ZCZC SPCSWOMCD ALL ACUS11 KWNS 282256 SPC MCD 282256 ILZ000-MOZ000-IAZ000-290030- MESOSCALE DISCUSSION 1224 NWS STORM PREDICTION CENTER NORMAN OK 0556 PM CDT SUN JUN 28 2015 AREAS AFFECTED...CNTRL AND NE MO THRU PARTS OF NW/W CNTRL IL CONCERNING...TORNADO WATCH 367... VALID 282256Z - 290030Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 367 CONTINUES. SUMMARY...SCATTERED STRONG TO LOCALLY SEVERE THUNDERSTORM ACTIVITY WILL GRADUALLY OVERSPREAD AREAS IN AND AROUND THE GREATER ST. LOUIS METROPOLITAN REGION THROUGH 01-02Z. DISCUSSION...NUMEROUS...SOMEWHAT SMALL...BUT VIGOROUS...THUNDERSTORMS HAVE DEVELOPED DURING THE PAST FEW HOURS ACROSS PARTS OF CENTRAL AND NORTHEAST MISSOURI...AND ADJACENT PORTIONS OF THE MIDDLE MISSISSIPPI VALLEY. THIS IS BEING AIDED BY FORCING FOR ASCENT ACCOMPANYING ONE OF AT LEAST A COUPLE OF DIGGING SHORT WAVE IMPULSES WITHIN CYCLONIC NORTHWESTERLY MID/UPPER FLOW. ACTIVITY HAS INITIATED IN A MODERATELY UNSTABLE BOUNDARY LAYER THAT APPEARS CHARACTERIZED BY CAPE ON THE ORDER OF 2000 J/KG... BUT AT LEAST ACROSS THE ST. LOUIS METRO AND AREAS TO THE NORTHEAST...THE TENDENCY WILL BE FOR ACTIVITY TO PROPAGATE INTO A SOMEWHAT COOLER AND LESS UNSTABLE ENVIRONMENT. INTERFERENCE FROM OTHER STORMS COULD ALSO BE A LIMITING FACTOR TO OVERALL STORM SUSTENANCE. IT REMAINS UNCLEAR WHETHER FORCING ASSOCIATED WITH AN AN AREA OF WEAK LOW-LEVEL WARM ADVECTION OVERSPREADING THE REGION WILL BE STRONG ENOUGH TO SUPPORT CONSOLIDATION AND UPSCALE GROWTH OF CONVECTION. DESPITE THESE POTENTIAL NEGATIVE FACTORS...THERE STILL APPEARS A WINDOW OF OPPORTUNITY THROUGH AROUND 01-02Z...FOR AT LEAST A COUPLE OF STORMS TO EMERGE WITH AT LEAST SOME INCREASE IN SEVERE WEATHER POTENTIAL. THIS WILL INCLUDE THE RISK FOR MARGINALLY SEVERE HAIL AND LOCALIZED STRONG WIND GUSTS. PERHAPS OF MORE CONCERN...20-30 KT SOUTHWESTERLY 850 MB FLOW WILL CONTINUE TO CONTRIBUTE TO SUFFICIENTLY LARGE LOW-LEVEL HODOGRAPHS TO SUPPORT THE RISK FOR AT LEAST RELATIVELY SHORT-LIVED TORNADOES WITH ANY OF THE POTENTIALLY STRONGER EMERGING STORMS THROUGH EARLY EVENING. ..KERR.. 06/28/2015 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...PAH...ILX...LSX...DVN...SGF...DMX... LAT...LON 39279208 40839227 39739053 39068895 38328931 37949009 37879099 38059169 38489240 39279208 NNNN