ZCZC SPCSWOMCD ALL
ACUS11 KWNS 231905 
SPC MCD 231905 
IAZ000-MNZ000-NEZ000-232000-

MESOSCALE DISCUSSION 1575
NWS STORM PREDICTION CENTER NORMAN OK
0205 PM CDT TUE AUG 23 2016

AREAS AFFECTED...NERN NEB...NWRN  IA...SRN MN

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 231905Z - 232000Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...IT IS NOT CERTAIN THE A WATCH WILL BE NEEDED...BUT
CONVECTIVE TRENDS ARE BEING MONITORED FOR THE POSSIBILITY OF
INCREASING SEVERE WEATHER POTENTIAL THAT COULD REQUIRE ONE WITHIN
THE NEXT HOUR OR TWO.

DISCUSSION...FORCING ASSOCIATED WITH AN APPARENT MESOSCALE
CONVECTIVE VORTEX HAS BEEN ACCOMPANIED BY SUSTAINED VIGOROUS
THUNDERSTORM DEVELOPMENT.  ACTIVITY HAS UNDERGONE FLUCTUATIONS IN
INTENSITY WHILE PROGRESSING ACROSS AND NORTHEAST OF THE SIOUX CITY
AREA OF THE MID MISSOURI VALLEY.  LOWER/MID TROPOSPHERIC WARM
ADVECTION ON THE SOUTHWESTERN FLANK OF THE CYCLONIC VORTICITY CENTER
MAY HAVE PROVIDED THE PRIMARY RECENT FORCING.  HOWEVER...INHIBITION
FOR DESTABILIZING MOIST BOUNDARY LAYER PARCELS /WITH SURFACE DEW
POINTS NEAR 70F/ IS GRADUALLY WEAKENING WITH INSOLATION...AND LIFT
ALONG A DEVELOPING SURFACE COLD POOL MAY BECOME INCREASINGLY
PROMINENT.

MID-LEVEL LAPSE RATES ARE GENERALLY WEAK TO THE SOUTH/EAST OF THE
WARMER ELEVATED MIXED LAYER AIR...BUT CAPE APPEARS MODERATELY LARGE
ON THE ORDER OF 2000 J/KG.   GIVEN THIS INSTABILITY...AND MODEST
SHEAR NEAR THE IMMEDIATE VICINITY OF THE CYCLONIC VORTICITY
CENTER...FURTHER CONVECTIVE INTENSIFICATION AND ORGANIZATION APPEARS
AT LEAST POSSIBLE IN THE PEAK AFTERNOON INSTABILITY.  THIS MAY BE
ACCOMPANIED BY SUFFICIENT COLD POOL STRENGTHENING TO SUPPORT AN
INCREASING RISK FOR POTENTIALLY DAMAGING WIND GUSTS...IN ADDITION TO
A CONTINUING RISK FOR SEVERE HAIL /MOSTLY MARGINAL/.

..KERR/WEISS.. 08/23/2016

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

ATTN...WFO...ARX...MPX...DMX...FSD...OAX...

LAT...LON   43679540 44289506 44229235 43369188 42219251 41639470
            41699650 41999649 42229574 42889523 43679540 

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