MESOSCALE DISCUSSION 1368 NWS STORM PREDICTION CENTER NORMAN OK 0723 PM CDT MON JUL 02 2012 AREAS AFFECTED...PORTIONS ERN WI...NERN IL. CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 030023Z - 030230Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...GROWING CLUSTERS OF STG-SVR TSTMS OVER NERN AND E-CENTRAL WI...INTERACTING WITH LM LAKE-BREEZE BOUNDARY -- APPEAR TO BE GETTING BETTER ORGANIZED AND GROWING UPSCALE SUCH THAT THEIR INITIALLY ISOLATED SVR THREAT MAY BECOME SOMEWHAT MORE WIDESPREAD. DISCUSSION...BOUNDARY WAS ANALYZED AT 00Z FROM COOK/LAKE COUNTIES IL NNWWD TO SRN CLUSTER OVER WINNEBAGO COUNTY WI...THEN NWD TO CONVECTION COVERING PORTIONS OCONTO/FOREST/LANGLADE COUNTIES. ALTHOUGH DEEP-LAYER SHEAR IS RELATIVELY WEAK...LACK OF MORE ROBUST DEEP-LAYER WINDS ACTUALLY WILL AID IN THE SORT OF REARWARD/DISCRETELY PROPAGATIONAL STORM-SCALE PROCESSES NECESSARY TO KEEP THIS ACTIVITY GOING...WITHOUT NECESSARILY MOVING OVER RELATIVELY STABLE AIR ON E SIDE OF LAKE BREEZE. ULTIMATELY...MIX OF FORWARD- AND REARWARD-PROPAGATIONAL PROCESSES IS POSSIBLE WITH THIS ACTIVITY...IF COLD POOL AND RELATED ISALLOBARIC PERTURBATIONS BUILD ENOUGH ON STORM SCALE. AS SUCH...THREAT FOR DAMAGING GUSTS AND OCNL LARGE HAIL MAY EXPAND LATERALLY E-W...AS WELL AS TRANSLATE SWD TOWARD SERN WI AND NERN IL. AIR MASS ON W SIDE OF BOUNDARY IS CHARACTERIZED BY SFC TEMPS MID-UPPER 90S F...FCST TO COOL TO LOW 90S IN NEXT 2-3 HOURS...AS WELL AS DEW POINTS RANGING FROM 70S OVER NRN WI TO LOW-MID 60S NEAR WI/IL BORDER. WELL-MIXED BOUNDARY LAYERS WITH HIGHER DEWPOINT DEPRESSIONS OVER SRN WI/NRN WILL WILL BE MORE SUITABLE FOR EVAPORATIONALLY DRIVEN OUTFLOW ACCELERATION...WHILE PRECIP-LOADING PROCESSES ON STORM SCALE WILL DRIVE MOST DAMAGING-WIND POTENTIAL WITH NERN WI ACTIVITY. BUOYANCY...THOUGH LARGER FARTHER N...IS AND WILL REMAIN SUFFICIENT FOR A FEW MORE HOURS TO SUPPORT STG-SVR TSTMS INTO SERN WI/NERN IL AS WELL...WITH MLCAPE STILL AROUND 2000 J/KG SW MKE.
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