065
FXUS63 KJKL 270025 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
825 PM EDT Sat Jul 26 2025

.KEY MESSAGES...

- Heat indices will approach 100 degrees in many places each day
  through Wednesday, and could be in excess of 105 degrees on the
  warmest days - Monday through Wednesday.

- Most days of the next week have a possibility of showers and
  thunderstorms, mainly in the afternoon and evening.

- A cold front will probably bring some relief from heat and
  humidity late in the new week.

&&

.UPDATE...
Issued at 800 PM EDT SAT JUL 26 2025

23Z sfc analysis shows eastern Kentucky between systems with low
pressure off to the northwest and high pressure to the southeast.
This is allowing the diurnal heating cycle to dominate the weather
cadence with scattered afternoon showers and thunderstorms around
that start to fade out towards sunset. Currently, temperatures
are running in the mid to upper 80s, away from any showers, to
the mid 70s with them. Meanwhile, amid light and variable winds,
dewpoints are generally in the sticky low to mid 70s. Have updated
the forecast mainly to add in the latest obs and trends for the
T/Td/Sky grids but also to fine tune the PoPs in the near term per
the newest CAMs guidance and radar depictions. These minor
adjustments have been sent to the NDFD and web servers along with
a freshening of the zones and SAFs.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 330 PM EDT SAT JUL 26 2025

Hot and steamy weather continues through the last weekend of
July. Temperatures at mid-afternoon range from the upper 80s to
lower 90s at most locations, outside of the ongoing scattered
showers and thunderstorms. Dew points in the lower to middle 70s
make those temperatures feel more like the upper 90s to lower
100s. A glance at the latest weather maps shows the big picture
weather pattern -- an ~596 dam high is slowly rotating over the
South Carolina Coast while associated ridging extends well to the
north and west. A notable 500 hPa shortwave trough, now situated
from northern Ontario to south of Kansas City, MO, is riding over
the high. This disturbance supports a weak wave of low pressure
tracking north of Chicago along a northward retreating frontal
boundary. This setup places eastern Kentucky and most of the Ohio
Valley region under a warm sector, southwesterly return flow
regime, which is pulling a juicy tropical air mass back across the
Coalfields (PWATs are presently in the 1.6 to 1.9 inch range).
Subtle perturbations riding around the upper-level high are
interacting with the juicy and moderately unstable air mass to
produce the showers and thunderstorms presently evident on the JKL
radar.

Through tonight, the present weak perturbation will support late
afternoon/evening convection, waning with the loss of daytime
heating. Another subtle perturbation could bring an isolated
shower or storm late tonight as moderate levels of elevated
instability (1,000-2,000 J/kg of MUCAPE) linger. On Sunday and
Sunday night, the upper-level high will retrograde substantially
westward to near/over New Orleans while strengthening slightly to
~597 dam. During the same timeframe, the aforementioned more
robust, albeit weakening, 500 hPa shortwave rides over the ridge
and then dives southeastward toward/into the Central Appalachians
Sunday afternoon/night. Height falls with this feature will be
minimal, but deep tropical moisture (PWATs rising to between 1.8
to 2.2 inches) leading to anomalously high dew points will support
surprisingly robust CAPE profiles (MUCAPE as high as 2,000 to
3,000 J/kg) in spite of weak mid-level lapse rates. RAP13 model
soundings support storm motions around 10 kts from the west
(unless altered by outflows). Of note, weak Corfidi Upshear
Vectors at around/under 5 kts are favorable for backbuilding. If a
stronger shower or storm lingers and torrentially dumps over a
given location, it wont take long for hydro issues to creep up.
This scenario is most favored to occur in northern portions of the
CWA where WPC has drawn a Marginal Risk in their Day 2
(Sunday/Sunday night) ERO, but hydro issues could occur further
south as well. The other concern remains our ongoing hot weather
pattern. While heat indices are forecast to briefly flirt with
Heat Advisory criteria in the Lake Cumberland (Wayne and Pulaski
counties) and Southern Bluegrass (Powell and Estill counties)
Sunday midday/afternoon, there is significant bust potential given
the likelihood of afternoon/evening convection. Finally, there
will, similar to tonight, again be the possibility of stray
convection on Sunday night.

In sensible terms, look for hot and humid conditions to continue,
with afternoon high temperatures within a few degrees of 90F
while nighttime lows range in the lower to middle 70s. Dew points
in the lower to middle 70s will combine with those hot air
temperatures to produce maximum heat indices in the upper 90s to
lower 100s at most locations. One exception, contingent upon
shower and thunderstorm timing and coverage, is in lowland areas
near Lake Cumberland and over the Southern Bluegrass, where
locally higher dew points may support heat indices closer to 105F.
There will be scattered to numerous thunderstorms each afternoon
and evening. Nights and mornings should be dry for most of the
area, but a stray shower or storm still cannot be ruled out
entirely during those times.

.LONG TERM...(Monday through Saturday)
Issued at 454 PM EDT SAT JUL 26 2025

Strong upper level high pressure centered over the lower
Mississippi Valley and southern plains will bring us hot weather
early in the long term period. Along with a humid lower level air
mass in place, heat indices are forecast to reach advisory level
in many places Monday through Wednesday. Even while the upper
high is our dominant feature, the heat and humidity should fuel
at least scattered showers/thunderstorms, mainly in the afternoon
and early evening hours. They are expected to be most plentiful on
Monday, when moisture through a deep layer will allow updrafts to
persist in a column with relatively tall and thin CAPE (especially
in our southern counties). Flow will also be light, and the
combination could allow for localized heavy downpours. Warmer and
drier air aloft is expected on Tuesday and Wednesday, and
although instability will still be present, the POP will be lower
because it will be more difficult to get updrafts sufficiently
large and strong enough to result in thunderstorms development.

The upper high should weaken and shift westward mid to late week,
while the upper level prevailing westerlies on it`s north side
buckle and develop a trough over southeast Canada and the
northeast CONUS and a ridge to the west. This would aid a surface
cold front to move southward and make it through our area. Model
timing of fropa is still uncertain, but it looks to be in the
Wednesday night to Thursday night time frame. Along with the
fropa would come an increased POP, as geopotential heights fall as
the upper trough grazes our area. Cooler and drier air behind the
front is expected to try to make headways into our area to finish
the week, but the extent is still uncertain. It may not be enough
to completely suppress precip, especially in our southern and
southeastern counties.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 825 PM EDT SAT JUL 26 2025

Isolated, pulsy showers and thunderstorms, ongoing at TAF
issuance, will fade out over the next couple of hours. While the
prevailing forecast is for VFR status, briefly IFR or worse
conditions are possible for any location directly impacted by a
stronger shower or thunderstorm.

Fog formation is likely to occur again in the more sheltered
river valleys, but a modest 10 to 20 kt southwesterly flow
developing at 925mb and areas of cloud cover are likely to
minimize fog impacts at the TAF terminals. Thus, cannot entirely
rule out a few brief wisps of fog, especially at airports that
experienced rainfall into the evening, but the modeled conditions
do not favor that fog lingering at the TAF terminals.

Winds will remain variable to southwesterly around 7 kts or less,
through the period, except for the possibility of erratic and
gusty winds adjacent to thunderstorms.

&&

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

&&

$$

UPDATE...GREIF
SHORT TERM...GEERTSON
LONG TERM...HAL
AVIATION...GEERTSON/GREIF