Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 302058
SWOMCD
SPC MCD 302057
SDZ000-302230-

MESOSCALE DISCUSSION 1780
NWS STORM PREDICTION CENTER NORMAN OK
0357 PM CDT TUE SEP 30 2014

AREAS AFFECTED...ERN SD

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 302057Z - 302230Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...LOW-TOPPED STORMS MAY DEVELOP WITHIN THE NEXT ONE TO TWO
HOURS WITH A RISK FOR A TORNADO OR TWO. CONVECTIVE TRENDS ARE BEING
MONITORED FOR A POSSIBLE WATCH.

DISCUSSION...AS OF 2040Z...VISIBLE SATELLITE IMAGERY INDICATED A
DEEPENING CUMULUS FIELD ALONG A COLD FRONT FROM EDMUNDS TO CHARLES
MIX COUNTIES IN CNTRL/ERN SD. IMMEDIATELY DOWNSTREAM FROM THIS
DEVELOPMENT...TEMPERATURES HAVE WARMED INTO THE 70S WHICH WHEN
COUPLED WITH A NARROW AXIS OF BOUNDARY-LAYER DEWPOINTS IN THE 50S
ALONG AND S/SW OF A NWD-MOVING COLD FRONT IS RESULTING IN SBCAPE OF
500-1000 J/KG.

BASED ON RECENT CONVECTION-ALLOWING MODEL RUNS...STORM INITIATION
AND SUSTENANCE REMAINS IN QUESTION. HOWEVER...TRENDS IN SATELLITE
DATA DO SUGGEST THAT ISOLATED DEVELOPMENT MAY OCCUR WITHIN THE NEXT
ONE TO HOURS...GENERALLY EAST OF THE U.S. 281 CORRIDOR. CURRENT VAD
DATA FROM ABERDEEN AND SIOUX FALLS INDICATE PRONOUNCED DIRECTIONAL
AND SPEED SHEAR IN THE LOWEST KILOMETER WITH GENERALLY
UNIDIRECTIONAL WINDS INCREASING WITH HEIGHT ABOVE THAT LAYER. AS
SUCH...THE KINEMATIC ENVIRONMENT WILL BE QUITE SUPPORTIVE OF
LOW-TOPPED SUPERCELLS CAPABLE OF A COUPLE OF TORNADOES AND PERHAPS
SOME HAIL GIVEN SUFFICIENT INSTABILITY FOR STORM DEVELOPMENT.

..MEAD.. 09/30/2014

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

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

LAT...LON   43669802 44319807 44979839 45339876 45859890 45899786
            45649714 44889671 44079667 43699695 43489751 43669802



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