ACUS11 KWNS 222039
SWOMCD
MESOSCALE DISCUSSION 1020
NWS STORM PREDICTION CENTER NORMAN OK
0338 PM CDT WED JUN 22 2016
AREAS AFFECTED...ERN IA...FAR SRN WI...NRN INTO CNTRL IL...NW IND
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY
VALID 222038Z - 222215Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP BY 23Z.
THESE STORMS WILL QUICKLY BECOME SEVERE WITH TORNADOES...DAMAGING
WINDS AND LARGE HAIL POSSIBLE INTO THE EVENING HOURS. A TORNADO
WATCH WILL LIKELY BE NEEDED WITHIN THE NEXT HOUR FOR PORTIONS OF THE
MCD AREA.
DISCUSSION...CONVECTION DURING MOST OF THE MORNING HOURS AND RELATED
CLOUD COVER ACROSS IA/WI/IL/IND HAS RESULTED IN MAINTENANCE OF
STRONG CAPPING /AS EVIDENT IN 19Z REGIONAL RAOBS/. HOWEVER...RECENT
CLEARING IN THE LAST 1-2 HOURS HAS ALLOWED FOR STRONG SURFACE
HEATING WITH TEMPERATURES CLIMBING FROM THE UPPER 60S F INTO THE MID
70S TO LOW 80S F AS FAR NORTH AS THE IL/WI BORDER. ADDITIONAL
HEATING AND MOISTENING SHOULD CONTINUE TO ERODE THE CAP. AS DEEP
LAYER FORCING FOR ASCENT INCREASES WITH THE APPROACH OF THE UPPER
SHORTWAVE IMPULSE...STORMS ARE EXPECTED TO DEVELOP ACROSS ERN IA/SW
WI/FAR NW IL BY 23Z. ONCE STORMS DEVELOP...THEY ARE EXPECTED TO
TRACK E-SE ALONG A STRONG INSTABILITY GRADIENT IN THE VICINITY OF A
WARM FRONT DRAPED ACROSS NRN IL INTO CENTRAL IND.
STEEP MIDLEVEL LAPSE RATES NEAR 7.5 C/KM PER DVN AND ILX 19Z RAOBS
AND 0-6 KM SHEAR GREATER THAN 50 KT WILL SUPPORT ROTATING UPDRAFTS
AND LARGE HAIL. FURTHERMORE...RICH BOUNDARY LAYER MOISTURE WITH
MIXING RATIOS NEAR 14 G/KG AND BACKED LOW-LEVEL WINDS EVIDENT IN 19Z
RAOBS AND...MORE RECENTLY...INDICATED BY REGIONAL VWP/S...WILL
SUPPORT A FEW TORNADOES /POTENTIALLY ONE OR TWO SIG TORS/. STORMS
ARE EXPECTED TO GROW UPSCALE INTO A SOUTHEASTWARD PROPAGATING MCS
WITH A COINCIDENT INCREASE IN DAMAGING WIND THREAT INTO
INDIANA...AND LATER TONIGHT THE OHIO VALLEY.
..LEITMAN/GUYER.. 06/22/2016
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...IWX...IND...LOT...ILX...MKX...DVN...ARX...
LAT...LON 41509103 42529189 42969203 43259176 43229105 42958906
42508793 41868652 41458606 40868600 40478615 39868638
39658669 39548714 39628784 39988867 40839009 41269075
41509103
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