Tornadoes and Hail in Tennessee, June 11, 2023

Area Forecast Discussion
National Weather Service Nashville TN
1232 PM CDT Sun Jun 11 2023

...New AVIATION...

.UPDATE...
Issued at 1019 AM CDT Sun Jun 11 2023

Quiet conditions so far across the mid state, with radar echoes
off to the east and west of the area. 12Z models are coming in,
and largely are unchanged in regards to timing of the main line of
storms later this afternoon and evening. CAMs still have some
variability on timing which is to be expected with a cold
front/cold pool driven line later today, but right now, the window
for the line per 12Z CAMs in the downtown Nashville area is 5 pm
to 8 pm, depending on which model you choose. The suite of WRF
models are the fastest, hinting at 5 pm and maybe even just before
if the cold pool runs ahead of the line a bit faster. HRRR has
been very consistent in the 6 or 7 pm timeframe, and the
NAMNest and RRFS suggest roughly the same.

Instability is still expected to continue climbing during the
day, supported by strong warm moist advection as well as diurnal
assistance. Deep layer shear is strong for this time of year, with
models showing 25 to 40 knots of 0-6km shear. Soundings do show
some mid level dry air during the afternoon, along with some steep
low to mid level lapse rates. The environment will support
damaging wind gusts as the primary threat with any severe storms
this afternoon and evening, but with that drier air and steep
lapse rates this afternoon, large hail will also be possible. PWAT
values around or above 1.5 inches for the day will support heavy
rainfall, and any areas that see training of storms will be at
risk for some flooding as well. The tornado threat remains low as
the EHI and SRH values are low, as well as the 0-1km shear, but,
any isolated storms out ahead of the line later today or during
the afternoon may increase the risk slightly. Severe risk should
diminish from northwest to southeast during the evening as diurnal
support is lost and the cold air moves in.

Stay weather aware today, especially if you have outdoor plans,
as this environment can kick off storms and can become severe
quickly! Make a plan ahead of time to know where to go for
shelter, and have multiple ways to receive watch and warning
information this afternoon and evening.

&&

.SHORT TERM...
(Today through Tuesday)
Issued at 308 AM CDT Sun Jun 11 2023

Tranquil weather in place currently with just a few light showers
across our southeast. Temperatures are generally in the 70 to 75F
degree range.

Look for conditions to begin to go down hill later today. Still
expecting a frontal passage to occur this evening. The primary
organizational forcing will reach the TN river around 3PM. At that
time, surface capes of 2000 j/kg will match up with LI's of -6C to
-8C and 850 mb winds of 30kts. Shear will increase across our
eastern half into early evening while instabilities back off. The
primary threat still looks to be straight line damaging winds.
Momentum driven activity will likely hold on on into our eastern
areas. And, we are now in an enhanced risk for the entire mid state.

It's important to note that in addition to some surface low
strengthening with time, the surface axis will be backing and will
pick up some added n-s extension as it crosses our area. This very
configuration will increase the wind threat while decreasing the
heavier rain threat. Earlier it was estimated that local areas could
receive as much as 3 inches of rainfall. It now looks like 1-2
inches of total rainfall. So, the event is looking more and more
like a potentially damaging wind event, primarily. The time frame
for severe remains as 3 pm in our far west, with the severe threat
ending around 9 pm across our Plateau.

Moving on, Monday will feature a partly cloudy morning and then a
mostly sunny day. The respite wont last long, however. The boundary
to our south will be working back to the north as a warm front and
will bring a returning chance of shower and tstm activity to the
area on Tuesday. The good news is that I'm not seeing anything
exceeding general convection at this time. Otw, rainfall amounts of
one half to three quarters of an inch will be possible, highest
totals south.

For the near term temps, humid and a little muggy today with mid 80s
expected. Not as warm behind the fropa with 75 to 80 for the
following two afternoons.

&&

.LONG TERM...
(Tuesday Night through next Sunday)
Issued at 308 AM CDT Sun Jun 11 2023

In the extended forecast, models have shied away a touch from the
earlier flood threat to our south. Northerly flow is looking a
little stronger and the higher 7 day qpf totals have shifted further
south. We still, however, are picking up on an active northwesterly
flow regime for the extended. A rather vigorous shortwave will be
moving southeastward and may cross our area on Friday. NBM only
shows 40-50 percent right now along with a half inch of rainfall.
The European shows the feature as well but not as strong with it.
Prior to Friday, Wed and Thu not looking to bad. The better rainfall
area will shift to our south as the northerly flow takes over.

For the extended temps, after a seasonal Wednesday, temps will climb
to a few degrees above normal as heights climb and sunshine
returns ahead of the shortwave. Overnight lows will be in the 60s.

&&

.AVIATION...
(18Z TAFS)
Issued at 1229 PM CDT Sun Jun 11 2023

Already we are seeing widely scattered convection pop up in this
afternoon's pre-frontal air mass. Winds have increased
considerably from the SW, and will continue that way until after
this evening's fropa. We don't expect much additional activity
until a squall line comes through Middle Tennessee with the front
during the late afternoon and early evening. The HRRR has been
very consistent in its timing throughout the morning, and we have
been able to narrow the window to 1-2 hours for each of our
terminals. Look for some lingering light showers after the initial
line of convection comes through, with ceilings lowering to
MVFR/IFR for several hours following the fropa.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      62  80  57  81 /  90   0  10  20
Clarksville    58  77  55  80 /  50   0   0  20
Crossville     57  71  49  73 /  90  10   0  30
Columbia       59  79  56  79 /  90   0  10  30
Cookeville     58  74  52  75 /  90  10   0  20
Jamestown      57  71  50  74 /  90  10   0  20
Lawrenceburg   59  79  56  77 /  90   0  10  40
Murfreesboro   60  80  54  79 /  90   0  10  30
Waverly        57  78  56  78 /  40   0  10  20

&&

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

UPDATE.......Barnwell
SHORT TERM...21
LONG TERM....21
AVIATION.....Rose

Special Weather Statement
National Weather Service Nashville TN
139 PM CDT Sun Jun 11 2023

TNZ008-111915-
Sumner TN-
139 PM CDT Sun Jun 11 2023

...A strong thunderstorm will impact portions of central Sumner
County through 215 PM CDT...

At 138 PM CDT, Doppler radar was tracking a strong thunderstorm near
Gallatin, moving northeast at 20 mph.

HAZARD...Winds in excess of 30 mph and half inch hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Gallatin and Cottontown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 3634 8651 3640 8662 3655 8652 3646 8628
TIME...MOT...LOC 1838Z 212DEG 17KT 3640 8654

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Whitehead