MESOSCALE DISCUSSION 0610
   NWS STORM PREDICTION CENTER NORMAN OK
   0630 PM CDT MON APR 27 2009
   
   AREAS AFFECTED...PORTIONS SE TX...EXTREME SWRN LA.
   
   CONCERNING...TORNADO WATCH 203...
   
   VALID 272330Z - 280130Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 203 CONTINUES.
   
   CONTINUE WW ALONG/AHEAD OF SVR/QUASI-LINEAR MCS NOW EXHIBITING NET
   MOTION SEWD 20-25 KT.  TORNADO THREAT WW SHOULD BE CLEARED BEHIND
   THIS COMPLEX...GIVEN STG LEADING-EDGE OUTFLOW BOUNDARY...MESOHIGH
   ANALYZED TO ITS N...AND RESULTANT DISRUPTION OF BOTH SHEAR AND
   BUOYANCY BEHIND INITIAL CONVECTION.
   
   SVR AND HEAVY RAIN POTENTIAL WITH MCS MAY EXTEND EWD ALONG COASTAL
   COUNTIES TOWARD SABINE PASS AREA.  SVR GUST MEASURED 50 KT AT VCT
   DURING PAST HOUR...AND RAIN RATES TO 3 INCHES/HOUR WILL REMAIN
   COMMON.  GIVEN NARROW LAND AREA AFFECTED AND FCST LOSS OF SFC
   HEATING -- EVENTUALLY REDUCING SFC-BASED BUOYANCY -- WHOLE NEW WW IS
   NOT ANTICIPATED ATTM.  HOWEVER...AS CONVECTIVE TRENDS WARRANT...A
   FEW ADDITIONAL COUNTIES MAY BE TACKED ONTO ERN EDGE OF WW 203 IN WFO
   HGX DOMAIN...AS WITH LIBERTY COUNTY ALREADY.  ACTIVITY IS BEING
   SUPPORTED BY RICH BOUNDARY LAYER MOISTURE AND FAVORABLE LOW LEVEL
   SHEAR -- WITH SELY/ONSHORE SFC WINDS TRANSPORTING PW TO 1.75 INCH
   BASED ON GPS READINGS AND MODIFIED RUC SOUNDINGS.  LOW LEVEL
   STORM-RELATIVE INFLOW WILL REMAIN STG...BETWEEN THOSE SE WINDS AND
   30-40 KT SLY-SSWLY LLJ EVIDENT IN HGX/CRP VWP.  THIS SHOULD AID BOTH
   IN POTENTIAL FOR MESOCYCLONIC SPINUPS ALONG LEADING EDGE OF
   MCS...AND IN PRECIP EFFICIENCY AS SLAB OF MARITIME/TROPICAL AIR IS
   FORCED ABOVE COLD POOL.
   
   ..EDWARDS.. 04/27/2009
   
   
   ATTN...WFO...LCH...HGX...CRP...
   
   LAT...LON   28179735 29129597 29639549 30349510 30509474 30289341
               29789313 29669384 29659408 29399471 29289470 29089512
               28739560 28349641 28049685 27729712 28179735