONVECTIVELY STABILIZED AIR…
PROSPECTS FOR ADDITIONAL SFC-BASED CONVECTIVE DEVELOPMENT MAY
BE RELATIVELY LOW OWING TO INCREASED MLCINH — NOCTURNALLY ENHANCED.

Continuing to monitor… tk