Area Forecast Discussion
Issued by NWS Nashville, TN

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FXUS64 KOHX 240730
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
130 AM CST Sat Feb 24 2018

.DISCUSSION...

Warm frontogenesis is currently underway across Middle Tennessee
as a strong low pressure system develops over the southern Plains.
As a result, a band of showers is tracking toward the northeast
and dew points along the Alabama/Tennessee line have already
crossed 60F. The warm front will gradually lift northward today as
the aforementioned low center moves toward the northeast to near
STL by 00Z Sunday. Model soundings continue to show a moderately
unstable environment today with CAPE`s on the order of 500-1000
J/kg. In addition, a highly-sheared low-level wind profile will
contribute to 0-3 km helicity values of 100-200 today, increasing
to 400-500 during the evening as the low-level jet intensifies
just ahead of the cold front. Given the thermodynamic and helicity
profiles characteristic of this environment, strong to severe
storms are probable, with damaging straight-line winds and 1 or 2
tornadoes possible. Look for a line of storms to develop along or
just ahead of the surface front, with isolated discreet supercells
possibly developing ahead of this convective line. As a result,
the latest SPC day 1 outlook places western Middle Tennessee under
and enhanced risk of severe storms, with the eastern portion
under a slight risk, as some weakening of the storms can be
expected as the convection penetrates eastward during the late
evening or early morning Sunday. The NAM/GFS/Euro models all bring
the surface front to the Tennessee River around 06Z, and east of
the Cumberland Plateau by 12Z. In addition to the threat of severe
storms, a Flood Watch remains in effect today and tonight for
most of Middle Tennessee west of I-65, and another 1 to 2 inches
of rain can be expected with this system. So localized flash
flooding and river flooding are also on the table. Looking ahead
briefly, the next major system will move into Middle Tennessee
Tuesday night and Wednesday and continue into Thursday with a cold
frontal passage. Storm total QPF from 00Z Wednesday to 00Z Friday
suggests another 2 to 3 inches of rain across Middle Tennessee.

&&

.AVIATION...
06Z TAF DISCUSSION.

Scattered showers overspreading Middle Tennessee are generally
very light with VFR conditions, although slightly heavier activity
spreading in from the south will likely bring ceilings down to
below 2000 feet later tonight. Scattered shower activity, possibly
with a few storms, will likely redevelop during the later
morning/early afternoon hours before conditions clear out in the
afternoon. A line of strong storms is likely to sweep across
Tennessee late Saturday night/early Sunday morning but will likely
wait until after 06Z for Middle TN.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      77  55  62  43  64 /  60 100  10  20  10
Clarksville    74  50  60  38  63 /  80 100  10  10  10
Crossville     72  56  62  44  60 /  60  90  50  40  10
Columbia       76  54  61  43  64 /  60 100  10  30  10
Lawrenceburg   76  55  62  44  64 /  60 100  20  40  10
Waverly        75  50  60  41  63 /  70 100  10  10  10

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for Cheatham-Davidson-Dickson-
Hickman-Houston-Humphreys-Lewis-Maury-Montgomery-Perry-Robertson-
Stewart-Sumner-Williamson.

&&

$$

DISCUSSION......08
AVIATION........Hawblitzel


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