JKL issues Area Forecast Discussion (AFD) at Jun 21, 6:29 AM EDT849
FXUS63 KJKL 211029
AFDJKL
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
629 AM EDT Sat Jun 21 2025
.KEY MESSAGES...
- Areas of dense fog expected again tonight in the deeper river
valleys and near bodies of water.
- Heat builds this weekend through the middle of next week. Heat
indices in the 100 to 105 degree range are forecast for many
locations from Sunday to Thursday.
&&
.UPDATE...
Issued at 1255 AM EDT SAT JUN 21 2025
Overnight forecast appears to be largely on track. Expect
widespread low temperatures in the lower to middle 60s with some
of the chilliest northeastern hollows perhaps dipping just below
60F. Still expect at least patchy/areas of fog to develop in the
river valleys and potentially becoming locally dense.
UPDATE Issued at 1026 PM EDT FRI JUN 20 2025
Forecast remains on track late this evening as temperatures fall
through the 70s for many and into the mid/upper 60s in more
sheltered valley locales.
UPDATE Issued at 800 PM EDT FRI JUN 20 2025
Temperatures are cooling into and through the 70s at mid-evening
update as wispy high clouds drift across the area. Only concern
through the overnight will be the potential for areas of dense fog
in the deeper river valleys and near larger sheltered bodies of
water.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 425 PM EDT FRI JUN 20 2025
20Z sfc analysis shows high pressure over eastern Kentucky. This
is making for a drier and more cloud-free day compared to those of
the last week. It is also keeping winds light from the south to
southwest. Plenty of sunshine has propelled temperatures to near
normal today with readings topping out in the lower 80s most
places. Meanwhile, dewpoints are in the more comfortable low to
mid 60s this afternoon compared to the past few days.
The models, and their individual ensemble suites, are in good
agreement aloft through the short term portion of the forecast.
They all depict one last minor mid level wave passing by to the
northeast of the area this evening before strong 5h ridging starts
to build over the region. This ridging, currently centered over
the Deep South, will build northeast and overhead for Kentucky in
earnest on Saturday while shunting the mid level flow of any
impulses north of the Ohio Valley. This strengthening 5h ridge
will then dominate the weather for eastern Kentucky through the
rest of the weekend and into the new work week. The small model
spread through Saturday night supported using the NBM as the
starting point for the forecast grids with minimal adjustments
needed - mainly just to add some terrain details for temperatures
each night owing to a good setup for ridge to valley differences.
Sensible weather features a cooler night than last night for most
valley locations, before the heatwave starts to establish itself
over the region this weekend and beyond. We again will likely see
some locally dense fog in the valleys by midnight continuing
through dawn. Warmer temperatures push toward 90 degrees for many
locations on Saturday under mostly sunny skies. Similarly,
Saturday night will be mild with a small to moderate ridge to
valley temperature difference through the night along with the
potential for river valley fog continuing - again locally dense.
The changes to the NBM starting point were primarily focused on
temperatures each night per our more typical terrain differences
under high pressure - also lowered dewpoints a tad in the
afternoon. PoPs and Wx were quiet in the NBM and kept that way
through the short term portion of the forecast.
.LONG TERM...(Sunday through Friday)
Issued at 335 PM EDT FRI JUN 20 2025
A near 596 dm 500 mb ridge is expected to be centered over the OH
Valley to TN Valley and Appalachians to mid Atlantic states as
the period begins, while an upper level trough should extend
across much of the western Conus. At the surface a frontal zone
should extend from the Northeast to the Northern Great Lakes to a
sfc low in in the SD vicinity with the front continuing west
southwest into the Southwest Conus. Meanwhile another frontal
zone is expected to extend from Quebec across portion to near the
US/Canadian border from MN west. A Sfc high pressure pressure
ridge should be centered over the Southern Appalachians.
