SPC MD 1954

MD 1954 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL NEBRASKA

MESOSCALE DISCUSSION 1954
NWS STORM PREDICTION CENTER NORMAN OK
0650 PM CST MON NOV 16 2015

AREAS AFFECTED...PORTIONS OF CENTRAL NEBRASKA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 170050Z - 170215Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...LOCALIZED SEVERE WEATHER THREAT WILL EXIST FOR A FEW HOURS
NORTH OF THE CURRENT SEVERE WEATHER WATCHES WITHIN A DEVELOPING
CONVECTIVE LINE SEGMENT IN THE VICINITY OF A DEVELOPING MESOSCALE
VORTEX. ALL SEVERE HAZARDS REMAIN POSSIBLE BEFORE STORMS OUTRUN THE
NARROW ZONE OF INSTABILITY AND MAY REQUIRE A LOCAL EXTENSION OF WW
#0538.

DISCUSSION...A MESOSCALE VORTEX HAS DEVELOPED IN AN EXPANDING
QUASI-LINEAR CONVECTIVE SYSTEM EXTENDING NORTHWARD INTO CUSTER
COUNTY PER KLNX VELOCITY AHEAD OF A NARROW ZONE OF POSITIVE BUOYANCY
THAT HAS SPREAD NORTHWARD TO ABOUT 42 DEG N LATITUDE AND EASTWARD
INTO THE GRAND ISLAND AREA. ALTHOUGH SURFACE TEMPERATURES ARE
COOLING DIURNALLY AND UNDER LIGHT PRECIPITATION AHEAD OF THE
APPROACHING STORMS...THE SURFACE STABLE LAYER LIKELY REMAINS
SHALLOW...AND ANY LOCALIZED CIRCULATIONS THAT DEVELOP ALONG THE
LEADING EDGE OF THE SYSTEM MAY NOT BE DECOUPLED FROM THE GROUND IN
THE NEXT FEW HOURS.  THE 0-1 KM SHEAR IN EXCESS OF 30 KT ORIENTED
NORMAL TO THE SURGING LINE SUGGESTS A POTENTIAL FOR QLCS TORNADOES
WITH THIS ACTIVITY. FURTHERMORE...ALTHOUGH THE STRONG 850-700 MB
FLOW IN EXCESS OF 50 KT REMAINS SOUTH OF THE MCD AREA...THEREBY
LIMITING THE CONTRIBUTION OF MOMENTUM TRANSFER TO SEVERE WIND
PRODUCTION...A NARROW MESO-BETA SCALE AREA OF REAR-INFLOW HAS
DEVELOPED IN ASSOCIATION WITH THE MESOVORTEX THAT COULD ENHANCE THE
SEVERE WIND POTENTIAL WITH THIS LINE.  HOWEVER...THE SPATIAL
COVERAGE AND DURATION OF THIS PARTICULAR THREAT IS EXPECTED TO
REMAIN SMALL ENOUGH TO PREVENT THE NEED FOR A WATCH AT THIS TIME BUT
MAY REQUIRE A LOCAL EXTENSION OF WW #0538 INTO CUSTER COUNTY.

..CONIGLIO/CORFIDI.. 11/17/2015

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

ATTN...WFO...OAX...GID...LBF...

LAT...LON   41300005 41599987 41759950 41929902 41909859 41829829
            41699807 41429794 41369805 41209834 41139901 41069951
            41079996 41080017 41300005 

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