JKL issues Area Forecast Discussion (AFD) at Sep 13, 8:40 PM EDT342
FXUS63 KJKL 140040 AAA
AFDJKL
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
840 PM EDT Fri Sep 13 2024
.KEY MESSAGES...
- Showers rotating around the upper level remnants of hurricane
Francine will dissipate over our area this evening.
- High pressure nudges into our area from the northeast later
tonight, with fair weather lasting into Monday.
&&
.UPDATE...
Issued at 840 PM EDT FRI SEP 13 2024
00Z sfc analysis shows eastern Kentucky between the sfc low
associated with Francine's remnants to the southwest and high
pressure to the north. This continues the easterly flow of air at
low levels over the area with a downslope component. this is
keeping much of the JKL area dry while a lingering band of light
rain is weakening in the north and a few more sfc based showers
are also mostly fading out in the far south. Under variable
clouds, temperatures are generally in the lower to middle 70s
while dewpoints vary from the lower 60s northeast to the upper 60s
in the southwest. Have updated the PoPs per the latest radar
tendencies and CAMs guidance into the night. Did also include the
current obs and trends for the T/Td/Sky grids with this update.
These minor adjustments have been sent to the NDFD and web
servers.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 430 PM EDT FRI SEP 13 2024
A remnant upper level low from dissipated Hurricane Francine is
near Memphis late today. A leading band of moisture rotating
around it is over our northern counties, resulting in light
showers from elevated moisture. Further south, drier air aloft
has allowed for more sunshine/destabilization and led to isolated
surface based showers developing. Won't rule out a thunderstorm
in our southern counties for a short time yet late today. Will
look for southern activity to die out with loss of heating.
Models indicate northern precip will also dissipate, but being
that models have underdone this precip, suspect it will be a
slower process than what models indicate.
Once we are dry later this evening, it should last through
Saturday night as high pressure at all levels nudges in from the
northeast. Greater sunshine on Saturday should allow for somewhat
warmer temperatures. Although it looks like some surface based
instability will develop on Saturday, dry air aloft and a lack of
strong features will tend to inhibit deep convection, and sub-20
POPs were used as suggested by the latest guidance.
.LONG TERM...(Sunday through Friday)
Issued at 430 PM EDT FRI SEP 13 2024
The remnants of Francine will continue to influence the sensible
weather here in Eastern Kentucky through the long term forecast
period, albeit in a much drier manner. The upper level ridge that
blocked Francine's northward progression will strengthen and expand
in the coming days. As it does so, drier air will filter into the
area, and the moisture associated with the remnant low will be
shunted further south to the Gulf Coast states. Together, these two
features create a Rex Block over the Eastern CONUS. This block
persists from Sunday to early Tuesday morning. Here in Eastern
Kentucky, we will generally be on the drier side of things. Under
the influence of the ridge component, most of the area will see
minimal Pops and partly cloudy skies on Sunday, Monday, and early
Tuesday. It is worth mentioning that there is a slight chance of
rain in southwestern portions of the forecast area on Sunday and
Monday afternoons, where daytime heating and proximity to moisture
could yield a few showers. Most of this activity should remain
southwest of the forecast area, however. Nocturnal ridge-valley
temperature splits will be mitigated due amidst the cloud coverage.
Expect afternoon highs near 80 degrees and overnight lows in the
upper 50s through the first half of the long term forecast period as
a result.
For Tuesday evening and beyond, there is more uncertainty in the
forecast. Deterministic model guidance continues to diverge on how a
developing low pressure system off the Carolina coast interacts with
the southern half of this Rex Block feature. The GFS continues to be
far more aggressive than its European counterpart on the strength of
the developing low and thus with how far northwest it progresses
into the Appalachian Mountains. This more aggressive solution would
yield in more widespread rain chances as a merging and evolving
upper level low retrogrades into the Ohio River Valley, with
stronger winds pulling more moisture into the area around its
backside and off the Atlantic. This is not climatologically
conventional, and the European model solution resolves a much weaker
and broader upper level low centered on the other side of the
mountains. Probabilistic forecast guidance suggests that the latter,
less aggressive solution is more likely, and the forecast reflects
this.
Low, slight chance PoPs are in the grids for the eastern tier
counties in the second half of next week. Chances peak just below
25% each afternoon in places like Pike, Harlan, Letcher, and Martin
Counties on Tuesday, Wednesday, and Thursday afternoons. These
listed counties are where diurnal heating processes may work with
slightly more favorable moisture parameters and lift (both
orographically forced and dynamic) to squeeze out a few showers.
Given that an upper level low looks to become the dominant weather
feature late next week regardless of the exact evolution of the
aforementioned (post/sub)tropical lows, afternoon high temperatures
will subtly cool down into the upper 70s late next week in Eastern
Kentucky. Overnight lows will remain in the 50s, and areas further
west may return to our conventional ridge-valley splits where cloud
coverage will be lesser.
As higher-resolution forecast guidance comes into perspective and
the exact positioning/strength of the Carolina disturbance is
clarified, confidence in the second half of the long term forecast
will improve. For now, we encourage interested parties to stay tuned
to future forecast updates.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 815 PM EDT FRI SEP 13 2024
a few showers are still affecting some locations at the start of
the period, but were generally light and not resulting in
restrictions. However, isolated sub-VFR conditions in the heavier
showers (or possibly a thunderstorm) can't be ruled out over the
next hour or so before the convection fades out leaving dry
weather for the remainder of the period. Some patchy valley fog
will probably bring MVFR or localized IFR late tonight into early
Saturday, but probably wont affect any TAF sites. Winds will
generally be from the east at 10 kts or less through the period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...HAL
LONG TERM...MARCUS
AVIATION...HAL/GREIF
Source:
JKL issues Area Forecast Discussion (AFD) at Sep 13, 8:40 PM EDT---------------
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