Severe Weather Potential Update

536
FXUS63 KJKL 311153 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
753 AM EDT Sat Oct 31 2026

.KEY MESSAGES...

- Mainly dry weather with warm afternoons persists into the
weekend.

- A low potential for rain will return on Sunday, with a more
significant system bringing a higher potential for widespread
rain arriving around the middle of next week.

&&

.UPDATE...
Issued at 735 AM EDT SAT OCT 31 2026

The varying degree of breaks in the clouds as well as some
valley locations decoupling and remaining decoupled overnight
led to a wide range of temperatures overnight. Some of the deeper
eastern and northeastern valleys were in the upper 30s to around
40 as of 7 AM EDT. Otherwise, temperatures ranged through the 40s
to the 50s on ridgetops and in areas of more open terrain. Some
river valley fog is also present in the southeast. This fog should
lift and dissipate over the next couple of hours. Otherwise,
hourly temperature and dewpoint grids for the next couple of hours
were freshened up based on recent observations.

&&

.SHORT TERM...(Today through Sunday)
Issued at 435 AM EDT SAT OCT 31 2026

Early this morning, an upper level ridge was centered in the
vicinity of the Southern Gulf and extended into FL and portions of
the Caribbean, with a ridge axis also extending northwest to the
Southern Appalachians to Lower OH Valley to sections of the mid MS
Valley. Further west, a shortwave trough extended from the
Central Plains to Arklatex vicinity downstream of an upper low off
the Pacific Northwest coast and an associated trough that is
gradually approaching the west coast of the Conus. At the surface,
a ridge of high pressure centered in the Great Lakes extended
into the OH Valley and Appalachians and much of the eastern Conus.
Meanwhile, the boundary that crossed eastern KY on Friday
continues to settle to to the south and southwest of eastern KY.
Temperatures have varied widely overnight pending the degree of
cloud cover and decoupling and also driven by where the drier air
had moved in behind the front. The pressure gradient across the
area is sufficient for some light northeast to east winds at
present for some locations. Several of the more sheltered
northeastern and eastern valley locations decoupled and are
currently as cool as around 40 degrees, with many of the remaining
valley locations in the north and east in the 40s to around 50.
Ridgetop and more open terrain locations ranged through the 50s.
Little or no valley fog was evident on satellite and webcams thus
far.

Today and tonight, the upper level ridge should remain in place from
southern sections of the Gulf to portions of the Caribbean and
the Atlantic, while the ridge axis extending to the northwest
will gradually shift to the east of eastern KY by this evening.
This will give way to west southwest to southwest flow aloft as
the shortwave trough/area of troughing at 500 mb gradually
approaches from the southwest. The axis of this trough should
reach portions of the mid to upper MS Valley to the Southeast
Conus to northeastern Gulf by Sunday morning. High and eventually
mid level moisture will increase generally from the top down today
and tonight. Mean PW per the 00Z REFS climbs to roughly the 0.6
to 0.85 inch range by this evening or roughly the 60th to 75th
percentile for the end of October, increasing slightly tonight
but not significantly, as low levels remain dry under downslope
flow. On Sunday, the axis of the shortwave trough gradually nears
from the west and southwest, with mainly a mid and upper level
moisture increase. Mean PW does climb to the 70th to 80th
percentile range per 00Z REFS by late Sunday afternoon, but again
lower levels continue to remain dry under downslope flow.

Any valley fog that manages to develop through dawn should lift and
dissipate within a couple hours of sunrise today. Otherwise, for
sensible weather, high clouds will gradually thicken and lower
from today into tonight and remain rather persistent through
Sunday. Some rain and sprinkles should attempt to reach the ground
from a mid level deck on Sunday as the atmosphere moistens from
the top down. The best chance for any measurable rain during the
day on Sunday in the west.

.LONG TERM...(Sunday night through Friday)
Issued at 457 AM EDT SAT OCT 31 2026

At the start of the long term period, a well defined shortwave
will be located just west of the forecast area. Otherwise,
midlevel ridging will dominate much of the eastern CONUS;
meanwhile, farther west, a substantial trough will be located over
the Intermountain West. At the surface, high pressure will sit
over the Northeast, with a cold air damming pattern on the other
side of the Appalachians. For our area, this pattern will favor
southeasterly downslope winds, which should work to suppress
dewpoints somewhat, even as total column moisture increases (with
PW values surpassing 1 inch in most locations, anomalously moist
compared to climatology). Despite the size of this shortwave,
height falls won`t be particularly intense, and this, in
combination with meager low level moisture (dewpoints in the upper
30s and low 40s), should work against any widespread rain,
particularly east of I-75. The best chance for appreciable rain
will be in our southwestern counties, where low level moisture
should be more robust, with rain chances and QPF generally
decreasing closer to Virginia and West Virginia. Even in our
southwestern counties, however, a lack of instability should keep
rain totals unimpressive.

Following the passage of this rather unimpressive shortwave, a
more substantial system will arrive next week, bringing more
widespread rain chances. Aloft, ridging will attempt to quickly
build back in by late Monday, though a second and more subtle
shortwave will cross through the area later in the day, with
associated cloud cover keeping lows fairly warm in the upper 40s
and low 50s. Should this wave be weaker than currently modeled, it
is possible some clearing allows valleys to cool slightly more
than is currently forecast; however, given ensemble preference
towards a mostly cloudy sky, terrain distinctions have been
neglected for now. Tuesday will also be dry during the day as
ridging amplifies aloft over our area, with the aforementioned
deep trough to the west now featuring two distinct closed lows
aloft: one in the Upper Midwest and another farther south near the
Southern Plains, although there is significant model discrepancy
regarding the positioning and evolution of this southern feature.
At the surface, an area of low pressure associated with this
potent system will push northeast, with southeasterly to southerly
winds locally ahead of this system, but atmospheric moisture will
be very high, with LREF mean PW values in the range of 1.1-1.3
inches, firmly above the 90th percentile according to climatology.
This moist environment and strong source of forcing will set the
stage for widespread rainfall, with the highest rain chances
currently on Wednesday and continuing into Thursday. With this
system, a tight pressure gradient will be in place, with fairly
strong flow just above the surface; despite sizable model
uncertainty, LREF mean 925 mb flow is around 25-30 kt for much of
the forecast area, indicating increasing confidence in breezy
conditions for our highest terrain as this system moves through.
Even so, despite such potent kinematics, meager instability should
limit any threat of severe weather.

Looking ahead, PoPs look to decrease on Friday, with a trend
towards cooler weather. However, immense model spread regarding
the evolution of this system adds considerable uncertainty by the
end of the period.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 750 AM EDT SAT OCT 31 2026

Some river valley fog was affecting a few locations generally
south of the TAF sites, with reductions likely to MVFR or lower.
This fog should lift and dissipate through around 14Z and TAF
sites will not be affected. VFR is expected to prevail through
the period, with gradually lowering high clouds and the arrival
of some mid level clouds during the second half of the TAF period
as an upper level ridge shifts east and a disturbance approaches
from the southwest. Light winds will become east to southeast
areawide around 14Z, but remain less than 10KT. Winds will become
light and variable around sunset and remain at that level to end
the period.

&&

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

&&

$$

UPDATE...JP
SHORT TERM...JP
LONG TERM...FAGAN
AVIATION...JP