[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 131648
SWOMCD
SPC MCD 131647 
IAZ000-NEZ000-MNZ000-SDZ000-131845-

MESOSCALE DISCUSSION 1498
NWS STORM PREDICTION CENTER NORMAN OK
1147 AM CDT THU JUL 13 2006

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

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 131647Z - 131845Z

POTENTIAL FOR THUNDERSTORMS TO BECOME SURFACE BASED OVER SERN SD
THROUGH ERN NEB IS INCREASING. THREAT WILL EXIST FOR STORMS TO
PRODUCE DAMAGING WIND AND VERY LARGE HAIL. A WW WILL LIKELY BE
NEEDED FOR THIS AREA WITHIN THE NEXT HOUR OR SO.

A SURFACE TROUGH EXTENDS FROM THE ERN DAKOTAS SWWD THROUGH SWRN NEB.
E OF THIS BOUNDARY...RICH LOW LEVEL MOISTURE WITH DEWPOINTS NEAR 70F
HAS ADVECTED NWD BENEATH STEEPENING MID LEVEL LAPSE RATES. THIS IN
CONJUNCTION WITH STRONG SURFACE HEATING WILL RESULT IN VERY UNSTABLE
CONDITIONS WITH MLCAPE NEAR 4000 J/KG FROM ERN NEB INTO ERN SD.
EXTENSIVE MID LEVEL CONVECTION CONTINUES FROM CNTRL NEB NEWD THROUGH
ERN SD. THIS ACTIVITY IS DEVELOPING WITHIN A ZONE OF MID LEVEL
ASCENT ASSOCIATED WITH A SHORTWAVE TROUGH MOVING EWD THROUGH THE
CNTRL AND NRN PLAINS. MORNING OBSERVED AND FORECAST RUC RAOB DATA
SUGGEST THE CAP WILL BECOME SUFFICIENTLY WEAK FOR STORMS TO BECOME
SURFACE BASED BY EARLY AFTERNOON. RADAR HAS SHOWN A RECENT INCREASE
IN INTENSITY WITH THIS ACTIVITY. VERTICAL WIND PROFILES INDICATE
THAT ONCE STORMS BECOME SURFACE BASED...THEY WILL TEND TO PROPAGATE
SEWD. DEEP LAYER SHEAR OF 20 TO 25 KT WILL SUPPORT MOSTLY MULTICELL
STORMS. HOWEVER...VEERING WIND PROFILES WITH POTENTIAL FOR STORMS TO
DEVIATE TO THE RIGHT OF THE MEAN WIND...AND INCREASING MID LEVEL
FLOW MAY ALSO SUPPORT SOME SUPERCELL STRUCTURES.

..DIAL.. 07/13/2006

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

ATTN...WFO...FSD...OAX...GID...LBF...

41209634 40599759 41299941 43059880 44509825 44429684
42919605 

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