Mesoscale Discussion 0470
   NWS Storm Prediction Center Norman OK
   0958 PM CDT Sat May 19 2018

   Areas affected...Parts of west and northwest TX and southwest to
   north-central OK

   Concerning...Severe Thunderstorm Watch 108...

   Valid 200258Z - 200445Z

   CORRECTED FOR TYPO OF WRONG WATCH NUMBER IN THE SUMMARY AND TEXT OF
   THE GRAPHIC.

   The severe weather threat for Severe Thunderstorm Watch 108
   continues.

   SUMMARY...A severe-weather threat for mainly large hail and damaging
   winds will persist for a few more hours (until at least midnight)
   across west Texas to western North Texas to southwest Oklahoma,
   while the severe threat extending north-northeast into north-central
   Oklahoma may be isolated.  WW 108 has been extended in time beyond
   03Z, with some areal expansion too.

   DISCUSSION...Trends in radar and surface observations showed a
   convectively enhanced boundary extending generally westward from
   Clay County TX through northern Haskell to Yoakum Counties TX.  A
   30-40 kt southerly low-level jet is providing a feed of moderate
   instability into and north of this boundary, enhancing lift for
   continued thunderstorm development from west through east of KLBB to
   near and north of KSPS.  Meanwhile, sporadic strong to severe storms
   were developing toward central and north-central OK in vicinity of a
   cold front that extended from eastern KS to southwest OK.

   Forcing for ascent attendant to low-level warm advection across
   northwest TX to southwest OK and along the path of a progressive
   shortwave trough moving toward OK is expected to maintain
   thunderstorm development through tonight.  Residual moderate
   instability and strong effective bulk shear should favor continued
   potential for organized severe storms in the short term.

   ..Peters.. 05/20/2018

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...TSA...ICT...FWD...OUN...SJT...LUB...MAF...

   LAT...LON   33860249 33940058 34319979 35329861 36099796 36859748
               37009699 36909627 36479630 35999688 35609751 34599753
               34309744 33899758 33539893 33210001 32940148 33040208
               33340283 33630267 33860249