AREAS AFFECTED...CNTRL INTO NRN IL
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 210017Z - 210115Z
PROBABILITY OF WATCH ISSUANCE...60 PERCENT
SUMMARY...THE THREAT FOR SEVERE STORMS CAPABLE OF DAMAGING
WINDS...LARGE HAIL...AND PERHAPS A TORNADO IS EXPECTED TO DEVELOP
NEWD ACROSS THE AREA THIS EVENING INTO TONIGHT. CONVECTIVE TRENDS
ARE BEING MONITORED FOR A POSSIBLE WW.
DISCUSSION...RECENT TRENDS IN REGIONAL RADAR DATA INDICATE TSTMS
DEVELOPING E OF THE MS RIVER /NW OF SPI/ IN ADVANCE OF AN EVOLVING
QLCS OVER MO. VISIBLE SATELLITE IMAGERY AND SURFACE OBSERVATIONS
SUGGEST THAT THE ERN-MOST STORMS ARE FORMING NEAR AN OUTFLOW
BOUNDARY LIFTING NWD THROUGH CNTRL IL. THE 00Z ILX APPEARS TO BE A
REASONABLE PROXY FOR THE ENVIRONMENT S OF THE OUTFLOW BOUNDARY WHERE
STEEP LAPSE RATES AND A MOIST PBL /LOWEST 100-MB MEAN-MIXING RATIOS
OF AROUND 13 G PER KG/ WERE YIELDING A MODERATELY UNSTABLE
ENVIRONMENT. WHEN COUPLED WITH A VERTICALLY VEERING WIND PROFILE
WITH 40-50 KT SWLY MIDLEVEL WINDS...THE ENVIRONMENT APPEARS
SUPPORTIVE OF ORGANIZED STORM MODES...INCLUDING SUPERCELLS AND
BOWING STRUCTURES WITH A RISK FOR DAMAGING WINDS...LARGE HAIL...AND
PERHAPS A TORNADO.
..MEAD/CORFIDI.. 05/21/2013
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LOT...ILX...MKX...DVN...
LAT...LON 40779036 41699026 42638960 42578839 41918782 40698769
40158830 40058942 40779036
