562
FXUS63 KLMK 150043
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
743 PM EST Thu Nov 14 2024

.KEY MESSAGES...

*  Dry but mostly cloudy Friday with near-normal temperatures.

*  Dry/quiet weather expected over the weekend with a moderation in
   temperatures.

*  Showers/possible storms are likely by Tuesday/Wednesday as a
   couple of systems push through the region.  A transition to a
   colder pattern is possible for the late week period.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 307 PM EST Thu Nov 14 2024

Synopsis...Mid-level shortwave trough and developing upper low will
slowly depart the region towards the Mid Atlantic while ridging and
positive height anomalies expand across the Ohio Valley from a high
over the Gulf of Mexico. At lower levels, occluded front will exit
the forecast area this afternoon with high pressure translating from
the Mid Mississippi to the Ohio Valley during the next 24 hours.

Tonight...Dreary afternoon with mostly cloudy skies and
drizzle/light rain chances based on light echo returns noted on
radar. On the other hand, most of the moderate rainfall has almost
moved away to eastern Kentucky following the departure of the
occluded front. Additionally, occasional westerly gusty winds of 18-
23 mph are observed in the wake of the front which will decrease
late this afternoon. For tonight, low-level moist layer, upper
subsidence, and PV-related forcing will continue promoting overcast
conditions with a slight chance of drizzle. Winds will gradually
turn to the northwest allowing temperatures to fall to the 40s.

Friday...Approaching surface high pressure will advect dry air and
increase subsidence over the region, eroding low-level saturation
and lifting the cloud base. Therefore, some cloud breaks and brief
periods of sun could be observed, especially closer to the surface
high in west- and south-central Kentucky per cloud field output from
HREF and ECMWF. Furthermore, a few patches of drizzle would still be
possible early in the morning, but overall should be a rain-free
day. Cloud coverage and NNW winds will maintain the small diurnal
range tendency with highs in the upper 50s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Issued at 307 PM EST Thu Nov 14 2024

Friday Night through Monday Night...

A highly amplified upper level pattern is expected through this
forecast period over the CONUS.  The Ohio Valley will be under the
influence of a ridge axis while the western CONUS will see a large
scale trough axis.  With the upper level ridge in place and surface
high pressure settling through the region, quiet and dry weather is
expected with a slow moderation in temperatures.

Temps will start off early Saturday with readings in the upper
30s/lower 40s.  Saturday afternoon highs will be in the upper 50s to
the lower 60s.  Lows Saturday night will dip back into the upper
30s/lower 40s.  Highs Sunday should be a bit warmer with readings in
the 63-68 degree range.  Lows Sunday night will be a bit milder with
mid-upper 40s expected.  By Monday, the upper level ridge will shift
eastward and a negative tilt trough will move into the southwestern
Plains.  We`ll see a bit of mid-upper level cloud cover stream into
the region, but we`ll certainly be in a warm advection pattern.
Highs should warm into the mid-upper 60s, though some spots along
the KY/TN border could get as warm as 70.

By Monday night, the southern Plains upper trough axis looks to
remain somewhat negatively tilted as it moves into the Midwest.  An
arcing cold frontal boundary will slowly move eastward into the
region with a band of showers pushing into the region during the
overnight hours.  Lows Monday night will be mild with low-mid 50s
being common.

Tuesday through Thursday...

Heading into Tuesday, we expect to have a large occluding cyclone
over the northern Plains and Midwest with an arcing frontal boundary
pushing eastward across the Ohio Valley.  A band of rain showers is
likely to accompany this front.  Severe potential here looks quite
limited as the stronger jet/upper dynamics become more northward
displaced from the better moisture/instability to our south. Tuesday
will feature mild temps with highs in the upper 60s to near 70.  It
appears that we should see a decrease in precipitation chances
Tuesday night as the boundary shifts to our east.  Lows will only
drop into the lower 50s.

For the Wednesday and Thursday period, model agreement dropped off
rather significantly overnight in the 14/00Z runs.  Cluster
analysis basically had two scenarios that could unfold.  The first
scenario is the GFS/GEFS evolution of a large scale deep
surface/upper level low holding sway across the eastern US with a
blast of cold air arriving into the Ohio Valley on Thursday.  This
scenario would also result in a potent long duration wind event
across the northern Plains and upper Midwest with the lake effect
snow machine going into high gear.

The second cluster is made up of the Euro/EPS solutions which have a
weaker lead upper low over the Great Lakes early in the period.
However, the Euro then drops a secondary wave into the Plains on
Wednesday which then wraps up into a rather large gyre over the
eastern US on Thursday.  This solution could give us another shot of
showers and perhaps storms late Wed/early Thursday.

Highs Wednesday look to warm into the low-mid 60s with highs on
Thursday dropping back into the low-mid 50s.

Beyond Thursday...

Fairly substantial model spread continues beyond Thursday as the
colder GFS becomes more progressive and moves a wave of colder air
through the region and then off to the east.  The Euro on the other
hand is much more wound up with a large gyre spinning across the
Midwest and into the Ohio Valley.  A large dry slot will likely move
across the region ahead of the core of the upper low and the timing
of that is far from certain.   However, showery conditions are
expected for Friday/Saturday.  Thermal profiles are quite different
in the Friday/Saturday period as the GFS is colder indicating a
wintry mix of rain/snow showers, but the Euro is significantly
warmer keeping much of the precipitation in the form of plain rain.

Moving into the week of Thanksgiving, a moderation of temperatures
continues to look likely as there is substantial agreement here in
the GFS/Euro solutions.  Still think we could see another system
come through around late Tuesday/Wednesday bringing another round of
precip to the region.

&&

.AVIATION /00Z TAFS THROUGH 06Z SATURDAY/...
Issued at 738 PM EST Thu Nov 14 2024

Impacts/Confidence:
- High confidence in MVFR or lower ceilings through Friday morning.
- Medium confidence in IFR ceilings/timing early Friday morning at
LEX/RGA.

Discussion...Lingering low level moisture trapped beneath an
inversion will lead to an extended period of MVFR ceilings overnight
and Friday morning. A period of IFR ceilings does look likely at LEX
and RGA, mainly between 06-15Z (confidence in exact timing of IFR is
slightly lower). Ceilings are forecast to gradually improve from
west to east Friday afternoon and evening. WNW winds will gradually
diminish tonight and remain relatively light out of the NW on
Friday.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

$$

SHORT TERM...ALL
LONG TERM...MJ
AVIATION...EBW