277
FXUS63 KJKL 040905
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
505 AM EDT Mon Aug 4 2025

.KEY MESSAGES...

- There is a possibility of showers and thunderstorms at times
  through the next week, mainly during the afternoon and evening
  hours on most days.

- Our ongoing break from the heat and humidity continues through
  Wednesday before temperatures warm late week.

&&

.SHORT TERM...(Today through Tuesday)
Issued at 440 AM EDT MON AUG 4 2025

08Z sfc analysis shows a weak inverted trough of low pressure has
drifted further west - out of eastern Kentucky - taking the
better rain chances with it. This also allowed skies to become
mostly clear overnight and prompted the development of river
valley fog - locally dense - early this morning. Currently
temperatures are fairly uniform and running in the low to mid
60s. Meanwhile, amid light and variable winds, dewpoints are
generally in the low to mid 60s, as well.

The models, and their individual ensemble suites, continue to be
in rather good agreement aloft through the short term portion of
the forecast. They all depict a strong 5h ridge over the Desert
Southwest while some energy is pooling downstream of this over
Missouri developing into a mid-latitude trough. This feature only
slowly works northeast into the western Ohio Valley today and
tonight keeping lower heights nearby along with a fair amount of
slow moving energy packets at mid-levels. The end of the period
has the still weak trough over Kentucky as the western ridge has
strengthened even further - as has the one off the Southeast
Coast - bookending Kentucky with higher 5h heights. The still
small model spread through Tuesday evening continued to support
using the NBM as the starting point for the forecast grids with
minimal adjustments needed - mainly just to tweak the PoPs by
enhancing them diurnally and adding some details from the latest
CAMs consensus guidance.

Sensible weather features a warmer day for most of the area, on
account of more sunshine, and a slightly more humid air mass but
still pleasant enough. The convection chances will be highest to
the west of the area closest to the lower sfc pressure - peaking
mid to late afternoon. A shower or storm cannot be ruled out for
even the northeast parts of the area today but better chances will
remain well to the southwest. Look for enough clear patches or
breaks in the clouds tonight allowing for the development of fog
in the river valleys - again locally dense. However, while showers
and a possible storm chances fade out in the evening to the west
we will see an uptick in potential convection in the far southeast
associated with a sfc wave lifting northeast through the southern
Appalachians. The influence of this feature continues into
Tuesday proper - still favoring the southeast with better rain
chances, plenty of clouds, and cooler afternoon temperatures. This
area will also need to be watched for excessive and training
rainfall potential - but the highest area of concern will be well
southeast of the state.

The changes to the NBM starting point were primarily focused on
maintaining the the diurnal nature to the PoPs each day along with
the latest CAMs consensus guidance details. Temperatures and
dewpoints were not changed much in this environment - aside from
with some extra drying included in the dewpoints each afternoon.

.LONG TERM...(Tuesday night through Sunday)
Issued at 505 AM EDT MON AUG 4 2025

The NBM starting point seems reasonable for the slowly evolving
pattern through the extended portion of the forecast. The
operational solution is generally on the cool side of the
ensembles through mid week with better centering later in the
period. This makes sense, in general, given the greater cloud
cover and better pcpn chances earlier in the period. The main
changes to the standard populated solution was to tweak low
temperatures for spot location specifics through the next 7 days.

The previous long term discussion follows:

As the period begins, guidance continues to have an upper level
ridge centered in the western Atlantic and another ridge centered
over NM and the Southern Plains and extending into the High
Plains. Meanwhile the OH Valley region should be in an area of
upper level troughing between the two ridges with the axis of this
troughing extending through the MS Valley. At the surface, the
period should begin with a ridge of sfc high pressure centered
over the mid Atlantic states with a nearly stationary front
extending from the Atlantic across northern FL and near the Gulf
coast and then into portions of the Plains. PW per the 12Z HREF
mean, the period should begin with PW Values of roughly 1.3 to 1.5
or close to the climatological mean.

From Tuesday to Wednesday night, ridging centered over the Southern
Rockies/NM vicinity is expected to strengthen a build east and
northeast into the Central and Southern Plains and Central Conus
and toward the mid MS Valley. Meanwhile, ridging centered in the
Atlantic near Bermuda is expected to remain. Upper level
troughing should remain in between these ridges with the axis of
it moving into the Great Lakes to OH and TN Valleys to sections of
the southeast by late Wed. The upper troughing will keep the
potential for clouds from time to time as well as convection
and there may be weak sfc troughs present across the OH valley as
well. A general diurnal peak in both clouds and convection is
anticipated each afternoon and evening from Tuesday to Wednesday.
The NBM continues to be rather consistent with temperatures
remaining near if not a few degrees below normal. With the
pattern and time of year not favoring much in the way of
ridge/valley temperature splits/differences for min T and guidance
in overall good agreement, no notable chances were needed for NBM
guidance into the middle of the week.

For Thursday to Friday night, the axis of upper level troughing
or a broad upper low should continue to remain near or west of
eastern KY with ridging centered in the western Atlantic
persisting along with another upper level ridge remaining from
northwest Mexico to NM into portions of the Central to Southern
Plains. An upper low and associated trough should also work
across sections of western Canada and the Northwest Conus and
Great Basin as well as parts of the Northern Rockies during this
period and near the Northern Plains. PW near climatology means is
anticipated as well per the 00Z LREF mean. As during the start of
the work week, the second half of the week should favor diurnally
driven convection though a bit less coverage is suggested by
guidance compared to Wednesday. With a bit less coverage of clouds
and convection, a modest upward trend in temperatures is
suggested by guidance to near normal. Again with the pattern not
favoring much in the way of ridge/valley temperature splits,
little if any changes were needed as compared to the NBM.

Saturday to Sunday, a weakness/weak troughing between ridging
centered in the western Atlantic that guidance generally builds
west toward sections of the eastern seaboard and upper level
ridging building into the Northwest Conus should remain for most
or all of the period. In addition, a much more significant trough
should reach portions of Canada into the Northern to Central
Plains and upper MS Valley over the weekend. A ridge of sfc high
pressure should remain into next weekend from portions of the
Northeast into the Appalachians with guidance generally supporting
500 mb height rises to end the weekend. Near to slightly above
normal temperatures are anticipated for next weekend with isolated
to scattered afternoon and evening convection.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
ISSUED AT 220 AM EDT MON AUG 4 2025

VFR conditions were reported at TAF issuance, though fog is
evident in many of the river valleys. Confidence in fog formation
is lower at the TAF sites, due to lingering modest southeasterly
low-level flow and some decent temp to dewpoint spreads away from
LOZ and SME. The lightest winds late in the night are expected at
SME and LOZ and that may allow for fog impacts, as depicted via
TEMPOs in the TAFs. Of note, the low-level flow strength slightly
favors the fog lifting into a low stratus deck so low ceilings are
also included at these terminals. Any low stratus or fog will
lift/dissipate later this morning with the onset of daytime
heating. There will also be a threat for a stray shower or
thunderstorm developing in the afternoon near the LOZ and SME TAF
sites - included as a PROB30. Winds will average less than 10 kts
through the period.

&&

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

&&

$$

SHORT TERM...GREIF
LONG TERM...JP/GREIF
AVIATION...GEERTSON/GREIF