172
FXUS63 KJKL 301131
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
731 AM EDT Tue Apr 30 2024

.KEY MESSAGES...

- Showers today, perhaps with a rumble of thunder. Not as warm.

- Dry and trending warmer midweek, with near record highs on
  Thursday.

- Unsettled weather returns for Friday and lingers through early
  next week.


&&

.SHORT TERM...(Today through Wednesday)
Issued at 335 AM EDT TUE APR 30 2024

Rain showers have arrived to the far southwest counties of the
forecast area as of this early-morning writing. Rain will continue
to progress slowly NNE through the day. I`ve removed the thunder
chance early this morning as instability is best over northern
Alabama, where thunder prevails at this time. There is a subtle
resurgence in instability by midday, but this varies greatly from
model to model. I say subtle because there will be plenty of
clouds to overcome. Lapse rates are generally be poor as well.
Additionally, in the wake of this cold front, a forcing mechanism
for any late-afternoon redevelopment is absent. Therefore, have
generally capped the thunder at "chance" today with dry weather
prevailing from west to east as this line of rain exits. Rainfall
today will generally total around 0.25" to as much as 0.50".

Clearing skies tonight with light wind. Add to the mix the fresh
rainfall and fog is likely overnight in the valleys.

500-mb heights will be on the rise Wednesday due in part to some
deepening of a trough over the Northern Rockies. This will propel
our highs back into the 80s following the  seasonably cool
temperatures of Tuesday.

.LONG TERM...(Wednesday night through Monday)
Issued at 400 AM EDT TUE APR 30 2024

The 30/00z model suite analysis beginning Wednesday evening shows
upper level ridging across the Tennessee and Ohio valleys while
an ~543 dam low is rotating over the Saskatchewan/Montana border.
A shortwave trough is passing over northern Ontario along the
eastern side of the low. At the surface, an ~1006 mb low is found
northeast of Sault Ste Marie. A cold front extends southward from
this low to near Toronto and then southwestward through Ohio,
southern Indiana/Illinois and then more westerly to another ~993
mb low over southeastern Colorado. A weak surface high pressure is
found over the Central Appalachians, to the south of the
aforementioned frontal boundary.

The upper level ridge over our region reaches peak strength Thursday
before being shunted southeastward by the upper low moving toward
northwest Ontario. During this time, the surface cold front may
sag a bit further south to near the Ohio River during the first
portions of Wednesday night. However that boundary will then
quickly retreat northward on Thursday as the low pressure in the
lee of the Coloradoan Rockies races northeastward toward Ontario,
eventually occluding on Friday. Across eastern Kentucky, this will
set the stage for near-record warmth on Thursday and possibly
Friday as southerly return flow boosts 850 mb temperatures to
between 16 and 18C. Given deep mixing, this will support maximum
daily temperatures in the 83 to 90 range. Eastern Kentucky should
remain dry until sometime on Friday when the low pressure`s
trailing cold front drifts into the Ohio Valley. Quasi-zonal flow
with embedded disturbances then sets up over Ohio Valley for the
weekend and early next week. These disturbances along with the
wavering remnants of a frontal boundary could become a focus for
diurnally modulated convection from Saturday through Monday.

In sensible terms, expect near record warmth on Saturday under
most sunny skies with widespread high temperatures in the mid to
upper 80s. In fact, a few of the warmest valleys in the Big Sandy
river basin could eclipse the 90 degree mark. Shower and thunder
chances return on Friday as that cold front approaches. The
arrival timing of that boundary`s associated cloud cover will
dictate whether temperatures run cooler across the board, or
whether ample sunshine will again be able to boost temperatures
deep into the 80s. Shower and thunderstorm chances will then
remain in the forecast through Monday as the front wavers nearby.
While a shower or thunderstorm appears possible at about any time,
the highest chances are generally during the afternoon and
evening coincident with peak heating/destabilization. Daily
maximum temperatures are forecast to drop back into the mid 70s to
lower 80s for the Saturday to Monday timeframe. Meanwhile, nighttime
lows are forecast to range between 48 and 66 throughout the
forecast period, coolest Wednesday night and warmest on Thursday
night.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
ISSUED AT 730 AM EDT TUE APR 30 2024

Rain will be tapering off toward central KY within the next
couple of hours. However, a few showers have redeveloped toward
Cincinnati and southwest of Lexington. Overall, as noted in the
forecast discussion above, redevelopment of showers (or
thunderstorms) seems unlikely this afternoon. For all sites today,
there continue to be a non-zero chance of thunder, but the risk
is overall too low to mention.

Ceilings are highly variable this morning which lowers confidence
in times of improvement (or degradation) of ceilings as the day
progresses. Ceiling trends will need to be monitored closely.

New for this issuance was the addition of fog overnight. High
pressure comes in resulting in calm wind. Paired with the recent
rainfall, there is high confidence in fog. LIFR visibility is
possible.

&&

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

$$

SHORT TERM...BROWN
LONG TERM...GEERTSON
AVIATION...BROWN