-- Discussion containing changed information from previous version are highlighted. --
082
FXUS64 KMRX 051712
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
112 PM EDT Wed Jun 5 2024

...New AVIATION...

.UPDATE...
Issued at 1019 AM EDT Wed Jun 5 2024

Showers continue to traverse across the eastern Tennessee Valley
late this morning. Expect the coverage of storms to increase
throughout the rest of the morning and early afternoon with
precipitation coming out of AL and middle TN. As of this writing
no lightning is detected in the storms, but expect to start to see
thunderstorms emerge once we get into better diurnal heating.

&&

.SHORT TERM...
(Today and tonight)
Issued at 315 AM EDT Wed Jun 5 2024

Key Messages:

1. Scattered to numerous showers and storms expected by late
morning into the afternoon hours. Brief lull in activity possible
for the late evening before a cold front brings additional
showers and storms overnight.

2. Gusty winds with locally heavy downpours and isolated flash
flooding are possible with any stronger storm. The flooding
concern will linger into the overnight hours more so than the
threat for a few stronger storms.

Discussion:

Similar to the previous morning, SPC mesoanalysis suggest weak vort
lobes continue to traverse the region as minor upper level
disturbances occur ahead of increasing troughing over the mid-west.
As a result, a few areas of showers remain over northeast Tennessee
& southwest Virginia. With the loss of solar heating lightning
threat remains minimal overnight. Coverage is expected to re-vamp
throughout the mid-morning hours and into the afternoon, with
scattered to numerous showers and storms expected across the region
once more.

Given expected early morning cloud cover and overall cooler trend in
temperatures the last 24 hours, model derived soundings all hint at
MLCAPE generally 1000J/kg or less. DCAPES will similarly range
between 500-1000J/Kg and some locally gusty winds cannot be ruled
out with stronger storms, much as we observed yesterday.
Additionally, PWAT values will continue to creep towards 1.7" per
HREF ensemble guidance. Heavy downpours will remain possible with
taller convection as well. Given some areas reported upwards of 1.5"-
2.0" of rain this past afternoon, believe flooding concerns are
actually greater than that of severe chances. Though, it will still
likely be conditional in that it is more likely to occur in the
event of training or repeated rounds of convection.

We look to have a lull in activity in the evening hours before a
surface cold front brings additional forcing along with chances for
showers & storms once more during the overnight. Overall, the main
message for the next 24 hours remains scattered to numerous showers
and storms at times, with locally heavy downpours and gusty winds
with the strongest storms.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 315 AM EDT Wed Jun 5 2024

1) A few showers and storms around Thursday morning, then drying out.

2) Drier and cooler Friday through Saturday.

3) Better model agreement on Sunday`s rain chances, but how much QPF
is still in question.

4) Slightly below normal temps in place through the long term.

Discussion:

A cold front will be pushing through our area to start the long term
on Thursday morning. A few showers and storms will likely be
ongoing, especially east of I-75 toward the east TN mountains and
foothills. We quickly dry out from west to east behind the front and
most places should be precip free by noon. Though a few showers may
linger across the east TN mountains into the afternoon hours. Deep
mixing is expected behind the cold front, 15 to 20 mph wind gusts
look likely for all areas during afternoon.

Friday will be quite nice with high temps in the mid 70s to near 80
with dewpoints down into the lower to mid 50s. Winds will again be
breezy due to deep afternoon mixing. Valley winds will gust from 15
to 20 mph and gusts from 20 to 30 mph are expected in the east TN
and southwest VA mountains. Pleasant conditions remain into Saturday.

By Sunday, a deepening longwave trough and cold front are
approaching from the north/northwest. The cold front is set to push
through the area during the day. This means higher confidence we
will see precip during this time but there is still a question of
how much. Because we were in northwest flow previously, there is
uncertainty on how much moisture return we see prior to the frontal
passage. At this time, it appears the heaviest rain may be off to
our southwest with lighter rain up into our neck of the woods. Having
said that, the southern TN Valley will be closer to the heavier rain
axis and will likely see more QPF compared to areas north of I-40.
Current QPF has the southern TN Valley seeing around 0.5 inches on
average while northeast TN is around 0.1 inches.

The pattern remains active Monday as a shortwave moves down through
the longwave trough, keeping chances for showers and storms in
place. For now, it looks like we begin to dry out Tuesday as the
trough pushes east and drier air moves in from the west.

&&

.AVIATION...
-- Changed Discussion --
(18Z TAFS)
Issued at 109 PM EDT Wed Jun 5 2024

Showers and a few embedded thunderstorms currently rolling
through the region will be the main impactful weather for the
first 6 hours of this TAF cycle. We`ll see a break in
precipitation for the late evening hours before the front moves
thorugh and brings a final round of rain at the end of this TAF
cycle, but certainty is somewhat low on the timing of the showers
overnight into tomorrow. Outside of any storms expect mainly VFR
conditions.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
-- Changed Discussion --
Chattanooga Airport, TN             69  87  64  82 /  70  40   0   0
Knoxville McGhee Tyson Airport, TN  69  84  62  79 /  70  60  10   0
Oak Ridge, TN                       68  85  60  80 /  80  50   0   0
Tri Cities Airport, TN              66  80  59  77 /  60  70  10   0
-- End Changed Discussion --

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&

$$

SHORT TERM...
AVIATION...