Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS11 KWNS 191051
SWOMCD
SPC MCD 191051
GAZ000-FLZ000-ALZ000-191245-

MESOSCALE DISCUSSION 0374
NWS STORM PREDICTION CENTER NORMAN OK
0551 AM CDT SUN APR 19 2015

AREAS AFFECTED...FL PANHANDLE/SOUTHWEST GA AND SOUTHERN/EASTERN AL

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 191051Z - 191245Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AT LEAST ISOLATED SEVERE THUNDERSTORMS MAY GRADUALLY
INCREASE THROUGH THE EARLY MORNING HOURS INITIALLY ACROSS THE
WESTERN FL PANHANDLE AND FAR SOUTHERN AL...BUT EVENTUALLY ALSO OTHER
PARTS OF SOUTHERN/EASTERN AL AND FL PANHANDLE/SOUTHWEST GA LATER
THIS MORNING. DEVELOPMENTAL TRENDS WILL BE MONITORED FOR A POSSIBLE
WATCH.

DISCUSSION...THUNDERSTORMS HAVE STEADILY INCREASED OVERNIGHT OFF THE
COAST OF SOUTHEAST LA AND SOUTHERN MS/AL...WITH MORE RECENT
DEVELOPMENT INTO INLAND AREAS OF EXTREME SOUTHWEST AL/WESTERN FL
PANHANDLE SINCE 0945Z. THIS DEVELOPMENT...AND EVEN OTHER SHOWERS/FEW
THUNDERSTORMS ACROSS CENTRAL/NORTHERN AL...APPEAR TO BE INFLUENCED
BY INCREASING LOWER-LEVEL CONFLUENCE AND THE LEADING EDGE OF HEIGHT
FALLS/FORCING ALOFT IN ASSOCIATION WITH A LEAD SHORTWAVE TROUGH OVER
THE LOWER MS VALLEY.

EVEN WITH SEMI-COOL OVERNIGHT TEMPERATURES...FACTORS SUCH AS
INCREASING FORCING/MIXING AND MODEST LOW-LEVEL MOISTENING APPEAR TO
BE LEADING TO DIMINISHING BOUNDARY LAYER INHIBITION EARLY THIS
MORNING WITHIN A NORTHWARD-EXPANDING WARM SECTOR CHARACTERIZED BY
UPPER 60S F DEWPOINTS. IN CONJUNCTION WITH INCREASINGLY STRONG
DEEP-LAYER SHEAR...SOUTH-SOUTHWESTERLY LOWER TROPOSPHERIC WINDS HAVE
INCREASED CONSIDERABLY OVERNIGHT...WITH REGIONAL WSR-88D VWP
GENERALLY CONSISTENT WITH 150-250 M2/S2 EFFECTIVE SRH. AS STORMS
CONTINUE TO STEADILY INCREASE IN COVERAGE/INTENSITY THROUGH THE
EARLY/MID-MORNING HOURS...AFOREMENTIONED INGREDIENTS WILL SUPPORT A
MIXED CONVECTIVE MODE POTENTIALLY INCLUDING A FEW SUPERCELLS AND
UPSCALE-GROWING LINEAR/BOWING SEGMENTS. WHILE THE SEVERE RISK MAY
REMAIN ISOLATED/RELATIVELY MARGINAL OVER THE NEXT FEW HOURS...A
CONTINUALLY INCREASING INTENSITY/COVERAGE TREND COULD PROMPT A WATCH
ISSUANCE LATER THIS MORNING.

..GUYER/EDWARDS.. 04/19/2015

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

ATTN...WFO...FFC...TAE...BMX...MOB...

LAT...LON   32208411 30668453 30198549 30298671 30148763 30758787
            33218625 32208411



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