948
FXUS64 KOHX 241708
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
1208 PM CDT Tue Sep 24 2024

...New SHORT TERM, LONG TERM...

.SHORT TERM...
(Rest of today through Wednesday)
Issued at 1114 AM CDT Tue Sep 24 2024

After parts of the area had morning showers and a few storms,
much of Middle Tennessee was experiencing a midday break. We do
expect showers and storms will build up again through the
afternoon and we continue to be under a marginal to slight risk
(level 1 to 2 out of 5) for severe storms with gusty winds.

Variably cloudy skies will allow for periods of sunshine and
heating into the 80s this afternoon. 1500-2000 J/kg ML cape still
looks on target today. The biggest differences from previous days
will be more forcing and much more shear. A couple of impulses
will precede an approaching surface front. Also, shear will
strengthen with 40KT deep layer shear and 500mb winds reaching
50KT. These factors will boost storm coverage and potential for
embedded damaging wind gusts. The tornado risk is very low, but
not zero.

Short range models seem to depict the general scenario well,
although exact timing and placement of main bands may be off.
Generally, bands of showers and storms will fire up this
afternoon with the main focus over our northwest counties starting just
after lunchtime. Then the focus will shift to Nashville Metro
southwest to Lawrenceburg area mainly 2 PM to 8 PM, then gradually
shifting east of I-65 into the evening from 6 PM to midnight.

The front moving in today will stall out tonight and Wednesday as
an upper level low pressure system cuts off just to our west.
This will keep showers and a few storms scattered across the area
tonight through Wednesday. The extra clouds and scattered rain
will limit Wednesday`s temps to the 70s for most areas. As shower
activity lessens in the nighttime hours, some partial clearing and
patchy fog will form.

&&

.LONG TERM...
(Wednesday Night through next Tuesday)
Issued at 1114 AM CDT Tue Sep 24 2024

Confidence continues to increase for soaking rainfall late this
week as the remnants of tropical system Helene impact the region.
The center of Helene is expected to move onshore Thursday evening
along the Florida Gulf Coast as a major hurricane. By that time,
heavy rain and gusty winds will have spread well north of the
center as the tropical moisture begins to interact with the
cutoff upper level low just to our west. The best time for
widespread and possibly heavy rainfall will be Thursday afternoon
through Friday morning. Although the heaviest rain with Helene is
expected to our east, Middle Tennessee is still in line for 2 to 3
inches of rain Thursday afternoon into Friday morning based on
the latest WPC QPF. The higher end amounts are expected over the
Plateau. Additional showers outside that time period could push
the late week event totals toward 4 or 5 inches. However, if the
track is farther east or the main swath of rain moves through
quickly, event totals could be lower. Model statistics give us at
least 80 percent chance for more than 1 inch late this week, so
we should be excited for some drought relief.

After the main swatch moves through by Friday afternoon, we will
have on and off scattered showers through the rest of the weekend.

&&

.AVIATION...
(12Z TAFS)
Issued at 618 AM CDT Tue Sep 24 2024

A band of showers is marching across Middle Tennessee this
morning, so we`ve got TEMPO -SHRA in for a couple of hours while
the cells make their way through. We expect additional convection
this afternoon, as the atmosphere is already showing some
instability in place. As the surface boundary that is instigating
this activity makes its way eastward overnight, look for
additional showers and maybe some fog and low ceilings, especially
after 06Z.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      86  67  80  64 /  70  50  40  60
Clarksville    83  63  79  60 /  70  40  30  30
Crossville     83  61  72  58 /  60  90  80  90
Columbia       86  65  78  60 /  80  60  40  50
Cookeville     83  63  74  60 /  80  80  60  70
Jamestown      83  63  73  59 /  80  80  80  80
Lawrenceburg   87  64  76  60 /  70  70  50  60
Murfreesboro   88  66  79  61 /  80  60  50  60
Waverly        83  62  78  59 /  80  40  30  30

&&

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

$$

SHORT TERM...13
LONG TERM....13
AVIATION.....Rose