Shively, Kentucky 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

091
FXUS63 KLMK 040558
AFDLMK

Area Forecast Discussion
National Weather Service Louisville KY
1258 AM EST Wed Dec 4 2024

...Updated Aviation Discussion...

.KEY MESSAGES...

*  Freezing sprinkles possible between 3am and 9am. Confidence in
   this is low, and any precipitation would be very light.

*  Windy conditions expected Wednesday with gusts of 35-40 mph
   possible.

*  Cold wind chills in the teens Thursday.

*  Light winds but cold temperatures Thursday night, with the
   traditional cold spots dropping into the single digits.

&&

.UPDATE...
Issued at 956 PM EST Tue Dec 3 2024

Satellite imagery is starting to show the persistent low cloud
cover we`ve had all day and evening finally eroding out of the area
as it continues to slowly lift off to the northeast. This will
provide a brief period of clearing and allow for temperatures to
fall into the low/mid 20s shortly after midnight before the next
wave of clouds associated with a strengthening LLJ and isentropic
lift work in over the area in the pre-dawn hours. We will also start
to see slow WAA advection both at the surface and between 900-800mb.
The one thing we continue to watch is the possibility of some
sprinkles that could occur just before sunrise tomorrow morning. We
currently have a mention of freezing rain, but more likely freezing
sprinkles in the forecast and decided to keep them in. Confidence
remains low as many models outside of the NAM3K want to keep this
time period dry. With a good amount of dry air at the surface and a
shallow saturation level between 3000-5000ft, it is likely that most
if not all of the precipitation would evaporate before reaching the
sfc. Even with the low confidence, seeing that neighboring WFO`s
have similar mention of freezing rain/drizzle in their grids,
decided to maintain consistency and not change the current forecast.
The rest of the going forecast looks to be on track.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 326 PM EST Tue Dec 3 2024

Low clouds will continue to break up this evening, with mostly clear
skies from mid-evening to shortly after midnight. This period of
time after we lose the low clouds and before winds begin to increase
overnight will be the window in which temperatures will fall the
most, bottoming out around 20 degrees around midnight. A new area
of clouds and increased SSW winds will move in during the pre-dawn
hours, causing temperatures to rise 3-5 degrees between midnight and
dawn.

The clouds moving in before sunrise may be thick enough to produce
some very light precipitation across southern Indiana and far north
central Kentucky. Lift is expected to be weak, and soundings and
atmospheric cross-sections are showing significant dry air beneath
the cloud layer, so any precipitation would be very light. However,
sounding progs suggest that any hydrometeors that do fall to the
ground may be liquid. With very cold ground temperatures, these
drops would freeze on contact. At this time, confidence is low in
the occurrence of any wintry precipitation, and anything that does
fall should be quite light...in the form of freezing sprinkles.
However, the freezing sprinkles would roughly coincide with the
morning rush. So, will go ahead and add them to the forecast, but
will keep PoPs very low and restrict them to the region of greatest
likelihood across southern Indiana and north central Kentucky north
of a Leitchfield-Bardstown-New Castle line.

During the day on Wednesday deepening low pressure near Lake
Superior will pull a trailing cold front reaching down to the
Ozarks. Between this system and a dome of high pressure slipping off
the Georgia coast, a tightening pressure gradient and brisk sfc-
925mb flow beneath a low level inversion will lead to a breezy,
gusty day under partly/mostly cloudy skies. Wind gusts of 35-40 mph
seem like a good bet. Temperatures will warm well into the 40s, with
some low 50s expected near the Tennessee line.

&&

.LONG TERM /TONIGHT THROUGH TUESDAY/...
Issued at 326 PM EST Tue Dec 3 2024

Wednesday Night - Thursday...

Wednesday evening, a stout shortwave disturbance will be moving
across the Great Lakes, pivoting to the east-southeast toward the
northeastern US by Thursday morning. A sfc cold front associated
with this upper disturbance will drop from NW to SE across the Ohio
Valley Wednesday night, bringing a strong blast of cold advection in
its immediate wake. As previous discussions mentioned, the moisture
along and ahead of this system is fairly shallow, with the greatest
saturation contained within the sfc-800 mb layer. However, lift
along the sfc front should help to spark light precipitation,
especially as you go farther to the north and east where there is
deeper moisture.

