MESO: Mesoscale Discussion 0308

ACUS11 KWNS 292347
SWOMCD
SPC MCD 292347
ALZ000-MSZ000-LAZ000-TXZ000-300145-

MESOSCALE DISCUSSION 0308
NWS STORM PREDICTION CENTER NORMAN OK
0647 PM CDT TUE MAR 29 2011

AREAS AFFECTED...SRN LA/SRN MS

CONCERNING...TORNADO WATCH 72...

VALID 292347Z - 300145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 72 CONTINUES.

A SYNOPTIC BAROCLINIC ZONE IS DRAPED FROM NEAR LCH TO JUST NORTH OF
BTR TO 25 MILES SSE OF ASD. THIS FEATURE IS LIFTING NWD AS A WARM
FRONT OVER SERN LA. SFC OBSERVATIONS INDICATE DEWPOINTS IN THE UPPER
60S AND LOWER 70S SOUTH OF THE FRONT...WHERE 23Z RUC OBJECTIVE
ANALYSIS INDICATES MLCAPE VALUES AOA 2000 J/KG. THIS FRONT IS
FORECAST TO BE NUDGED INTO SRN MS DURING THE NEXT FEW HOURS BY
INCREASING SLY LOW-LEVEL FLOW. SURFACE-BASED CONVECTION IS
DEVELOPING NEAR AND SOUTH OF THIS WARM FRONT...AND THIS WILL
CONTINUE TO OCCUR INTO THIS EVENING AS DEEP-LAYER ASCENT INCREASES.
FARTHER TO THE NORTH...A SECONDARY/MESOSCALE WARM FRONT EXTENDS FROM
S-CNTRL INTO SERN MS...AND IS FOLLOWED BY DEWPOINTS IN THE LOWER AND
MIDDLE 60S. BETWEEN THIS FEATURE AND THE SYNOPTIC BOUNDARY...MODEST
CONVECTIVE INHIBITION FOR A SURFACE-BASED PARCEL WILL RESULT IN A
CONTINUED POTENTIAL FOR SLIGHTLY ELEVATED CONVECTION. HOWEVER...AS
THE SYNOPTIC WARM FRONT LIFTS NWD...THIS CONVECTION WILL LIKELY
BECOME SURFACE BASED.

MODERATE TO STRONG DEEP-LAYER SHEAR /52 KT OF 0-6 KM SHEAR PER VWP
AT LIX/ IS ALLOWING CONVECTION TO EXHIBIT SUPERCELLULAR
CHARACTERISTICS...AND THIS WILL LIKELY CONTINUE THROUGH THE EVENING
HOURS. LOW-LEVEL VERTICAL SHEAR IS FORECAST TO INCREASE DURING THE
NEXT FEW HOURS...PARTICULARLY INVOF THE SYNOPTIC WARM FRONT...AS A
LOW-LEVEL JET MATERIALIZES EAST OF A DEEPENING TROUGH EXTENDING FROM
THE OZARKS TOWARD THE SABINE RIVER VALLEY. THIS IS EXPECTED TO
RESULT IN AN INCREASING POTENTIAL FOR TORNADOES ACROSS WW72 THROUGH
THE EVENING HOURS...ESPECIALLY WITH ANY SUPERCELLS. THE CONVECTION
COULD ALSO GROW UPSCALE INTO ONE OR MORE CONVECTIVE CLUSTERS/LINE
SEGMENTS...WITH AN ATTENDANT POTENTIAL FOR DMGG WINDS.

..COHEN.. 03/29/2011

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

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

LAT...LON 29338969 29159108 29219314 29679373 30649370 31359326
31779163 31959016 31938863 30598836 29758874 29338969

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