[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 212306
SWOMCD
SPC MCD 212306
TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-220030-

MESOSCALE DISCUSSION 2104
NWS STORM PREDICTION CENTER NORMAN OK
0506 PM CST SAT DEC 21 2013

AREAS AFFECTED...LA...MS...TN..NW AL

CONCERNING...TORNADO WATCH 580...582...

VALID 212306Z - 220030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 580...582...CONTINUES.

SUMMARY...THE SEVERE THREAT WILL CONTINUE AS A LINEAR MCS MOVES INTO
MIDDLE TN...WRN MS AND SE LA BY EARLY THIS EVENING. WIND DAMAGE WILL
BE LIKELY AND TORNADOES WILL BE POSSIBLE WITH THE STRONGER LINES
SEGMENTS AND ROTATING CELL ELEMENTS. WW ISSUANCE WILL BECOME LIKELY
ACROSS PARTS OF THE MCD AREA AS THE LINE MOVES TOWARD THE ERN EDGE
OF WW 580 AND WW 582.

DISCUSSION...A WELL-DEVELOPED LINEAR MCS WILL CONTINUE MOVE QUICKLY
EWD INTO THE TN VALLEY AND LOWER MS VALLEY FROM LATE THIS AFTERNOON
INTO THE EARLY EVENING. SFC ANALYSIS SHOWS A SFC LOW NEAR THE MS
RIVER SOUTH OF MEMPHIS WITH A COLD FRONT EXTENDING SWD FROM THE LOW
JUST BEHIND THE SQUALL-LINE. ENHANCED LOW-LEVEL CONVERGENCE ALONG
THE FRONT COMBINED WITH STRONG LARGE-SCALE ASCENT ASSOCIATED WITH A
NEGATIVELY-TILTED SRN PLAINS UPPER-LEVEL TROUGH WILL HELP THE LINE
TO REMAIN ORGANIZED THROUGH THIS EVENING. AHEAD OF THE
SQUALL-LINE...AN AXIS OF INSTABILITY IS ANALYZED FROM SE LA NNEWD
ACROSS WCNTRL MS INTO MIDDLE TN WITH MLCAPE ESTIMATED IN THE 600 TO
1200 J/KG RANGE. IN ADDITION TO THESE FACTORS...THE WIND SHEAR
ENVIRONMENT IS VERY FAVORABLE FOR SEVERE STORMS. THE WSR-88D VWP AT
JACKSON MS SHOWS STRONG SPEED SHEAR FROM THE SFC TO 1 KM WITH A
GRADUALLY VEERING PROFILE ABOVE THAT. THIS SHOULD BE FAVORABLE FOR
TORNADOES WITH ROTATING CELLS EMBEDDED IN OR JUST AHEAD OF THE LINE.
WIDESPREAD WIND DAMAGE WILL BE LIKELY WITH THE LINE DUE TO A FAST
FORWARD NELY MOTION AROUND 50 KT.

..BROYLES.. 12/21/2013

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

ATTN...WFO...OHX...BMX...HUN...MEG...JAN...LIX...LZK...LCH...

LAT...LON   30519020 29979084 30149166 30679205 31349190 32529151
            33749101 34669005 35518904 35828857 35738787 34858754
            32728951 30519020


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