
MESOSCALE DISCUSSION 0225
NWS STORM PREDICTION CENTER NORMAN OK
0315 PM CDT TUE MAR 10 2009
AREAS AFFECTED...PORTIONS OF ERN/SRN MO ACROSS CENTRAL AND PORTIONS
OF SRN IL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 102015Z - 102215Z
SUFFICIENT HEATING HAS OCCURRED AHEAD OF COLD FRONT THAT IS
DIAGONALLY NE/SW ACROSS MO FOR SURFACE BASED CONVECTION TO DEVELOP.
THE PRIMARY LIMITING PARAMETER FOR SEVERE IS THE INSTABILITY. WITH
MLCAPES GENERALLY LESS THAN 500 J/KG...EVEN WITH SURFACE TEMPS INTO
THE MID 70S F AND DEWPOINTS MID/UPR 50S...UPDRAFTS WILL BE SLOW TO
INTENSIFY. HOWEVER A VERY STRONG WIND PROFILE IS TRANSLATING ACROSS
THE MID MS VALLEY AS AN INTENSE S/WV AND 100 KT 500 MB WIND MAX
TRACKS FROM IA TO WI THIS EVENING.
THERE IS STILL SOME UNCERTAINTY WITH REGARDS TO EXTENT OF ANY SEVERE
THREAT SUFFICIENT TO WARRANT A WATCH...BUT GIVEN THE VERY IMPRESSIVE
KINEMATIC SUPPORT WITH SFC-6KM SHEAR OF 60KT...POTENTIAL EXISTS FOR
NOT ONLY LOW TOPPED THUNDERSTORMS TO FORM INTO SHORT LINE
SEGMENTS/BOWS WHICH WOULD ENHANCE A WIND DAMAGE CONCERN BUT ALSO
DEVELOP AT LEAST LOW LEVEL ROTATION FOR AN ISOLATED TORNADO THREAT.
THE CURRENT LOW TOPPED CONVECTION DEVELOPING VICINITY COU SWWD
TOWARD SGF SHOULD INCREASE IN COVERAGE AND GRADUALLY INTENSITY
SPREADING EWD ACROSS ERN/SRN MO INTO CENTRAL IL REMAINDER OF THE
AFTERNOON.
..HALES.. 03/10/2009
ATTN...WFO...IND...PAH...ILX...LSX...SGF...