MESO: Mesoscale Discussion 1616

ACUS11 KWNS 142056
SWOMCD
SPC MCD 142055
SDZ000-NDZ000-142300-

MESOSCALE DISCUSSION 1616
NWS STORM PREDICTION CENTER NORMAN OK
0355 PM CDT THU JUL 14 2011

AREAS AFFECTED...PARTS OF NRN AND CNTRL SOUTH DAKOTA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 142055Z - 142300Z

A WATCH LIKELY WILL BE NEEDED AT SOME POINT LATE THIS AFTERNOON OR
EVENING...PERHAPS WITHIN THE NEXT HOUR OR TWO.

GIVEN LINGERING INHIBITION ASSOCIATED WITH A VERY WARM ELEVATED
MIXED LAYER...TIMING OF STORM INITIATION REMAINS A BIT UNCLEAR. BUT
A WEAK SHORT WAVE TROUGH CONTINUES TO GRADUALLY LIFT OUT OF WYOMING
INTO THE NORTHERN PLAINS. BETWEEN NOW AND EARLY EVENING...STRONGER
FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED WITH THIS FEATURE IS
EXPECTED TO SPREAD ACROSS A WARM FRONTAL ZONE ACROSS NORTHERN SOUTH
DAKOTA INTO EXTREME SOUTHERN NORTH DAKOTA...WHERE LOW-LEVEL
CONVERGENCE IS MAXIMIZED...AND LOWER/MID 70S SURFACE DEW POINTS ARE
CONTRIBUTING TO MIXED LAYER CAPE UP TO AROUND 4000 J/KG. AT THE
PRESENT TIME...GUIDANCE APPEARS SUGGESTIVE THAT VIGOROUS BOUNDARY
LAYER BASED STORM DEVELOPMENT MAY NOT OCCUR UNTIL CLOSER TO 15/00Z
NEAR THE MOBRIDGE AREA. HOWEVER...DEEPENING CONVECTION NOW APPEARS
TO BE IN THE PROCESS OF DEVELOPING OFF/EAST NORTHEAST OF THE BLACK
HILLS AREA. IT IS POSSIBLE THAT THIS IS BEING AIDED BY AN AREA OF
ENHANCED LIFT THAT COULD SUPPORT STORMS WEST OF MOBRIDGE PRIOR TO
15/00Z.

REGARDLESS...ONCE STORMS FORM...AND BEFORE UPSCALE GROWTH OCCURS
LATER THIS EVENING...VERTICAL SHEAR NEAR A 40-50 KT 500 MB JET
STREAK NOSING EASTWARD ACROSS SOUTH DAKOTA WILL BE FAVORABLE FOR
SUPERCELLS. VERY LARGE HAIL IS POSSIBLE...ALONG WITH A RISK FOR
TORNADOES...BEFORE STRONG/DAMAGING WIND GUSTS BECOME MORE PROMINENT
WITH AN EVOLVING MESOSCALE CONVECTIVE SYSTEM.

..KERR.. 07/14/2011

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

ATTN...WFO...FSD...ABR...BIS...UNR...

LAT...LON 45890324 46180182 46169995 45899835 45469793 44269810
44499956 44610110 44420248 44540322 45170360 45890324

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