894
FXUS63 KJKL 110840
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
440 AM EDT Thu Jul 11 2024

.KEY MESSAGES...

- Seasonable temperatures, but relatively less humid weather will
  continue today.

- Hotter conditions make a comeback as we move into the weekend
  and for next week.

- The next significant chance of rain will hold off until the
  middle of next week.

&&

.SHORT TERM...(Today through Friday)
Issued at 440 AM EDT THU JUL 11 2024

08Z sfc analysis shows a pleasant area of high pressure over
eastern Kentucky early this morning. This is keeping skies mostly
clear and the winds light. This allowed for some radiational
cooling through the night making for a small ridge to valley
temperature split. Accordingly, temperatures currently vary from
near 60 in the sheltered low spots while the hills, and more open
areas, are running in the mid 60s. These conditions have also
led to the formation of fog in the valleys with some locally
dense patches around. The fog will start to clear out by 13Z.

The models, and their individual ensemble suites, are in
excellent agreement aloft through the bulk of the short term
portion of the forecast. They all depict general troughing through
the Great Lakes and Ohio Valley to close out the work week. This
pattern is fairly stable as it is downstream from a persistent
large ridge over the Desert Southwest. Within this eastern trough
several impulse will strafe northern parts of the state through
the short term portion of the forecast. There is some model
spread, including in the CAMS, with a wave that passes by north
of the JKL CWA on Friday afternoon. Overall, the consensus is that
this will not impact the area south of the Ohio River, but trends
with this feature will need to be watched with future model runs.
Given the overall limited model spread have gone with the NBM as
the starting point for the forecast grids.

Sensible weather features a more seasonable day of weather today
than yesterday as the summertime temperatures and some humidity
return to the area. High pressure will keep conditions dry into
tonight with another small ridge to valley temperature split and
development of valley fog into Friday morning. For Friday proper,
the heat builds further with highs on the warm side of normal
along with increased humidity. Currently, the forecast is for dry
conditions on Friday, but we will need to watch for potential
incursions from more active weather to the northwest of eastern
Kentucky. For now, though, have kept the forecast dry but
confidence is not as high as it is for dry conditions today. As it
stands, most would welcome such incursions bringing needed rain
and some cooling.

The main changes to the NBM starting point consisted of adjusting
the temperatures to better account for more terrain details
tonight into Friday morning. PoPs were kept in the single digits
from the NBM through the period, though with the caveats outlined
above.

.LONG TERM...(Friday night through Wednesday)
Issued at 357 AM EDT THU JUL 11 2024

Pattern aloft suggests a relatively quiet (uneventful) forecast
for our area. We start the extended with mean ridging across the
western CONUS and a mean trough over the east. Core of westerlies
generally remains along the Northern Tier, or just south, with
wind fields that are seasonably weak, particularly at the start of
the extended. Shortwave energy eventually slides southward from
northern Canada and strengthen winds fields along the Northern
Tier, resulting in a general weakening of the western ridge, along
with a flattening of the ridge eastward as the mean trough in the
east fills and lifts northward. The end result is predominant
zonal flow pattern aloft with the Commonwealth just south of the
track of most shortwave energy. Pattern does amplify just a bit at
the end of the forecast window, as shortwave energy carves out a
trough over the Upper Midwest, which begins to impact the Ohio
Valley at the very end of the forecast window, or just beyond. At
the surface, high pressure remains over the Ohio Valley until the
end of the period, when it succumbs to a surface cold front
dropping southeastward into the Midwest by Wednesday.

Sensible weather features seasonably warm and humid weather
through the extended...or very typical summertime conditions. The
less amplified pattern aloft, a mean westerly (versus southerly)
synoptic wind or flow, and weaker ridging across the region, will
tend to keep afternoon surface dew points in the 60s (versus mid
to upper 70s) through much of the extended. While this will still
result in muggy weather, but it should not feel quite as
oppressive as we have occasionally experienced over the past
several weeks. Wednesday could be the exception as moisture is
drawn northward into the Ohio Valley ahead of an approaching cold
front. Heat indices will still climb to around the 100 degree mark
each afternoon from Monday through Wednesday, though suspect the
NBM afternoon maximum temperature guidance is a bit too high. This
has been the case in the majority of cases over the past several
weeks.

The potential for rain (showers and thunderstorms) will be
limited to those times where northern stream energy manages to dig
far enough south to impact eastern Kentucky. That would be mainly
our northern zones for Sunday and late Monday, and then all of
eastern Kentucky Tuesday and Wednesday afternoon and evening. PoPs
will be low (20%) across the north Sunday and Monday evening, and
20- 30% for most of the area Tuesday afternoon into Tuesday
evening. Our highest PoPs (up to 50%) during the period will be
realized by Wednesday afternoon as the aforementioned trough drops
southeastward into the Upper Midwest and its associated cold
front moves into the Midwest proper.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
ISSUED AT 150 AM EDT THU JUL 11 2024

Mostly clear skies coupled with ample low level moisture will
lead to fog development in the valleys into the morning. The
coverage of this fog remains somewhat in question with the
national blend of models showing only around a 30-40 percent
chance of visibilities below 5 miles. However, given the added
moisture from the recent rainfall and the cool temperatures seen
on Wednesday would suspect at least some fog to develop in river
valley locations. Accordingly have continued MVFR to IFR fog at
most of the TAF sites later this early morning via a TEMPO group,
with lowest vis sites being SME and LOZ. This fog will disperse
as we mix out toward the 13Z timeframe. This will leave us with
VFR CIGs and visibility for the remainder of the period along with
light and variable winds.

&&

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

$$

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