MESOSCALE DISCUSSION 1683
   NWS STORM PREDICTION CENTER NORMAN OK
   0750 PM CDT THU JUL 21 2011
   
   AREAS AFFECTED...PORTIONS OF CNTRL MAINE...NRN NH...NRN VT...FAR
   NERN NY
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 220050Z - 220215Z
   
   CLUSTERS OF STRONG TO POSSIBLY SVR STORMS WILL OCCUR THROUGH THIS
   EVENING...AND THE ISSUANCE OF A WW IS POSSIBLE.
   
   SFC MESOANALYSIS REVEALS AN E/W-ORIENTED CONFLUENCE AXIS DRAPED
   ACROSS PORTIONS OF NEW ENGLAND AND SRN QUEBEC. THIS FEATURE IS
   EXPECTED TO REMAIN THE FOCUS FOR MULTICELLULAR CONVECTIVE CLUSTERS
   SHIFTING EWD/ESEWD THROUGH THIS EVENING. MODERATELY UNSTABLE INFLOW
   -- I.E. 2375 J/KG OF MLCAPE PER GRAY MAINE 00Z OBSERVED SOUNDING --
   WILL OFFER SUPPORT FOR VIGOROUS UPDRAFTS...WITH A THREAT FOR STRONG
   TO POSSIBLY SVR STORMS ENSUING. EFFECTIVE BULK SHEAR MAGNITUDES OF
   40 TO 50 KT WILL MAINTAIN SOME STORM ORGANIZATION/SUSTENANCE...WITH
   THE THREAT FOR DMGG WIND GUSTS EMANATING FROM MORE ORGANIZED BOWING
   STRUCTURES. THE ABSENCE OF MID-LEVEL FORCING FOR ASCENT /LITTLE
   MID-LEVEL HEIGHT CHANGE NOTED OVER RECENT TIME/ AND WEAK MID-LEVEL
   LAPSE RATES WILL LIKELY MITIGATE THE SVR THREAT TO SOME DEGREE.
   HOWEVER...MODERATE TO STRONG FLOW ALOFT PER AREA VWP DATA AND THE
   PRESENCE OF MID-LEVEL DRY AIR MAY ENHANCE THE THREAT FOR STRONG AND
   POSSIBLY DMGG WIND GUSTS AT THE SFC. WHILE THE THREAT FOR A TORNADO
   CANNOT BE RULED OUT SOUTH OF THE CONFLUENCE AXIS WHERE SUBTLE
   LOW-LEVEL DIRECTIONAL SHEAR IS PRESENT...THIS THREAT WILL LIKELY BE
   LIMITED WITH THE ANTICIPATION OF A PRIMARILY LINEAR CONVECTIVE MODE.
   
   ..COHEN.. 07/22/2011
   
   
   ATTN...WFO...CAR...GYX...BTV...
   
   LAT...LON   44356969 44377203 44337255 44587406 45067392 45027193
               45387113 45677061 45776916 45476812 44936777 44616814
               44506858 44356969