[MCD] SWOMCD

[MCD at goshenarc.org]

ACUS11 KWNS 102019
SWOMCD
SPC MCD 102016 
SDZ000-102215-

MESOSCALE DISCUSSION 2195
NWS STORM PREDICTION CENTER NORMAN OK
0316 PM CDT FRI SEP 10 2004

AREAS AFFECTED...WRN/CNTRL SD

CONCERNING...CONVECTIVE TRENDS/SEVERE THUNDERSTORM POTENTIAL 

VALID 102016Z - 102215Z

STRONG/ISOLATED SEVERE STORMS APPEAR POSSIBLE FOR A BRIEF PERIOD
LATE THIS AFTERNOON AND EARLY EVENING. RISK APPEARS RELATIVELY
LOW...AND WW IS NOT CURRENTLY ANTICIPATED.

IN WAKE OF SURFACE TROUGH/INITIAL WEAK SURFACE FRONT...BOUNDARY
LAYER HAS MOISTENED NORTHEAST OF RAPID CITY INTO THE MOBRIDGE AND
PIERRE AREAS.  DEW POINTS HAVE INCREASED TO NEAR 60F...AND
TEMPERATURES HAVE HEATED TO NEAR 80F.  THIS IS CONTRIBUTING TO MEAN
MIXED LAYER CAPE ON THE ORDER OF 1000 TO 1500 J/KG...THOUGH WARM
LAYERS IN THE LOWER/MID TROPOSPHERE ARE INHIBITING CONVECTIVE
DEVELOPMENT.

WHILE CAP AND WEAK LOW-LEVEL FORCING FOR CONVECTION PROVIDE
CONSIDERABLE UNCERTAINTY WITH REGARD TO INITIATION...UPPER FLOW
FIELD IS BECOMING INCREASINGLY DIVERGENT.  THIS FORCING WILL
CONTINUE TO STRENGTHEN THROUGH LATE AFTERNOON...AS FAIRLY VIGOROUS
UPPER TROUGH SHIFTS EASTWARD OUT OF THE NORTHERN/CENTRAL ROCKIES. 
TOWARD 10/23Z-11/00Z...PRIMARY SURFACE COLD FRONT COULD PROVIDE
FOCUS FOR THUNDERSTORM ACTIVITY NEAR MOBRIDGE AND AREAS TRAILING TO
THE SOUTHWEST. OTHERWISE...IN MOIST BOUNDARY LAYER AHEAD OF THIS
FRONT...MID-LEVEL COOLING MAY WEAKEN CAP SUFFICIENTLY FOR WIDELY
SCATTERED THUNDERSTORMS.

GIVEN SHEAR ASSOCIATED WITH BELT OF MODERATE CYCLONIC MID-LEVEL
FLOW...THERMODYNAMIC ENVIRONMENT WITH STEEP LAPSE RATES AND WEAK TO
MODERATE CAPE MAY PROVE FAVORABLE FOR LARGE HAIL IN STRONGER CELLS. 
WINDOW OF OPPORTUNITY FOR SEVERE STORMS APPEARS RATHER SMALL...WITH
THUNDERSTORMS LIKELY WEAKENING BY 11/01-02Z WITH LOSS OF DAYTIME
HEATING.

..KERR.. 09/10/2004

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

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

45090276 45750125 45930033 45559980 44980011 44459989
44040008 43850064 43820136 43890224 44420287 

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