MESOSCALE DISCUSSION 1646
   NWS STORM PREDICTION CENTER NORMAN OK
   0417 PM CDT SAT AUG 04 2007
   
   AREAS AFFECTED...WRN ND
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 042117Z - 042345Z
   
   AN ISOLATED SVR TSTM OR TWO MAY DEVELOP BETWEEN A DRYLINE AND A
   SLOWLY MOVING WARM FRONTAL BOUNDARY ACROSS WRN ND IN THE NEXT FEW
   HOURS. LIMITED AREAL COVERAGE OF THE SVR THREAT SHOULD PRECLUDE THE
   NEED FOR A WW. 
   
   WV IMAGERY SHOWS A SUBTLE SHORTWAVE TROUGH APPROACHING THE REGION
   FROM CENTRAL MT. AS A RESULT OF A SHORTWAVE TROUGH PASSAGE TROUGH
   SASKATCHEWAN...A DRYLINE HAS PUSHED EWD ACROSS FAR ERN MT INTO FAR
   WRN ND. MEANWHILE...A SLOW MOVING WARM FRONT EXTENDS N-S ACROSS WRN
   ND FROM NEAR MOT SWD TO 40 SW OF BIS. BETWEEN THE TWO BOUNDARIES...A
   NARROW INSTABILITY /MLCAPE VALUES FROM 1000-1500 J/KG/ EXISTS.
   ALTHOUGH INHIBITION REMAINS MODEST /AROUND 50 J/KG/...INCREASING
   CONVERGENCE/VERTICAL MOTION DUE TO APPROACHING UPPER WAVE AND
   CONTINUED HEATING MAY SUPPORT ISOLATED SVR TSTM OR TWO ACROSS THE
   AREA BEFORE 23Z. GIVEN A NARROW AND RELATIVELY MARGINAL INSTABILITY
   AXIS A WW IS NOT EXPECTED.
   
   ..CROSBIE.. 08/04/2007
   
   
   ATTN...WFO...BIS...
   
   49050093 48290153 47240217 45960273 46100371 47530366
   48180334 48990314