Severe Storm Outlook Narrative (AC)
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000
ACUS11 KWNS 271244
SWOMCD
SPC MCD 271244
MSZ000-LAZ000-271415-

MESOSCALE DISCUSSION 0480
NWS STORM PREDICTION CENTER NORMAN OK
0744 AM CDT MON APR 27 2015

AREAS AFFECTED...CENTRAL/SOUTHERN LA AND FAR SOUTHERN MS

CONCERNING...TORNADO WATCH 125...126...

VALID 271244Z - 271415Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 125...126...CONTINUES.

SUMMARY...A FAST-MOVING SQUALL LINE WILL CONTINUE TO POSE A DAMAGING
WIND/SOME TORNADO RISK THIS MORNING ACROSS MUCH OF SOUTHERN/CENTRAL
LA POTENTIALLY INTO FAR SOUTHWEST/SOUTHERN MS. TORNADO WATCH 126
CONTINUES UNTIL 18Z.

PENDING SQUALL LINE TRENDS...A NEW WATCH MAY BE NEEDED FOR
ADDITIONAL PORTIONS OF SOUTHEAST LA AND POSSIBLY FAR SOUTHERN MS BY
MID-MORNING.

DISCUSSION...A FAST-MOVING ASYMMETRIC SQUALL LINE WITH LEADING BOW
AND NORTH-SIDE EMBEDDED COMMA HEAD CONTINUES TO QUICKLY /50+ KT/
MOVE EASTWARD ACROSS SOUTH-CENTRAL LA AS OF 1230Z/730AM CDT. THIS
SYSTEM REMAINS VERY WELL-BALANCED/ORGANIZED WITH VERY COLD CLOUD
TOPS /ROUGHLY -80C/ AND A TIGHT LEADING-EDGE RADAR REFLECTIVITY
GRADIENT. LOW-LEVEL STORM RELATIVE INFLOW REMAINS RELATIVELY STRONG
AND RECENT WSR-88D VWP DATA FROM FORT POLK IS SAMPLING A VERY STRONG
/60 KT BETWEEN 2-4 KM AGL/ REAR-INFLOW JET IN THE IMMEDIATE WAKE OF
THE BOW ECHO. A PROXIMITY 12Z OBSERVED SOUNDING FROM LAKE CHARLES
SAMPLED AROUND 2700 J/KG MLCAPE AND VERY STEEP MID-LEVEL LAPSE RATES
/8.1 C PER KM BETWEEN 700-500 MB/ WITH VERY STRONG LOW-LEVEL
SRH/DEEP-LAYER SHEAR...WITH A RELATIVELY SIMILAR LAPSE RATE/VERTICAL
SHEAR PROFILE NOTED DOWNSTREAM PER THE 12Z SLIDELL OBSERVED
SOUNDING. WHILE SOME BOUNDARY LAYER INHIBITION/MODEST LOW-LEVEL
LAPSE RATES MAY BE SOMEWHAT MITIGATING MORE ROBUST
DOWNDRAFTS...EMBEDDED POCKETS OF DAMAGING WINDS AND POSSIBLY A
TORNADO WILL REMAIN CONCERNS THIS MORNING.

..GUYER.. 04/27/2015

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

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

LAT...LON   30659283 31359281 31489179 31419083 31208982 30678924
            29139023 29779315 30659283



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