MESO: Mesoscale Discussion 1215

ACUS11 KWNS 061833
SWOMCD
SPC MCD 061832
SDZ000-NEZ000-062000-

MESOSCALE DISCUSSION 1215
NWS STORM PREDICTION CENTER NORMAN OK
0132 PM CDT TUE JUL 06 2010

AREAS AFFECTED...S-CENTRAL SD...FAR N-CENTRAL NEB

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 061832Z - 062000Z

THUNDERSTORM INITIATION OVER S-CENTRAL SD AND FAR N-CENTRAL NEB
APPEARS POSSIBLE BY MID-AFTERNOON. THREAT FOR A TORNADO OR TWO...IN
ADDITION TO LARGE HAIL/DAMAGING WIND GUSTS EXISTS. AREA IS BEING
MONITORED FOR A WW.

EARLY AFTERNOON SURFACE OBSERVATIONS INDICATE A WEAK SURFACE WAVE
DEVELOPING ALONG A QUASI-STATIONARY FRONTAL BOUNDARY OVER S-CENTRAL
SD. FOCUSED AREA OF LOW-LEVEL CONVERGENCE AND BOUNDARY LAYER
DESTABILIZATION EXISTS OVER THIS AREA...WITH AGITATED CUMULUS FIELD
BEGINNING TO DEVELOP IN RESPONSE. HOWEVER...STRONGEST LARGE SCALE
FORCING FOR ASCENT ASSOCIATED WITH NRN ROCKIES S/W WILL REMAIN WELL
W OF THE REGION DURING MUCH OF THE AFTERNOON...LEADING TO SOME
UNCERTAINTY REGARDING CAP REMOVAL/TIMING OF CONVECTIVE INITIATION.
DESPITE THESE CONCERNS...DETERMINISTIC AND SREF MODEL GUIDANCE ARE
IN AGREEMENT THAT AT LEAST ISOLATED THUNDERSTORM DEVELOPMENT WILL
TAKE PLACE OVER S-CENTRAL SD BY MID-AFTERNOON.

WITH MID 60S F DEWPOINTS PRESENT E OF THE SURFACE WAVE...COMBINED
WITH STRONG BOUNDARY LAYER DESTABILIZATION TO THE SW AND STEEPENING
MID-LEVEL LAPSE RATES...MLCAPE VALUES AOA 2000 J/KG APPEAR PROBABLE
BY PEAK HEATING. IN ADDITION...LOW-LEVEL WINDS ARE FORECAST TO
REMAIN BACKED OUT OF THE E-SE...WHILE SRN EDGE OF 40 KT MID-LEVEL
SWLY/S OVER-SPREADS THE REGION. THIS WIND PROFILE WILL BE FAVORABLE
FOR SUPERCELL THUNDERSTORMS...POSING A RISK FOR LARGE HAIL AND
DAMAGING WIND GUSTS. STRONG LOW-LEVEL SHEAR AND FAVORABLE
INSTABILITY ENVIRONMENT INVOF THE BOUNDARY WILL ALSO RESULT IN A
RISK FOR A FEW TORNADOES.

..GARNER.. 07/06/2010

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

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON 43180160 44010158 44610072 44659907 43839853 43199877
43009945 42980076 43180160

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.