-- Discussion containing changed information from previous version are highlighted. --
156
FXUS64 KMRX 111133 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
733 AM EDT Sat May 11 2024

...New AVIATION...

.SHORT TERM...
(Today and tonight)
Issued at 320 AM EDT Sat May 11 2024

Key Messages:

1. Scattered showers expected this afternoon. Possibly a rumble of
thunder or two in the north.

2. Pleasant weather expected for the Mother`s Day holiday.

Discussion:

I would love to talk about the breathtaking aurora display that
we`ve seen across the United States tonight, but that`s neither
weather-related nor something I have any expertise in so I`ll move
along. But we all agree it was an amazing experience, right?

Early morning satellite imagery shows patchy fog across river
valleys in our Virginia counties as well as areas north of
Knoxville on the Tennessee side of things. It was quick to develop
but has been slow to spread through the night, and while there are
observations to our north that show dense fog, it doesn`t seem to
be producing particularly low visibility in our CWA so will forego
a dense fog advisory at this time.

For today, a weak shortwave moving through the Ohio valley will
push a cold front our direction, sparking off some shower activity
this afternoon into the early evening hours. Similar to
yesterday, I have very high confidence in the presence of showers
this afternoon but coverage will be a bit hit and miss I think.
Once again limited afternoon PoPs to the chance level due to
coverage uncertainties. That said, unlike yesterday, these showers
won`t be confined to areas north of the I-40 corridor. Instead
isolated to scattered showers will extend into the southern parts
of the CWA this afternoon. Forecast soundings show a fairly
pronounced EML in place later today, so expect convection to be
shallow overall. However, the combo of low freezing levels and the
EML height may be sufficient for some thunder to occur in the
north today so will leave a slight chance of thunder in the
forecast there.

Otherwise, not much to talk about in the short term. The incoming
front will usher in a reinforcing shot of dry air which will
allow for another cool night tonight. But dry conditions and near
normal temperatures are expected for Mother`s Day

&&

.LONG TERM...
(Sunday through Friday)
Issued at 320 AM EDT Sat May 11 2024

Key Messages:

1. Dry weather and near normal or slightly below normal temps to
finish out the weekend on Sunday.

2. An active pattern sets up starting Monday afternoon, with rain
and thunderstorm chances through at least Wednesday. Another system
possible at the end of the week.

Discussion:

Mother`s Day is shaping up to be a nice day for the entire forecast
area, as ridging and surface high pressure build in from the west.
High temperatures will either be around normal or just a couple
degrees below normal. Should be a great day for outdoor plans with
dry weather expected, mostly sunny skies, and comfortable dew points.

The first part of Monday should start out dry as ridging edges
eastward, but later Monday into the end of the forecast period, we
will return to an active pattern. A low pressure center that will
track eastward from the central part of the country, will increase
precipitation chances late Monday from the west and southwest. PoPs
expected to be categorical Tuesday, with widespread rain and
thunderstorms. WPC already has most of the area under MRGL for flash
flooding given the amount of rainfall we`ve just had and the
flooding that came with it. Right now, models say there is a
marginal severe threat, but too early to know for sure. One would
assume directional shear to favor a stronger storm variety given our
possible proximity to the low. Precip from this system appears will
stick around through Wednesday within northwest flow, although best
chances will be upslope favored terrain.

Thursday tries to dry out with ridging and high pressure following
the Tuesday system. Thursday looks to also be the warmest day of the
long term period with lower 80s for highs in parts of the valley.
Lower chances for showers and thunderstorms that will most likely be
diurnally driven.

Headed into Friday another system tries to develop and move our way,
but models have diverged on agreeability because of what looks like
a low pressure center tracking across our north and potentially one
that will develop over the Gulf. Albeit, another shot at
thunderstorms and moisture the area doesn`t need so soon.

&&

.AVIATION...
-- Changed Discussion --
(12Z TAFS)
Issued at 729 AM EDT Sat May 11 2024

Fog is prevalent in river valleys this morning and is currently
affecting KTRI. This should dissipate by 15z, returning all sites
to VFR levels. Models continue to show showers developing
ahead/along a cold front that will move through the region later
this afternoon. Given what high resolution guidance is showing,
think it`s reasonable to stick with VCSH. But I did add that into
the KTYS forecast instead of only having it at KTRI. Lastly, fog
development seems likely again tonight. Have gone ahead and added
some of that into the KTRI TAF, but uncertainty of it affecting
other sites is too low to include at this time.
-- End Changed Discussion --

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             78  54  81  57 /   0   0   0   0
Knoxville McGhee Tyson Airport, TN  72  50  76  53 /  20  10   0   0
Oak Ridge, TN                       73  48  77  53 /  20   0   0   0
Tri Cities Airport, TN              67  46  73  48 /  30  10   0   0

&&

.MRX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
NC...NONE.
TN...Dense Fog Advisory until 9 AM EDT this morning for Anderson-
     Campbell-Claiborne-Grainger-Hamblen-Hancock-Hawkins-Johnson-
     Northwest Carter-Northwest Greene-Southeast Carter-
     Southeast Greene-Sullivan-Unicoi-Union-Washington TN.

VA...Dense Fog Advisory until 9 AM EDT this morning for Lee-Russell-
     Scott VA-Washington VA-Wise.
-- End Changed Discussion --

&&

$$

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