[MCD] SWOMCD

[Mesoscale Convective Discussions]

ACUS11 KWNS 171910
SWOMCD
SPC MCD 171910 
SDZ000-MTZ000-WYZ000-172115-

MESOSCALE DISCUSSION 1829
NWS STORM PREDICTION CENTER NORMAN OK
0210 PM CDT THU AUG 17 2006

AREAS AFFECTED...WRN SD

CONCERNING...SEVERE THUNDERSTORM POTENTIAL 

VALID 171910Z - 172115Z

STORMS ARE EXPECTED TO DEVELOP INITIALLY OVER THE BLACK HILLS AREA
OF WRN ND AND SPREAD NEWD. SUPERCELLS WITH LARGE HAIL WILL BE THE
INITIAL PRIMARY THREAT. ISOLATED DAMAGING WIND WILL ALSO BE
POSSIBLE. A WW WILL LIKELY BE NEEDED ONCE IT APPEARS INITIATION IS
IMMINENT.

A FRONTAL BOUNDARY HAS SETTLED SWD ACROSS SD AND EXTENDS FROM MN
SWWD THROUGH CNTRL AND SWRN SD AND INTO NERN WY. LOW LEVEL DEWPOINTS
HAVE STARTED TO MIX DOWN INTO THE 40S SW OF THE FRONT OVER NERN WY. 
HOWEVER...ELY LOW LEVEL COMPONENT N OF FRONT SHOULD HELP MAINTAIN
DEWPOINTS IN THE UPPER 50S INTO PARTS OF WRN AND NWRN SD. THIS
MOISTURE EXISTS BELOW 8.5 C/KM 850-500 MB LAPSE RATES AND WILL
CONTRIBUTE TO DESTABILIZATION AS THE BOUNDARY LAYER WARMS. MLCAPE
FROM 1500 TO 2000 J/KG IS EXPECTED ACROSS WRN AND NRN SD. THE CAP
SHOULD CONTINUE TO WEAKEN...AND STORMS ARE EXPECTED TO DEVELOP
INITIALLY OVER THE BLACK HILLS WHERE STRONG SURFACE HEATING AND
ENELY UPSLOPE COMPONENT EXISTS. ELY LOW LEVEL FLOW VEERING TO WLY 30
KT AT 500 MB IS CONTRIBUTING TO 40+ KT DEEP LAYER SHEAR SUFFICIENT
FOR SUPERCELLS. OTHER STORMS MAY INITIATE WITHIN DEVELOPING WARM
ADVECTION REGIME N OF THE BOUNDARY OVER NWRN SD TOWARD EVENING AS
THE LOW LEVEL JET STRENGTHENS. ACTIVITY MAY LATER EVOLVE INTO AN MCS
WITH AN INCREASING THREAT FOR DAMAGING WIND.

..DIAL.. 08/17/2006

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

ATTN...WFO...ABR...UNR...BYZ...

43890109 44060353 44670430 45730372 45920064 44829957 

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