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303
FXUS63 KJKL 231913
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
313 PM EDT Sun Jun 23 2024

.KEY MESSAGES...

-- Changed Discussion --
- A few storms may approach severe thresholds with damaging winds
  being the primary threat this afternoon and evening.

- Tuesday and Wednesday will see the afternoon highs return to the
  low 90s. Friday and Saturday will be the hottest 2 days of the
  forecast, with highs in the low to mid 90s.

- The next best chance for showers and thunderstorms will be
  Wednesday.
-- End Changed Discussion --

&&

.SHORT TERM...
-- Changed Discussion --
(This evening through Monday night)
Issued at 313 PM EDT SUN JUN 23 2024

The surface analysis this afternoon shows a cold front pushing
toward the Ohio River and low pressure pushing into the New England
region. There is a mid- and upper level trough axis noted and will
lead to some height falls through the afternoon and evening. A line
of left over convection and mostly sprinkles now has pushed toward
far southeast parts of Kentucky this afternoon. We are starting to
see shallow convection develop this afternoon amid increasingly
unstable region mainly northwest of eastern Kentucky. These seem to
be having trouble develop amid capping and increased cloud cover.
SPC did put out and MCD this afternoon highlighting the threat of
severe weather mainly in the form of severe wind gusts for areas
primarily along and north of I-64. The latest trends in the
mesoanalysis data show MLCAPE of of around 1000-1500 J/kg building
into the area amid a less than ideal 20-30 knots of effective
shear. If cells can develop into multicell clusters this could
help promote stronger updrafts, with notable dry air in the mid-
levels that could aid in strong winds gusts given the 90th
percentile 850mb jet for this time of year. However, mesoanalysis
is also showing more ideal DCAPE remains mostly north and west of
I-64. The CAMs want to build activity through the afternoon and
evening, with the experimental MPAS model data showing clusters of
storms mainly later this afternoon and early evening. Leaned
toward the NBM mostly for PoPs with some modifications given it
seemed bullish in the southeast.

This cold front will lag behind the convection expected this
afternoon and evening. Therefore, the front will pass through late
tonight into early morning on Monday. This could spark off a shower
late tonight into early Monday morning, but there remains lots of
uncertainty this will happen as we quickly loose better moisture.
The convection will decrease through the evening and clouds are
expected to clear some through the night. This would lead to a
degree or 2 difference from the Ridges and valleys. There is also
some uncertainty on the amount of fog we see tonight, as there is
uncertainty on the coverage a amounts of rainfall. Even so, valleys
will have a shot of seeing patchy to areas of fog tonight.

Monday will certainly be one of the better days of the week, with
PWATs in the HREF of less than 1 inch. This decrease in moisture,
northwest flow, and high pressure will lead to sunny skies and
seasonable temperatures with highs in the low to mid 80s. This high
pressure and clear skies will go into Monday. Given the dry day
Monday, we will see a little more notable temperatures split of 5
degrees or a little more. This will also lead to another period
of fog in the valleys late tonight into Tuesday morning.

.LONG TERM...(Monday night through Saturday)
Issued at 346 AM EDT SUN JUN 23 2024

The forecast starts off with one of the few dry spells of the
extended period, as an area of high pressure passes over and upper
level heights are on the rise behind the exiting trough that will
impact us today. Dry weather is expected to remain in place through
the day Tuesday. However, KY will find itself in the return flow
backside of the passing high on Tuesday, allowing WAA into the
region. This will couple with good radiational heating, allowing
temps to rise to around or just above 90 degrees again by the
afternoon.

This pattern won`t continue past Tuesday, unfortunately, as another
upper level system passes into South-Central Canada Tuesday
afternoon. This will also result in a low pressure system in the
same vicinity, reaching the western border of Quebec by 0Z
Wednesday. From this system, a cold front will extend southwestward,
with showers and thunderstorms possible along it. This will make
it`s way into the state by Tuesday night, coupling with a
strengthening shortwave which will also be traversing the state late
Tuesday night and through Wednesday. While chance pops are expected
to begin infiltrating the CWA early Wednesday morning, the increased
energy of the shortwave, combined with daytime heating, will amplify
both pops and QPF during the afternoon Wednesday. Strong SW flow
just ahead of this frontal boundary will keep temperatures in the
low 90s for most locations, despite the clouds and rain.

Pops will continue into Wednesday night, slowly diminishing to the
east as the front and upper-level shortwave slowly transition away
from the state. Unfortunately they won`t be far enough away by
Thursday to not influence some continued precip chances, mainly in
the far SE. These should be mainly upslope flow and diurnally
driven, quickly diminishing by Thursday evening. Post-frontal temps
on Thursday will be a bit cooler than Wednesday, but still warm,
with highs in the mid and upper 80s.

Once this system finally exits Friday night, another round of high
pressure to our northeast will take hold. Models show generally dry
conditions then until Saturday, though the ECMWF and consequently
the NBM do try to show some pop up convection across the far eastern
CWA during the afternoon hours Friday. The current NBM only has it
impacting a couple counties for a few hours, but didn`t have the
confidence to remove it at this point, especially with one of the
models showing it. Again, during this spurt of high pressure, winds
will become more southerly and sunshine will be abundant, so
temperatures will easily climb back into the low to mid 90s on
Friday. Humidity will make it feel several degrees warmer still.

This SW flow and heat will only increase for Saturday, as yet
another system begins to approach the region. It will be very
similar to the mid-week system, with a surface low and upper level
trough passing across southern Ontario, and a cold front stretched
southwestward across much of the US. This front and associated
precip will move into the state Saturday night and continue into
Sunday. All the models also show generally isolated pop up
convection ahead of the system during the day Saturday as well.
Highs on Saturday will easily top the mid 90s in most locations,
with heat indices even higher.
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&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
ISSUED AT 118 PM EDT SUN JUN 23 2024

A line of mainly sprinkles continues to push southward across the
area this afternoon. We are mainly seeing mid- and high level
clouds as a result. However, some lower cloud bases are working
across northern Kentucky this afternoon and could lead to some
near MVFR Cigs through the afternoon and evening. The potential
also still exists for increasing chances of showers and
thunderstorms through the afternoon and evening, but still some
uncertainty on if and when these will occur at the TAF sites.
Opted to add in some rain showers/VCTS between 22Z and 23Z when it
seemed like we would see peak in the deeper moisture and moderate
instability. Outside of this, river valley fog could be a concern
later tonight and will be some what dependent on the amount of
rainfall we see from any storms that develop this afternoon. The
winds will be out of the southwest this afternoon at 5-10 knots,
with gusts of around 15 to 20 knots. These could be higher and
more erratic at TAF sites that happen to experience any
thunderstorms. However, the wind will slacken through the later
evening hours to around 5 knots or less.

&&

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

$$

SHORT TERM...DJ
LONG TERM...JMW
AVIATION...DJ