Shepherdsville, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

036
FXUS63 KLMK 230818
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
318 AM EST Sat Nov 23 2024

.KEY MESSAGES...

*  Low clouds will gradually clear from southwest to northeast later
   today. Areas along and north of I-64 will likely remain under
   pesky cloud cover until after sunset this evening.

*  Rain showers are likely Monday with a cold frontal passage.

*  Another round of rain showers is likely for Wednesday and into
   Thanksgiving Day, with colder conditions arriving Thursday night.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 317 AM EST Sat Nov 23 2024

Weak northwest flow and CAA regime remains in place this morning,
resulting in widespread low stratus across the entire area and
trapped under a stout 850mb inversion. Dry weather is expected today
as we will be located between systems, with the departing upper low
shifting off the coast of New England, and upper ridging building in
from the west as sfc high pressure sits across the Lower Mississippi
River Valley.

Low clouds will linger this morning, but a slight shift in our winds
from a cooler west-northwest flow to a warmer southwest flow will be
enough WAA to finally begin to erode the cloud deck later today. The
clearing will be gradual, beginning along our border with TN, and
slowly working northeastward through the entire afternoon and
evening. HREF and NBM skycover guidance agreement increases the
confidence for areas along and north of I-64 to remain under pesky
low stratus through the daylight hours, and will likely not clear
out until after sunset. Temperatures for today will be highly
dependent on the amount of cloud cover, so confidence does remain on
the lower side for highs this afternoon. However, generally
speaking, upper 40s to low 50s are forecast, with the cooler spots
associated with our northern half where cloud cover will linger, and
slightly warmer temps across our south where they should get a bit
of sunshine today.

For tonight, dry weather will continue as the sfc high pressure
slides across the Deep South and upper ridging shifts eastward.
Light southwest winds and steady low-level WAA will result in
additional gradual clearing of low clouds tonight. By the overnight
hours, partly cloudy to mostly clear skycover and light winds will
support fog development for late Saturday night and into early
Sunday morning. Low temps should reach the low to mid 30s across the
area.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
Issued at 317 AM EST Sat Nov 23 2024

Sunday through Tuesday Night...

Fairly zonal flow pattern will be seen at the start of the forecast
period with some weak/flat upper level ridging building into the
region.  We`ll get into a southwest flow during the day on Sunday
which should result in some moderate warm air advection across the
area.  Sensible weather looks to feature mostly sunny skies with
afternoon highs warming into the upper 50s and lower 60s.  Clouds
will likely be on the increase Sunday night ahead of an approaching
weather system.  Lows will range from the lower-mid 40s in the east
to the upper 40s in the I-65 corridor and points west.

On Monday, we`ll see an amplifying shortwave trough axis move
through the northern Plains and into the Great Lakes.  Associated
surface cyclone will move from the Midwest into the eastern Great
Lakes by late Monday and the trailing cold front will slice through
the region.  Light to moderate rain showers are likely Monday
afternoon and evening as this system moves through.  Most areas
could pick up a quick quarter to maybe a third of an inch of
precipitation with this activity.  Highs Monday will be mild with
readings in the lower 60s ahead of the front.  Rain showers will end
fairly quickly Monday night with colder/drier air pouring into the
region.  Looks for lows to dip into the lower-mid 30s west of I-65
by sunrise Tuesday and mainly mid-upper 30s east of I-65.

High pressure is forecast to build into the region on Tuesday with
partly cloudy skies.  The cold advection will keep temps down in the
lower-mid 40s across southern IN and the northern half of KY.  Mid-
upper 40s will be seen across far southern KY.  By late Tuesday
we`ll be watching for the next upper level wave to push into the
Plains.  Weak warm advection may result in an increase in sky cover
late Tuesday night, especially in areas of western KY.  Where
clouds hold off, lows Tuesday night across the Bluegrass will
likely drop into the upper 20s.  Out near the I-65 corridor and
points west, lows look to settle into the lower 30s.

Wednesday through Friday...

Zonal flow aloft early Wednesday will gradually become southwesterly
as the next in the series of perturbations moves into the central
Plains.  Cloud cover should be on the increase during the day.
Within the warm advection scheme, we`ll probably see some light
precipitation develop during the early afternoon.  Initial dry lower
atmosphere may take some time to saturate up, but it appears that
rain will be likely by Wednesday evening.  Highs on Wednesday will
be in the low-mid 40s across southern IN and the northern half of
KY.  Highs up in the lower 50s will be possible across southern KY.

Wednesday night will feature widespread precipitation falling across
the region as a wave of low pressure transverses the region.  MOdel
soundings suggest precipitation will be in the form of cold rain for
much of the night.  Toward sunrise, thermal profiles may become cold
enough to support some light snow in areas along I-64.  Overnight
lows look to cool into the lower 30s across southern IN and the
northern half of KY.  Upper 30s are expected across southern KY.

For Thanksgiving Day, unsettled weather is expected as lingering
cold rain showers will continue to move across the region before
diminishing in the evening.  NBM temps yield readings in the upper
40s to lower 50s across the region.  This looks a bit too warm here
as the latest 00Z guidance is suggesting highs mainly in the upper
30s/lower 40s.  So I suspect that we`ll see the next iterations of
the blend come down in subsequent forecasts.  Precipitation looks to
push off to the east Thursday night with another shot of colder air
coming into the region.  As that colder air comes in, left over
precipitation may end as a period of snow showers.  Lows will range
from the upper 20s to the lower 30s.

Northwesterly flow will be in place for Friday.  Not sure how much
clearing we`ll see behind the departing system, but I suspect we`ll
have plenty of cloud cover across the region with perhaps a few snow
flurries across southeast IN and into the Bluegrass region.  Highs
will be cold with upper 30s in southern IN and across the northern
half of KY.  Slightly milder temps will be found south of the
Cumberland Parkway where lower 40s will be possible.

Extended Forecast Discussion...

As we close out November and head into December, the longer range
teleconnection pattern is forecast to feature a -AO/-NAO/-EPO/+PNA
pattern.  This would favor a colder than normal temperature pattern
for the Ohio Valley during this period.  The MJO pulse is forecast
to be rotating through phase 4 and 5.  Normally, phase 4/5 is a warm
pattern, but during ENSO neutral periods, it favors more of a colder
pattern, which the dynamical models are already indicating.

Early November signal analysis thus far has done quite well in
tracking systems through the region.  Our current analysis supports a
stronger signal passage centered around 12/1 with another around
12/4 and then a third around 12/8.  The 12/1 signal is interesting
in that we`ll have some cold air in place which may result in a
period of wintry weather to close the Thanksgiving Holiday weekend.
After that systems passes, the first week of December looks to have
well below normal temperatures with some moderation as we get toward
the 7th or so.

&&

.AVIATION /06Z TAFS THROUGH 12Z SUNDAY/...
Issued at 1255 AM EST Sat Nov 23 2024

Low stratus continues to impact flight categories at all terminals
this morning. MVFR ceilings will remain until this afternoon, with
LEX having the best chance for ceilings to bounce between IFR and
MVFR. Gradual clearing of the cloud deck will spread from southwest
to northeast, so expect BWG to be the first to see improvements. By
later this afternoon and evening, all terminals are forecast to
return to VFR conditions. Winds will switch from northwest flow to
southwest later today.

&&

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

&&

$$

SHORT TERM...CJP
LONG TERM...MJ
AVIATION...CJP