-- Discussion containing changed information from previous version are highlighted. --
524
FXUS63 KJKL 221100
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
700 AM EDT Wed May 22 2024

.KEY MESSAGES...

- There is a potential for showers and thunderstorms at times from
  today through Tuesday.

- A few storms today could be strong to severe, with damaging
  winds the primary threat, and large hail as a lesser threat.

- Very warm temperatures will persist today. An increase in clouds
  and the possibility of rain will lead to somewhat cooler
  temperatures from Thursday into the first of next week.

&&

.UPDATE...
-- Changed Discussion --
Issued at 700 AM EDT WED MAY 22 2024

Did a quick update to the forecast grids using trends from the
latest obs. Temperatures have been running warmer than forecast
overnight, so the latest obs were used to establish new trends and
to also update this mornings lows, as they were a bit too warm as
well.
-- End Changed Discussion --

&&

.SHORT TERM...(Today through Thursday)
Issued at 401 AM EDT WED MAY 22 2024

A somewhat challenging forecast in the short term this time
around. A cold front will approach the area from the northwest
through out the day today, and will be the trigger for showers and
storms around eastern Kentucky today through Thursday. The front
is expected to eventually stall out somewhere along the Ohio
River. The challenge will be determining how far south the front
will go before it stalls. The further southeast the front goes,
the higher our rain chances will be today. The position of the
front varies a bit from model to model, so no solid consensus has
been reached as of yet regarding the boundary. Due to this
uncertainty, decided to keep precip chances a bit lower than the
latest NBM data was suggesting, going more toward the lower MOS
guidance for PoPs. The latest runs of the higher resolution
models(HRRR, NAMNEST, CAMS, etc) differed as well with the start
times and initiation of showers and storms today. Having said
that, liked the latest HRRR solution for initiation and evolution
of convection across our area, especially late tonight and
Thursday, when the cold front is forecast to push through. In a
nutshell, the highest probability for showers and storms occur
during from very late tonight and through the day on Thursday
during frontal passage.

What we do know is with plenty of low level moisture and
instability will be in place to support convection, and that
showers and storms will form and move across eastern Kentucky
today, especially this afternoon and evening, during peak heating.
We also know that a few storms could be strong to severe and
could produce damaging wind gusts or even an isolated instance of
large hail. After a few days of extremely warm temperatures,
things will finally cool off a bit today and Thursday due to
persistent, increasing cloud cover and repeated rounds of showers
and storms. Winds will be on the increase today as well and will
be generally out of the southwest at 5 to 10 mph, with gusts of 15
to 20 mph possible at times.

.LONG TERM...(Thursday night through Tuesday)
Issued at 314 AM EDT WED MAY 22 2024

An unsettled long-term period is expected as active northern and
southern streams will push a train of shortwave disturbances east-
northeast across the Ohio and Tennessee River Valleys through
Sunday. From Monday onward, there is more uncertainty as the GFS and
ECMWF operational runs differ in placement of a large upper low in
proximity of the Great Lakes and southeastern Canada, especially as
it pertains to the strength, timing, and placement of shortwave
disturbances moving toward and through the Ohio Valley for the early
to middle part of next week.

While there is high confidence in the synoptic pattern, there is
practically no skill in accurately timing the shortwave disturbances
more than about 12 to 18 hours in advance, which means human
forecaster predicting hourly precipitation probabilities with high
skill is practically impossible. This is one of the primary reasons
the NBM was created, in order to synthesize dozens of ensemble
members into a calibrated consensus forecast that does show
considerably higher skill on average than a human forecaster. Have
thus used the NBM PoPs as-is for the duration of the long-term
period, with oscillations between chance (30 to 50 percent) and
categorical (75 to 100 percent) PoPs as the systems move across the
region in quick succession.

Above average temperatures can be expected from Thursday evening
through Monday as the region will mostly see light southerly winds
at the surface and west to southwest flow aloft. Clouds and periods
of precipitation will limit these warm anomalies to about 3 to 8
degrees above normal. Temperatures fall to near normal to slightly
below normal by Tuesday of next week as a cold front passes the
region and brings a more northerly component to the westerly flow,
especially aloft.

&&

.AVIATION...
-- Changed Discussion --
(For the 12Z TAFS through 12Z Thursday morning)
ISSUED AT 700 AM EDT WED MAY 22 2024

For early this morning, SCT to BKN middle and high level clouds,
left over from earlier thunderstorms, will stream over the area.
Isolated to scattered showers and storms are then expected to
form and move across eastern Kentucky today, especially late this
afternoon through this evening, when a cold front will approach
from the northwest. Winds will increase to 5 to 10 kts by late
this morning, and could gust to 15 to 20 kts at times. A few
storms this afternoon and evening could be strong to severe, and
produce damaging wind gusts or even isolated instances of large
hail. VFR conditions should prevail, unless an airport is directly
affected by a storm, during which time we could see MVFR or even
IFR conditions for brief periods of time. Clouds will be on the
increase today and tonight and will become BKN to OVC at times.
Showers and storms could become more widespread and lead to more
direct impacts on TAF sites should the approaching front not stall
as far north as currently forecast.
-- End Changed Discussion --

&&

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

$$

UPDATE...AR
SHORT TERM...AR
LONG TERM...CMC
AVIATION...AR