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fxus64 kohx 212017 
afdohx

Area forecast discussion
National Weather Service Nashville Tennessee
217 PM CST Thu Nov 21 2019

Discussion...

Echoes currently on radar are showing the moisture aloft but most
of that having a tough time making it to the surface with the
drier air still in the low levels. That will be short lived since
the shortwave trough ahead of the larger plains trough will be
able to bring in some additional moisture and widespread showers
tonight. Amounts are relatively unchanged, with consensus still
showing 1-2 inches across the area through Saturday afternoon, but
some heavier rain will be possible Friday morning north of I-40.
In the afternoon on Friday, the shortwave will move off to the
northeast and before the strong closed low in the plains can bring
in the second round of rain, we may have a break in the rainfall
with ridging in between the troughs Friday afternoon. As the
upper closed low moves into the mid MS River Valley Friday night,
additional warm air advection and moisture advection will bring in the next round
of showers from the south. Models have a bit of instability, but
a lot of shear thanks to the strong upper low, so added in
slight chance mention of thunder during the evening and overnight
hours Friday night into Saturday morning. The upper low will
continue eastward through the Midwest Saturday, and the cold front
will move through during the day as well, so precip should come
to an end from west to east during the day Saturday with lingering
chances on the plateau Saturday night. Cloud cover will hang
around most of the day Saturday as well with the upper low/trough
still overhead, so wont take too much to keep drizzle/light rain
in the forecast behind the front Saturday and Saturday night
across the area.

Sunday will see the clouds move off to the east with northwest
flow aloft and Monday will remain dry with flow becoming more
zonal. Tuesday will have yet another plains trough move through
the Midwest, and will be quite strong. Thankfully it moves east-northeast and
limits the cold air advection behind the cold front late Tuesday and should
prevent any frozen precip. Models have 850 mb temps around 0c when
the precip is off to the east, so it appears that rain will still
be the precip type Tuesday and Tuesday night. Wednesday looks to
be dry, but models do not agree on timing of the Tuesday trough so
didn't abandon pops for the daytime Wednesday just yet. The GFS
and European model (ecmwf) have backed off a bit for Thanksgiving day rainfall and
pushed it into the evening with weak shortwave activity moving
through the upper ridge. Models continue to show different
solutions for Friday and into the weekend, but it still looks to
be wet with a continued active pattern.

&&

Aviation...
18z taf discussion.

Chances for showers will increase today, along with dropping cigs.
MVFR cigs look likely late evening through the overnight, with IFR
cigs and vis possible with heavier rainfall. Rain will hold off at
kcsv until just before sunrise with vcsh nearby overnight. A break
in the rain will be possible Friday afternoon which may allow for
cigs to return to MVFR and possibly VFR in the afternoon, but rain
chances will return late Friday night. Southwest winds will be
around 10 to 15 knots during the day today and around 5 to 10
knots overnight and into the morning Friday.



&&

Preliminary point temps/pops...
Nashville 51 55 48 57 35 / 100 100 90 60 10
Clarksville 49 50 43 49 32 / 100 100 70 40 10
Crossville 46 56 47 59 31 / 90 100 90 80 20
Columbia 51 59 49 58 34 / 90 100 90 50 10
Lawrenceburg 51 60 50 58 33 / 70 100 90 50 10
Waverly 52 59 50 55 33 / 80 100 90 40 10

&&

Ohx watches/warnings/advisories...
none.

&&

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