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fxus64 kohx 152335 
afdohx

Area forecast discussion
National Weather Service Nashville Tennessee
535 PM CST sun Dec 15 2019

Update...
for 00z aviation discussion.

&&

Discussion...

The beginnings of a very dynamic system are starting to come
together west of middle Tennessee this afternoon. Frozen precip isn't all
that far off to our northwest, but no, that's not going to affect
US. Instead, the warm front that will be responsible for our
overnight rainfall has come together to our southwest. Currently
draped over Arkansas and northern Louisiana, it will push to the
northeast over the next several hours and should help to produce
showers in our northwest counties starting this evening. This
should be a light rain prior to midnight and then pick up in
intensity around midnight. By daybreak, the cold front should be
breaking into our northwest counties, spreading these showers and
maybe even a few rumbles of thunder southward into the I-40
corridor.

This is where things get tricky. By late tomorrow morning, the cold
front could push back towards the Kentucky state line. This slow
down/slight northward movement could help concentrate a strong low
level jet streak and anomalously high precipitable water values (1.3-1.4 inches)
over the northern half of middle Tennessee until mid-afternoon. Storm
motions along the front may lead to training storms over the same
areas for at least a few hours. Due to the uncertainty of where
the highest amounts of rainfall will occur, i'm going to hold off
on any watches for now however, 2 to 3 inches of rain will be
possible which could lead to localized flooding issues by Monday
evening.

Around the same time this is going on, we're still going to be
dealing with the potential for strong to marginally severe storms
south of I-40. Forecast soundings are still suggesting 300-400
MLCAPE values creeping into our southern counties and with 50-60
kts of deep layer shear and plenty of helicity, a few strong wind
gusts (40-50 mph) will be possible south of I-40. Storms that will
present these concerns should start to move into our southern
counties in the 1 to 4 PM time frame, with any thunderstorms that
do develop moving off the plateau prior to midnight.

After tomorrow night, rain chances don't move back into middle Tennessee
until at least Friday, but models are very wishy-washy with this
next system, so i'll just carry a slight chance pop for now. Look
for a drop into the low 20s Wednesday and Thursday mornings, but
temperatures should bounce back toward seasonal norms pretty quickly.

&&

Aviation...
00z taf discussion.

Bna/mqy/ckv...vcsh has already started with VFR skies. Expect
skies to become MVFR by 03z. Gusty westerly winds of 15-20 kts
expected through the night and becoming southerly. -Dz should
begin around 03z for ckv and -shra after 06z for bna and mqy. Also
expect low level wind shear from 06z-15z. By sunrise cigs will become IFR/LIFR as
the rain increases in intensity. Also including some -tsra after
21z.

Csv...VFR conditions...it will take some time for the showers to
reach the terminal in the east and have this happening after 05z
when cigs become MVFR. Winds will be southerly and gusty 10-20kts.
Also expect low level wind shear from 06z-15z. As the cold front sweeps through
tomorrow IFR/LIFR conditions expected along with -tsra.

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Ohx watches/warnings/advisories...
none.

&&

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