MESOSCALE DISCUSSION 1694
   NWS STORM PREDICTION CENTER NORMAN OK
   0517 PM CDT FRI JUL 22 2011
   
   AREAS AFFECTED...ERN MT...SW ND...WRN SD
   
   CONCERNING...TORNADO WATCH 671...
   
   VALID 222217Z - 222345Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 671 CONTINUES.
   
   THE SEVERE THREAT ACROSS THE CNTRL PART OF WW 671 WILL LIKELY SPREAD
   ESEWD LATE THIS AFTERNOON. AN MCS WILL LIKELY ORGANIZE THIS EVENING
   WITH THE ACTIVITY MOVING SEWD INTO WRN ND AND NW SD. IN
   ADDITION...ISOLATED THUNDERSTORMS ARE INITIATING WELL TO THE EAST OF
   THE LINE IN SW ND WHERE A WW WILL LIKELY BE NEEDED. LARGE
   HAIL...WIND DAMAGE AND POSSIBLY A FEW TORNADOES WILL LIKELY EXIST
   WITH THE MORE INTENSE CELLS.
   
   A BROKEN LINE OF STRONG THUNDERSTORMS IS ONGOING ON THE WRN EDGE OF
   MODERATE INSTABILITY WHERE MLCAPE VALUES ARE ESTIMATED IN THE 2000
   TO 3000 J/KG RANGE. THE STORMS ARE BEING SUPPORTED BY LARGE-SCALE
   ASCENT ASSOCIATED WITH A SHORTWAVE TROUGH OVER CNTRL MT EVIDENT ON
   WATER VAPOR IMAGERY. A WELL-DEFINED 50 TO 60 KT MID-LEVEL JET ACROSS
   SRN MT ASSOCIATED WITH THE SHORTWAVE IS CREATING STRONG DEEP LAYER
   SHEAR PROFILES WHICH COMBINED WITH STEEP MID-LEVEL LAPSE RATES WILL
   BE FAVORABLE FOR SUPERCELLS AND LARGE HAIL. DISCRETE CELLS ARE ALSO
   INITIATING IN SW ND WELL AHEAD OF THE LINE WHERE SFC WINDS ARE
   BACKED. AS LOW-LEVEL FLOW INCREASES EARLY THIS EVENING...THE THREAT
   FOR TORNADOES AND LARGE HAIL SHOULD INCREASE WITH SUPERCELLS THAT
   INITIATE AHEAD OF THE LINE WHERE SFC DEWPOINTS IN WRN AND SRN ND ARE
   IN THE MID TO UPPER 60S F. AN ISOLATED TORNADO THREAT WILL ALSO
   EXIST WITH THE MORE DOMINANT CELLS EMBEDDED IN THE LINE. IF A COLD
   POOL CAN ORGANIZE...THEN A WIND DAMAGE THREAT WILL ALSO EXIST AS THE
   LINE MOVES INTO WRN ND AND NW SD LATER THIS EVENING.
   
   ..BROYLES.. 07/22/2011
   
   
   ATTN...WFO...ABR...BIS...UNR...BYZ...GGW...TFX...
   
   LAT...LON   47100093 48090306 48490576 48530693 48220773 46860879
               45730942 45100895 44980748 44930637 44870459 44640281
               44930179 45590130 46500082 47100093