MESOSCALE DISCUSSION 0425
   NWS STORM PREDICTION CENTER NORMAN OK
   0133 PM CDT THU APR 14 2011
   
   AREAS AFFECTED...PORTIONS CENTRAL/N-CENTRAL/NE TX...ERN OK.
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 141833Z - 142100Z
   
   EXPECT DEVELOPMENT OF SEVERAL POTENTIALLY LONG-LIVED SUPERCELLS
   ALONG/AHEAD OF DRYLINE BEGINNING IN 20-22Z TIME FRAME...COVERAGE
   INCREASING THROUGH REMAINDER AFTERNOON/EVENING AS ACTIVITY MOVES EWD
   TO NEWD.  DAMAGING HAIL IS LIKELY...SOME EXCEEDING 3 INCHES
   DIAMETER.  THREAT WILL INCREASE FOR TORNADOES AS TSTMS MATURE AND
   MOVE INTO PROGRESSIVELY MORE MOIST/HIGH-SRH AIR MASS...WITH TIME AND
   EWD EXTENT.
   
   18Z SFC MESOANALYSIS SHOWS DRYLINE JUST E OF US-81 CORRIDOR IN OK
   THEN SWWD ACROSS JACK COUNTY TX...WHERE VIS IMAGERY INDICATES
   CONCENTRATION OF DEEP CU.  DRYLINE SHOULD CONTINUE TO MIX/ADVECT EWD
   ACROSS I-35 FROM PVJ AREA NWD...BEFORE DECELERATING AROUND 23Z.  TX
   DRYLINE SEGMENT SHOULD MOVE EWD TO JUST W OF DFW METROPLEX...NEAR
   PRESENT LOCATION OF CONFLUENCE LINE THAT EXTENDS NNEWD FROM HILL
   COUNTRY.  DRYLINE MAY SHARPEN FURTHER...GIVEN COMBINATION OF
   1. CONTINUING MOST ADVECTION TO ITS E...
   2. BACKING 850-MB WINDS EVIDENT PAST COUPLE HOURS IN CENTRAL OK
   VWP/PROFILER DATA...AND
   3. GEOMETRY OF PRESSURE FALLS OVER KS/OK THAT MAY KEEP SLGT ELY
   COMPONENT TO SFC FLOW IN MOIST SECTOR IN CORRIDOR FROM OSAGE COUNTY
   SWD TO DUA AREA THROUGH 00Z.
   
   EXPECT CONTINUED STG SFC HEATING...DEW POINTS RANGING FROM UPPER 50S
   F IN NRN OK TO MID 60S FROM ADM-ATOKA AREA SWD ACROSS RED
   RIVER...AND STEEPENING LAPSE RATES ALOFT.  THIS WILL BOOST MLCAPE TO
   2000-3000 J/KG RANGE OVER PORTIONS N TX AND SERN OK BASED ON
   MODIFIED 18Z FWD/OUN RAOBS...AND 1500-2000 J/KG NEAR OK/KS BORDER. 
   MEANWHILE...DEEP-LAYER SHEAR WILL STRENGTHEN...AS ALREADY EVIDENT
   WITH LOWERING OF 50-KT MIDLEVEL ISOTACH AT TCU PROFILER.  EFFECTIVE
   SHEAR SHOULD INCREASE TO 50-60 KT.  HODOGRAPH SIZE...NOW INDICATING
   SOME WEAKNESSES AROUND 1-3 KM AGL...WILL INCREASE MARKEDLY DURING
   LATE AFTERNOON AND EARLY EVENING OVER ERN OK...BECOMING POTENTIALLY
   FAVORABLE FOR SIGNIFICANT TORNADO PRODUCTION.  STG ORTHOGONAL
   COMPONENT OF MEAN WIND AND DEEP-SHEAR VECTORS...RELATIVE TO
   DRYLINE...INDICATES STORMS CAN REMAIN DISCRETE FOR AT LEAST A FEW
   HOURS AFTER INITIATION.  COVERAGE SWD INTO CENTRAL TX SHOULD BE MORE
   ISOLATED/CONDITIONAL.
   
   SRN END OF KS CONVECTIVE ARC REGIME -- SEE MESOSCALE DISCUSSION 424
   FOR DETAILS -- MAY BACKBUILD INTO PORTIONS N-CENTRAL/NERN OK AFTER
   ABOUT 21Z AS WELL.
   
   ..EDWARDS.. 04/14/2011
   
   
   ATTN...WFO...SHV...TSA...FWD...OUN...SJT...
   
   LAT...LON   31749881 33009777 34999746 36999738 36959512 34449494
               32919559 31549697 31379781 31749881