687
FXUS63 KJKL 311908
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
308 PM EDT Fri May 31 2024

.KEY MESSAGES...

- Dry weather can be expected today and into Saturday. The next
  system will then begin to impact the region starting late
  Saturday and continuing into Sunday.

- It will become warmer and more humid with a potential of
  showers and thunderstorms continuing into the new work week.

&&

.SHORT TERM...(This evening through Saturday night)
Issued at 308 PM EDT FRI MAY 31 2024

Northerly flow aloft gives way to amplified upper ridging over the
area by this evening, which then gives way to southerly flow aloft
and weak warm advection overnight tonight. A weak slow-moving
shortwave disturbance then moves east up the Ohio River Valley
Saturday into Saturday night bringing increasing moisture and
meager instability.

With upper ridging moving over the area tonight expect another night
of good to excellent radiational cooling conditions, though high
clouds could disrupt that somewhat. Nevertheless, COOP MOS suggests
many sheltered valley locations will fall down well into the 40s,
with the potential for lower 40s at the coldest locations, with
lower to mid 50s on the ridgetops as warm advection begins to
increase and amplify ridge-valley temperature differences.

Warm advection begins to increase in the early morning hours
Saturday, with thickening cloud cover and moisture arriving from
west to east through the daytime hours. Instability is
significantly lacking so lowered the PotThunder grids about 5
percent, enough to keep any mention of thunderstorms out of the
forecast through early Saturday evening. With thicker cloud cover
beginning in the morning in the southwest and not reaching the far
eastern areas until later in the afternoon, highs in the west,
and southwest especially, are only expected to reach the mid 70s,
while highs in the lower to mid 80s are expected in the Big Sandy
basin.

The model consensus continues to delay arrival of precipitation into
and across the forecast area until later in the day Saturday.
Nevertheless, shower and thunderstorm chances increase Saturday
evening into the overnight, especially western and northern parts of
the forecast area, with highest QPF approaching 0.50-0.75 inches
along and north of Interstate 64 and lowest QPF of 0.10" or less
across the southeastern third of the forecast area. With increased
cloud cover and moisture, lows Saturday night look to be warmer
in the mid 50s to around 60 degrees.



.LONG TERM...(Saturday night through Thursday)
Issued at 440 AM EDT FRI MAY 31 2024

Unfortunately this cooler and quiet spell of weather must come to an
end. By Saturday evening/night, the next weather system will begin
bearing down on eastern KY. High pressure and an upper level ridge
will be in place across JKL during the day Saturday, but by Saturday
evening, these will be exiting east of the state. This will allow a
shortwave to make its way into the Commonwealth starting in the
afternoon in the west, and slowly continue east throughout the
evening and overnight. This will be accompanied by a surface low
pressure system which will skirt north of the Ohio River Saturday
evening and night. Much of KY will find itself near the warm front,
with a surge of warm/moist SW flow ahead of the cold frontal
passage. This associated cold front should make it to eastern KY
by Sunday. Showers and thunderstorms are expected along and ahead
of this cold front, with pops moving in from the west and becoming
widespread overnight Saturday night, then continuing into Sunday
before exiting to the east by the afternoon/evening. Thankfully
this shortwave and surface system are not connected to a larger-
scale troughing pattern, so there isn`t going to be a clash in
airmasses and temperature. Therefore, don`t expect much in the way
of severe weather concerns (SPC is also not highlighting it at
this time), and shouldn`t see too much of a temperature drop
behind the departing cold front.

Rather, instead of a cooler airmass setting in, Monday actually gets
warmer as upper level ridging and high pressure set in briefly. The
NBM has temperatures rising well into the low and mid 80s across
eastern KY, some 10 degrees higher than the previous day in multiple
locations. Models are already starting to show disagreement in their
solutions from this point forward, especially when it comes to pops
affecting the region. Therefore, stuck with the NBM, which does
introduce mainly diurnally driven convection, peaking in the
afternoon and decreasing overnight. The better chance for pops may
come Wednesday and Wednesday night, as a large upper level low
tracks across the Canadian border, with an occluded surface low
pressure center and cold front which will make its way across the
state. Didn`t see any reason to deviate from NBM pops through the
extended given uncertainties, but do expect some changes in their
solutions as we get closer.

Temperatures should remain in the low to mid 80s through the
remainder of the period after Monday. Overnight lows are a bit more
interesting. The NBM shows some amount of cloud cover moving across
the region every night of the work week, though not completely
obscuring the sky. There is a lot of uncertainty here. Where and
when and how much these clouds set up will inevitably make an impact
on the overnight temperatures. And because there is chances of
convection just about every day, we won`t get the strong radiational
cooling like we would if we were sitting under strong high pressure
(subsidence) and clear skies. Did put in some ridge/valley
temperature differences, but didn`t go too crazy, since there may
still be quite a bit of variability. Generally expect temperatures
in the upper 50s and low 60s for Sunday night after the frontal
passage, and then in the 60s for the lows moving forward.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
ISSUED AT 130 PM EDT FRI MAY 31 2024

VFR conditions are expected through most of the period. The only
exception will be localized valley fog during early morning and
late night hours, but TAF sites are unlikely to be significantly
impacted. Light east to southeast winds less than 10 kts will
become light and variable tonight, but then become southerly at 5
to 9 kts after around ~14z beginning from west to east. Lower
clouds and possibly some showers will begin to move toward KLOZ
and KSME at the end of the TAF period.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...CMC
LONG TERM...JMW
AVIATION...CMC