292
FXUS63 KJKL 062044
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
444 PM EDT Thu Jun 6 2024

.KEY MESSAGES...

- Isolated showers or sprinkles are anticipated through this
  evening ahead of a secondary cold front.

- Cooler and noticeably less humid air will arrive behind this
  cold front and reside over the area Friday and into Saturday.

- A rapid succession of more frontal boundaries will keep a
  potential for showers or thunderstorms in the forecast at times
  next week.

&&

.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...(Friday night through Wednesday)
Issued at 436 AM EDT THU JUN 6 2024

The 06/00z model suite begins the long-term period in good synoptic
agreement, leading to a high confidence forecast through the
upcoming weekend, before increasing model spread results in lower
forecast confidence heading into the new work week. Initially,
500H ridging will be solidly in place over northern Mexico and the
Southern Plains. Meanwhile two sub-550 dam lows lie in a
northwest-southeast oriented trough from the Upper Mackenzie
Valley to Lower Great Lakes. Subtle disturbances aloft are riding
through the northwest flow over the Central Plains between the
ridging further south and the troughing further north. At the
surface, a developing wave of low pressure is found over the
Dakotas with a trailing cold front across the northern Rockies,
while high pressure is meanders east of the 500H ridge across the
Lower Ohio/Tennessee and Mississippi river valleys.

The surface high pressure will shift east, cresting over the
Central/Southern Appalachians late Friday night. As that high
continues to press east on Saturday, focus will turn toward the weak
low pressure passing through the Southern Great Lakes and dragging a
cold front into the Ohio Valley. Meanwhile, the more easterly
upper level low (over Quebec) will elongate and rotate toward the
Ohio Valley, shoving the cold front south of the Commonwealth and
allowing cool Canadian air to pour across eastern Kentucky on
Sunday night and Monday. Height rises return Monday night and
Tuesday as the trough axis shifts to our east and high pressure
passes over the Ohio Valley/Central Appalachians. The second upper
level low and/or an associated trough may then impact eastern
Kentucky during the middle of next week but the specifics are
uncertain due to significant model spread.

Sensible weather will feature fair conditions through Saturday along
with seasonably cool temperatures. Morning low temperatures are
forecast to range from the lower to mid 50s while afternoon highs
top out in the mid 70s to lower 80s. A few of the coldest
northeastern valleys could briefly dip into the upper 40s early
Saturday morning. Shower chances rise again Saturday night as the
cold front drops into the Ohio Valley and peak ~40 to 60 PoP as
that cold front passes over eastern Kentucky on Sunday. A weak
thunderstorm cannot be ruled out ahead of or along the front.
Behind that front, diurnally-driven showers (20-30 PoP) are again
expected to bubble up on Monday, along with a possible rumble of
thunder. After one more day with highs in the mid to upper 70s on
Sunday, Monday`s maximum temperatures will be noticeably cooler,
primarily in the lower to middle 70s. A few of the cooler locales
may fail to even reach 70. A downright chilly night for mid-June
is in store for Monday night, likely deep into the lower and
middle 50s for most locations and perhaps even in the 40s through
the more sheltered valleys and hollows. (Normal highs for June
11th at the lower elevations range from ~79 to 83 while normal
lows range from 56 to 64.) Once the high pressure crests overhead,
winds will turn southerly on Tuesday leading to a quick warming
trend -- high temperatures return to the 80s by Wednesday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Friday afternoon)
ISSUED AT 210 PM EDT THU JUN 6 2024

Mainly VFR was observed across the region at issuance time with
some MFR near the VA border and likely some brief VFR reductions
were occurring in isolated light showers located generally
southeast of the TAF sites. A secondary cold front may lead to
additional isolated showers generally after 20Z moving from
northwest to southeast through about 03Z. Some very localized
brief reductions to MVFR cannot be completely ruled out in these.
Otherwise, VFR should generally prevail to end the period,
although some valley fog between 06Z to 13Z could lead to MVFR or
perhaps lower visibility. Winds will average west to northwest at
10KT or less through the period.

&&

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

$$

SHORT TERM...JP
LONG TERM...GEERTSON
AVIATION...JP