MESOSCALE DISCUSSION 2171
   NWS STORM PREDICTION CENTER NORMAN OK
   0222 PM CDT TUE SEP 13 2011
   
   AREAS AFFECTED...MAINE...NRN NH
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 131922Z - 132045Z
   
   A SEVERE THREAT SHOULD DEVELOP ACROSS WRN MAINE AND NRN NH AS STORMS
   MOVE INTO THE AREA FROM THE WEST. HAIL AND WIND DAMAGE WILL BE
   POSSIBLE WITH THE STRONGER CELLS. WW ISSUANCE MAY BECOME NECESSARY
   THIS AFTERNOON ACROSS PARTS OF MAINE AND NH WHERE AN UPGRADE TO
   SLIGHT RISK IS PLANNED FOR THE 20Z OUTLOOK.
   
   A LINE OF THUNDERSTORMS CURRENTLY IN SRN QUEBEC IS LOCATED TO THE
   EAST OF SFC TROUGH AND ALONG A NARROW AXIS OF LOW-LEVEL MOISTURE.
   THE THUNDERSTORMS ARE BEING SUPPORTED BY A SHORTWAVE TROUGH EVIDENT
   ON WATER VAPOR IMAGERY OVER SRN QUEBEC WITH A WELL-DEFINED VORTICITY
   MAXIMA ANALYZED BY THE RUC. THE LIFT ASSOCIATED WITH THE SHORTWAVE
   TROUGH AND INCREASING INSTABILITY ACROSS NEW ENGLAND SHOULD HELP THE
   LINE OF STRONG THUNDERSTORMS TO BE MAINTAINED EWD INTO WRN MAINE AND
   NRN NH LATER THIS AFTERNOON. FORECAST SOUNDINGS IN WRN MAINE THIS
   AFTERNOON SUGGEST 0-6 KM WILL CONTINUE TO INCREASE TO AROUND 40 KT
   AS THE STRUCTURE OF A LOW TO MID-LEVEL JET SHIFTS EWD INTO THE MCD
   AREA. THIS COMBINED WITH STEEPENING LOW-LEVEL LAPSE RATES AND A
   LINEAR ORIENTATION OF THE CONVECTION SHOULD BE FAVORABLE FOR WIND
   DAMAGE WITH SHORT BOWING LINE-SEGMENTS. THE LINE OF STORMS IS TIMED
   INTO WRN MAINE AROUND 22Z SUGGESTING A WW MAY BE NEEDED BEFORE THAT
   TIME.
   
   ..BROYLES.. 09/13/2011
   
   
   ATTN...WFO...CAR...GYX...BTV...
   
   LAT...LON   47396824 47426874 47026959 46357005 45717056 45377113
               44937145 44407170 44077160 44007110 44716973 46056828
               46976778 47396824