490
FXUS64 KOHX 270026
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
726 PM CDT Thu Sep 26 2024

...New AVIATION...

.SHORT TERM...
(Rest of today through Sunday)
Issued at 1200 PM CDT Thu Sep 26 2024

Hurricane Helene is the big weather story and will be the main
impact on our local wx over the next couple of days. The mid
morning update had the center of Helene located 255 miles
southwest of Tampa with max sustained winds of 105 mph. Helene is
expected to make landfall in the Florida Big Bend region this
evening as a large, major Hurricane. The storm will move north
then northwest, weakening to a tropical depression as it moves
over Middle Tennessee and hangs around late Friday through
Saturday.

The main impacts for Middle Tennessee will be heavy rainfall
possibly causing localized flooding and gusty winds with
potential for a few downed trees and scattered power outages. We
have our entire coverage area under a Flood Watch and Wind
Advisory, both from 7 PM this evening until 7 AM Saturday.

Models have remained in pretty good agreement with the general
scenario, moving Helene toward Middle Tennessee, interacting with
a big cutoff low just to our west. Then the low pressure systems
will spin around and merge. A surge of tropical moisture will
precede the main center of Helene causing rain to spread quickly
across the area later today through tonight. Rain will become
heavy at times. As the center of Helene moves closer, winds will
increase with frequent gusts of 20 to 30 mph.

For rainfall, the heaviest and most widespread rain will occur
tonight through midday Friday. During this time, most areas are
expected to have 2 to 3 inches of rain with locally higher totals.
Additional on and off rain is then expected Friday night through
the weekend. Event totals will be mostly in the 2 to 4 inch range
with some areas up to 5 or 6 inches. By Sunday, there will be a
notable decease in coverage of showers as the low weakens and
starts to move out the area. Flooding is expected to be generally
localized, impacting roads and low lying areas. Small streams will
rise, some possibly reaching bankfull. Main rivers are expected
to handle the rainfall without reaching flood stage.

For winds, the strongest winds will occur in the early morning
hours Friday with another peak late Friday as low center
repositions and shifts wind directions from mainly north to
mainly south. Generally, the strongest gusts are expected across
our northeast half (generally along and northeast of I-24) with
some episodes of 40 to 45 mph gusts. Our southwest counties may
not reach advisory level, but given uncertainties about the
wobbling track, we decided to include all areas in the advisory.

Thankfully, parameters for severe storms and tornadoes are
looking low thanks to extensive coverage of showers and clouds.
Still, the setup is a little unusual and we may have a few pockets
of storms this weekend in areas of partial clearing or within
heavier rainfall bands. Very low risk, but something to keep in
mind.

&&

.LONG TERM...
(Monday through next Thursday)
Issued at 1200 PM CDT Thu Sep 26 2024

Some straggling showers may occur Monday, then we may have a few
showers with a cold front Tuesday. Otherwise the trend for next
week is for dry wx with seasonable temperatures.

&&

.AVIATION...
(00Z TAFS)
Issued at 617 PM CDT Thu Sep 26 2024

Rain from Helene will continue spread across airports tonight with
VFR conditions becoming MVFR then IFR/LIFR. Rain and IFR will
then continue through the TAF period at airports as Helene rotates
around the area. Northeast winds will slowly increase overnight
with gusts to 20 knots, then increase further with gusts to 30
knots on Friday while switching around to the southwest.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      67  74  63  71 / 100 100 100  90
Clarksville    65  73  62  70 / 100 100 100 100
Crossville     60  69  57  67 / 100 100 100  90
Columbia       63  71  61  69 / 100 100  90  90
Cookeville     63  70  61  67 / 100 100 100  90
Jamestown      63  70  59  68 / 100 100  80  90
Lawrenceburg   63  70  61  68 / 100 100  90  80
Murfreesboro   65  72  62  70 / 100 100  90  90
Waverly        63  71  59  68 / 100 100 100  90

&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Saturday morning for Bedford-Cannon-Cheatham-
Clay-Coffee-Cumberland-Davidson-De Kalb-Dickson-Fentress-Giles-
Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-Lewis-Macon-
Marshall-Maury-Montgomery-Overton-Perry-Pickett-Putnam-Robertson-
Rutherford-Smith-Stewart-Sumner-Trousdale-Van Buren-Warren-Wayne-
White-Williamson-Wilson.

Wind Advisory until 7 AM CDT Saturday for Bedford-Cannon-
Cheatham-Clay-Coffee-Cumberland-Davidson-De Kalb-Dickson-
Fentress-Giles-Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-
Lewis-Macon-Marshall-Maury-Montgomery-Overton-Perry-Pickett-
Putnam-Robertson-Rutherford-Smith-Stewart-Sumner-Trousdale-Van
Buren-Warren-Wayne-White-Williamson-Wilson.

&&

$$

SHORT TERM...13
LONG TERM....13
AVIATION.....Shamburger