Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 241821
SWOMCD
SPC MCD 241820
INZ000-ILZ000-241945-

MESOSCALE DISCUSSION 1580
NWS STORM PREDICTION CENTER NORMAN OK
0120 PM CDT WED AUG 24 2016

AREAS AFFECTED...PARTS OF CNTRL ILLINOIS THROUGH CNTRL/SRN IND

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 241820Z - 241945Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...IT IS NOT CERTAIN THAT A SEVERE WEATHER WATCH WILL BE
NEEDED THIS AFTERNOON.  HOWEVER...CONVECTIVE TRENDS WILL CONTINUE TO
BE MONITORED FOR THE POSSIBILITY OF INCREASING SEVERE WEATHER
POTENTIAL WHICH COULD EVENTUALLY REQUIRE ONE.

DISCUSSION...RECENT THUNDERSTORM INTENSIFICATION TO THE EAST
SOUTHEAST OF DANVILLE IL IS OCCURRING ALONG A NORTHWEST-SOUTHEAST
ORIENTED ZONE OF STRENGTHENING DIFFERENTIAL SURFACE HEATING.  THIS
IS ALSO JUST AHEAD OF A REMNANT CONVECTIVELY GENERATED OR ENHANCED
LOW/MID-LEVEL CYCLONIC VORTICITY CENTER...WHICH ALSO APPEARS TO BE
AIDING INITIATION OF NEW CONVECTIVE DEVELOPMENT EITHER SIDE OF THE
SURFACE BOUNDARY ACROSS NORTHERN/CENTRAL ILLINOIS.

ALONG AND SOUTH OF THE SURFACE BOUNDARY...THE BOUNDARY LAYER IS
BECOMING MODERATELY UNSTABLE /AS CHARACTERIZED BY CAPE IN EXCESS OF
2000 J PER KG/ WITH CONTINUING INSOLATION.  THIS IS OCCURRING IN THE
PRESENCE OF A BELT OF AT LEAST MODESTLY SHEARED 30+ KT WESTERLY DEEP
LAYER MEAN FLOW.  ALTHOUGH VARIOUS HIGH-RESOLUTION CONVECTION
ALLOWING MODEL OUTPUT REMAIN UNCLEAR CONCERNING POTENTIAL FURTHER
CONVECTIVE DEVELOPMENT THIS AFTERNOON...THIS ENVIRONMENT APPEARS
CONDUCIVE TO THE EVOLUTION OF AN UPSCALE GROWING THUNDERSTORM
CLUSTER AND STRENGTHENING SURFACE COLD POOL THAT COULD EVENTUALLY BE
ACCOMPANIED BY THE RISK FOR STRONG SURFACE GUSTS.

..KERR/WEISS.. 08/24/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...ILN...LMK...IWX...IND...LOT...ILX...

LAT...LON   41068851 40938730 40528574 39988497 38898520 38838671
            38998789 39608925 40528944 41068851



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