Special Weather Statement, NWS Nashville, TN

Area Forecast Discussion
National Weather Service Nashville TN
222 PM CDT Fri Jul 9 2021

.DISCUSSION...

Showers and thunderstorms continue to develop this afternoon ahead
of a weak upper level disturbance in the northwest flow. Enough
instability is out there for a strong storm or two capable of some
gusty winds, and deep layer shear is just strong enough to help
maintain some updrafts for heavy rain. Dewpoints in the low 70s
providing plenty of moisture and PWAT values showing 1.5 to 2
inches across the models and will continue the heavy rain threat
with any stronger updrafts. A brief lull in convective activity
should move in this evening after sunset, but CAMs and even long
term models bring in additional showers and thunderstorms
overnight ahead of another stronger shortwave moving in from the
Plains. This shortwave will be ahead of the larger and stronger
Plains trough that will move southward later on Saturday and sit
over northern MO on Sunday. Showers and thunderstorms will develop
again during the day Saturday, especially in the afternoon east of
I-65 according to CAM guidance with that shortwave in the OH River
Valley ahead of the larger upper low in the Plains.

The question will remain on how far south and east the trough
gets Saturday night, and how strong outflow will be to get
convection into the mid state Saturday night into Sunday morning.
Currently SPC has a slight risk in our northwest, and should the
trough and earlier convection Saturday afternoon/evening move
further southeast, we could see some strong to severe storms with
a damaging wind threat overnight Saturday night into Sunday
morning. The HRRR and ARW are the CAMs that are showing the
strongest storms over our area Saturday night, but the other CAMs
have convection weakening as it gets further from the upper
trough and closer to the mid state. Confidence is low on severe
convection making it to the northwest Saturday night into Sunday
morning with current guidance, but should more CAMs get on board
or if convection developing Saturday afternoon to our northwest
strengthens enough for strong outflow, chances for severe storms
Saturday night will increase. The HRRR/ARW do suggest a line of
storms, so again looking at the main threat being damaging winds
with any strong to severe convection should it make it to the mid
state Saturday night/Sunday morning.

Showers and storms will continue on Sunday thanks to the upper low
to our northwest bringing additional southerly flow, moisture, and
lift over the region. We may get a short break late Sunday night
but another lobe of the upper low will aid diurnal convection
during the day Monday. Models have been quite high with pops
lately, but with a strong trough to our NW did not back off pops
too much Sunday and Monday. On Tuesday the trough begins moving
northwest towards the eastern Great Lakes, so higher pops will
end, but mainly afternoon chances of showers and storms will
continue with southwest flow aloft in the wake of the low. Second
half of next week will have a high develop off the SC coast, and
help southerly flow remain over our region. This will keep the
afternoon storm chances in place into next weekend.

&&

.AVIATION...
18Z TAF DISCUSSION.

BNA/MQY/CKV/CSV...A surface boundary appears to be stretched along
the Tennessee Valley which is providing the focus for ongoing
convection. However, the terminals are all well north of this
activity, and the HRRR is only showing isolated cells developing
across Middle Tennessee this afternoon and evening. We'll handle
this with VCSH remarks for now, but will certainly amend if we end
up with more development than what we're currently expecting.
Outside of any showers/storms, look for VFR wx the next 24 hrs.,
except at CSV, where low ceilings are likely to develop later
tonight and tomorrow morning.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      72  89  74  88  71 /  50  60  50  80  70
Clarksville    71  87  73  84  69 /  60  60  70  90  60
Crossville     67  81  67  81  67 /  40  60  40  70  60
Columbia       70  88  72  87  69 /  40  50  50  80  70
Lawrenceburg   70  86  71  84  69 /  30  40  40  80  80
Waverly        71  88  72  85  69 /  30  40  50  80  80

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

DISCUSSION......Barnwell
AVIATION........08

Hazardous Weather Outlook
National Weather Service Nashville TN
511 AM CDT Fri Jul 9 2021

