AREAS AFFECTED...NRN/CNTRL IL/IND
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 291422Z - 291645Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...CLUSTER OF ELEVATED TSTMS CROSSING THE MS VALLEY IN IA/IL
SHOULD GROW UPSCALE AND BECOME SURFACE-BASED AS DOWNSTREAM HEATING
INTENSIFIES. PRIMARY SEVERE THREATS WILL BE DAMAGING WINDS AND LARGE
HAIL...WHICH SHOULD BECOME SCATTERED IN COVERAGE THIS AFTERNOON.
DISCUSSION...DOWNSTREAM OF AN MCV OVER ERN NEB...CLUSTER OF ELEVATED
TSTMS HAS ERUPTED IN ERN IA INTO NWRN IL. THIS ACTIVITY IS N OF THE
QUASI-STATIONARY FRONT EXTENDING FROM NEAR BRL TO IND. WITH
EXTREMELY BUOYANT MU PARCELS NOTED IN THE 12Z DVN/ILX RAOBS...MUCAPE
AOA 6000 J/KG...CONVECTION-ALLOWING MODELS ARE FAIRLY CONSISTENT
THAT AN MCS SHOULD EVOLVE E/SEWD FROM THE MS VALLEY
ACTIVITY...ESPECIALLY RECENT HRRR RUNS. WITH INTENSE SURFACE HEATING
EXPECTED DOWNSTREAM...THIS SCENARIO APPEARS PROBABLE WITHIN A
MODERATE NEARLY UNIDIRECTIONAL WLY FLOW REGIME. GIVEN THE DEGREE OF
INSTABILITY...THREATS FOR LARGE HAIL AND DAMAGING WINDS SHOULD
INCREASE THROUGH THE AFTERNOON ESPECIALLY WITHIN BOWING LINEAR
SEGMENTS.
..GRAMS/RACY/THOMPSON.. 06/29/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...ILN...IWX...IND...LOT...ILX...DVN...
LAT...LON 41828936 41368696 40728455 39758465 39268486 39218579
39708853 40319008 40679057 41289033 41828936
