MESOSCALE DISCUSSION 0752
   NWS STORM PREDICTION CENTER NORMAN OK
   0119 PM CDT TUE MAY 21 2013
   
   AREAS AFFECTED...NRN TX INTO THE ARKLATEX REGION
   
   CONCERNING...TORNADO WATCH 201...
   
   VALID 211819Z - 212015Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 201 CONTINUES.
   
   SUMMARY...STORMS ARE GRADUALLY INCREASING IN COVERAGE...AND MAY
   RAPIDLY INTENSIFY CLOSE TO OR JUST E OF THE DALLAS/FT. WORTH AREA
   EWD INTO THE ARKLATEX WITH MAINLY DAMAGING WINDS AND HAIL.
   
   DISCUSSION...SURFACE ANALYSIS AND VISIBLE IMAGERY SHOW THAT A BAND
   OF THICK STRATUS CONTINUES TO HAMPER HEATING AND SURFACE BASED
   DESTABILIZATION W OF THE I-35 CORRIDOR IN TX AS OUTFLOW AND COLD
   FRONT CONTINUE TO RAPIDLY TRAVEL SEWD OVER WRN N TX.
   CURRENTLY...THESE STORMS ARE FORMING MAINLY BEHIND THE LEADING
   OUTFLOW...DUE IN PART TO THE COOLER SURFACE AIR AND MARGINAL STORM
   RELATIVE INFLOW.
   
   HOWEVER...HEATING PERSISTS ALONG AND E OF I-35...WITH TEMPERATURES
   MAINLY IN THE 82-84 F RANGE. MODIFICATION OF THE 18Z FWD SOUNDING
   SUGGESTS CAPPING IN THESE AREAS IS AT A MINIMUM...AND THAT THE
   APPROACHING LINE OF CONVECTION WILL STRENGTHEN AS IT BEGINS TO
   INGEST MORE UNSTABLE AIR. A GENERAL SWWD GROWTH ALONG THE COLD FRONT
   IS ALSO EXPECTED LATER THIS AFTERNOON TOWARD THE WACO AREA. GIVEN
   THE RAPIDLY ADVANCING GUST FRONT...AND VEERED 850 MB WINDS PRIMARILY
   PARALLEL TO THE BOUNDARY...THE TORNADO THREAT MAY NOT BE HIGH...BUT
   IF SUPERCELLS CAN FORM THEN ROTATION COULD DEVELOP ALONG ANY
   INFLECTION POINTS IN THE LINE.
   
   ELSEWHERE...AN OUTFLOW BOUNDARY CONTINUES TO SAG SWD ACROSS THE RED
   RIVER INTO NRN TX AND SWRN AR...WITH SPORADIC SMALL STORMS FORMING
   TO THE N OF IT. THESE CELLS MAY BECOME A BIT BETTER ORGANIZED AS THE
   UPPER TROUGH NEARS...AND SOME FURTHER DESTABILIZATION OCCURS
   UPSTREAM. DEEP LAYER SHEAR WILL REMAIN FAVORABLE FOR ELEVATED SEVERE
   HAIL WITH THIS ACTIVITY PRIOR TO THE MAIN LINE OF STORMS ARRIVING
   ACROSS THE RED RIVER VALLEY AND SWRN AR. ALSO...THERE IS A
   CONDITIONAL TORNADO THREAT IF CELLS CAN MATURE BEFORE THEY CROSS THE
   OUTFLOW BOUNDARY. HOWEVER...CELL MOTION WOULD CAUSE THESE STORMS TO
   LOSE TORNADO THREAT QUICKLY ONCE THEY CROSS THE FRONT.
   
   ..JEWELL.. 05/21/2013
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...EWX...SJT...
   
   LAT...LON   31809521 30370000 31639999 31789932 32529810 33249758
               34009713 34539520 31809521