318
FXUS64 KMRX 090724
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
324 AM EDT Sun Jun 9 2024

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

.SHORT TERM...
(Today and tonight)
Issued at 305 AM EDT Sun Jun 9 2024

Key Messages:

1. Morning showers from a remnant MCS will affect southern
sections this morning.

2. Scattered to numerous showers and thunderstorms ahead of a cold
front this afternoon.

Discussion:

The MCS currently in West TN is expected to weaken considerably as
it crosses Middle TN in the next few hours. Some remnant showers
are shown by the models to move into our Plateau and southern
Valley counties this morning. Meanwhile, a cold front currently
located north of the OH River will be approaching from the north.
Scattered to numerous showers and thunderstorms are expected to
develop along and ahead of this front, affecting our area this
afternoon. With a very weakly amplified trough in the mid/upper
levels and the jet stream well to the north, synoptic forcing is
weak. With a deep westerly flow, instability and shear will not
be favorable for a threat of severe storms. Initial showers/storms
with the front will be in northern sections, then spread south
through the afternoon and evening. Most activity should end by
midnight once the cold front exits to our south.

Cloud cover from the morning MCS remnants will limit daytime
heating, especially in the northern half, so highs will lean
toward the cooler side of guidance, in the mid/upper 70s north to
lower/mid 80s south. Lower dewpoints build in through the night,
resulting in lows mainly in the mid 50s to lower 60s.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 305 AM EDT Sun Jun 9 2024

Key Messages:

1. Cooler than normal Monday and Tuesday behind cold front. Then
warmer Wednesday.

2. Much warmer Thursday with valley highs near 90 to the lower 90s
through Saturday.

3. Now Tuesday and Wednesday look to be dry, but Thursday into the
weekend isolated to scattered showers and thunderstorms each day,
with highest rain chances during the afternoon and early evening
hours and southern and eastern part of the area.

Discussion:

We begin the extended period Monday behind the cold front. Upper
trough with deep upper low over the Canadian Maritimes will bring
drier air and cooler than normal temperatures into the east
Tennessee Valley region Monday and Tuesday with surface high
pressure slowly dropping southeast from the mid Mississippi and Ohio
Valleys. Dewpoints lower into the mid 40s to upper 50s each day.
Highs will be in the 70s to lower 80s around Chattanooga. Nights
will be in the cool 50s.

After Tuesday, the upper trough moves off the east coast with
ridging aloft moving into the Tennessee Valley. Surface high
pressure should hold one more day but temperatures warm into the 80s
more near average for mid June. The flow aloft will be weak but
higher pressure shifts east and some southerly flow and building
heights will raise high temperatures close to 90 and then lower 90s
Thursday through Saturday. With increased heating there will be a
slight chance to chance of afternoon and evening showers and
thunderstorms Thursday through Saturday. Also heat index values will
reach the mid 90s over the central and southern Tennessee Valley
locations especially near Knoxville and Chattanooga. A weak front
will also drop south into the Ohio Valley Friday and then may become
stationary over the forecast area Friday. This could increase rain
chances even more Saturday but will not have any areas above 40
percent at this time.

&&

.AVIATION...
(06Z TAFS)
Issued at 117 AM EDT Sun Jun 9 2024

Showers are likely so spread into the area this morning from the
west, associated with a weakening convective system ahead of a
cold front. Shower coverage is expected to be scattered to
numerous through the day at all sites, with a lower chance of
thunderstorms, so VCSH with PROB30 for TS and MVFR vis/cigs will
be forecast. Most of this activity will end in the evening, around
00Z. Winds will shift from W-SW during the day to NW in the
evening behind the front.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             86  65  83  58 /  50  50  10   0
Knoxville McGhee Tyson Airport, TN  80  61  79  56 /  60  40  10   0
Oak Ridge, TN                       79  60  80  56 /  60  30  10   0
Tri Cities Airport, TN              77  56  76  52 /  50  20  10   0

&&

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

$$

SHORT TERM...DGS
LONG TERM....TD
AVIATION...DGS