442
FXUS63 KJKL 242328
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
728 PM EDT Sat May 24 2025

.KEY MESSAGES...

- Below normal temperatures linger through the first half of the
  new week.

- There will be possibilities for showers and/or thunderstorms at
  times from Sunday to Saturday.

- There is a Marginal Risk for Excessive Rainfall (5 to 14%
  chance) near Lake Cumberland late Monday night.

- There is a Marginal Risk for Excessive Rainfall (5 to 14%
  chance) areawide Tuesday into Tuesday night.

&&

.SHORT TERM...(This evening through Sunday night)
Issued at 313 PM EDT SAT MAY 24 2025

A surface ridge to our northeast is still supplying cool and dry
air to our area this afternoon. High clouds are streaming over the
region from the west blowing off of prior convection well to our
west. A frontal boundary is stalled well to our south across the
Deep South, with warmer and more humid air on the other side. The
clouds should thin out enough tonight to allow for radiating and
at least some pooling of cool air in valleys.

Weak shortwaves moving through largely zonal flow aloft over our
area will interact with warm, moist air overriding the frontal
boundary on Sunday into Sunday night. This presents a possibility
of showers/thunderstorms. Models have not been in good agreement
on model-model and run-run, and there`s not high confidence in the
POP.

.LONG TERM...(Monday through Saturday)
Issued at 445 PM EDT SAT MAY 24 2025

The period is expected to start with an upper level low east of with
a trough trailing south and southwest to the Southern Appalachian
region, narrow/subtle upper level ridging from the Gulf across GA
to the TN Valley to Lower OH Valley to western Great Lakes, while
another shortwave/upper level low is expected to extend from
western Ontario to the Four Corners region to Mexico. Another
narrow upper level ridge is progged to extend from the Pacific
into the Southeast Conus across portions of the Great Basin to MT
to Saskatchewan with a shortwave extending from the Gulf of AK to
Pacific Northwest to CA coast at that point. At the surface, a
ridge of high pressure should extend from near James Bay across
western Ontario and the Great Lakes toward the mid Atlantic coast
and also west into the upper MS Valley. Meanwhile, an initially
quasi-stationary boundary is expected to extended from a sfc low
off the NC Outer Bands to SC and then across the Gulf coast states
to a sfc low in northwestern portions of TX and then west into NM
and then north near the frontal range to CO. At that point, PW
per the 00Z HREF mean is forecast to be in the 0.9 inch to 1.1
inch range from near the Mtn Pkwy and points south and 0.6 to 0.9
further north.

The shortwave trough axis initially east of the Commonwealth will
move east on Monday and Monday night and into the Atlantic while
the upper ridge axis also shifts east and northeast of eastern KY
late Monday through Monday night. Subsequently the depth of south
to southwesterly upper level flow is expected with a shortwave
trough approaching the Lower OH Valley late Monday night and
crossing eastern KY on Tuesday. At the same time, the upper level
troughing from Ontario into the Four Corners region to Mexico
will shift east into the Plains and Central Conus with an upper
level low evolving over the Northern Plains/Dakotas/Upper MS
Valley regions. As ridging departs, southwesterly flow ahead of
the shortwave will more fully engage with PW progged to increase
above 1 inch areawide later Tuesday evening into the overnight
per the 00Z LREF mean, with PW values per the 00Z LREF mean rising
to 1.5 to 1.7 inches from north east east to the I-75 corridor to
Lake Cumberland region early Tuesday. A surface low associated
with the shortwave should track northeast from the Southern Plains
to the mid MS to western TN/Lower OH Valley Monday through Monday
night with the initial quasi stationary boundary to its east
lifting into the TN Valley and parts of the southeast as a warm
front. As a result, after initially minimal chances for showers
and showers during the diurnal cycle min early on Monday, shower
and storm chances will gradually increase from south to
north/northeast Monday evening into Monday night. There may even
be a bit of a lull between more diurnally driven convection
Monday afternoon to early evening and then higher chances for
convection later on with the approach of the shortwave and warm
front/warm air advection late Monday evening into Monday night.
The heaviest QPF which is very modest with this is generally west
of the I-75 corridor.

The sfc waves or waves should move north and northeast to near
the confluence of the OH and MS Rivers and into IL/IN through
Tuesday and Tuesday night. Following the initial shortwave trough
on Tuesday, another shortwave trough approaches and moves across
eastern KY later Tuesday night to early Wednesday in advance of
the upper level low meandering over the upper MS Valley to
western Great Lakes regions and associated troughing in the
Central Conus to MS Valley vicinity. The upper level trough axis
is progged to remain west and northwest of eastern KY on
Thursday, before approaching late Thursday night into Friday.
Another disturbances may rotate around the upper low meandering
toward Quebec/St Lawrence Valley to end the period. Guidance
varies with the strength of the midweek features, with the ECMWF
12Z operational stronger with the sfc low at midweek reaching the
Great Lakes while the 12Z GFS is weaker and further south in IN to
near the OH River. An eventual frontal passage should occur
during the Wednesday to Wednesday night period. PW remains
maximized in the 1.5 to 1.7 inch range per the 00Z LREF mean
through Tuesday and into Tuesday night and somewhat elevated for
the rest of Tuesday night, before decreasing to 1.1 to 1.2 per
the 00Z LREF mean on Wednesday behind the second shortwave. PW is
then in the 0.8 to 1.1 inch range through the end of the week per
the 00Z HREF mean.

The main weather concern is a limited/marginal threat for
excessive rainfall starting as early as late Monday night near
Lake Cumberland and then areawide for Tuesday into Tuesday night
especially if storms were to train (move repeatedly over a
location). There will have been several rain free or nearly rain
free days leading into this period with somewhat elevated moisture
throughout the column. Instability will be lower end, though
MUCAPE should be sufficient to maintain rounds of showers and some
storms. On average, the current forecast QPF for the extended
period from Monday afternoon through Tuesday night is 1.5 inches
or less near the VA border and 2 inches or more from near
Monticello to Jackson to Prestonsburg and Inez and point west and
north of that line as there may be some rain-shadowing effects in
parts of the southeast and/or forcing may be more focused further
north and west. These values are generally on the upper end/half
of 00Z LREF percentiles. Chances for strong storms are minimal at
best to near nil during the period per recent probabilistic
guidance.

Overall, the weather during the period will generally be unsettled
with a general diurnal peak in convective coverage expected each
afternoon to evening for the most part. However, with the passage
of a couple of shortwaves and a sfc system near the area, pops
peak late Monday night to Tuesday night with a secondary diurnally
on Wednesday. Isolated to scattered pops remain to end the week,
peaking each afternoon and evening.

Temperatures will generally be below normal for the next week,
especially for highs. During the extended period, diurnal ranges
should be more limited than during the long term period as
compared to the near term period.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
ISSUED AT 728 PM EDT SAT MAY 24 2025

Prevailing VFR conditions are forecast through the period. Some
light rain showers are possible beginning around 18z Sunday and
lingering until 00z Monday, but will keep VFR conditions in the
PROB30 and prevailing FM groups for now given the high likelihood
of these showers remaining light given the lack of convective
instability.

&&

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

&&

$$

SHORT TERM...HAL
LONG TERM...JP
AVIATION...CMC