Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS11 KWNS 181949
SWOMCD
SPC MCD 181949
NEZ000-KSZ000-COZ000-182145-

MESOSCALE DISCUSSION 0356
NWS STORM PREDICTION CENTER NORMAN OK
0249 PM CDT SAT APR 18 2015

AREAS AFFECTED...PARTS OF NWRN KS...SWRN NEB...AND ADJACENT NE CO

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 181949Z - 182145Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...THE RISK FOR THUNDERSTORM ACTIVITY CAPABLE OF PRODUCING
MARGINALLY SEVERE HAIL AND RELATIVELY SHORT-LIVED TORNADOES US
EXPECTED TO CONTINUE TO INCREASE THROUGH 23-00Z.

DISCUSSION...CONVECTIVE DEVELOPMENT APPEARS TO BE IN THE PROCESS OF
DEEPENING EAST NORTHEAST OF GOODLAND...PERHAPS IN RESPONSE TO AN
AREA OF ENHANCED CONVERGENCE WITHIN THE LEE SURFACE TROUGH.  BENEATH
A BELT OF BROADLY CYCLONIC 40-50 KT 500 MB FLOW...AND SEASONABLY
COLD MID-LEVEL TEMPERATURES...DAYTIME HEATING IS CONTRIBUTING TO
MODEST BOUNDARY LAYER DESTABILIZATION.  THE LATEST OBJECTIVE
ANALYSIS SUGGEST CAPE IS NOW ON THE ORDER OF 1000 J/KG...WITH
INHIBITION BECOMING INCREASINGLY NEGLIGIBLE.  AS DESTABILIZATION
CONTINUES...AN APPRECIABLE INCREASE IN THUNDERSTORM ACTIVITY IS
EXPECTED THROUGH THE REMAINDER OF THE AFTERNOON.  DESPITE RATHER
WEAK LOW-LEVEL FLOW FIELDS...AMBIENT LOW-LEVEL VERTICAL VORTICITY
BENEATH THE NORTHEASTERN PERIPHERY OF THE MID-LEVEL CLOSED LOW NOW
EAST OF THE COLORADO ROCKIES APPEAR SUFFICIENT TO SUPPORT A RISK FOR
RELATIVELY SHORT-LIVED TORNADOES IN THE MORE SUSTAINED STORMS.  AND
THIS APPEARS SUPPORTED BY A RECENT TORNADO REPORTS WITH CONVECTION
IN WASHINGTON COUNTY COLORADO.

..KERR/HART.. 04/18/2015

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

ATTN...WFO...GID...LBF...DDC...GLD...BOU...

LAT...LON   40130223 40830190 41620189 41310041 40480017 40109907
            38929989 39040090 39250174 40130223



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