MESOSCALE DISCUSSION 0492
   NWS STORM PREDICTION CENTER NORMAN OK
   1056 PM CDT THU APR 16 2009
   
   AREAS AFFECTED...LOW ROLLING PLAINS AND PERMIAN BASIN EWD INTO THE
   BIG COUNTRY...CONCHO VALLEY AND PERHAPS EDWARDS PLATEAU
   
   CONCERNING...TORNADO WATCH 157...
   
   VALID 170356Z - 170530Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 157 CONTINUES.
   
   CURRENT INDICATIONS ARE THAT AT LEAST AN ISOLATED SEVERE WEATHER
   THREAT MAY CONTINUE BEYOND 05Z.  AN ADDITIONAL WW MAY BECOME
   NECESSARY PRIOR TO THAT TIME.
   
   AS OF 0340Z...REGIONAL RADAR IMAGERY INDICATED A BROKEN LINE OF
   TSTMS /INCLUDING SUPERCELLS/ FROM ALONG I-27 BETWEEN AMA AND LBB
   SSWWD TO E OF FST.  THE MOST INTENSE STORMS WERE LOCATED OVER HOWARD
   COUNTY AND ERN PECOS COUNTY AT THIS TIME.  RECENT TRENDS IN THESE
   DATA INDICATE A SLOW DECREASE IN INTENSITY OF STORMS OVER THE TX
   SOUTH PLAINS INTO LOW ROLLING PLAINS WITH THE ABOVE-MENTIONED...MORE
   INTENSE STORMS ROOTED IN A COMPARABLY MORE MOIST BOUNDARY LAYER OVER
   THE PERMIAN BASIN INTO TRANS-PECOS.
   
   BASED ON 00Z DRT SOUNDING AND LATEST SHORT TERM MODEL
   GUIDANCE...ONGOING STORMS ARE STARTING TO EXPERIENCE PROGRESSIVELY
   GREATER CONVECTIVE INHIBITION OWING TO THE RESIDUAL EML AND SLOW
   COOLING OF THE BOUNDARY LAYER.  MOREOVER...WATER VAPOR IMAGERY
   IMPLIES THAT THE STRONGER DYNAMIC FORCING FOR ASCENT IS RAPIDLY
   LIFTING N OF THE REGION.  THEREFORE...THERE IS SOME UNCERTAINTY AS
   TO WHETHER ONGOING STORMS WILL BE ABLE TO MAINTAIN THEIR INTENSITY.
   
   CURRENT THINKING IS THAT AT LEAST ISOLATED STORMS /SUPERCELLS/ WILL
   LIKELY CONTINUE BEYOND 05Z EWD INTO PARTS OF THE BIG
   COUNTRY...CONCHO VALLEY AND EDWARDS PLATEAU.  WHILE THE GREATEST
   SEVERE WEATHER THREAT WILL LIKELY BE HAIL...THE PRESENCE OF THE
   STRONG LOW-LEVEL SHEAR /REF. CURRENT SJT VWP/ AND LOW LCL HEIGHTS 
   SUGGEST A CONTINUED TORNADO THREAT.
   
   ..MEAD.. 04/17/2009
   
   
   ATTN...WFO...EWX...SJT...LUB...MAF...
   
   LAT...LON   30780193 32560107 33340068 33360002 33029956 31909951
               30889996 30320048 30110094 30140158 30780193