MESOSCALE DISCUSSION 1872
   NWS STORM PREDICTION CENTER NORMAN OK
   1131 PM CDT WED OCT 21 2015

   AREAS AFFECTED...FAR SOUTHEAST NM AND SOUTHWEST TX

   CONCERNING...SEVERE THUNDERSTORM WATCH 517...

   VALID 220431Z - 220530Z

   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 517
   CONTINUES.

   SUMMARY...WW 517 MAY NEED TO BE EXTENDED IN TIME AND AREA FOR
   PORTIONS OF THE MAF COUNTY WARNING AREA...AS THE GREATEST SEVERE
   WEATHER THREAT IS EXPECTED TO PERSIST MAINLY ACROSS THIS REGION OF
   SOUTHWEST TX AND FAR SOUTHEAST NM INTO THE EARLY OVERNIGHT PERIOD.

   DISCUSSION...AT 04Z...LIGHTING DATA AND RADAR IMAGERY INDICATED
   STORMS EXTENDED FROM THE TX PANHANDLE SOUTH-SOUTHWESTWARD IN
   VICINITY OF THE TX/NM BORDER THROUGH LEA COUNTY NM TO PRESIDIO
   COUNTY TX...WITH THE STRONGER/SUSTAINED STORMS LOCATED FROM WESTERN
   GAINES COUNTY TX TO REEVES COUNTY TX.  MOST OF THESE STORMS ARE
   LOCATED ALONG A FRONT ADVANCING SLOWLY TO THE EAST AND JUXTAPOSED
   WITH DEEP-LAYER FORCING FOR ASCENT WITHIN THE EASTERN PERIPHERY OF
   THE SOUTHWEST STATES CLOSED LOW.  GIVEN ONLY SLOW EASTWARD MOVEMENT
   EXPECTED OF THIS PARENT LOW/TROUGH SYSTEM WITH WEAK HEIGHT FALLS
   ACROSS WEST AND SOUTHWEST TX...EASTWARD ADVANCEMENT OF THE STRONG TO
   SEVERE WEATHER THREAT WILL BE SMALL.  THIS SUGGESTS THE REMAINING
   SEVERE WEATHER THREAT INTO THE EARLY OVERNIGHT SHOULD BE ACROSS
   PORTIONS OF THE MAF COUNTY WARNING AREA...WHERE RESIDUAL MODERATE
   INSTABILITY AND STRONG BULK SHEAR WILL FAVOR THIS POTENTIAL.

   A STRONG TO ISOLATED STORM CANNOT BE RULED OUT FARTHER NORTH ACROSS
   WEST AND NORTHWEST TX..AND PERHAPS INTO THE TX PANHANDLE...AS THIS
   REGION WILL ALSO BE UNDER THE INFLUENCE OF STRONG FORCING FOR ASCENT
   AND FAVORABLE BULK SHEAR.  HOWEVER...WEAK INSTABILITY SUGGESTS THE
   SEVERE THREAT SHOULD BE LOW AND NOT WARRANT A WW ISSUANCE.

   ..PETERS/HART.. 10/22/2015


   ATTN...WFO...SJT...LUB...MAF...

   LAT...LON   30650425 31170396 32150362 32860326 32970258 32900170
               32840113 32020130 31500145 30810197 30390240 30260284
               30270353 30650425