SWODY1
SPC AC 231619
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1119 AM CDT WED JUN 23 2010
VALID 231630Z - 241200Z
...THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON AND EARLY TONIGHT
OVER PARTS OF NRN IL...NRN IND...SRN LWR MI..NRN OH...WRN PA AND
UPSTATE NY......
...THERE IS A SLGT RISK OF SVR TSTMS FROM PARTS OF THE SRN PLNS
THROUGH THE MID MS VLY TO THE APPALACHIANS...
...SYNOPSIS...
AS HEIGHTS RISES OVER THE WRN U.S. THE FINAL IN A SERIES OF S/WV
TROUGHS NOW MOVING ACROSS UPPER MS VALLEY WILL ACCELERATE EWD ACROSS
THE GREAT LAKES THIS FORECAST PERIOD. STRONG MID/UPPER JET PRECEDES
TROUGH CURRENTLY EXTENDING FROM SRN MN/NRN IA EWD TO LWR MI WILL
TRANSLATE EWD ACROSS LOWER LAKES INTO WRN NY/PA BY THIS EVENING.
WHILE THE COLD FRONT IS STILL LOCATED FROM ERN MN TO CENTRAL
KS...THE PRIMARY AREA OF INTEREST WITH REGARDS TO TODAYS MDT RISK IS
THE CONVECTIVELY INDUCED OUTFLOW BOUNDARY CURRENTLY FROM SERN MI
WSWWD ACROSS NRN IND TO SERN IA.
S OF BOUNDARY AIR MASS IS VERY WARM AND MOIST AND WITH STRONG
HEATING WILL BECOME VERY UNSTABLE BY MID AFTERNOON.
...MID/UPR MS VALLEY EWD TO LWR GREAT LAKES...
...PRIMARY ADJUSTMENT TO MDT RISK WAS TO MOVE IT S OUT OF WI AND
MUCH OF MI DUE TO THE EFFECTIVE BOUNDARY LOCATION TO THE S...
WITH STRONG HEATING OF THE ALREADY MOIST AIR MASS S OF THE E/W
CONVECTIVE BOUNDARY...MLCAPES WILL CLIMB TO 3K J/KG OR GREATER BY
MID AFTERNOON ACROSS MUCH OF MID MS AND OH VALLEYS. ONGOING
THUNDERSTORMS ALONG AND N OF BOUNDARY WILL INCREASE RAPIDLY IN
INTENSITY BY EARLY/MID AFTERNOON FROM ERN/IA NRN IL EWD TO NRN OH.
WITH 50-60KT OF SHEAR AND STEEP LOW/MID LEVEL LAPSE RATES...MIXED
CONVECTIVE MODES ARE INITIALLY EXPECTED...SUPERCELLS EVOLVING INTO
BOWS/LINE SEGMENTS.
WHILE LARGE HAIL AND ISOLATED TORNADOES ARE LIKELY DURING THE EARLY
STAGES OF SEVERE DEVELOPMENT THIS AFTERNOON...MODE SHOULD QUICKLY
EVOLVE INTO FORWARD PROPAGATING LINEAR STRUCTURES AS COLD POOLS
DEVELOP. WIND DAMAGE POTENTIAL SHOULD INCREASE RAPIDLY BY MID/LATE
AFTERNOON WITH MORE SIGNIFICANT WIND DAMAGE ASSOCIATED WITH ANY
BOWS/LINE SEGMENTS.
WITH THE STRONG JET FEATURES SPREADING EWD ACROSS LOWER GREAT LAKES
THIS EVENING SO WILL THE SEVERE THUNDERSTORM THREAT. BY THIS EVENING
ONE OR MORE FAST MOVING LINEAR MCS/S IS LIKELY EACH ASSOCIATED WITH
A SWATH OF DAMAGING WIND. AS THE MOISTURE/INSTABILITY OVER OH
VALLEY SPREADS EWD ON THE STRONG WLY FLOW SO WILL THE CONCERN OF
POTENTIAL FOR AN ORGANIZED DAMAGING WIND EVENT.
ADDITIONAL SEVERE THREAT WILL BE ALONG/AHEAD OF COLD FRONT ACROSS WI
WHERE UPPER TROUGH WILL BE TRACKING THRU THIS AFTERNOON. AIR MASS
THIS AREA IS MOIST AND WITH HEATING WILL PROVIDE MLCAPES UPWARDS TO
1500 J/KG. PRIMARY CONCERN GIVEN THE RATHER WEAK LOW LEVEL SHEAR
WILL BE HAIL...LOCAL DAMAGING WINDS.
...LWR MO VLY TO SRN HI PLNS THIS AFTN/EVE...
WITH UPR RIDGE HOLDING FIRMLY OVER THE SRN PLNS...LARGE
SCALE FORCING FOR ASCENT WILL BE LIMITED ACROSS THIS REGION.
NONETHELESS...FRONTAL UPLIFT AND MOIST/WEAKLY-CAPPED/MODERATELY
UNSTABLE ENVIRONMENT WILL BE SUFFICIENT FOR ISOLD TO SCTD STRONG TO
SVR STORMS ALONG/JUST AHEAD OF SE-MOVING COLD FRONT. DMGG WINDS/SVR
HAIL WILL BE POSSIBLE LATE THIS AFTN INTO EARLY TONIGHT.
...CNTRL APPALACHIANS/CAROLINAS THIS AFTN/EARLY EVE...
AIDED BY A WEAK/CONVECTIVELY-INDUCED VORT MAX...SCTD TSTMS SHOULD
REDEVELOP OVER THE HIGHER TERRAIN OF THE CNTRL APPALACHIANS TO
PORTIONS OF THE DOWNSTATE CAROLINAS THIS AFTN. SPORADIC DMGG WIND
GUSTS WILL POSSIBLE DURING THE AFTN/EARLY EVE.
..HALES/STOPPKOTTE.. 06/23/2010
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