JKL issues Area Forecast Discussion (AFD) at May 4, 8:00 AM EDT
673
FXUS63 KJKL 041200
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
800 AM EDT Sun May 4 2025
.KEY MESSAGES...
- The periodic potential for showers and thunderstorms continues
through the next week.
- Near normal to below normal temperatures will envelop eastern
Kentucky through most of the next week.
&&
.UPDATE...
Issued at 800 AM EDT SUN MAY 4 2025
Showers continue to pinwheel around an upper level low centered
near/over the Bowling Green and Glasgow areas this morning.
Scattered to numerous showers are noted on regional radar along
the western and northern sides of the low. Activity is much more
sparse along the southern and eastern sides of the low due to dry
slotting. However, expect that showers will increase in coverage
later this morning into the afternoon as the upper low drifts
closer and daytime heating leads to weak surface-based
instability.
UPDATE Issued at 1155 PM EDT SAT MAY 3 2025
No significant changes were made to the forecast with mainly just
the inclusion of the latest obs and trends for the T/Td/Sky grids.
Did also fine tune the PoPs and fog overnight along with taking
out the thunder chances. These adjustments have been sent to the
NDFD and web servers along with a freshening of the zones, SAFs,
and HWO.
UPDATE Issued at 730 PM EDT SAT MAY 3 2025
23Z sfc analysis shows a large area of low pressure holding over
Kentucky beneath an approaching stacked upper low. This is
keeping showers in the weather picture this evening with the main
band, and best chance for thunder, pressing deeper into the far
eastern parts of the state. Currently temperatures and dewpoints
are fairly uniform in the mid to upper 50s - though in the low 60s
in the far east ahead of the lower clouds and steadier rains.
Meanwhile, winds are generally light and variable away from any of
the more robust showers. Have updated the forecast mainly to add
in the latest obs and trends for the T/Td/Sky grids. Did also fine
tune the PoPs and fog potential through the night per the radar
and CAMs tendencies. These adjustments have been sent to the NDFD
and web servers.
&&
.SHORT TERM...(This evening through Sunday night)
Issued at 418 PM EDT SAT MAY 3 2025
A cloudy and damp Derby Day afternoon is unfolding across eastern
Kentucky. Temperatures range in the 60s across most of the forecast
area under overcast skies and a few light showers. The rain is now
coming down more steadily though west of a Morehead to Stanton to
London line as a precipitation band with embedded thunder makes
painfully slow eastward progress. This band of rain is associated
with a cold front trailing WSW from an ~1005 mb surface low over
Carlisle, KY through Irvine, Whitley City and beyond. This area of
low pressure is forced by an upper low presently closing off over
St. Louis, MO.
The upper low will continue to deepen and shift southeastward ever
so slowly this evening and tonight, likely reaching peak intensity
over the Nashville/Bowling Green area toward sunrise on Sunday. In
response, the surface low will drift into southeast Ohio while
its cold front (and band of frontal precipitation) gradually
pivots counterclockwise through the rest of eastern Kentucky this
evening and exits into the Central/Southern Appalachians
overnight. A mid/upper level dry slot wraps around the southern
side of the upper low late tonight, but abundant low-level
moisture and the proximity of the upper low leaves any sustained
clearing doubtful. If any brief breaks in the clouds do occur,
locations further from the approaching upper level low (near the
Virginia border) have the greatest opportunity. In general, expect
leftover showers yielding low stratus and patchy fog overnight.
Slightly greater fog extent is possible in valleys, should they
experience brief clearing. Temperatures will turn cooler, settling
into the lower 50s for most locations by daybreak.
The cold core upper low waffles northeastward to nearly over
Lexington, KY by Sunday afternoon. Enough thinning of the low clouds
is possible over southeastern Kentucky for temperatures to recover
into the 60s before rising instability causes clouds to fill back
in as showers and possibly even a few thunderstorms bubble up.
