488
FXUS64 KMRX 300210
AFDMRX

Area Forecast Discussion
National Weather Service Morristown TN
1010 PM EDT Mon Apr 29 2024

...New UPDATE...

.UPDATE...
Issued at 1007 PM EDT Mon Apr 29 2024

The main change with the evening update was a faster increase in
PoPs over the next several hours. Current radar has revealed some
additional showers ahead the main complex. The latest high-res
model guidance has also emphasized this quicker trend in arrival.
Otherwise, the main forecast message has remained the same with
minimal changes to other weather elements.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 244 PM EDT Mon Apr 29 2024

Key Messages:

1. Showers and embedded thunderstorms return late tonight and into
Tuesday.

Discussion:

Main forecast concern for the short term period revolves around
what to expect with rain chances tomorrow. An upper trough will
approach from the west late tonight and into Tuesday morning. This
will usher in widespread showers and even some embedded
thunderstorms to the forecast area after roughly 09z or so early
Tuesday morning. As the day progresses the southern end of this
wave attempts to transition to a closed low, likely slowing down
the departure of rainfall tomorrow. Stuck with the NBM PoPs for
this event which are pretty high through the day tomorrow. But I`m
not particularly confident if likely PoPs well into the afternoon
hours will be justified or not. I`m very confident showers will
be around later in the day, just not so much on whether the
coverage will be great enough to warrant the high rain chances. My
initial gut reaction to this pattern is that the wave of showers
and embedded thunderstorms pushing in from the west just before
daybreak weakens or moves east of the CWA by midday, leaving us
with a lull in rainfall activity until mid afternoon when
redevelopment of scattered showers occurs.

Severe storms do not appear to be a concern whatsoever as
instability will barely be enough to support thunder, much less
any severe storms. And rainfall amounts should remain within
reason so flooding doesn`t appear to be a concern either.

&&

.LONG TERM...
(Tuesday night through next Monday)
Issued at 244 PM EDT Mon Apr 29 2024

Key Messages:

1. Above normal temperatures at least through next week, with the
highest occurring on Thursday.

2. Active weather pattern to bring chances for showers and
thunderstorms Friday through early next week.

Discussion:

At the start Tuesday night, showers and Thunderstorms will be moving
out of the area to the east after a cold frontal passage from
earlier in the day. Wednesday will begin the considerable warm-up
the forecast area will experience the rest of the period, with
Thursday looking to be the warmest with mid to upper 80 highs in
valley locations. For comparison for early May, Chattanooga averages
around 78 degrees. The conditions will be as a result of surface
high pressure building in as well as ridging aloft extending up from
the Gulf, so dry weather can be expected through early Friday.

Friday through the rest of the period Monday will be an active
pattern with chances for showers and thunderstorms each day.
Longwave troughing will situate to the north, sending shortwave
troughs our direction through the weekend. At least two systems
develop, maybe three, but the third is too far out in the forecast
to know for certain. The first develops over the Central U.S.
Thursday eventually becoming a deep low that tracks for the Upper
Midwest/Western Great Lakes region. A cold front extending from it
will approach the region Friday, eventually moving over the area
late Friday into Saturday. This will be monitored for the potential
for strong storms, but of course too early to know.

Post FROPA, Saturday into Monday become more uncertain as the Friday
system slows and hangs to our southeast, while another low pressure
center looks to develop off the Central Rockies. The second system
appears to take about the same track as the first towards the Upper
Midwest region. So between those systems and potential moisture
advection from the Gulf region as well, the Southeast U.S. will
remain in an active and wet pattern. Temperatures do cool some from
the mid to upper 80s Thursday to upper 70s to low 80s the rest of
the weekend and long term period.

&&

.AVIATION...
(00Z TAFS)
Issued at 708 PM EDT Mon Apr 29 2024

The evening and the first half of the night will be fairly quiet
aviation-wise with lighter winds and mainly mid to high clouds.
Towards the early morning, showers and embedded thunderstorms will
arrive from the west, first impacting CHA, then TYS followed by
TRI. The intensity is expected to decrease as they move east, but
MVFR reductions are expected at all of the sites. Some improvement
to VFR is likely at CHA and TYS, but TRI is forecast to stay MVFR
through the day. Additional showers and storms will develop in the
afternoon hours with a PROB30 included in CHA. However, any of the
sites could see impacts from this additional development.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             63  76  58  84 /  90  70   0   0
Knoxville McGhee Tyson Airport, TN  62  74  58  80 /  80  80  20   0
Oak Ridge, TN                       61  74  57  82 /  90  80  20   0
Tri Cities Airport, TN              58  75  57  79 /  20  90  30  10

&&

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

$$

SHORT TERM...CD
LONG TERM....KS
AVIATION...BW