363
FXUS63 KJKL 140345
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1145 PM EDT Sat Jul 13 2024

.KEY MESSAGES...

- Hotter conditions make a comeback this weekend and into early
  next week.

- The next significant chance of rain will hold off until the
  middle of next week.

&&

.UPDATE...
Issued at 1145 PM EDT SAT JUL 13 2024

Forecast has been well on track throughout the evening given the
fair weather, with precip diminishing to our west and south, and
mostly clear skies plus light winds in place. Other than some
minor adjustments to the ongoing temps and winds based on the
latest observations, no large updates have been needed thus far.
The main concern as we head into the overnight will be fog
development, specifically in the deeper valleys.

UPDATE Issued at 757 PM EDT SAT JUL 13 2024

Forecast has been in good shape so far this evening. Showers and
thunderstorms were ongoing to our west and south throughout the
last few hours, but never did make it across CWA boundaries, and
are now dissipating. Therefore, no need to update the pops/weather
at this point to include mention of precip. Otherwise, loaded in
the latest observation temps and winds to make sure the near term
forecast is still on track with the current conditions. Will
continue to monitor temps and will update throughout the rest of
the evening as needed. All updates have been published and sent to
NDFD/web.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 420 PM EDT SAT JUL 13 2024

Current 18Z surface analysis continues to show surface high pressure
situated over much of the eastern CONUS. A surface low is moving
across southern Canada with cold front extending southward into the
US. This will fire off pockets of severe weather across much of the
Upper Midwest; however, in eastern Kentucky, high pressure remains
dominate with mostly sunny skies. Radar has been a little active
over the last hour or so with pop-up showers developing along and
southwest of the Mountain Parkway.

Aloft, mostly zonal flow is building into the region which will
advect drier air into the region but forecast SBCAPE from 500 to
1,000 J/kg could and has allow for a few pop-up thunderstorms across
the area. Mainly along and south of the Mountain Parkway. Showers
will taper off toward sunset with skies largely expected to clear.
This clearing could allow for valley fog development but could be
very dependent on the amount of clearing expected overnight.

Upper-level flow turns northwesterly with the approach of a trough.
Height falls are forecast to arrive early Sunday. At the surface,
high pressure will remain present but CAM guidance has been very
persistent bringing a potential MCS into the region toward the late
afternoon into evening hours Sunday but with the ambient environment
rather dry and void of moisture, the lack of moisture could keep the
area dry. Opted to keep the area largely dry aside from a few
isolated showers and storms mainly along and north of I-64. For the
overnight Sunday, surface high pressure building in could allow for
clearing skies leading to radiational cooling in the river valleys.
Thus allowing for the development of areas of valley fog through the
early morning hours of Monday.

Otherwise, the period will be mostly dry aside from a few isolated
showers or storms this afternoon and again Sunday afternoon/evening.
Highs are forecast to be in the low to mid-90s today and Sunday.
Overnight lows will remain mild across the area too, as lows tonight
will drop into the mid to upper-60s for tonight and again Sunday
night.

.LONG TERM...(Monday through Saturday)
Issued at 441 PM EDT SAT JUL 13 2024

There is reasonable model agreement through Friday. The prevailing
westerlies aloft will be to our north on Monday, and we will be
beneath a relative weakness in the subtropical high aloft. Won`t
completely rule out a shower or thunderstorm popping up in the
weakness, but forecast NAM soundings don`t look favorable due to
warm temperatures around 750-800 mb providing a cap. If anything did
go up it would have very little movement, thus limiting coverage.
Have opted to use a 10% POP.

After this, a large scale upper trough will be dropping southeast
out of Canada toward the Great Lakes and Ohio Valley. This will
support a cold front which will approach the Ohio Valley on Tuesday
and then move through KY on Wednesday. Flow will increase in all
levels of the atmosphere as the surface front and upper trough
approach, providing movement for anything precip that develops.
Forecast NAM soundings for Tuesday show the subtle cap of Monday
disappearing as slight cooling aloft occurs. There`s still no clear
focus for convection on Tuesday, but modest flow and the lack of a
noticeable cap justify carrying at least a mention of a low POP in
the forecast. The highest area wide POP will be on Wednesday as the
front arrives, and likely category was used. The heart of the upper
trough will begin to pull out to the northeast by Thursday and the
front`s southward progress will slow, leaving lingering precip over
the JKL forecast area, especially in south central and southeast KY.
Enough progress is expected for the POP to drop off substantially
from northwest to southeast late Thursday and Thursday night, with
only a low chance POP remaining in southeast KY by Friday.

Model agreement and forecast confidence drops off after this
point. The GFS leaves a larger portion of the upper trough behind
over the lower/middle Mississippi Valley as compared to the ECMWF.
This results in increasingly meridional flow out of the south
southwest over our area on the east side of the trough, yielding
more moisture and precip potential as compared to the ECMWF on
Saturday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 802 PM EDT SAT JUL 13 2024

VFR conditions are prevailing across all TAF sites this evening.
Guidance is continuing to suggest overnight fog, so did keep
mention at all TAF sites generally from 08Z-12Z. However, with a
relatively dry day today, kept fog impacts at MVFR for the TAF
sites at this time, before returning back to VFR after daybreak
once the fog lifts up. Otherwise, mostly sunny skies are on tap
for much of the day Sunday, with a few mid-level afternoon CU.
Light and variable winds will also persist through the duration of
the period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...JMW
SHORT TERM...VORST
LONG TERM...HAL
AVIATION...JMW