Severe Storm Outlook Narrative (AC)
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
ACUS11 KWNS 242242
SWOMCD
SPC MCD 242242
INZ000-MIZ000-ILZ000-250015-

MESOSCALE DISCUSSION 1390
NWS STORM PREDICTION CENTER NORMAN OK
0542 PM CDT SUN JUL 24 2016

AREAS AFFECTED...PORTIONS OF NE IL...NW IND...AND FAR SW MI

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 242242Z - 250015Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A FEW STRONG WIND GUSTS WILL BE POSSIBLE THIS EVENING
ACROSS PORTIONS OF NE IL INTO NW IND AND POSSIBLY FAR SW MI. IT IS
UNCLEAR IF A SEVERE THUNDERSTORM WATCH WILL BE NEEDED AND TRENDS
WILL BE MONITORED CLOSELY.

DISCUSSION...THUNDERSTORMS WERE DEVELOPING THIS EVENING ALONG A
PRE-FRONTAL TROUGH AHEAD OF THE MAIN SYNOPTIC COLD FRONT  ACROSS
NORTHERN IL FROM NEAR CHICAGO SWWD TO NEAR PIA. THE AIRMASS IS
EXTREMELY UNSTABLE WITH MLCAPE VALUES GREAT THAN 4000 J/KG
WIDESPREAD AS SURFACE DEWPOINTS GREAT THAN 75 F WERE NOTED IN LATEST
OBS. DEEP LAYER SHEAR IS RATHER WEAK AT 25 KT OR LESS AND MIDLEVEL
LAPSE RATES ARE UNIMPRESSIVE. LARGE CAPE WILL ALLOW FOR VIGOROUS
UPDRAFTS...BUT OVERALL ORGANIZATION OF STORMS WILL BE DIFFICULT TO
MAINTAIN GIVEN THE LACK OF UPPER FORCING FOR ASCENT AND POOR
KINEMATICS/LAPSE RATES. THAT BEING SAID...PW VALUES GREATER THAN 2
INCHES COULD ALLOW FOR ISOLATED WET MICROBURSTS. SHOULD STORM
COVERAGE INCREASE AND UPSCALE GROWTH ENSUE...THE DAMAGING WIND
THREAT COULD BECOME SUFFICIENT FOR POSSIBLE WATCH ISSUANCE.
CONVECTIVE EVOLUTION IS UNCERTAIN AT THIS TIME GIVEN THE
AFOREMENTIONED LIMITING FACTORS AND TRENDS WILL BE MONITORED
CLOSELY.

..LEITMAN/THOMPSON.. 07/24/2016

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

ATTN...WFO...IWX...GRR...IND...LOT...ILX...DVN...

LAT...LON   40078801 40158857 40298901 40548934 40868950 41288920
            42288789 42428759 42538708 42398628 42088593 41488596
            40908618 40358668 40098744 40078801




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.