[BNAWX] Severe Storm Outlook Narrative

Tue May 21 18:23:51 CDT 2013

ACUS11 KWNS 212323
SWOMCD
SPC MCD 212323
TNZ000-ALZ000-MSZ000-ARZ000-220030-

MESOSCALE DISCUSSION 0762
NWS STORM PREDICTION CENTER NORMAN OK
0623 PM CDT TUE MAY 21 2013

AREAS AFFECTED...WRN-MIDDLE TN / FAR NWRN AL / NRN MS / FAR SERN AR

CONCERNING...TORNADO WATCH 207...

VALID 212323Z - 220030Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 207 CONTINUES.

SUMMARY...ISOLD POCKETS OF WIND DAMAGE APPEAR TO BE THE MAIN THREAT.
 TORNADO POTENTIAL WILL LIKELY REMAIN LIMITED BASED ON LINEAR
CONVECTIVE MODE.

DISCUSSION...RADAR MOSAIC SHOWS AN ORGANIZED QLCS FROM FAR SRN IL
SWD TO E OF THE GREATER MEMPHIS METRO SWWD INTO SERN AR.  THE NRN
PORTION OF THE QLCS FROM NEAR MEM NWD INTO WRN KY REMAINS LARGELY
SUB-SEVERE AND SURFACE OBS OVER WRN TN SUPPORT THIS NOTION WITH ASOS
GUSTS AT TIME OF QLCS PASSAGE REMAINING BELOW 30 KT.  SURFACE
ANALYSIS SHOWS A LARGELY WEST-EAST ORIENTED OUTFLOW BOUNDARY
EXTENDING FROM THE TRAILING PORTION OF THE SRN APPALACHIANS QLCS
WESTWARD AND INTERSECTING THE QLCS 25 MI ESE MEM.  EARLIER IN THE
DAY SUBSTANTIAL CONVECTIVE OVERTURNING OCCURRED N OF THIS BOUNDARY
ACROSS WRN AND MIDDLE TN -- LIMITING THE MAGNITUDE OF
DESTABILIZATION OCCURRING IN ITS WAKE.  CURRENT THINKING IS THE TN
PORTION OF THE QLCS MAY ONLY POSE A LOW DAMAGING WIND THREAT.

FARTHER S OVER NRN MS...A WARM/UNSTABLE AIRMASS AHEAD OF THIS
CONVECTIVE LINE IS MORE FAVORABLE FOR ISOLD POCKETS OF WIND DAMAGE
GIVEN THE STEEPER LOW LEVEL LAPSE RATES.  IT IS UNCERTAIN HOW FAR
EAST THIS QLCS MAY POSE AN ISOLD DAMAGING WIND THREAT...ESPECIALLY
SINCE THE BOUNDARY LAYER WILL BEGIN TO COOL BY THE TIME THE QLCS
APPROACHES THE ERN EDGE OF THE WATCH NEAR THE NERN MS/NWRN AL
BORDER.  ALTHOUGH A BRIEF TORNADO IS POSSIBLE NEAR THE OUTFLOW
BOUNDARY-QLCS INTERSECTION...THIS THREAT WILL LIKELY REMAIN LIMITED
BASED ON THE LINEAR CONVECTIVE MODE.

..SMITH.. 05/21/2013

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

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

LAT...LON   36478874 35098975 33489168 33019107 33018934 34268807
            35638754 36378760 36478874

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