The main intrigue with this system will be the potential for wintry
precip as the cold air intrudes from the northwest. Analysis of
soundings depicts a classic "cold air chasing moisture" setup, with
only a narrow window where temps are cold enough for snow while
there is sufficient moisture depth for precipitation. The main
window for a transition from rain to snow would be from around
midnight north of the Ohio River to around 4 am along the TN border.
If there are heavier bursts of snow, a quick dusting would be
possible, primarily across the KY Bluegrass region. By sunrise
Thursday, temperatures will have plummeted into the teens across
southern IN and north central KY, with low 20s expected across
southern KY.

Cold advection will continue during the day on Thursday, suppressing
diurnal warming in spite of what should be clearing skies.
Persistent breezy NW winds will make temps feel like the single
digits Thursday morning, with apparent temps remaining in the teens
during the afternoon. Near record cold highs are likely Thursday,
with highs ranging from the mid 20s across southern IN to the low
30s across southern KY.

Thursday Night - Sunday...

There is high confidence in gradually warming temperatures Friday
through the weekend as the upper trough over the eastern half of
North America ejects into the North Atlantic. High pressure will
move across the region on Friday and will be centered over the
southeast US during the weekend. This will return our area to a
pattern favoring warmer return flow, though this return flow will be
somewhat limited by split flow across the western CONUS, which will
prevent amplification of the synoptic pattern until late in the
weekend. This should also keep the bulk of the moisture to the south
and west of the region, and dry weather is expected from Thursday
through most of the weekend. By Sunday, temperatures should return
to near or slightly above normal levels, with highs making it back
into the 50s.

Sunday Night into Early Next Week...

Upper level energy from the aforementioned low over the southwest US
will finally be able to eject eastward Sunday into Monday as it is
expected to phase with a northern stream wave coming in from the
Gulf of Alaska over the weekend. There is still only modest forecast
confidence in this solution given the amount of lead time and the
requisite phasing in the upper level pattern; however, it is looking
increasingly likely that next week will start off mild and wet
across the Ohio and Tennessee Valleys. Once the two pieces of upper
energy phase, deep SW flow and enhanced moisture return is expected
to approach from the lower Mississippi Valley. 3/00Z ECMWF ensemble
mean PW begins to exceed the 90th percentile of model climatology by
Monday morning, and strengthening low-level SW jet will promote the
onset of precipitation Sunday night into Monday morning.

While most ensemble members have some precipitation Sunday night
into Monday, there is still considerable spread in expected
precipitation amounts. ECMWF Extreme Forecast Index shift of tails
shows some potential for a heavy rainfall event, and about 25% of
ENS members exceed 1" 24-hr QPF next Monday. Model soundings
generally show a saturated profile, limiting the potential for any
instability and thunderstorms. Temperatures will continue to warm
into next Monday, with highs expected to reach the upper 50s and
lower 60s.

&&

.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1255 AM EST Wed Dec 4 2024

Impacts:

* Marginal LLWS at HNB/SDF this morning.

* Gusty winds from the SSW, especially after 15Z.

Discussion: Mostly VFR conditions during this forecast period. The
primary aviation impact will be wind. Southerly sfc winds will
gradually increase through the early to mid-morning hours as a
strengthening SW LLJ overspreads the area. This will produce brief
marginal LLWS conditions mid-morning, but sfc winds will also be
increasing out of the SW. SW winds are forecast to gust to 30+ kts
between 15-21Z today ahead of a strong cold front. We will stay
mainly dry during the daytime due to limited moisture depth.

SCT showers are likely to develop late this evening and overnight as
the cold front sweeps through the region. Highest confidence in
prevailing SHRA is at LEX/RGA. A brief changeover to snow showers
will also be possible late tonight near the end of this TAF period.

&&

.CLIMATE...
Issued at 326 PM EST Tue Dec 3 2024

================== Near-Record Cold Max Thursday ==================


                             Thursday 12/05/2024
                          Max T Fcst/Cold Max (Year)

Louisville:                  29/27     (1895)

Bowling Green:               30/32     (2008)

Lexington:                   27/22     (1895)

&&

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

&&

$$

UPDATE...BTN
SHORT TERM...13
LONG TERM...CSG
AVIATION...EBW
CLIMATE...CSG