Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 270738
SWOMCD
SPC MCD 270737
SDZ000-270930-

MESOSCALE DISCUSSION 1749
NWS STORM PREDICTION CENTER NORMAN OK
0237 AM CDT THU AUG 27 2015

AREAS AFFECTED...PORTIONS OF CENTRAL SD

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 270737Z - 270930Z

PROBABILITY OF WATCH ISSUANCE...5 PERCENT

SUMMARY...A CLUSTER OF STORMS MAY MAINTAIN THE CAPABILITY TO PRODUCE
ISOLATED STRONG TO SEVERE WIND GUSTS FOR THE NEXT FEW HOURS ACROSS
SOUTH-CENTRAL SD.  FARTHER N...A SECOND AREA OF STORMS SHOULD ALSO
PERSIST FOR THE NEXT FEW HOURS /UNTIL 10-11Z/ ACROSS NORTH-CENTRAL
SD...WITH MOST OF THIS ACTIVITY TENDING TO REMAIN SUB-SEVERE AS
CURRENT TRENDS SHOW A WEAKENING IN REFLECTIVITY.

DISCUSSION...AT 07Z...MOSAIC RADAR IMAGERY INDICATED TWO AREAS IN
CENTRAL SD WITH SUSTAINED STORMS...1/ IN JONES/MELLETTE COUNTIES IN
SOUTH-CENTRAL SD WITHIN THE SOUTHERN PERIPHERY OF A LARGE CONVECTIVE
COMPLEX...AND 2/ IN CORSON TO WALWORTH COUNTIES...WHILE STORMS ARCED
SOUTH-SOUTHEASTWARD BETWEEN THESE TWO STRONGER STORM AREAS.  THIS
ACTIVITY IS LOCATED WITHIN A NNW-SSE ORIENTED CORRIDOR OF DEEP-LAYER
MOISTURE-FLUX CONVERGENCE WHERE THE AXIS OF GREATER MOISTURE AND
STRONGEST INSTABILITY TENDS TO RESIDE TO THE WEST OF THE MO RIVER.

DEEP-LAYER ASCENT ATTENDANT TO HEIGHT FALLS ACROSS SD DURING THE
OVERNIGHT TO EARLY THIS MORNING AHEAD OF A PROGRESSIVE WY SHORTWAVE
TROUGH WILL SUPPORT ADDITIONAL TSTM DEVELOPMENT.  MEANWHILE...THE
STORMS IN SOUTHERN SD WILL BE FURTHER AIDED BY LOW-LEVEL WAA WITHIN
THE NOSE OF A 40-KT SWLY LLJ EXTENDING INTO SOUTH-CENTRAL SD.  THESE
STORMS IN SOUTH-CENTRAL SD SHOULD BEGIN TO DIMINISH IN STRENGTH AND
COVERAGE BY 12Z AS THE LLJ WEAKENS. FARTHER N...THE STORMS IN CORSON
TO WALWORTH COUNTIES APPEAR TO BE DEVELOPING IN VICINITY OF A WARM
FRONT EXTENDING W-E ACROSS FAR NORTHERN SD FROM A SURFACE LOW IN
SOUTHEAST MT.  ANY STORMS MOVING TOWARD THE EAST SHOULD DECREASE IN
INTENSITY AS THEY MOVE GENERALLY EAST OF THE MO RIVER WHERE MOISTURE
CONTENT AND INSTABILITY DECREASE WITH EASTWARD EXTENT.

..PETERS/EDWARDS.. 08/27/2015

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

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

LAT...LON   43730083 44270048 44910062 45200109 45580165 45800162
            45810027 45249959 43859902 43259901 43069913 43000007
            43040073 43130093 43500092 43730083



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