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Area forecast discussion...updated 
National Weather Service Memphis Tennessee
611 am CDT Thursday Apr 24 2014


Updated to include the 12z aviation discussion below.



Discussion... /issued 320 am CDT Thursday Apr 24 2014/

Currently the midsouth was sandwiched between an approaching potent
surface low in southwest Kansas and an exiting surface ridge over
the Appalachians. On satellite...high level moisture from ongoing
storms in the plains was spreading over the area...ahead of a
sharp shortwave trough exiting the southern rockies. Ground
observations were indicating mainly light easterly winds with
temperatures ranging from the middle the upper 50s.

For today and tonight...the plains storm is expected to track from
Kansas to Illinois through the period...with an associated cold
front also advancing eastward. Aloft...the strong shortwave will
cross the Southern Plains and the Ozarks today...and over the
midsouth this evening. Current convection in the Red River valley
will increase in coverage over the Ozarks by early this afternoon
as a plume of near 60f dewpoints surges northeastward. Feel that
the best timing for severe weather will be late this afternoon
along an axis from the arklatex to south central Missouri where
cape values will climb to over 1500 j/kg. Storm Mode at this time will
be more discrete in nature...with a better chance for isolated
tornadoes. Model guidance indicates convection becoming more linear
in the early evening between Memphis and Little Rock...reaching
the Mississippi River in the 8-10pm time frame. Off set somewhat
by the expected height falls...the instability will fall to less
than 800 j/kg by this time. So severe potential will have to be
more influenced from the approaching 50-60 knots middle level jet and
aided by any cold pools generated from the ongoing storms. For these
reasons...I have placed in the severe weather potential statement the potential for an isolated
tornado west of the MS river...and extended the damaging wind
threat over all of west Tennessee and north Mississippi. Forecast
soundings indicate the best severe hail threat will be over
Arkansas before sunset.

Thursday night through Saturday...storms will exit the midsouth
from west to east later tonight with the cold front slowly
reaching the I-20 corridor by noon Friday. High pressure at all
levels will build in behind the front and provide for a very nice
start to the last weekend in April. Temperatures will be in the
70s tomorrow..with widespread 80s Saturday. Models are trending
to lower dewpoints this overnight lows will likely drop
back into the 50s...and possible upper 40s along the Tennessee
River Saturday morning.

Sunday through Wednesday...a stormy period is still anticipated by
the GFS and Euro with good agreement that the upper level pattern
will shift from a steady flow of troughs and a closed
persistent closed low over the central U.S. This feature will
spark a surface low in the plains that will quickly
deepen...occlude and also meander in the same general area. Thus
the midsouth will likely see several rounds of storms...each
potentially severe beginning as early as Sunday afternoon through
Tuesday. All severe hazards will be possible including flash
flooding. Temperatures will start off above normal for
Sunday...cooling a few degrees each that by Wednesday as
the upper low finally moves up the Ohio Valley highs across the
midsouth will drop to the low and middle 60s.




12z taf cycle (24/12z-25/12z)

Southerly winds will increase today and become gusty ahead of a cold
front and upper level trough that will move into the area from the
west this evening. VFR conditions will persist much of today.
Numerous showers and thunderstorms will develop ahead of the front
along and west of the MS river by middle to late afternoon with lower
ceilings and visibilities possible...then spread eastward this
evening. The showers and thunderstorms will then end from the west
beginning by late evening. MVFR ceilings will follow the front
tonight...clearing from the west by late tonight. Winds SW-west tonight
and remaining gusty much of the night.



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