338
FXUS63 KJKL 051207
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
807 AM EDT Sat Jul 5 2025

.KEY MESSAGES...

- The hottest temperatures of the next week are forecast this
  weekend. Although slight cooling is expected as we move into the
  new week, humidity will increase.

- Increasing humidity in the new week will be accompanied by a
  potential for showers/thunderstorms from Monday onward.

&&

.UPDATE...
Issued at 807 AM EDT SAT JUL 5 2025

Just a little refresh of the grids to account for the latest
surface observations and worked those trends through the
afternoon. Morning text and radio products have been updated to
reflect the changes. Grids have been saved and sent.

UPDATE Issued at 1125 PM EDT FRI JUL 4 2025

Freshened up grids with latest observations. No major changes.

UPDATE Issued at 821 PM EDT FRI JUL 4 2025

Did a quick refresh of the grids heading into the evening,
and ran new diurnal curves for the evening. No major changes were
made.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 232 PM EDT FRI JUL 4 2025

Surface high pressure continues to exert its dominance across much
of the CONUS. This persistent pattern has maintained, and will
continue to maintain, warm and dry conditions over the forecast area.

Today, temperatures will feature highs in the low 90s, with heat
indices feeling a degree or two warmer as dew points remain in the
mid-60s. CAMs have been hinting at the possibility of very isolated
showers and thunderstorms developing this afternoon. However, any
development will struggle to sustain itself due to subsidence under
the dome of high pressure, a deep layer of dry air aloft, and
minimal vertical wind shear. If any activity does occur, it is
expected to dissipate around sunset. Overnight, anticipate lows in
the mid-60s and areas of river valley fog.

Saturday will feature largely similar weather to Friday, given the
minimal change in the synoptic pattern. Upper-level ridging and
surface high pressure will allow temperatures to climb into the low
to mid-90s, with heat indices a few degrees warmer. Similar to
Friday afternoon, isolated chances for showers and thunderstorms
will exist Saturday afternoon. However, as with Friday, the same
atmospheric factors (subsidence, dry air aloft, minimal shear) will
combine to inhibit CI and widespread convective development. Again,
any activity that does develop will dissipate toward sunset, leading
to another night of lows in the mid-60s and areas of valley fog.

In summary, surface high pressure will maintain mostly dry weather,
with high temperatures climbing into the low to mid-90s. Overnight
lows will generally remain in the mid-60s, with areas of valley fog
expected.

.LONG TERM...(Sunday through Friday)
Issued at 355 PM EDT FRI JUL 4 2025

Upper level ridging of the short term period will have largely
broken down by the start of the long term period, but the prevailing
westerlies aloft will still be to our north. This will leave us with
amorphous conditions aloft on Sunday. A series of shortwave troughs
and a weakening of subtropical high pressure off the southeast coast
will then lead to upper level troughing deepening over the eastern
CONUS through Thursday. We still will not have a substantial return
of gulf moisture early in the week, but the air mass will undergo
slow modification toward higher dew points. As geopotential heights
fall during the week and flow aloft increases, conditions will
become more favorable for mostly diurnal convection. Models show the
trough amplifying to the point that it supports a cold front
approaching KY by Thursday, which is when our highest POP arrives.

It is unclear how far the front will progress at the end of the
week, but models are suggesting it will make it to our south Friday.
Even if it passes, it is also uncertain how much change in air mass
will occur. By Friday, the front`s supporting upper trough is
expected to be weakening and lifting out to the east northeast as
another more significant trough drops southeast to the north
central CONUS. Even if there is little change in air mass, the
rising geopotential heights and weakening flow aloft would suggest
less coverage of precip for Friday. This is supported by lower
QPF values on Friday vs. Thursday in the latest runs of the ECMWF,
GFS, and GFS ensemble, and is also supported by the fastest GFS
and ECMWF MOS products. The NBM and its cron-based load into the
forecast has not picked up on this (yet), but may in subsequent
runs.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 625 AM EDT SAT JUL 5 2025

VFR conditions are expected to prevail through the majority of the
TAF period. There is currently some river valley fog that`s
reducing visibilities primarily at KSME, however this is expected
to dissipate by ~13Z. Additional river valley fog will be possible
again towards the end of the period. Light and variable winds are
expected.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

UPDATE...VORST
SHORT TERM...VORST
LONG TERM...HAL
AVIATION...WFO SGF