MESO: Mesoscale Discussion 0563

ACUS11 KWNS 271855
SWOMCD
SPC MCD 271855
ALZ000-TNZ000-MSZ000-ARZ000-LAZ000-272100-

MESOSCALE DISCUSSION 0563
NWS STORM PREDICTION CENTER NORMAN OK
0155 PM CDT SAT APR 27 2013

AREAS AFFECTED...NRN/CNTRL MS...NWRN AL...WRN TN...ERN AR

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 271855Z - 272100Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...SEVERE TSTMS SHOULD DEVELOP ACROSS PARTS OF THE MID-SOUTH
TOWARDS THE TN VALLEY BY LATE-AFTERNOON. A TORNADO AND PERHAPS A
SEVERE THUNDERSTORM WATCH WILL BECOME NECESSARY AT SOME POINT...BUT
CONFIDENCE IS LOW ON TIMING OF WW ISSUANCE THIS AFTERNOON.

DISCUSSION...18Z SURFACE ANALYSIS PLACED A 1015 MB CYCLONE 30 W KHOT
WITH A WARM FRONT EXTENDING EWD TO NEAR KMEM TO KHSV AND A COLD
FRONT EXTENDING SWWD INTO NERN TX. ABUNDANT CLOUD COVERAGE WAS
PREVALENT ALONG THE FRONTAL ZONES. NEVERTHELESS...SURFACE
TEMPERATURES HAD WARMED THROUGH THE 70S IN MUCH OF THE WARM SECTOR
INTO THE LOWER 80S ACROSS CNTRL/SRN MS...WHILE DEW POINTS HAVE HELD
IN THE MIDDLE 60S. THIS IS FOSTERING THE INCREASING PRESENCE OF A
MODERATELY BUOYANT AIR MASS.

CONVERGENCE ALONG PRIMARILY THE COLD FRONT...AS WELL AS BANDS OF
CONFLUENCE WITHIN THE WARM SECTOR WILL YIELD INCREASING TSTM
COVERAGE AS THE AIR MASS CONTINUES TO DESTABILIZE. WITH A BELT OF
STRONG 700-500 MB FLOW ATTENDANT TO THE COMPACT SHORTWAVE IMPULSE
MOVING EWD ACROSS SRN MO...SETUP SHOULD YIELD SEVERAL
SUPERCELLS/MULTICELL CLUSTERS CAPABLE OF LARGE HAIL AND DAMAGING
WIND. 0-1 KM SHEAR OF 15-25 KT WILL ALSO SUPPORT A RISK FOR A FEW
TORNADOES...MOST LIKELY NEAR THE WARM FRONT FROM ERN AR INTO WRN TN.

..GRAMS/HART.. 04/27/2013

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

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

LAT...LON 35808793 35228761 34328764 33558772 32958795 32768825
32638876 32668946 32859081 33149159 33709206 34209210
34999179 35859056 36018929 35808793

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