455
FXUS63 KJKL 302002
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
402 PM EDT Wed Jul 30 2025

.KEY MESSAGES...

- Peak afternoon heat index values are expected around 105 through
  early evening.

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

- Thunderstorms could bring isolated excessive rainfall through
  early this evening and on Thursday to Thursday evening.

- A cold front will bring significant relief from the heat and
  humidity starting late Thursday night and Friday

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 234 PM EDT WED JUL 30 2025

Current satellite shows a variety of clouds across the forecast
area. Along and north of Rockcastle to Breathitt to Johnson have a
mid-level cumulus field over them, while areas south of this have
cumulonimbus clouds, riding a boundary along the Kentucky, Virginia,
Tennessee boarder. This is where shower and storm activity has
already begun, and is expected to  continue through the afternoon
hours. The 12Z sounding out of BNA had a notable dry layer, and
lower PWAT at 1.29 inches. Earlier SPC mesoanalysis was poorly
handling estimated PWAT across the region, over doing it. Winds
continue to be out of the northeast, so any additional moisture
working into eastern Kentucky is unlikely. A stalled frontal boundary
across the Tennessee-Virginia boarder does provide a slight risk of
excessive rainfall, and flood advisories have already been issued
early this afternoon for training storms. This general areas has been
added to a Slight Risk from the SPC.

At current, temperatures have climbed into the mid to upper 80s
across eastern Kentucky, with dew points in the low to mid 70s. This
has already led to heat indices in the upper 90s to low 100s.
Temperatures may rise another 2-4 degrees this afternoon flirting
with low 90s in places, if this occurs heat indices may rise above
100F and approach 105F. A heat advisory remains in effect for the
area through 8PM this evening. After storms clear out this evening,
fog is expected to develop during the overnight hours, however this
is expected to mix out by 9 or 10 am Thursday morning. Overnight
lows will be in the upper 60s to low 70s.

Due to a delayed frontal passage, messaging has changed in regard to
heat being "done with" after Wednesday. While guidance has increased
temperatures over the area for Thursday, as well as keeping dew
points in the mid to upper 70s, an extention of the current heat
advisory is not expected at this time. The 50th percentile of all
guidance was used in bumping the high temperature down slightly for
Thursday, with temperatures expected to reach the upper 80s, and 90
in places. This solution puts heat indices in the upper 90s, to
low 100s across the forecast area. While still hot and humid, most
of the public has already adjusted to the last week. Euro, GFS and
NBM all have solutions in the low 90s, 850-mb temperatures do not
favor this outcome. Looking at them, temperatures are roughly 66-
68F. If the entire column from 850-mb down to the surface was mixed
down using the dry adiabatic lapse rate (DALR), It would equate to a
surface temperature of 90-92F. Rarely if ever does the entire
column of air mix at the DALR, even though some dry air was noted
in the morning sounding out of Nashville today. Additionally, added
cloud cover in association with an approaching cold front could
obscure prime warming conditions. Lastly, showers and storms are
expected to begin in the afternoon, also adding to a potential
challenge of highs getting into the low 90s.

.LONG TERM...(Friday through Wednesday)
Issued at 355 PM EDT WED JUL 30 2025

The period is expected to begin with upper level ridging centered
in the western Atlantic to the east of Bermuda and extending to FL
and the Gulf with another upper level ridge centered over the
southwest Conus into northern Mexico vicinity and extending north
into sections of the Rockies. Further west, an upper level low
should initially be in place west of the BC with a trough
extending south west of the west coast of the Conus. Meanwhile,
an upper level trough is progged to extend from Canada across the
Great Lakes to mid MS Valley region with a lead shortwave trough
in the vicinity of the mid Atlantic/Northeast coast. At the
surface as the period begins, a frontal zone should precede this
troughing and extend from the Atlantic to a sfc low near or
southeast of the Delmarva before trialing across VA and Carolinas
and Gulf coast states to the Southern Plains and then north near
the front range. A ridge of sfc high pressure should extend from
the upper MS Valley to Quebec as that point as well.

Friday to Friday night, upper troughing is progged to shift a bit
to the east and southeast and extend from eastern Canada into the
eastern Great Lakes/Northeast to OH Valley while upper level
ridging becomes centered east of Bermuda in the western Atlantic
and generally extends from the Gulf across the Southern Plains and
SOuthwest Conus into the Pacific during this timeframe. At the
same time, the frontal zone should sag a bit further south down
the eastern seaboard and further south across the Gulf coast
states and then into the Southern Plains to High Plains. At the
same time, the ridge of high pressure should settle across the
Great Lakes region to the mid MS valley region. Near or in advance
of the upper level trough axis, an inverted through is progged to
develop from GA into portions of the Appalachians. Cooler and
drier air is expected to filter into the region, especially the
more northern sections with dewpoints per the NBM falling into the
60s areawide for Friday afternoon and to the mid 50s to mid 60s
on Friday night. Diurnal convection will be possible, with chances
peaking Friday afternoon to early evening, especially south and
southeast nearer to the sagging boundary. Below normal
temperatures by 5 degrees or so are anticipated behind the
boundary to end the workweek.

Saturday to Sunday night, the region is progged to remain in a
general area of troughing/weakness between ridging centered in
the western Atlantic and another ridge centered over the Southwest
Conus. During the weekend, the frontal zone to the south remain
across the Gulf states or near the Gulf coast as sfc high pressure
shifts to the mid Atlantic states. Temperatures should remain a
few degrees below normal over the upcoming weekend. Diurnally
driven convection will remain possible, especially for locations
nearer to the TN and VA border on Saturday and over the southwest
for Sunday as moisture begins to increase on return flow.

Monday to Tuesday, upper level ridging centered in the Southwest
Conus is progged to build into sections of the Plains Plains with
another upper level ridge centered east of Bermuda in the western
Atlantic. In between, the axis of upper level troughing should
gradually progress east to the Great Lakes to OH and TN Valley
regions. As this occurs, a shortwave trough is expected to move
across the Northwest Conus and southwest Canada. That shortwave
should progress to Saskatchewan and Manitoba vicinity to the
Dakotas/upper MS Valley through midweek. Guidance strengthens the
upper ridge centered in the southwest Conus at that point with
ridging likely remaining in place centered over the western
Atlantic in the vicinity of Bermuda. Upper troughing should extend
from Canada into the eastern Conus/Appalachians for Tuesday night
into Wednesday. As the shortwave previously mentioned moves from
the Northwest Conus and southwest Canada and then east into
sections of the Canadian prairies and north central Conus, it
will be preceded by a sfc low with the boundary initially stalled
south and west of the OH and TN Valley region US/Canadian border
likely to lift northeast toward the Commonwealth. Temperatures
should moderate slightly to near normal during this period, with
convection remaining possible with the upper trough axis near or
much of the time west of eastern KY. Convection should generally
peak each afternoon and evening.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 144 PM EDT WED JUL 30 2025

Best chances for convection continue to be toward the Virginia
and Tennessee border areas, so left any mention out of the TAFs.
Winds will be light and variable through the period. VFR
conditions are expected at all TAF terminals through 04Z this
evening, after which lowering ceilings and visibilities will
likely put many TAF sites into MVFR or IFR conditions through
13-14Z. Beyond 14Z most fog should start to mix out if not having
doing so already.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 8 PM EDT this evening for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.


&&

$$

SHORT TERM...GINNICK
LONG TERM...JP
AVIATION...GINNICK