JKL issues Area Forecast Discussion (AFD) at Jun 7, 5:25 AM EDT708
FXUS63 KJKL 070925
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
525 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.
&&
.SHORT TERM...(Today through Saturday)
Issued at 450 AM EDT FRI JUN 7 2024
08Z sfc analysis shows high pressure building into Kentucky from
the west in the wake of a cold front that passed through on
Thursday. This has now cleared out most of the clouds and brought
light and variable winds overnight. Drier and cooler air is also
noted this night from advection along with a decent bout of
radiational cooling underway. Accordingly, temperatures currently
vary from the mid 50s in the sheltered valleys to the low to mid
60s on the ridges and more open terrain. Meanwhile, dewpoints are
generally in the middle to upper 50s. The clearing skies and still
damp ground also allowed for fog to form in the river valleys and
become locally dense. This should start to clear out after 9 am.
The models, and their individual ensemble suites, are in good
agreement aloft through the short term portion of the forecast.
They all depict Kentucky between a cluster of 5h troughs to the
north and ridging along the Gulf Coast. This keeps the area in
northwest mid level flow through the start of the weekend. This
pattern will support a few impulses passing overhead into
Saturday. The early Saturday one appears to have the best chance
to be impactful and crosses the JKL CWA around midday. Despite
some model difference with that latter wave, the spread is small
enough that the NBM was used as the starting point for the short
term grids along with the incorporation of the CAMs' details for
PoPs on Saturday.
Sensible weather features a pleasant end to the week and start of
the weekend thanks to an area of high pressure working through the
area and keeping humidity lower than the past few days. Dry
weather will hold through Saturday morning with a small chance
for showers around into the afternoon, but limited instability for
thunder - as modeled at this point. It still looks like a storm
cluster develops to the northwest of eastern Kentucky later
tonight and propagates toward the area with the expectation that
it will basically die out before it reaches the JKL CWA by midday
Saturday. However, there is a small potential for it to hold
together or get a second wind so while thunder has been left out
for now the potential is non zero. Do also expect more in the way
of valley fog and a ridge to valley temperature split tonight
- again potentially mitigated should that anticipated storm
cluster hold together better and results in clouds pushed into the
area towards dawn.
The main adjustments to the NBM starting point consisted of
adjusting the NBM PoPs to include CAMs details for the shower
chances on Saturday. The temperatures from the NBM were adjusted
early this morning and again tonight to allow for more terrain
details.
.LONG TERM...(Saturday night through Thursday)
Issued at 525 AM EDT FRI JUN 7 2024
The 07/00z model suite begins the long-term in good synoptic
agreement. An ~592 dam subtropical high will be found along the
central Gulf Coast while multiple upper lows are found within a
trough extending from Maine/Atlantic Canada to the southern
Canadian prairies. Multiple disturbances will be passing through
the flow aloft between the troughing to our north and the ridging
to our south. Ahead of a more substantial disturbance, a weak
surface low is found over southern Illinois with a warm front
extending southeast into Middle Tennessee and a cold front
trailing back to the southwest into the Southern Plains.
Model agreement undergoes rapid degradation in the first 48 hours of
the long-term period. While there is good agreement that the surface
low and upper level disturbance to our west will pass through the
Ohio Valley on Sunday, there is uncertainty as to how the upper
level troughing to our north evolves as it tries to pivot
cyclonically and potentially shears apart leaving a closed low to
drift across the Ohio Valley during the early and mid-portions of
the week. If this low does form, as depicted in recent runs of
the 00z GFS, several days of wet weather can be anticipated for
many locations through mid-week. (Note: The GFS solution does
appear to be a minority solution based off of a cluster analysis.)
On the other hand, if the trough remains more open and
progressive, such as the 00z ECWMF/Canadian solutions, then a much
drier and warmer scenario is likely to unfold once the trough
axis crosses our area early in the week. Accordingly, chance to
likely PoPs (40 to 80% chance) are in the forecast for Sunday with
the initial low/frontal passage. Lower PoPs follow for Monday (30
to 40% chance) to account for the approach and/or passage of the
upper level trough axis/low. Thereafter, the NBM solution was
favored as it offers a compromise solution with just slight to low
chance PoPs to account for the potentially wetter but currently
less favored scenario. Daily forecast highs are only in the 70s
through Tuesday before trending back above normal late in the
week. Nighttime lows start in the lower to middle 60s on Saturday
night before retreating into the 50s for the remainder of the
forecast period. A few upper 40s cannot be ruled out in the most
sheltered valleys on Monday and Tuesday nights if skies clear.
&&
.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.
&&
$$
SHORT TERM...GREIF
LONG TERM...GEERTSON
AVIATION...CMC/GREIF
Source:
JKL issues Area Forecast Discussion (AFD) at Jun 7, 5:25 AM EDT---------------
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