MESOSCALE DISCUSSION 1129
   NWS STORM PREDICTION CENTER NORMAN OK
   1236 PM CDT WED JUN 13 2007
   
   AREAS AFFECTED...SWRN KS...FAR ERN OK/TX PANHANDLE...WRN OK
   
   CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 
   
   VALID 131736Z - 132000Z
   
   SCT TSTMS ARE EXPECTED TO DEVELOP ALONG BOTH A COLD FRONT AND
   OUTFLOW BOUNDARY OVER THE AREA IN THE NEXT 2-3 HOURS. A FEW OF THE
   TSTMS ARE EXPECTED TO POSE A SVR THREAT SHORTLY AFTER DEVELOPMENT
   WITH LARGE HAIL/DMGG WINDS AND POSSIBLY AN ISOLATED TORNADO. WW IS
   LIKELY...POSSIBLY BY 19Z.
   
   LATEST VISIBLE SATELLITE/RADAR IMAGERY SHOWS TSTMS WERE BEGINNING TO
   DEVELOP NEAR THE UPPER LOW CENTER AND IN THE POST FRONTAL AIRMASS OF
   SERN CO. RECENT MESOANALYSIS SHOWED A WEAK COLD FRONT EXTENDED FROM
   A SFC LOW CENTERED IN THE ERN OK PANHANDLE SWD ACROSS THE FAR ERN TX
   PANHANDLE. A SLOW WWD MOVING OUTFLOW BOUNDARY EXTENDED FROM THE SFC
   LOW ESEWD TO NEAR ALVA AND THEN TO JUST NW OF OKC. RECENT RUC
   FORECAST SOUNDINGS AND THE MODIFIED 12Z OUN/DDC SOUNDINGS INDICATED
   CONVECTIVE TEMPERATURES BETWEEN 80-85 DEG F OVER THE AREA...WHICH
   HAVE BEEN REACHED AT 17Z. HOWEVER... CONVECTIVE INITIATION APPEARS
   TO STILL BE ANOTHER 1-2 HOURS AWAY AS SOME SUBSIDENCE IS APPARENT IN
   THE WAKE OF AN UPPER LEVEL SHORTWAVE TROUGH /PER WV IMAGERY/ AND
   GRAVITY WAVES BENEATH A CAPPING INVERSION WERE NOTED OVER SWRN KS. A
   FEW MORE HOURS  HEATING WILL SUPPORT A VERY UNSTABLE AIRMASS WITH
   MLCAPES FROM 2500-3500 J/KG /GREATEST OVER WRN OK/. ALONG WITH WEAK
   TO MODERATE CONVERGENCE NEAR BOTH BOUNDARIES...TSTM INITIATION IS
   EXPECTED BY 20Z. BASED ON THE 12Z AMA SOUNDING...25-30 KTS OF MID
   LEVEL WINDS WILL OVERSPREAD MUCH OF WRN OK/ERN TX PANHANDLE THIS
   AFTERNOON...WITH WEAKER WINDS CLOSER TO THE UPPER LOW OVER SWRN KS.
   WITH BACKED 10-15 KT LOW LEVEL WINDS /ESPCLY INVOF THE OUTFLOW
   BOUNDARY/ MODERATE VERTICAL SHEAR /AROUND 35 KTS/ SHOULD SUPPORT
   ISOLATED SUPERCELLS WITH THE THREAT FOR DMGG WINDS AND POSSIBLY VERY
   LARGE HAIL. GIVEN WEAKER MID LEVEL WIND FIELDS FURTHER NORTH...A
   MORE MULTICELLULAR STORM MODE IS EXPECTED OVER SWRN KS. RECENT VWP
   DATA FROM VANCE AFB INDICATED FAIRLY STRONG LOW LEVEL SHEAR /15-20
   KTS OF 0-1 KM VECTOR SHEAR/ JUST EAST OF THE OUTFLOW BOUNDARY.
   COMBINED WITH ENHANCED VORTICITY INVOF THE OUTFLOW BOUNDARY AND
   FAIRLY HIGH 0-3 KM CAPE /150 J/KG/... ANY SUPERCELL THAT DOES
   DEVELOP WILL BE CAPABLE OF PRODUCING AN ISOLATED TORNADO /ESPECIALLY
   NEAR AND JUST WEST OF THE OUTFLOW BOUNDARY/.
   
   ..CROSBIE.. 06/13/2007
   
   
   ATTN...WFO...OUN...DDC...LUB...AMA...
   
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