ZCZC SPCSWOMCD ALL
ACUS11 KWNS 172212 
SPC MCD 172212 
IAZ000-MNZ000-SDZ000-NEZ000-180015-

MESOSCALE DISCUSSION 1042
NWS STORM PREDICTION CENTER NORMAN OK
0512 PM CDT TUE JUN 17 2014

AREAS AFFECTED...NERN NEB...SERN SD...EXTREME SWRN MN AND NWRN IA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY 

VALID 172212Z - 180015Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...THUNDERSTORMS ARE EXPECTED TO INITIATE OVER NERN
NEB...SERN SD OR NWRN IA BY 00Z. SUPERCELLS WITH VERY LARGE HAIL AND
A FEW TORNADOES WILL BE INITIAL PRIMARY THREATS, BUT THE THREAT FOR
MORE WIDESPREAD DAMAGING WIND WILL INCREASE THROUGH THE EVENING.

DISCUSSION...EARLY THIS EVENING A WARM FRONT EXTENDS FROM EXTREME
NRN NEB INTO SERN SD THEN SEWD THROUGH NRN IA. ELEVATED MIXED LAYER
WITH VERY STEEP /8.5-9 C/KM/ 700-500 MB LAPSE RATES HAVE ADVECTED
ABOVE THE AXIS OF RICH GULF MOISTURE THAT EXISTS IN VICINITY OF AND
SOUTH OF THIS BOUNDARY RESULTING IN 3000-4000 J/KG MLCAPE. VISIBLE
SATELLITE SHOWS CUMULUS INCREASING ALONG THE FRONT...ESPECIALLY FROM
NERN NEB INTO SERN SD AND EXTREME NWRN IA...WHILE WV IMAGERY SHOWS
WHAT APPEARS TO BE A SHORTWAVE TROUGH LIFTING NEWD THROUGH THE CNTRL
PLAINS. DEEPER FORCING ASSOCIATED WITH APPROACHING SHORTWAVE TROUGH
AND STRENGTHENING LLJ WILL AUGMENT MESOSCALE ASCENT ALONG THE
FRONT...EVENTUALLY RESULTING IN THUNDERSTORM INITIATION EARLY THIS
EVENING. WINDS ARE ESELY IN VICINITY OF THE FRONT WITH VEERING
LOW-LEVEL WINDS AND UP TO 40 KT DEEP SHEAR. UPDRAFTS INITIATING
WITHIN THIS ENVIRONMENT WILL LIKELY UNDERGO EXPLOSIVE DEVELOPMENT
GIVEN THE DEGREE OF INSTABILITY. STORMS SHOULD MOVE EWD WHERE THEY
WILL INTERACT WITH ZONE OF ENHANCED VORTICITY ALONG THE
BOUNDARY...AUGMENTING THE THREAT FOR LOW-LEVEL MESOCYCLONES AND
TORNADOES.

..DIAL/THOMPSON.. 06/17/2014

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

ATTN...WFO...DMX...FSD...OAX...LBF...

LAT...LON   42609624 42559774 42449920 43349919 43939751 43609553
            42989468 42539521 42609624 

NNNN