485
FXUS63 KJKL 070545 AAA
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
145 AM EDT Fri Jun 7 2024

.KEY MESSAGES...

- Cooler and noticeably less humid air is expected to reside over
  the area today into Saturday.

- The next passing cold front will bring increasing rain chances
  to eastern Kentucky Saturday night into Sunday.

- Cooler air will be reinforced across the region early next
  week, before temperatures modify back to above normal by the end
  of the period.

&&

.UPDATE...
Issued at 130 AM EDT FRI JUN 7 2024

Just a quick update to the forecast through dawn mainly to add in
the latest obs and trends for the T/Td/Sky grids in addition to
beefing up fog in the river valleys. These minor adjustments have
been sent to the NDFD and web servers along with a freshening of
the zones and SAFs.

UPDATE Issued at 1101 PM EDT THU JUN 6 2024

Removed all mention of sprinkles and showers from the forecast for
the remainder of this evening. Otherwise, the forecast is on track
with the only other modifications being to blend in latest
observations to the forecast for the next couple of hours.

UPDATE Issued at 632 PM EDT THU JUN 6 2024

Modified slight chance (~15) PoPs for the near-term next few
hours to accommodate latest observed trends based on satellite and
radar. Otherwise, the forecast is on track with no significant
changes.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 438 PM EDT THU JUN 6 2024

Late this afternoon, an enlongated upper level low/trough
extended from Alberta and Saskatchewan to the northern Great Lakes
with a 500 mb trough axis extending south to the Lower OH Valley
and into the Southeastern Conus. A weak impulse/shortwave is
moving through the OH Valley ahead of this trough axis. Meanwhile
an upper level ridge extended from northern Mexico north through
the Rockies. Further northwest, a shortwave trough was moving into
BC and the Northwest. At the surface, an area of low pressure was
over Ontario with the frontal zone trailing into the Lower OH
Valley to the Southern Plains. A ridge of sfc high pressure
extended through the Central to the Northern Plains.

This evening and tonight, the lead weak shortwave/impulse will
move from the OH Valley to the mid Atlantic states as the 500 mb
trough axis also approaches from the west. At the same time, the
enlongated upper low/trough will trend to two closed upper lows
one centered over the northern Great Lakes/Ontario and another
centered over Saskatchewan. The 500 mb trough axis will move east
of eastern KY late tonight to early on Friday. The associated
frontal zone will will move across the Commonwealth as well. Mid
level capping has kept upstream activity and cumulus rather
shallow. However, there are some upstream returns. Some sprinkles
or light showers will be possible with the boundary and the
shortwave trough moving through the area through this evening.
Clear or clearing skies and slackening winds despite drier air
advecting into the region will probably set the stage for at least
some patchy valley fog late tonight following recent wet weather.

Sfc high pressure will build into the mid to Lower MS Valley as
well as the southeast and OH Valley behind the boundary late
tonight and through Friday combined with mid level height rises in
the OH Valley. Following any early day valley fog, sunny or mostly
skies are expected with a few passing cirrus and the potential for
a few shallow cumulus developing during peak heating cannot be
ruled out. The cooler and drier airmass ushered into the region
will lead to highs about 3 to 5 degrees below normal. High
pressure will continue working across the area on Friday night
along with the mid level ridge as the next shortwave/system the
one now near the BC coast and Pacific Northwest having moved near
the US/Canadian border and then southeast into the Central Conus.
A ridge/valley temperature split will be favored across the area,
especially south and southeast for Friday night and valley fog at
least along the largest creeks, ares rivers, and lakes is
favored.

.LONG TERM...(Saturday through Thursday)
Issued at 530 PM EDT THU JUN 6 2024

At the start of the weekend, an elongated east to west trough,
with several embedded vorticity maxima/closed lows, will be stretched
from southeastern Quebec/northern New England to southern Alberta,
while a subtropical ridge is centered across the north central
Gulf of Mexico. Troughing will pivot southeast through the end of
the week, reinforcing lower 500 mb heights across the Ohio and
Tennessee valleys, with a passing surface cold front to bring
increasing rain chances to eastern Kentucky Saturday night through
Sunday. PoPs will peak in the likely range (40-70%) Sunday
afternoon. Troughing will remain in place the majority of the
time east of the Mississippi River through mid-week, although
model agreement and smaller scale feature prediction becomes
increasingly problematic with time. As such, have maintained at
least a small chance of mainly diurnally-driven PoPs in place
over the Ohio Valley each day, very close to the offered blended
guidance.

Temperatures will average below normal through Tuesday, with
highs mainly in the 70s and lows in the 50s. Monday looks to be
the coolest day overall, with highs in the low to mid 70s, and
overnight lows in the lower 50s, with some upper 40s not out of
the question in the typically colder valley locations. Stronger
ridging building in over the central CONUS, will then spread
increasing 500 mb heights over the Tennessee and Ohio Valleys
Wednesday and especially Thursday, with highs returning to the
80s, and lows mainly back in the 60s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 145 AM EDT FRI JUN 7 2024

VFR conditions will hold through the TAF period, while fog will be
confined to the river valleys. Winds will average west to
northwest at 10 kts or less during the day and light and variable
at night.

&&

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

$$

UPDATE...GREIF
SHORT TERM...JP
LONG TERM...GEOGERIAN
AVIATION...CMC/GREIF