526
FXUS63 KJKL 240618 AAC
AFDJKL

AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
218 AM EDT Fri May 24 2024

.KEY MESSAGES...

- Showers and thunderstorms are expected from time to time through
  the middle of next week, especially during the afternoon and
  early evening hours.

- There is a potential for severe thunderstorms on Sunday, with
  damaging winds and large hail being the primary threats.

&&

.UPDATE...
Issued at 218 AM EDT FRI MAY 24 2024

Quick update to increase PoPs early across the east but also to
reduce the chance of thunder as more intense convection has moved
east of our forecast area. Showers will continue to move eastward
out of the area through dawn. Not seeing a noticeable increase in
fog on web cams. However, am seeing an increase in low stratus on
the regional satellite loop in the wake of a precipitation band
that has filled in across our eastern zones. Seems as though fog
is building down for areas across the east, but is more limited
to the river valleys further west where where rainfall has ended
and skies have at least partially cleared. Consequently beefed up
the fog just a bit across the east where low stratus is
developing.


UPDATE Issued at 1155 PM EDT THU MAY 23 2024

The severe weather has cleared out as the MCS that brought it to
the region continues to weaken and dissipate. This will set the
stage for fog formation when the clouds of the system thin and
clear. Have updated the forecast to speed up the diminishment of
the showers and also to add in the current 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 840 PM EDT THU MAY 23 2024

00Z sfc analysis shows a meso-high working through eastern
Kentucky south of a stalled frontal boundary. The latest MCS is
starting to rain itself out over the CWA this evening but a few
strong to severe storms will be possible for another hour or so
out ahead of the main storm cluster. For this reason, and in
coordination with MRX and SPC, we have extended the severe watch
until 10 pm but dropped it generally west of I-75 where conditions
have stabilized. Temperatures currently vary from the lower 60s
in the recently rain cooled areas to the low 70s in the far east.
Dewpoints remain elevated in the mid to upper 60s most places amid
mostly light winds away from any thunderstorms. Have updated the
forecast mainly to fine tune the PoPs through the rest of the
night per radar and CAMs trends. Did also include the current obs
and tendencies for the T/Td/Sky grids. Additionally, the fog was
hit hard late tonight with clearing and thinning of the mid and
high clouds anticipated. These adjustments have been sent to the
NDFD and web servers along with a freshening of the zones, SAFs,
and HWO - primarily to address the extension of the watch.

&&

.SHORT TERM...(This evening through Friday night)
Issued at 455 PM EDT THU MAY 23 2024

A stalled, ill-defined frontal boundary is located just north of
KY late this afternoon. On the south side of the front, our air
mass is mild and fairly humid, with dew points running in the 60s.
Temperatures are running in the 70s, being held back during the
day by earlier clouds and precip. Never the less, it`s enough to
support another round of thunderstorms heading in from central KY,
helped along by a weak mid/upper level trough. Modest shear is
also present, and marginally severe storms can`t be ruled out with
the instability/shear combo, with Severe Thunderstorm Watch 293
continuing until 8 PM for our western counties.

The convection is expected to weaken as it exits east tonight.
Clouds will try to break up as mid-upper levels dry, but
radiational cooling after the precip will probably result in fog
and low clouds developing and lasting into Friday morning.

The fog and low clouds will dry up by mid day and sun/heating will
cause destabilization again. However, the currently stalled
frontal boundary will lift north away from the region as a warm
front, and the only mid/upper level wave to be seen in models
should have its main influence to our south in the afternoon and
evening. That being the case, despite instability, the probability
of rain appears to be relatively low Friday and Friday night due
to lack of support, and nothing more than a small chance (30%) has
been used.

.LONG TERM...(Saturday through Thursday)
Issued at 610 PM EDT THU MAY 23 2024

The models are in general agreement with an unsettled pattern to
remain across the Ohio and Tennessee valleys through early next
week. Above normal temperatures, higher humidity, and daily
rain chances will be on tap. A more decisive cold front will move
through by the middle of next week, with cooler and drier air
filtering into the region. Short wave ridging will move in over
eastern Kentucky on Saturday; however, with a surface cold front
still in the general vicinity, at least a 50% chance of showers
and storms are possible. Did undercut the blended guidance a bit
here, as the short wave ridging has been consistently showing up in
the guidance for the past few days.

Meanwhile, deeper mid and upper level energy will shift east from
the Rockies through the Plains, likely cutting off as the main
short wave curls northeast through the Upper Midwest/western
Great Lakes region by Sunday. This will result in a stronger
surface low genning up across the southern Plains and move
through the middle Mississippi Valley and into the Great Lakes.
There is some uncertainty as to the position of the associated
warm front, which would branch east southeast somewhere near the
Ohio River on Sunday, with eastern Kentucky more planted within
the warm sector. Given the stronger system and likely increased
coupled effective shear and instability in place, a severe weather
threat exists, with all hazards a possibility, although specifics
still remain lower confidence at this time. Depending on how much
of a break portions of our area see as far as rainfall leading
into this next uptick, at least a renewed minor flooding threat
would also accompany the additional severe weather hazards. PoPs
will peak in the 60-90% range Sunday night and Monday, as the cold
front approaches and eventually progresses through the region.

At least chance PoPs (20-40%) linger through Wednesday,
as broad cyclonic flow remains in place across the northeastern
quadrant of the CONUS, although they will be decreasing each day,
as moisture gradually decreases. 500 mb heights make a better
recovery by Thursday, with dry weather finally returning. Above
normal temperatures will reign through Monday, with highs ranging
from the upper 70s to mid 80s, with lows mainly in the low to mid
60s. Cooler air will then move in from Tuesday through Thursday,
with highs retreating to the mid 70s, and lows mainly in the 50s,
with a few upper 40s possible in the typically colder valleys by
early Thursday morning.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
ISSUED AT 218 AM EDT FRI MAY 24 2024

A band of showers has increased in coverage across our east and is
currently moving eastward. However, the threat of thunder is
waning quickly as more intense convection has moved east of our
forecast area. Not seeing a noticeable increase in fog on web
cams. However, am seeing an increase in low stratus on the
regional satellite loop in the wake of a precipitation band that
has filled in across our eastern zones. Based on observations,
fog is building down for areas in our east, but is more limited
to the river valleys further west where rainfall has ended and
skies have at least partially cleared. Consequently a mix of
aviation conditions continues to exist across the area as the
remnants of yesterday afternoon and evening`s convection continues
to dissipate. Expect flights conditions will be quite variable
through the remainder of the early morning to around sunrise. Have
trended VSBYS and CIGS downward, especially across our east with
the developing stratus and fog. Generally went with a pessimistic
start to flight conditions through dawn, IFR or worse. VFR
conditions are expected to return mid to late Friday morning.
Winds will be generally light and variable through the period -
away from any storms.

&&

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

$$

UPDATE...RAY
SHORT TERM...HAL
LONG TERM...GEOGERIAN
AVIATION...HAL/GREIF/RAY