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993
FXUS63 KJKL 220801
AFDJKL

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

.KEY MESSAGES...

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- 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.
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&&

.SHORT TERM...
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(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.
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&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
ISSUED AT 135 AM EDT WED MAY 22 2024

A challenging TAF forecast tonight, as uncertainty looms in the
latest model data. What is know is that a cold front will approach
the area from the northwest on Wednesday, and will eventually
stall out somewhere along the Ohio River. The coverage of showers
and storms we see today will depending largely on exactly where
the front sets up and activates. If the boundary moves further
southeast and sets up more directly over eastern Kentucky, the
TAF sites, and forecast area as a whole, will see more widespread
showers and storms. If, however, the boundary stalls out further
north and northwest, isolated to scattered activity is more likely
to occur. With so much uncertainty, decided to err on the side of
a little less shower and storm activity across our area today. We
will still see scattered showers and storms, and some of these
could at least move within the vicinity of any given airport, but
we will not go beyond that for now. Will continue to monitor
incoming model data and trends in the obs to determine if more
widespread rain should be forecast during the second half of the
TAF period. We should see southwest winds pick up late this
morning to around 10kts, with gusts of 15 to 20 kts possible at
times. SCT to BKN mid and high level clouds will stream in through
out the period, as cloud debris from approaching but decaying
thunderstorm cluster moves our way. It looks like, for now at
least that more widespread showers and storms may hold off until
near the end of the TAF period, as the cold front finally begins
to push our way again. In summary, VFR conditions should prevail,
but MVFR could occur if a shower or storm happens to directly
impact a TAF site.

&&

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

$$

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