MESOSCALE DISCUSSION 0872
   NWS STORM PREDICTION CENTER NORMAN OK
   0348 PM CDT TUE MAY 26 2009
   
   AREAS AFFECTED...PORTIONS OF N-CNTRL TX TO THE BIG COUNTRY
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 262048Z - 262215Z
   
   UNCERTAINTY REMAINS HIGH OVER TIMING AND LOCATION OF TSTM INITIATION
   INTO LATE AFTERNOON...ESPECIALLY WHERE BUOYANCY APPEARS MAXIMIZED.
   BUT...AT LEAST ISOLATED TSTMS SHOULD DEVELOP BY 22Z ALONG VARIOUS
   SURFACE TROUGH/OUTFLOW BOUNDARIES ACROSS W-CNTRL TX INTO THE BIG
   COUNTRY. DESPITE MODEST DEEP-LAYER FLOW...STEEP LOW/MID-LEVEL LAPSE
   RATES SHOULD SUPPORT POTENTIAL FOR SEVERE HAIL/WINDS. A WW DOES NOT
   APPEAR IMMINENT...BUT THE AREA WILL CONTINUE TO BE MONITORED FOR A
   POSSIBLE WW.
   
   20Z SUBJECTIVE SURFACE ANALYSIS PLACED A MESOLOW AROUND 20 N MWL
   WITH SEVERAL RATHER DIFFUSE TROUGHS/BOUNDARIES REMAINING EVIDENT IN
   THE WAKE OF CONVECTION NOW OVER ERN TX. RECENT VISIBLE SATELLITE
   IMAGERY DEPICTED CU/TCU INCREASING FROM THE PERMIAN BASIN INTO THE
   BIG COUNTRY. MODIFIED 12Z MAF RAOB SUGGESTS THIS AREA IS UNCAPPED TO
   MIXED-LAYER PARCELS. GIVEN TEMPERATURE/DEW POINT SPREADS AOA 40 DEG
   F...DRY MICROBURSTS AND HAIL MAY OCCUR. FARTHER EAST...MIDDLE 60S TO
   LOWER 70S SURFACE DEW POINTS PERSIST ACROSS NERN TX...ALTHOUGH
   SHRINKING IN AREAL EXTENT AS DRIER AIR CONTINUES TO MIX NWD.
   CONVECTIVE INITIATION IN THE NEAR-TERM MAY REMAIN SUPPRESSED BY
   LARGER-SCALE DESCENT IN THE AFTERMATH OF MCS ALONG THE SABINE RIVER
   VALLEY. OPERATIONAL AND HI-RES MODEL GUIDANCE VARY SUBSTANTIALLY
   WHETHER OR NOT CONVECTIVE INITIATION WILL OCCUR INTO EARLY EVENING
   ACROSS N-CNTRL TX. IF IT DOES OCCUR...THE VERY UNSTABLE AIR MASS
   WOULD SUPPORT RAPID TSTM DEVELOPMENT WITH LARGE HAIL AND DAMAGING
   WINDS AS THE PRIMARY THREATS.
   
   ..GRAMS.. 05/26/2009
   
   
   ATTN...WFO...FWD...OUN...SJT...LUB...MAF...
   
   LAT...LON   33729676 32879655 32139688 31839750 31579846 31619981
               31670029 31890134 32340144 32960053 33549939 33959815
               33959729 33729676