ZCZC SPCSWOMCD ALL
ACUS11 KWNS 062047 
SPC MCD 062047 
IAZ000-MNZ000-NEZ000-062315-

MESOSCALE DISCUSSION 1650
NWS STORM PREDICTION CENTER NORMAN OK
0347 PM CDT TUE SEP 06 2016

AREAS AFFECTED...ERN NEB...IA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 

VALID 062047Z - 062315Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...A SEVERE THREAT IS EXPECTED TO DEVELOP FROM ERN NEB ENEWD
ACROSS WRN AND NRN IA. LARGE HAIL AND WIND DAMAGE ARE EXPECTED TO BE
THE PRIMARY THREATS. WW ISSUANCE MAY BE NEEDED ACROSS THE REGION
LATE THIS AFTERNOON.

DISCUSSION...LATEST SFC ANALYSIS SHOWS A COLD FRONT FROM SCNTRL MN
EXTENDING SWWD INTO ERN NEB WITH A VERY MOIST AIRMASS IN PLACE AHEAD
OF THE FRONT. SFC DEWPOINTS AHEAD OF THE FRONT ARE GENERALLY IN THE
UPPER 60S AND LOWER 70S F WHICH IS CONTRIBUTING TO MODERATE
INSTABILITY. RAP MESOSCALE ANALYSIS DATA SHOWS AN AXIS OF
INSTABILITY FROM SE NEB EXTENDING NEWD ACROSS WCNTRL IA WHERE MLCAPE
VALUES ARE ESTIMATED FROM 2000 TO 3000 J/KG. IN ADDITION TO THE
INSTABILITY...THE CAP HAS DIMINISHED ALONG THIS CORRIDOR WHICH
SHOULD ALLOW FOR CONVECTIVE INITIATION OVER THE NEXT COUPLE OF
HOURS. THERE IS FAIRLY GOOD AGREEMENT AMONG SHORT-TERM MODELS THAT
CONVECTION WILL INITIATE IN THE 22Z TO 23Z TIMEFRAME ACROSS ERN NEB
OR WCNTRL IA WITH THUNDERSTORMS THEN MOVING NEWD INTO NCNTRL IA. 

THE WSR-88D VWP AT DES MOINES IA AND SIOUX FALLS SD SHOW MODERATE TO
STRONG DEEP-LAYER SHEAR WITH WINDS INCREASING FROM NEAR 20 KT JUST
ABOVE GROUND LEVEL TO 40 TO 50 KT IN THE MID-LEVELS. THIS SHOULD
SUPPORT STORM ROTATION WITH SUPERCELL DEVELOPMENT POSSIBLE. ANY
STORM THAT ROTATES SHOULD HAVE POTENTIAL FOR HAIL AND ISOLATED WIND
GUSTS. SHORT CONVECTIVE LINE SEGMENTS THAT OBTAIN A BOWING STRUCTURE
SHOULD ALSO HAVE A WIND DAMAGE THREAT.

..BROYLES/HART.. 09/06/2016

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

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

LAT...LON   42779170 42049409 41429548 40829654 41059724 41569767
            42049693 43189481 43559309 43529218 42779170 

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