621 
FXUS64 KMRX 111053 AAA
AFDMRX

Area Forecast Discussion...UPDATED
National Weather Service Morristown TN
653 AM EDT Tue Aug 11 2026

...New AVIATION...

.KEY MESSAGES...
Updated at 645 AM EDT Tue Aug 11 2026

- Showers and thunderstorms will be possible each day through the
  end of the work week, with the best chance of rain during each
  afternoon.

- There will be potential for a few storms to become strong to 
  severe each afternoon with damaging winds and localized flooding
  the main threats.

- Temperatures will be generally not be far either side of normal
  for this time of year.

&&

.DISCUSSION...
Issued at 117 AM EDT Tue Aug 11 2026

A cluster of thunderstorms can be noted across portions of Ohio 
as latest satellite imagery paints mostly clear skies across the 
southern Appalachians this evening. Mostly clear skies will likely
result in some patchy fog across CWA, though, latest HREF 
probabilities of visibility less than 4 miles is not nearly as 
widespread as what was observed this past morning. This is likely 
due to the lack of precip observed across the area today. While 
mostly dry, the NAM3km has been initializing the activity to our 
north fairly well this evening and suggest a few morning 
shower/storms cannot be ruled out in SW VA/NE TN, with the very 
low chance of some strong wind gusts.

On the synoptic scale, we are generally expected to remain in a 
northwest flow pattern through Thursday as we sit beneath that 
transition zone between a strong ridge axis to our west and a 
trough axis to our north and east. Unfortunately, this pattern 
promotes lower confidence levels when really trying to hone in on 
exact hazards and timing of expected rounds of showers and 
thunderstorms, as each round(or lack thereof) can impact the next.

Latest Hi-res guidance suggest the potential for convective 
initiation in the early to mid-afternoon. If these storms are able
to develop, ample instability will promote potential for damaging
wind gusts, isolated flooding, and perhaps small hail as the 
primary hazards. While I suppose the threat of a brief spin-up is 
not zero with the afternoon activity, shear is more borderline at 
that timeframe. A more pronounced vort max is expected to swing 
into the Ohio Valley this evening/tonight, with the potential for 
an MCS to bring increased coverage of showers and storms. Though 
timing is fairly broad with the latest HREF suite depicting 
really anytime between about 00-12Z, or some models not even 
initializing this second round. Damaging wind and flooding will 
remain the primary hazard, but with enhanced shear due to an 
increase in the low-level jet, a spin-up or two would be possible 
conditional on the activity not moving through too late into the 
overnight so that a surface inversion begins to develop. 
Additional rounds of showers and storms are possible Wednesday and
Thursday, as more bouts of energy translate through mean flow, 
but timing is highly uncertain. With a warm and moist airmass, 
cannot rule out localized flooding and strong to damaging winds 
with any activity.

The upper level ridge will shift eastward Friday into the 
weekend, and while some precipitation chances continue, the chance
for any organized MCSs trends downward while temperatures trend 
slightly warmer.

&&

.AVIATION...
(12Z TAFS)
Issued at 645 AM EDT Tue Aug 11 2026

Not exceptionally confident in timing storms today, but current 
thinking is to side more with the 3km NAM guidance in bringing an
MCS through East Tennessee between roughly 20-22z in the north 
and maybe 00-02z in the south or thereabouts. I'd say confidence
in occurrence is high enough to have a TEMPO or even prevailing
group in, but the uncertainty in timing made a PROB30 group the 
more reasonable approach. The environment will support strong 
storms so VSBY below 3SM and CIGS at/below BKN025 seem likely. Do
have some reduced VSBY late in the period at KTRI, which will be
behind the storms. They may clear out for long enough for fog to
develop, but I didn't take them too low for the time being as 
there may be another round of storms move in overnight tonight.

&&

.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN             93  74  94  75 /  40  20  30  20 
Knoxville McGhee Tyson Airport, TN  91  73  92  74 /  20  40  40  40 
Oak Ridge, TN                       91  72  92  73 /  20  30  40  30 
Tri Cities Airport, TN              88  69  88  70 /  40  60  60  50 

&&

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

$$

DISCUSSION...KRS
AVIATION...CD


--- MBSE BBS v1.1.7.2 (Linux-x86_64)
 * Origin: Outpost BBS * Johnson City, TN (618:618/1)