625
FXUS63 KJKL 030655
AFDJKL

AREA FORECAST DISCUSSION
National Weather Service Jackson KY
255 AM EDT Wed Jul 3 2024

.KEY MESSAGES...

- Warm and humid weather continues for Wednesday to Friday and
  afternoon heat indices may reach near 100 in some locations
  Wednesday through Friday.

- Dry weather lasts into early Wednesday afternoon, then the
  potential for showers and thunderstorms returns and lingers into
  the weekend.

- The highest probability of rain is on Thursday and Friday and a
  few thunderstorms could produce strong to damaging wind gusts.

&&

.UPDATE...
Issued at 1140 PM EDT TUE JUL 2 2024

No significant changes to the forecast other than the inclusion
of the latest obs and trends for the T/Td/Sky grids. These minor
adjustments have been sent to the NDFD and web servers along with
a freshening of the zones and SAFs.

UPDATE Issued at 745 PM EDT TUE JUL 2 2024

23Z sfc analysis shows our cool and comfortable Canadian high
pressure area from yesterday now well off to the east of the
area. This made for a warmer and much more humid day across
eastern Kentucky. Southerly winds of 5 to 10 mph, with occasional
higher gusts, contributed to the rise in temperatures and higher
dewpoints this afternoon under mostly sunny skies. After peaking
in the mid to upper 80s earlier, temperatures are starting to fall
back to the upper 70s and lower 80s currently. Meanwhile,
dewpoints are staying up across the board - in the upper 60s to
lower 70s most places. The current forecast is on track for a
small to moderate ridge and valley temperature split along with
patchy valley fog developing after midnight. Accordingly, have
mainly just added in the latest obs and trends for the T/Td/Sky
grids. These minor adjustments have been sent to the NDFD and web
servers.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 450 PM EDT TUE JUL 2 2024

Late this afternoon, an upper level ridge of high pressure was
centered over the lower MS Valley into the Southeast and extended
across much of the eastern Conus as well. The axis of this upper
ridge is currently west of eastern KY, but return flow in the
lower levels as ushered warmer and more moist air back into the
region. PW is currently analyzed in the 1.2 the 1.6 inch range
with the lower values in the north and east and the higher values
near Lake Cumberland. Dewpoints have risen about 10 to 20 degrees
compared to 24 hours ago while temperatures are on average about
10 degrees warmer as well. With the increase in moisture rather
extensive, but shallow cumulus has developed across the region
with some cirrus passing overhead at times as well. Meanwhile an
upper level low was centered near the Manitoba and Ontario border
with an associated upper level trough south across the Northern
Plains and into parts of the southwest Conus.

Tonight and Wednesday, the axis of the upper level ridge will
shift east across the OH valley region including eastern KY this
evening and then east of the area overnight. Upper level ridging
will remain anchored over the southeastern Conus to the eastern
seaboard. At the same time, the upper level low is expected to
move toward Hudson and James Bay and begin to merge with a deeper
upper low and trough over Southern Canada. A shortwave trough
should move across the upper MS Valley to western Great Lakes
tonight and then across the eastern Great Lakes and into Quebec.
Another shortwave trough moving around ridging in the eastern
Pacific should emerge from the Rockies and into the Plains through
Wednesday afternoon and evening. This shortwave trough should
advance east and reach the mid MS to Lower OH Valley through the
end of the period. Meanwhile, at the surface, a frontal zone
preceding the shortwave trough should reach the Great Lakes
tonight reaching western Quebec to the eastern Great Lakes to the
mid MS Valley to the Southern Plains becoming stationary or nearly
stationary on the southern end. As the upper trough approaches
the boundary should sag to near the OH Valley to end the period.

Dry weather should persist through tonight to midday on Wednesday
as the dominance of ridging begins to dwindle. Further warming
along with an increase in moisture should continue in southwest
flow between departing sfc high pressure and a front beginning to
approach. PW is forecast to climb to to the 1.4 inch southeast to
1.8 inch range west and northwest by Wednesday evening and then
to about 1.8 to 2.2 inch range from southeast to northwest to end
the period. Afternoon dewpoints outside of the highest elevations
near the VA border should be in the upper 60s to low 70s. This
will allow heat indices to peak in the mid 90s to near 100 degree
range. The increase in moisture, daytime heating as well as weak
height falls could lead to some convection developing in or moving
into the northwest and perhaps portions of the west by late
afternoon and evening. If convection does not move into that
regions some CAM runs have an outflow moving in that could be a
focus for some convection. Limited instability and shear should
limit storm strength, some storms could produce brief heavy
downpours. Continued increasing moisture, the approach of a cold
front and the approach of a shortwave trough and perhaps a weaker
lead one should lead to coverage of convection increasing into
Wednesday night. Some locally heavy rain is not out of the
question in the more northern areas if convection were to train,
but the probability is rather low.

.LONG TERM...(Thursday night through Tuesday)
Issued at 255 AM EDT WED JUL 3 2024

The forecast period will begin with mean upper-level zonal flow but
a digging shortwave moving through upper-Mississippi valley will
eject into the Great Lakes. At the surface, a stationary boundary is
draped across the CWA keeping chances of PoP across the area to
start the period but to the west, the aforementioned shortwave will
bring a renewed chance of PoP as a surface cold front approaches the
area. Along and ahead of the front, showers and thunderstorms are
likely through the day Friday into Saturday before the front exits
Saturday evening. Severe chances look to be largely limited with
FROPA as widespread cloud cover will inhibit instability and shear
is fairly weak ahead of the boundary. However, can`t rule out an
isolated severe thunderstorm with FROPA during the day Friday. Also,
there`s forecast 90-99th percentile above climatological
precipitable water values, 2.10" to 2.30", through FROPA is
expected. Which, if these showers and storms are efficient, heavy
rainfall leading to possible hydro issues could be possible before
the front exits on Saturday.

High pressure builds in for Sunday into Monday before another double-
barreled surface low sets up for next week. The first is another
shortwave developing in the upper-Mississippi Valley and ejecting
into the Great Lakes with a cold front crossing through the
Commonwealth. The second feature is a weak surface low riding along
a low-level jet streak. The second feature will bring increasing
showers and thunderstorms to the region Monday afternoon before the
first system drags a cold front through the region on Tuesday.
Showers and thunderstorms are forecast to persist through the day
Tuesday and linger through the remainder of the forecast period.

Overall, the period will highlighted with periods of showers and
thunderstorms that`ll bring much needed rain to the area. Also,
temperatures will return to more seasonal ranges as daytime highs in
the mid-80s to low-90s and overnight lows ranging from the upper-50s
to upper-60s.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 830 PM EDT TUE JUL 2 2024

VFR will persist through the period though there will be a bit of
valley fog between about 06 and 13Z. This should not affect any
TAF sites. Winds should generally be less than 10 kts through 12Z
from the southeast to south. Winds then become increasingly
southwest at around 10 kts for more western and northwest
locations such as KSME, KLOZ, and KSYM through the end of the
period.

&&

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

$$

UPDATE...GREIF
SHORT TERM...JP
LONG TERM...VORST
AVIATION...JP/GREIF