684
FXUS63 KJKL 151725
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
125 PM EDT Wed May 15 2024

.KEY MESSAGES...

- Shower and thunderstorm chances will be around through this
  evening. After a lull on Thursday, the shower and thunderstorm
  chances return to close out the week.

- Near normal to slightly above normal temperatures are expected
  through the work week following a bit of a cool down today
  owing to the showers around.

&&

.UPDATE...
Issued at 125 PM EDT WED MAY 15 2024

Made adjustments to the forecast based on trends in both recent
obs and the latest short term higher resolution model data. With
low pressure spinning place directly overhead, and with plenty
moisture in place, it seemed reasonable to keep fairly high rain
chances in the forecast through early this evening. However, over
the past few hours the actual coverage of showers and storms has
been significantly lower than previously forecast, so the forecast
grids and the zones were updated based on this to a large degree.
Went lower with todays max PoPs, and lower with today`s min PoPs,
using a range of 50-80 percent on average. Sky cover has been on
track for all but our far eastern counties, where some clearing
occurred earlier today, but has since filled in. Temperatures
across the area have been all over the place, with some locations
running within a degree of forecast(hourlies) while other areas
were off by as much as 3 to 7 degrees. Adjusted both the hourly
and max temps for today based on observed trends. The general
trend for todays highs was cooler than previously expected.

UPDATE Issued at 1040 AM EDT WED MAY 15 2024

Just sent out a quick update to remove mention of morning fog from
the forecast now that fog has dissipated/lifted into low stratus
across the area. Also incorporated the latest obs into the hourly
T/Td forecast elements to establish new trends there. Made a few
adjustments to cloud cover based on current satellite trends as
well, but these should not lead to any sky cover changes in the
zone forecast text product. Based on current trends, may also need
to adjust today`s high temperatures a bit by noon to 1 pm today
at several locations around the forecast area. Still expecting
shower and storm coverage to gradually increase through out the
day, especially during peak heating this afternoon, so no changes
made to the overall precip probability forecast just yet.

UPDATE Issued at 740 AM EDT WED MAY 15 2024

Just a quick update to the grids, mainly to fine tune the PoPs and
thunder chances per the latest radar trends. Did also include the
current obs and tendencies into the T/Td grids. These minor
adjustments have been sent to the NDFD and web servers.

&&

.SHORT TERM...(Today through Thursday)
Issued at 425 AM EDT WED MAY 15 2024

08Z sfc analysis shows a broad area of stacked low pressure
spinning over Kentucky and slowly working east. This has kept damp
conditions around through the night with times of showers and fog
beneath mostly cloudy skies and amid light southerly winds.
Temperatures and dewpoints are similar throughout the forecast
area - in this mild and moist environment - with readings in the
upper 50s to lower 60s, most places.

The models, and their individual ensemble suites, are in better
agreement aloft through the short term portion of the forecast
compared to 24 hours ago. They all depict an open 5h low easing
east through Kentucky today along with a healthy amount of mid
level energy. The cyclonic flow associated with this low also
tracks off to the east later tonight with a weak area of ridging
moving to over eastern Kentucky on Thursday - as 5h heights peak
that afternoon. Thereafter, the pattern starts to flatten and more
energy starts to work into the state well in advance of the next
area of troughing inbound from the southern Plains. The model
spread has shrunk with the latest runs on account of the ECMWF
and NAM/GFS timing of the exiting trough being more similar.
Accordingly, the NBM was used as the starting point for the short
term grids along with the incorporation of the CAMs` details for
PoPs and timing through tonight.

Sensible weather features a damp and somewhat cool day with
scattered to numerous showers and potential thunderstorms around
into the evening. Some drying will take place tonight, but most
likely this will only prompt the development of a thicker, and
possibly widespread, blanket of fog for much of the late night
hours. In addition, the higher moisture than normal will make for
another mild night and near uniform temperatures. Thursday looks
to be one of the drier days of the week but still a stray shower
or storm will be possible late in the afternoon and during the
evening - mainly in the east. Less showers around will make for a
warmer day with near normal temperatures, as well.

The main adjustments to the NBM starting point consisted of
adjusting the NBM PoPs to include CAMs details for the shower and
thunder chances through this evening. The temperatures and
dewpoints from the NBM were not adjusted much considering the high
levels of RH through the night time periods.

.LONG TERM...(Thursday night through Tuesday)
Issued at 434 AM EDT WED MAY 15 2024

Eventful extended period yet again. The period will start Thursday
night with increasing clouds, followed by incoming showers and
thunderstorms throughout the day on Friday, as a stationary front is
laid out across the state.  This will eventually transition to a low
pressure system and warm front moving through the state throughout
the day on Saturday, combined with an upper level shortwave and low
moving across the state. Expect widespread showers and thunderstorms
on both days, mainly in the afternoon during peak heating. SPC and
WPC both have marginal risk areas across the CWA from Friday into
Saturday morning, so will need to keep an eye out on convection
during this time period. This system will eventually exit on Sunday.
However, NW flow at the surface on the back edge of the shortwave,
and residual moisture at the surface, will lead to chance pops in
the afternoon, mainly in the far eastern CWA.

Monday looks to be one of our better days during the extended
period, with a brief upper level ridge passing over during the first
half of the day, and fair weather diurnal clouds expected. However,
by the afternoon a shortwave starts to impact the Ohio Valley from
the west, which could lead to some isolated pops as it passes over,
mainly during the evening and overnight for the JKL CWA.

Admittedly models are not in good agreement through much of the
extended period, but by Tuesday, they are completely unreliable. The
NBM went with chance pops throughout the day, likely pulling from a
combination of no pops and high pressure from the ECMWF, and the GFS
which shows 2 separate systems passing over the state during the
day with more widespread pops.

Overall, temperatures should remain fairly even-kill throughout the
period despite the frontal boundaries and airmass changes. Highs
should generally be in the upper 70s and low 80s. Lows will be in
the upper 50s and low 60s. Monday will start to see some change in
this pattern. Monday morning will see the lowest temperatures in the
mid and upper 50s due to mostly clear skies and high pressure
overhead, leading to some potential ridge/valley differences. By
Tuesday, stronger SW flow will take hold, which could potentially
increase afternoon temperatures into the low to mid 80s. Then again,
this is also the point in the forecast where uncertainty is high, so
these values are subject to change over the coming days.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
ISSUED AT 125 PM EDT WED MAY 15 2024

A challenging TAF forecast in store for today, as shower and
storm coverage has been difficult to pin down. That being said,
even though precip chance in general have been lowered somewhat,
with low pressure in place overhead, and with plenty of moisture
to work, we should still see at least scattered showers and storms
around the area for the remainder of daylight hours. The showers
and storms could become widespread for brief periods late this
afternoon, between 19 and 22Z, before tapering off quickly after
sunset. We will see VFR conditions where rain does not occur
today, but any location that experiences a shower or storm could
see MVFR or IFR conditions for breif periods. Fog could also be an
issue late tonight into early Thursday morning, as moisture from
today rain along with some breaks in the clouds and light winds,
could allow for widespread fog to occur. Some locations may even
experience dense fog at times where more rain has fallen. As for
the TAF sites, decided to go with MVFR to IFR conditions due to
fog between 8 and 11Z Thursday, although this could vary depending
on which TAF sites receive the most rain and see the most breaks
in cloud cover overnight.

&&

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

$$

UPDATE...AR
SHORT TERM...GREIF
LONG TERM...JMW
AVIATION...AR