MESO: Mesoscale Discussion 1976

ACUS11 KWNS 172011
SWOMCD
SPC MCD 172011
KSZ000-NEZ000-OKZ000-COZ000-172145-

MESOSCALE DISCUSSION 1976
NWS STORM PREDICTION CENTER NORMAN OK
0311 PM CDT MON SEP 17 2007

AREAS AFFECTED...WRN KS...SERN CO...S-CNTRL NEB

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 172011Z - 172145Z

THREAT FOR DAMAGING WINDS/LARGE HAIL WILL INCREASE THROUGH LATE
AFTERNOON AS TSTMS CONTINUE TO DEVELOP ALONG A SURFACE
TROUGH/OUTFLOW SURGE. DEEP-LAYER SHEAR PROFILES SHOULD BE FAVORABLE
FOR ISOLATED SUPERCELLS INITIALLY IN IMMEDIATE VICINITY OF THE
BOUNDARY...DESPITE MODEST INSTABILITY. THE AREA WILL BE MONITORED
FOR A POSSIBLE SEVERE THUNDERSTORM WATCH.

RECENT VIS SATELLITE/RADAR IMAGERY DEPICT GROWING CB/TSTM COVERAGE
ALONG A SURFACE TROUGH WHICH HAD RECENTLY BEEN OVERTAKEN BY A
PRECIPITATION-INDUCED OUTFLOW SURGE FROM EARLIER CONVECTION OVER THE
NEB PANHANDLE/ERN CO. AS OF 20Z...THIS BOUNDARY ROUGHLY EXTENDED
FROM A MESOLOW AROUND 25 N SPD NEWD TO BBW AND ON NORTH INTO THE
CNTRL DAKOTAS. ALTHOUGH SURFACE TEMPERATURES HAVE WARMED INTO THE
UPPER 80S TO MIDDLE 90S AHEAD OF THIS BOUNDARY...DEW POINTS ONLY IN
THE MIDDLE 50S TO LOWER 60S HAS RESULTED IN MODEST INSTABILITY WITH
MLCAPES NEAR 1000 J/KG. REGIONAL VAD/PROFILER DATA INDICATE 40 TO 50
KTS OF 6 KM FLOW ATOP RELATIVELY STRONG LOW-LEVEL FLOW /FROM 20 TO
40 KTS/ ACROSS MUCH OF THE WARM SECTOR. HOWEVER...A NARROW CORRIDOR
OF WEAKER LOW-LEVEL FLOW AS INFERRED BY RECENT SURFACE OBSERVATIONS
INVOF THE BOUNDARY MAY PROVE FAVORABLE FOR GREATER DEEP-LAYER SHEAR
AND POSSIBLY ISOLATED SUPERCELLS WITH INITIAL STORMS.
HOWEVER...GIVEN THAT THE DEEP-LAYER FLOW WILL REMAIN PARALLEL TO THE
BOUNDARY...UPSCALE GROWTH/CONSOLIDATION SHOULD RESULT IN LARGELY
MULTICELLULAR TYPE MODE WITH A MORE MARGINAL HAIL/WIND THREAT.

.GRAMS.. 09/17/2007

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

ATTN...WFO...GID...LBF...DDC...GLD...AMA...PUB...

37460312 38090260 38660186 39670093 40880006 41459949
41379883 40049881 38779975 37590086 37060192 36960259

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