MD 0910 CONCERNING SEVERE POTENTIAL…WATCH LIKELY FOR ERN MO THROUGH CNTRL IL
MESOSCALE DISCUSSION 0910 NWS STORM PREDICTION CENTER NORMAN OK 0521 PM CDT FRI MAY 31 2013 AREAS AFFECTED...ERN MO THROUGH CNTRL IL CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 312221Z - 312315Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...STORMS ARE EXPECTED TO DEVELOP EWD THROUGH PARTS OF ERN MO AND CNTRL IL THIS EVENING. DAMAGING WIND...LARGE HAIL AND ISOLATED TORNADOES WILL BE POSSIBLE. WW WILL LIKELY BE NEEDED SOON. DISCUSSION...EARLY THIS EVENING A LINE OF STORMS EXTENDS FROM SERN KS ENEWD ACROSS NCTRL MO WITH THE OUTFLOW BOUNDARY EXTENDING FARTHER EAST THROUGH CNTRL IL. THE ATMOSPHERE IN VICINITY OF THIS BOUNDARY HAS BECOME MODERATELY TO STRONGLY UNSTABLE WITH 2000-3000 J/KG MLCAPE. THE STRONGER INSTABILITY AND STEEPER LAPSE RATES ARE PRESENT ACROSS MO COMPARED TO FARTHER EAST INTO IL. VWP DATA INDICATE DEEP SHEAR FROM 45-50 KT AND 0-2 KM STORM RELATIVE HELICITY FROM 150-200 M2/S2 BASED ON ENEWD STORM MOTIONS. STORMS ARE EXPECTED TO CONTINUE DEVELOPING EWD ALONG THE CONVECTIVE OUTFLOW BOUNDARY DURING THE EVENING. CHARACTER OF THE CLOUDS SOUTH OF THE OUTFLOW BOUNDARY INCLUDING THE ST LOUIS METRO AREA SUGGESTS THE SFC LAYER MIGHT STILL BE CAPPED IN WARM SECTOR. HOWEVER...TENDENCY WILL PROBABLY BE FOR STORMS TO SLOWLY PROPAGATE SWD AS A COLD POOL BECOMES BETTER ESTABLISHED LATER THIS EVENING. BOTH LINE SEGMENTS AND SUPERCELL STRUCTURES APPEAR LIKELY WITH ALL HAZARDS POSSIBLE. ..DIAL/KERR.. 05/31/2013 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...ILX...LSX... LAT...LON 39129161 39799039 40258918 39428890 38209130 39129161
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