Severe Thunderstorm Warning 196, NWS Nashville, TN

Area Forecast Discussion
National Weather Service Nashville TN
712 PM CDT Sat Aug 5 2023

...New AVIATION...

.SHORT TERM...
(This afternoon through Monday Night)
Issued at 221 PM CDT Sat Aug 5 2023

Surface low located over IL this afternoon with a warm front
trailing off to the southeast and across the mid state. Cold front
extends southwestward from the low to across southern MO and
northern KN. The cold front and areas just south will continue to
serve as a breeding ground for MCS development going forward.

Currently, the remnants of the latest system covers our
north central and northeastern areas and will continue to
weaken with time. Model data going forward is not very dependable
in terms of futuristic MCS timing and approximate location. That
said, we'll be adhering to the short term cams and current and
expected trajectory patterns for the forecast through Monday
night.

We are currently outlooked with a marginal risk through tonight.
Expectations are for an mcs to develop across eastern AR and move
eastward and reach our area this evening. Hrrr and Namnest are in
agreement with this expectation. Since its noteworthy, The GFS
also shows some enhancement for this evening, though the Euro is
not in support. Straight line strong to perhaps damaging winds
will be the threat. The degree of afternoon destabilization may be
overdone as the current cloudiness and rainfall may be a little
slower to end. We are getting some better destabilization across
our southwest. The surface low to our north could generate a
little more in the way of helicity magnitudes but that should
generally remain to or north. Localized flooding will also be a
possibility. Cams show up to 1-2 inch localized amounts through
sunrise. Some areas across our northwest have received 1-2 inches
since midnight.

Moving on, perhaps a break for the first portion of your Sunday.
Then we will see convection ramp up once again for the late
afternoon/evening period. At that time, a more vigorous surface low
across nrn IL will contain a southward extending cold front. Shear
values will be picking up with good instability levels in advance of
it. Our entire area is in a slight risk and we do see some better
helicity values of 200+ at that time. Otw, straight line damaging
winds will be the primary threat.

On Monday, we'll carry highest pops along the Plateau where
instabilities will ramp up significantly by afternoon. The slight
risk will still be in effect for areas east of I-65. Mid level lapse
rates approach 8C at that time with strong cape through the -20C
level. Can't rule out some hail at that point. Look for improving
conditions by Monday night.

Through Monday night, WPC is carrying areal average qpf amounts of
around 2 inches west to an inch east.

For the near term temps, we should warm into the upper 80s on Sunday
with that non active morning and early afternoon period expected.
More in the way of sunshine will keep us near 90 for Monday.

&&

.LONG TERM...
(Tuesday through next Saturday)
Issued at 221 PM CDT Sat Aug 5 2023

In the extended forecast, not much pattern change as in general, a
broad troughing regime resides. Westerlies will remain semi-active
but we can hone in on Wednesday and Thursday as rather wet. At that
time, a more robust series of shortwaves will impact our area. The
NBE numbers have shown some copious rainfall amounts with the last
several runs. Looks like the builder will give us 2 inch amounts, or
so, area wide. GFS is showing quite a bit more with the Euro close
to 2 inches. In terms of severe potential, SPC shows some activity
upstream from us on Day 5, but there is no Day 6 eastward
prorogation indicated at this time.

For the extended temps, with the expected clouds and precip for Wed
and Thu along with the aforementioned gentle troughing, temps will
run a few degrees below normal. Then, look for conditions to
normalize by the weekend with near 90 for highs returning.

&&

.AVIATION...
(00Z TAFS)
Issued at 708 PM CDT Sat Aug 5 2023

A broken line of storms is expected to move from west to east
across Middle TN this evening. Heavy rain could cause decreased
visibilities and gusty winds will likely accompany any storm.
Storms should clear CSV by 09Z. Low cigs and patchy fog may
develop overnight...with SRB and CSV being the most likely to
experience deteriorated conditions. Broken mid clouds are
expected to hang around throughout the day on Sunday. Additional
storm development is expected Sunday afternoon, but coverage is
uncertain. Mentioned vcts for now. Winds will remain out of the
west for most of the period.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      74  90  75  89 /  50  70  60  50
Clarksville    72  89  73  88 /  50  50  60  30
Crossville     67  84  68  82 /  60  70  60  70
Columbia       72  91  73  90 /  50  70  30  50
Cookeville     69  87  71  85 /  60  70  60  60
Jamestown      69  85  68  82 /  60  60  70  70
Lawrenceburg   71  90  72  89 /  50  70  30  50
Murfreesboro   72  92  72  90 /  50  70  50  50
Waverly        71  88  71  87 /  60  50  60  40

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&

SHORT TERM...21
LONG TERM....21
AVIATION.....Whitehead