Sunday to Sunday night, the 500 mb ridge is expected to strengthen
a bit and become centered over the Mid Atlantic states by late
Sunday night with the axis extending west across the OH Valley to
TX. Meanwhile an upper level low within troughing over the
western Conus should become an open wave and move around the upper
level ridge across the Northern Rockies and MT and portions of
the Northern Plains to Saskatchewan and Manitoba while the axis
of an upper level trough remains across the western Conus. At the
surface, the high pressure ridge should remain centered over the
Southern Appalachian region as return moisture beings to move
north from the Gulf States into parts of the MS Valley and into
the TN Valley and the Lower OH Valley. Meanwhile. the two frontal
zones to the north should more or less consolidate with sfc low
reaching the Lake Huron vicinity late Sunday night with the
trailing frontal zone into the Central Plains to western Conus.
This pattern will remain conducive for a continued warming trend
with initially valley fog Sunday dissipating and valley fog
favored to develop near the larger creeks, rivers, and lakes for
Sunday night. Highs should peak in the 90s for locations below
2500 feet on Sunday with relief at night beginning to decrease on
Sunday night with upper 60s to near 70 valleys and low 70s
elsewhere. Heat indices on Sunday should near the 100 degree mark
in some areas. If the temperature reaches 90 degrees or higher as
forecast at JKL on Sunday, it would be the first occurrence of 90+
at JKL so far this calendar year.
From Monday to midweek, upper level ridging is expected to remain
centered near the Mid Atlantic states Monday to Tuesday extending
into the TN and OH Valleys and the mid MS Valley before gradually
becoming centered further southwest into the Southern Appalachians
to OH and TN Valleys by Wednesday weakening a bit at that point.
As this occurs the ridge should become increasingly flatter or
elongated from west to east as multiple shortwaves move from the
western Conus trough and across portions of the Central to
Northern Plains to the Great Lakes and Ontario and Quebec with
additional shortwaves also moving east near the US/Canadian border
in the primary band of westerlies. The ridge should remain in
place over the eastern Conus through the end of the long term
period while the upper level troughing initially over the western
Conus may migrate to the Central Plains. OH Valley and eastern KY
will remain well south of a frontal zone from the Northeast to the
Great Lakes vicinity to the Plains and well into the warm sector
through the end of the long term period as sfc high pressure
remains centered over the Southern Appalachians but also weakens.
Temperatures should warm a bit each day from Monday to Wednesday
into the low to mid 90s and remain near that level into Thursday
into Friday, with perhaps a few upper 90s for highs Tuesday or
Wednesday in some lower elevation spots such as Big Sandy Valley
cities. Lows gradually warm was well, especially valleys and
mainly in the 70s by Tuesday night if not Monday night. Heat
remains the main concern in the long term period and the next 7
days for that matter. Messaging has been increased in the HWO and
social media with an SPS also sent. One or more of the days from
Monday to Wednesday, especially Tuesday to Wednesday may near or
reach heat advisory criteria in portions of the region.
Experimental Heat Risk suggests rather anomalous heat for late
June/early Summer.
Some diurnally driven isolated convection could affect the TN
Cumberland Plateau to the KY/VA/TN Tri State Area portions of the
Cumberland Basin as early as Wednesday though isolated to perhaps
scattered convection will be more probable by Thursday to Friday
with differential heating possibly providing a trigger and with
the ridging gradually weakening and eventually becoming centered
further from eastern KY a bit less capping is anticipated.
&&
.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
ISSUED AT 626 AM EDT SAT JUN 21 2025
There is some radiation fog in the valleys of eastern Kentucky to
start the TAF period, but no fog impacts at any TAF sites. Fog
will lift and dissipate after sunrise this morning. Winds will be
light (<5 kts) and generally variable, with some transient
scattered high clouds dotting otherwise clear VFR skies.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...GEERTSON
SHORT TERM...GREIF
LONG TERM...JP
AVIATION...CAMDEN/SGF
Source:
JKL issues Area Forecast Discussion (AFD) at Jun 21, 6:29 AM EDT---------------
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