MESOSCALE DISCUSSION 2012
   NWS STORM PREDICTION CENTER NORMAN OK
   0729 PM CDT SUN SEP 13 2009
   
   AREAS AFFECTED...ERN MT
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 740...
   
   VALID 140029Z - 140200Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 740
   CONTINUES.
   
   A HAIL THREAT WILL CONTINUE ACROSS ERN MT THIS EVENING. AN ISOLATED
   WIND DAMAGE THREAT MAY DEVELOP AS STORMS INCREASE IN COVERAGE. THE
   SEVERE THREATS SHOULD GRADUALLY SHIFT NWD TOWARD THE CANADIAN BORDER
   BY THE MID TO LATE EVENING.
   
   SCATTERED STRONG TO SEVERE THUNDERSTORMS ONGOING IN ERN MT ARE BEING
   SUPPORTED BY A LOBE OF VORTICITY EVIDENT ON WATER VAPOR AND RUC
   ANALYSIS ASSOCIATED WITH AN UPPER-LEVEL LOW IN CNTRL MT. LIFT IS
   ALSO BEING ENHANCED BY MODERATE INSTABILITY AND A LOW-LEVEL JET
   LOCATED NEAR THE ND AND MT STATE-LINE. THE LOW-LEVEL JET ALONG WITH
   A MID-LEVEL JET OVER SRN MT IS HELPING TO CREATE VERTICAL SHEAR
   SUPPORTIVE OF SEVERE STORMS. STEEP MID-LEVEL LAPSE RATES AND COLD
   AIR ALOFT ASSOCIATED WITH THE UPPER-LEVEL LOW WILL BE FAVORABLE FOR
   HAIL. ROTATING STORMS MAY HAVE A POTENTIAL FOR LARGER HAIL. AN
   ISOLATED WIND DAMAGE THREAT WILL ALSO BE POSSIBLE ESPECIALLY WITH
   ANY LINE-SEGMENTS THAN CAN ORGANIZE LATER THIS EVENING.
   
   ..BROYLES.. 09/14/2009
   
   
   ATTN...WFO...BIS...UNR...BYZ...GGW...TFX...
   
   LAT...LON   48980823 47990842 47890886 47720885 47610855 47580793
               47040798 46490778 46500725 46280697 45670686 45670667
               45160672 45160630 45780622 45770496 46140492 46130457
               46020454 46020437 45950436 45950415 45830410 45830404
               48990404 49000823 48980823