Closer to the low, especially west of I-75 and north of I-64,
clouds and showers are likely to be more prevalent, keeping a lid
on temperatures (perhaps remaining in the 50s). Models are in
relatively good agreement showing the 500H upper low gradually
wobbling back to the west on Sunday night. However, the core of
the coldest 850H temperatures nearing 2C or colder will be
pivoting around the southern periphery of the low and into eastern
Kentucky along with a nearly saturated profile up to 500 mb. This
will likely keep clouds, isolated light showers, and patchy
drizzle across the area overnight. Temperatures will also be
rather chilly, settling into the mid 40s for most of the area
except upper 40s over the Big Sandy basin.
.LONG TERM...(Monday through Saturday)
Issued at 515 PM EDT SAT MAY 3 2025
The long-term period will open with a blocky large-scale weather
pattern over the CONUS. The 03/12z model suite is in good agreement
on Monday morning showing an ~553 dam cutoff low centered over
Kentucky while a decaying omega-type blocking ridge extends
northward through the Plains, Upper Great Lakes, and into adjacent
portions of Canada. A second ~554 dam low is centered over the
Desert Southwest. To the north, a positively-tilted trough
extends from an ~507 dam low over northern Baffin Island southwest
to over the Northern Rockies.
The first upper low over the Commonwealth will drift back to the
northeast on Monday across the Bluegrass, and toward the Upper
Ohio Valley on Monday night. Guidance shows the northern stream
trough sweeping through southern Canada, squashing the blocking
ridge sufficiently to recapture this cutoff low by mid-week.
However, there is substantial spread with regard to how quickly
this might occur (Tuesday night-Wednesday night). Meanwhile, the
closed low over the Desert Southwest will become trapped south of
a developing rex-block ridge extending into the Northern Plains.
Consequently, the closed low will drift toward Missouri while an
associated warm front begins lifting northward toward the
Tennessee Valley. At the same time, potent energy dropping out of
the Arctic will cause the troughing over over eastern Canada to
dig deeply over New England and potentially close off into a
another cutoff low. This would send another cold front diving
southward on the western side of the low. By this time, there is
large spread in the solutions as to where the northeastern cutoff
low might be. Model agreement is slightly better with the western
cutoff low to our west, favoring an unphased solution where the
low dives southward into the Lower Mississippi Valley by late in
the week.
Sensible weather through the period will be strongly dependent upon
the evolution of this convoluted, blocky upper level pattern.
Forecast confidence is high that Monday will be a cool, mostly
cloudy, and showery day with maximum temperatures hard-pressed to
reach 60F in many locales. As the first upper low starts to drift
away, the possibility for some clearer skies grows during the
Monday night to Tuesday timeframe. This would allow for some
modest ridge- valley temperature splits at night with lows in the
40s and mild afternoon readings in the 60s to near 70F. Rain
chances are likely to become more confined to northeastern
Kentucky before ending entirely. Clouds and shower chances are
favored to increase again from the southwest during late Tuesday
night to Wednesday night timeframe and persist at least until the
passage of cold front late in the week. The deterministic NBM
favors temperatures reaching their zenith of the work week on
Thursday with widespread highs in the lower to middle 70s.
&&
.AVIATION...(For the 12Z TAFS through 12Z Monday morning)
ISSUED AT 700 AM EDT SUN MAY 4 2025
Confidence is high that MVFR (brief IFR) ceilings will continue
through about 18z with some scattered showers at the sites. Some
improvement to VFR ceilings is briefly expected for the afternoon
hours however there will be continued chances for scattered
showers and a few isolated thunderstorms. Confidence is low in the
coverage of thunderstorms as they could remain just north of the
sites and have included VCTS at a few sites. Winds will generally
be light from the southwest at 5 to 10 kts through the day - away
from any low probability thunderstorm. Ceilings and vis are likely
to drop back into IFR after 06z, especially at JKL and SJS where
thicker fog may develop closer to 12z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...GEERTSON
SHORT TERM...GEERTSON
LONG TERM...GEERTSON
AVIATION...WFO SGF
Source: JKL issues Area Forecast Discussion (AFD) at May 4, 8:00 AM EDT (https://mesonet.agron.iastate.edu/p.php?pid=202505041200-KJKL-FXUS63-AFDJKL)
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