290
FXUS64 KOHX 221823
AFDOHX

Area Forecast Discussion
National Weather Service Nashville TN
123 PM CDT Sun Sep 22 2024

...New AVIATION...

.SHORT TERM...
(Rest of today through Monday)
Issued at 1136 AM CDT Sun Sep 22 2024

An upper-level high pressure remains centered to our south, but
with plenty of instability and moisture, some storms have already
begun developing late this morning. Low confidence in how
widespread this activity will become through the remainder of
today as convection will likely be dependent on outflow boundaries
that push out of storms over KY. Storms will be hit-and-miss, but
with an unstable atmosphere of SBCAPE values around 1500-2000
J/kg, bulk shear values of 25 to 30 knots, and high PWAT values
approaching 2 inches, the ingredients are there to allow for a
pulsy storm that can produce gusty winds and heavy rain. Any storm
activity will diminish after sunset with the loss of daytime
heating.

By Monday, the high pressure gets suppressed as a trough digs into
the Great Plains. Storm chances increase on Monday ahead of this
feature, and with better forcing present from this trough, activity
won`t be so outflow-dependent as is the case today. The latest SPC
Day 2 Outlook also places roughly the northern half of Middle TN in
a marginal risk for strong to severe storms. This is likely due to
increased mid-level winds from a jet that passes through,
allowing for increased wind shear near 40 knots Monday afternoon.
While small hail can`t be ruled out, large hail is unlikely with
mid-level lapse rates at only 6 to 6.5 C/km. Gusty winds will be
the main threat with stronger storms.

&&

.LONG TERM...
(Monday Night through next Sunday)
Issued at 1136 AM CDT Sun Sep 22 2024

The trough sends a cold front through the area on Tuesday, allowing
for the best rain chances of this forecast so far. This Tuesday
event is still not looking like a big rain-maker. Rain amounts are
still generally expected to be around a quarter of an inch or less,
but areas north of I-40 could get closer to half an inch where
forcing is better from the trough. But chances of exceeding half an
inch is currently less than 20 percent.

It`s still an uncertain forecast Wednesday and beyond as models are
struggling with a developing low to our west and a developing
tropical system in the Gulf. What these two systems do and how much
rain we may or may not get is uncertain. Rain chances have trended
up slightly late week into the 30 to 50 percent range as model
solutions are trending wetter, but confidence remains low as to
any specifics regarding timing or amounts.

&&

.AVIATION...
(18Z TAFS)
Issued at 123 PM CDT Sun Sep 22 2024

Isolated convection developing for locations across mid state
region, especially for locations around and east of I-65
Corridor Region. Continued 23/12Z aviation forecast discussion
reasoning with VCTS possible 22/21Z - 23/00Z with VFR BKN 3-4
Kft. LIFR fog development possible 23/12Z-23/14Z SRB. Again,
another round of shwrs and even potential tstms approaching
once again mid state terminals around 23/15Z-23/18Z, but not
enough to mention prevailing.

&&

.PRELIMINARY POINT TEMPS/POPS...
Nashville      72  91  70  86 /  20  40  50  70
Clarksville    70  87  68  83 /  30  50  70  70
Crossville     64  85  62  83 /  10  50  40  70
Columbia       69  91  68  87 /  10  30  50  70
Cookeville     67  86  66  83 /  20  60  40  70
Jamestown      65  84  64  81 /  20  60  50  80
Lawrenceburg   68  90  68  87 /  10  30  30  60
Murfreesboro   69  92  69  88 /  10  40  40  70
Waverly        69  88  67  82 /  10  30  70  70

&&

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

$$

SHORT TERM...Clements
LONG TERM....Clements
AVIATION.....JB Wright