Area Forecast Discussion
Issued by NWS Memphis, TN

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FXUS64 KMEG 221743

Area Forecast Discussion
National Weather Service Memphis TN
1243 PM CDT Tue May 22 2018


Updated to include 18Z aviation discussion.


.PREV DISCUSSION... /issued 1154 AM CDT Tue May 22 2018/

DISCUSSION...Surface analysis this morning places a weak upper
level low off the Texas Gulf Coast near Houston while a weak and
nearly quasi-stationary boundary GOES-16 Water Vapor Satellite
trends indicate additional moisture advecting north from the Gulf
of Mexico into the Lower Mississippi Valley. Scattered showers and
thunderstorms have gradually developed since mid morning with the
best coverage at the moment just east of the Memphis metro area in
West Tennessee. Latest meso-analysis indicates surface based CAPE
values have already increased to 3000 J/kg, LI`s around -5, and
0-6 km Bulk Shear values around 20 kts indicate pulse type
thunderstorms will be the primary mode of convection. A few strong
to perhaps severe thunderstorms will be possible with damaging
winds possible from wet microbursts along with perhaps hail up to
one inch.

Will make some minor adjustments to temperatures and rain chances
to account for short term trends. Otherwise, forecast overall is
in good shape.



.PREV DISCUSSION... /issued 322 AM CDT Tue May 22 2018/


Currently...A weak surface pressure pattern is in place across
the Mid-South accompanied by weak ridging aloft. It is much
quieter tonight with no precipitation and partly cloudy skies. All
the recent rain has led to some patchy fog across parts of the
area so use caution while driving this morning. Temps range from
the upper 60s to lower 70s with nearly calm winds.

Today through Thursday...Generally expect weak upper ridging to
continue to build over the area while a back door cold front
pushes into the region today and then stalls just south of the
region Wednesday and Thursday. As the weak front pushes south
today along with a weak upper level disturbance the latest hi res
models indicate that the best chances for showers and thunderstorms
will be across West Tennessee into North Mississippi this
afternoon. Expect highs in the mid to upper 80s. A few of these
storms could be strong with perhaps a severe storm as well. By
Wednesday and Thursday the front will be south of the area with
some drier air, PWs drop below an inch, expected to work into
northern and eastern areas with mainly afternoon rain chances
confined to the southern part of the forecast area. Highs will
generally reach the upper 80s. Cannot rule out a strong to severe
storm or two across North Mississippi.

Friday through Memorial Day...Models are in pretty good agreement
with moving a disturbance from the Gulf of Mexico into the lower
Mississippi Valley and eventually into the Mid-South during this
period. There is some disagreement with the exact track of the
system but an increase in moisture across the area seems likely.
This will result in more numerous showers and thunderstorms by the
weekend, probably continuing into next week. Clouds and
precipitation will keep temps in the 80s. Will continue to mention
the possibility of a strong to perhaps a severe storm through
this period since the airmass should continue to destabilize each
afternoon. Heavy rain may become more of a concern this weekend
into early next week depending on the evolution and track of this



/18z TAFs/

Mainly VFR conditions expected over the next 24 hours. The
exception will be temporary VSBY and CIG reductions near showers
and thunderstorms. The best chance of convection will be near
MEM...MKL...and TUP as a weak front moves south across the area.

Winds will generally be light and variable through the entire
period. Any site that stays clear overnight will have the
potential for at least some light to moderate MVFR fog.




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