MESOSCALE DISCUSSION 0482
   NWS STORM PREDICTION CENTER NORMAN OK
   0156 PM CDT THU APR 16 2009
   
   AREAS AFFECTED...PORTIONS TX SOUTH-PLAINS REGION...TX PANHANDLE...OK
   PANHANDLE.
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 161856Z - 162000Z
   
   --- RE-TRANSMITTED ---
   
   SFC-BASED CONVECTION IS DEVELOPING BETWEEN LBB-EVW...WITH ADDITIONAL
   CONVECTION POSSIBLE NWD THROUGH CENTRAL PANHANDLE AND SWWD TOWARD
   TX/NM BORDER AREA E HOB.  DAMAGING GUSTS AND LARGE HAIL WILL BE
   POSSIBLE FROM ACTIVITY OVER THIS AREA THROUGH REMAINDER OF AFTERNOON
   INTO EVENING.
   
   SFC MESOANALYSIS INDICATES DRYLINE BULGE OVER THIS REGION...WITH
   DRYLINE ARCHING THROUGH ERN DALLAM...ERN CASTRO...HALE...WRN LUBBOCK
   COUNTIES...THEN SWD TO NEAR MAF. MESOANALYSIS...RADAR REFLECTIVITIES
   AND VIS IMAGERY INDICATES BOUNDARY LAYER CONVERGENCE LINE COLLOCATED
   WITH DRYLINE N OF LBB COUNTY...THEN EXTENDING SWWD THROUGH NWRN
   GAINES COUNTY.  DRYLINE SHOULD KEEP MIXING EWD ACROSS MOST OF SOUTH
   PLAINS REGION...BUT BECOME MORE NW-SE ALIGNED FARTHER N AS
   BACKED/INTENSIFYING LOW LEVEL FLOW PERSISTS ACROSS CENTRAL/NRN
   PANHANDLE AND OK PANHANDLE.  DRYLINE ACTUALLY MAY RETREAT WWD
   SOMEWHAT OVER NRN TX AND OK PANHANDLES AMIDST STRENGTHENING
   ISALLOBARIC FORCING...EXTENDING SOME SVR POTENTIAL INTO WHAT NOW IS
   DRY AIR MASS.  MODIFIED RUC/OBSERVED SOUNDINGS INDICATE VERY STEEP
   MIDLEVEL LAPSE RATES ACCOMPANYING ERN EDGE OF COOLING ALOFT
   OVERSPREADING REGION.  FURTHER DESTABILIZATION ALOFT IS EVIDENT JUST
   UPSTREAM OVER SERN NM -- WHERE CONSIDERABLE MIDLEVEL CONVECTION HAS
   DEVELOPED OVER VERY DRY NEAR-SFC LAYER.  THIS...COMBINED WITH SFC
   DEW POINTS 50S F E OF DRYLINE...YIELDS MLCAPE 1500-2000 J/KG
   IMMEDIATELY E OF DRYLINE...IN NARROW ZONE OF FAVORABLY STG
   INSOLATION W OF CLOUD SHIELD FROM ACTIVITY DISCUSSED IN MESOSCALE
   DISCUSSION 481.
   
   FAVORABLE STORM-RELATIVE FLOW IS EXPECTED...GIVEN RELATIVELY BACKED
   SFC WINDS EVIDENT IN TX MESONET DATA AND FCST TO CONTINUE BETWEEN
   THIS AREA AND CAPROCK.  MODIFIED RUC SOUNDINGS SUGGEST SE FLOW WILL
   CONTRIBUTE TO FAVORABLE DEEP-LAYER SHEAR...E.G. EFFECTIVE SHEAR
   MAGNITUDES 45-50 KT FOR SFC-ROOTED PARCELS.  WEAK WINDS JUST ABOVE
   SFC...IN 1-2 KM AGL LAYER -- WILL KEEP LOW LEVEL HODOGRAPHS
   RELATIVELY SMALL OVER INITIATION AREA.  HOWEVER...HODOGRAPHS WILL
   EXPAND EWD WITH PROXIMITY TO 40-50 KT LLJ...AND WITH TIME THIS
   EVENING.
   
   ..EDWARDS.. 04/16/2009
   
   
   ATTN...WFO...DDC...LUB...AMA...MAF...PUB...
   
   LAT...LON   32790203 33650199 34400193 35970239 36870268 37080202
               36900102 35910052 34380053 33210050 32830091 32790203