MESO: Mesoscale Discussion 2033

ACUS11 KWNS 290027
SWOMCD
SPC MCD 290027
NEZ000-KSZ000-290200-

MESOSCALE DISCUSSION 2033
NWS STORM PREDICTION CENTER NORMAN OK
0727 PM CDT FRI SEP 28 2007

AREAS AFFECTED...WRN KS AND SWRN-NCNTRL NEB

CONCERNING...SEVERE THUNDERSTORM WATCH 692...693...

VALID 290027Z - 290200Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
692...693...CONTINUES.

TSTMS THAT DEVELOPED ALONG THE LEE-TROUGH EARLIER HAVE MOVED VERY
SLOWLY EWD INTO PARTS OF SWRN NEB AND WRN KS EARLY THIS EVENING.
STORMS HAVE BEEN THRIVING WITHIN A NARROW INSTABILITY AXIS
CHARACTERIZED BY MLCAPES OF 2000-2500 J/KG. STRONGER MID-LEVEL FLOW
OBSERVED EARLIER ACROSS NM AND SRN CO HAS TRANSLATED ONTO THE HIGHER
PLAINS...BOOSTING VERTICAL SHEAR INTO THE 35-45 KT /SUPERCELLULAR/
RANGE. RWD PROFILER HAS SAMPLED THE INCREASE IN MID-LEVEL WIND
SPEEDS AND CORRESPONDING ACCELERATION OF THE FLOW AROUND 1-1.5 KM
DURING THE PAST COUPLE OF HOURS. GIVEN THE COMBINATION OF THE
INSTABILITY/STEEP LAPSE RATE ENVIRONMENT AND MAGNITUDE OF SHEAR...A
FEW STORMS HAVE EXHIBITED SUPERCELL CHARACTERISTICS WITH LEFT-RIGHT
MOVING MEMBERS AND STORM COLLISIONS/ENHANCEMENTS. HAIL HAS BEEN THE
PRIMARY SVR THREAT THUS FAR THIS EVENING.

LONGEVITY OF ACTIVITY ACROSS NW KS AND NUMBER OF STORM MERGERS WILL
LIKELY RESULT IN A STRENGTHENING COLLECTIVE COLD POOL. THIS SHOULD
CAUSE A SUBSEQUENT WEAKENING TREND IN THE 01-02Z TIME FRAME. A BRIEF
TORNADO CANNOT BE RULED OUT BEFORE THIS OCCURS...GIVEN DECREASE IN
EVENING LCLS AND AT LEAST 150-175 M2/S2 0-1KM SRH.

FARTHER N...ACTIVITY SHOULD ALSO BEGIN TO WANE GIVEN LOSS OF
INSOLATION. HOWEVER...MORE ELEVATED ACTIVITY MAY EVOLVE N AND NE
INTO ERN SD AND SWRN MN LATER TONIGHT ALONG THE LLJ AXIS. IN THE
SHORT TERM...THOUGH...AS THE STORMS COLLAPSE...DMGG WIND GUSTS WILL
BE THE PRIMARY SVR THREAT.

.RACY.. 09/29/2007

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

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

37550165 39000185 40460174 41580123 41940017 41719943
41109923 40459941 39829973 39259999 38570018 37820031
37620090

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