TNZ005>011-023>034-056>066-075-077>080-093>095-101015-
Stewart-Montgomery-Robertson-Sumner-Macon-Clay-Pickett-Houston-
Humphreys-Dickson-Cheatham-Davidson-Wilson-Trousdale-Smith-Jackson-
Putnam-Overton-Fentress-Perry-Hickman-Lewis-Williamson-Maury-
Marshall-Rutherford-Cannon-De Kalb-White-Cumberland-Bedford-Coffee-
Warren-Grundy-Van Buren-Wayne-Lawrence-Giles-
511 AM CDT Fri Jul 9 2021

This Hazardous Weather Outlook is for Middle Tennessee.

.DAY ONE...Today and tonight.

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

A few strong to isolated severe storms are possible late Saturday.
Gusty winds and heavy downpours can be expected.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

11

Special Weather Statement
National Weather Service Nashville TN
916 AM CDT Fri Jul 9 2021

TNZ093-094-091500-
Lawrence TN-Wayne TN-
916 AM CDT Fri Jul 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN WAYNE AND SOUTHERN
LAWRENCE COUNTIES UNTIL 1000 AM CDT...

At 916 AM CDT, Doppler radar was tracking a strong thunderstorm 9
miles south of Collinwood, or 15 miles north of Florence, moving east
at 20 mph.

Pea size hail and winds in excess of 40 mph will be possible with
this storm.

Locations impacted include...
Loretto, Collinwood, St. Joseph, Cypress Inn, Westpoint and Iron
City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3501 8788 3524 8785 3511 8722 3510 8721
      3509 8722 3500 8722
TIME...MOT...LOC 1416Z 281DEG 19KT 3504 8773

Barnwell

Special Weather Statement
National Weather Service Nashville TN
943 AM CDT Fri Jul 9 2021

TNZ095-091530-
Giles TN-
943 AM CDT Fri Jul 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN GILES COUNTY UNTIL 1030
AM CDT...

At 943 AM CDT, Doppler radar was tracking a strong thunderstorm near
Pulaski, moving east at 30 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Pulaski, Elkton, Goodspring and Frankewing.

This includes Interstate 65 between mile markers 2 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3507 8720 3529 8718 3526 8683 3500 8684
TIME...MOT...LOC 1443Z 279DEG 25KT 3514 8700

Barnwell

Special Weather Statement
National Weather Service Nashville TN
1017 AM CDT Fri Jul 9 2021

TNZ093>095-091600-
Lawrence TN-Wayne TN-Giles TN-
1017 AM CDT Fri Jul 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN WAYNE...SOUTHERN
LAWRENCE AND SOUTHWESTERN GILES COUNTIES UNTIL 1100 AM CDT...

At 1016 AM CDT, Doppler radar was tracking a strong thunderstorm 9
miles north of St. Florian, or 12 miles north of Florence, moving
east at 30 mph.

Winds in excess of 40 mph will be possible with this storm.

Locations impacted include...
Loretto, St. Joseph, Minor Hill and Iron City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3500 8770 3513 8768 3511 8712 3500 8712
TIME...MOT...LOC 1516Z 277DEG 26KT 3501 8761

Barnwell

Special Weather Statement
National Weather Service Nashville TN
300 PM CDT Fri Jul 9 2021

TNZ061-075-092030-
Bedford TN-Marshall TN-
300 PM CDT Fri Jul 9 2021

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN MARSHALL AND WESTERN
BEDFORD COUNTIES UNTIL 330 PM CDT...

At 300 PM CDT, Doppler radar was tracking a strong thunderstorm 11
miles northwest of Shelbyville, moving south at 25 mph.

Pea size hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
Shelbyville, Lewisburg, Chapel Hill, Belfast, Farmington and
Unionville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3563 8674 3564 8652 3537 8641 3537 8679
TIME...MOT...LOC 2000Z 357DEG 40KT 3556 8663

07