375
FXUS63 KJKL 122056
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
456 PM EDT Wed Jun 12 2024

.KEY MESSAGES...

- Hot and uncomfortable weather builds through this weekend, with
  highs in low to mid 90s and heat indices peaking out around 100
  degrees in many locations each afternoon Sunday through
  Tuesday.

&&

.SHORT TERM...(This evening through Thursday night)
Issued at 456 PM EDT WED JUN 12 2024

Kentucky lies south of the core westerlies locked up across the
Great Lakes and north of a deep south west to east oriented
trough. Shortwave energy riding west to east along the Northern
Tier will help amplify the flow across the Midwest through the
period. This will drop a weak frontal boundary southward close to
the Ohio River by the end of the short term. Return southwesterly
flow around the periphery of the surface high that has moved off
to our east will continue to pull warm air in from the southwest.
Moisture return will be more slow/gradual since the flow is out of
the southwest versus from out of the Deep South.

Sensible weather features continued dry, fair weather for the
short term. With the slow moisture recovery, surface Tds are only
responding very gradually, climbing to around the 60 degree mark
by tomorrow. Thus while temperatures will climb to the mid and
upper 80s tomorrow, conditions will not feel as oppressive as they
might be otherwise. In addition, overnight lows will continue to
run cool, in the low 50s in our coolest valley locations tonight
and around 60 tomorrow night. Coolest temps will be in the east as
western valleys will tend to remain more mixy under the influence
of slightly stronger return flow. Valley fog will continue to
develop each night through the period, perhaps becoming a bit more
widespread with each passing night due to the gradual increase in
moisture. However, moderating temperatures through the period
will also tend to keep temperatures elevated from crossover
thresholds. Thus fog, while becoming a bit more widespread, will
probably not become so dense as to become a problem...or from from
becoming more impactful than what is typically experienced during
the morning commutes.

.LONG TERM...(Friday through Wednesday)
Issued at 456 PM EDT WED JUN 12 2024

The period will start with a progressive upper level trough axis
passing over the region, and an upper level high over the southern
plains ridging northward. The trough will support a cold front
nearing the Ohio River from the northwest. Although little in the
way of low level advection (moisture or temperature) will be
occurring in our region ahead of the front, air mass modification
will be ongoing, and dew points are forecast to rise at least to
the mid 60s by the time the front arrives late Friday or Friday
evening. Forecast soundings still suggest some potential for deep
convection, and model QPFs support carrying minimal POPs in the
afternoon and early evening. Unlike recent frontal passages, the
cool and dry air mass behind this front will skirt by our area,
remaining mostly to our northeast. It will largely serve to delay
an inevitable arrival of hotter weather.

By Saturday, the northeast CONUS trough will be departing
eastward and the aforementioned upper ridge will be building into
the Ohio Valley and southeast CONUS. At the surface, high pressure
passing by to our northeast will be departing off the coast on
Sunday. Return flow on the back side of the high, along with
rising geopotential heights, will result in mainly dry weather
with climbing temperatures and dew points during the weekend.

Model differences become a little more significant Monday through
Wednesday, centering on the strength of the upper high and how
quickly it transitions eastward. Overall in recent runs, the GFS
takes the center out over the western Atlantic faster than the
ECMWF and allows an increase in deep tropical for our area. It
allows for at least scattered thunderstorms each day. Meanwhile,
the ECMWF does have some light precip at times, but is drier and
favors stronger ridging holding over us which limits deep
moisture. Will continue to use a blended solution with only low
POPs each day.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 144 PM EDT WED JUN 12 2024

VFR flight conditions expected throughout the period outside of
the river valleys where fog will develop overnight and not clear
out until early to mid morning. Winds will be light and variable
through the period, at less than 5 kts.

&&

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

$$

SHORT TERM...RAY
LONG TERM...HAL
AVIATION...GREIF/RAY