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ACUS11 KWNS 162238
SWOMCD
SPC MCD 162238
MSZ000-LAZ000-170015-

MESOSCALE DISCUSSION 0663
NWS STORM PREDICTION CENTER NORMAN OK
0538 PM CDT THU MAY 16 2013

AREAS AFFECTED...NORTH-CENTRAL/NORTHEAST LA AND FAR SOUTHWEST MS

CONCERNING...TORNADO WATCH 164...

VALID 162238Z - 170015Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 164 CONTINUES.

SUMMARY...LARGE HAIL/DAMAGING WIND AND SOME TORNADO POTENTIAL WILL
CONTINUE ESPECIALLY WITH A SOUTHEASTWARD-MOVING SUPERCELL ACROSS
NORTH-CENTRAL/NORTHEAST LA. TORNADO WATCH 164 CONTINUES UNTIL 01Z.
MONITORING TRENDS FOR A NEW WATCH TO THE EAST-SOUTHEAST OF WW
164...POTENTIALLY INCLUDING ADDITIONAL PORTIONS OF LA/FAR SOUTHWEST
MS.

DISCUSSION...A SUPERCELL ACROSS NORTH-CENTRAL LA CONTINUES TO MOVE
SOUTHEASTWARD AND ROUGHLY PARALLEL I-49 TO THE NORTHEAST...NEARING
THE WINNFIELD LA VICINITY AS OF 2230Z. THIS SUPERCELL WILL LIKELY
CONTINUE TO SPREAD EAST-SOUTHEASTWARD ACROSS THE MOIST/INSTABILITY
AXIS ACROSS NORTH-CENTRAL LA IN THE SHORT-TERM...WHERE SURFACE
DEWPOINTS ARE IN THE MIDDLE 60S F AND MLCAPE IS ESTIMATED TO BE
AROUND 1250-1500 J/KG.

LARGE HAIL WILL LIKELY REMAIN THE MOST COMMON RISK THROUGH THE
23Z-00Z TIME FRAME. HOWEVER...SOME TORNADO POTENTIAL WILL CONTINUE
AS WELL. WSR-88D VWP DATA FROM FORT POLK INDICATES AS MUCH AS 80-100
M2/S2 OF 0-1 KM SRH...ALTHOUGH STRONGER /30-45 KT/ SOUTHWESTERLIES
ARE NOTED JUST ABOVE THAT WITHIN THE 2-3 KM LAYER. GIVEN THAT THIS
SUPERCELL MAY BEGIN TO MOVE OUTSIDE THE WATCH AFTER 00Z...CURRENT
TRENDS WILL CONTINUE TO BE MONITORED FOR THE POSSIBILITY OF A NEW
WATCH TO THE EAST-SOUTHEAST OF TORNADO WATCH 164...INCLUDING
ADDITIONAL PORTIONS OF LA/FAR SOUTHWEST MS.

OTHERWISE...A TREND TOWARD SUBSIDENCE ALOFT IN THE IMMEDIATE WAKE OF
THE UPPER LOW PUTS ADDITIONAL DEVELOPMENT ACROSS THE ARKLATEX A BIT
INTO QUESTION. HOWEVER...SUFFICIENT CONVERGENCE/WEAK CAPPING ALOFT
SUGGESTS THAT SOME ADDITIONAL DEVELOPMENT CANNOT BE ENTIRELY RULED
OUT OVER THE NEXT HOUR OR TWO.

..GUYER.. 05/16/2013

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

ATTN...WFO...JAN...LIX...LCH...SHV...

LAT...LON   32829395 32289266 31919153 31499115 30919140 30839192
            31619337 32829395

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