LMK issues Area Forecast Discussion (AFD) at Dec 11, 12:51 AM EST ...Updated Aviation Discussion...663
FXUS63 KLMK 110551
AFDLMK
Area Forecast Discussion
National Weather Service Louisville KY
1251 AM EST Wed Dec 11 2024
...Updated Aviation Discussion...
.KEY MESSAGES...
* Brief period of light snow after midnight tonight. Though any
snow will be very light, damp roads could form slick spots as
temperatures fall to or below freezing, especially in areas east
of I-65.
* Scattered snow showers and snow squalls are expected Wednesday
afternoon and evening. Light snow accumulations will be possible
in spots.
* Colder and blustery conditions for Wednesday and Thursday with
highs in the 30s and wind chills in the 20s.
&&
.UPDATE...
Issued at 953 PM EST Tue Dec 10 2024
Conditions are dry this evening, though we already have evidence of
a mid-level frontogenetical precip band (light) stretching SW to NE
over Arkansas and the Missouri Bootheel. Recent SDF ACARS soundings
as well as hi-res model data continue to show notably dry air in the
mid-levels. The column is expected to briefly moisten during the
early to mid-morning hours, when we still expect a light snow band
to develop over central Kentucky.
The main time window of concern is 4-8 AM EST, but the band itself
will be fairly narrow and moving east with time. So the residence
time of light snow should be quite short (1-2 hours) at any one
location. There is still potential for the band to both widen and
intensify slightly over the Bluegrass Region when it crosses that
area between 6-8 AM EST, an idea supported by the 11.00Z runs of the
HRRR/NAM 3 km. The Bluegrass Region is the area most likely to see a
dusting of accumulation, mainly on grass and elevated surfaces such
as rooftops and decks. Confidence in accumulation on road surfaces
is much lower, though bridges and overpasses may be slick for the
Wednesday morning commute. Temperatures are forecast to dip slightly
below the freezing mark. Fortunately, the snow is expected to exit
the eastern forecast area by 9 am with temperatures slowly rising
through midday.
Additional scattered snow showers Wednesday evening may bring more
notable, albeit spotty, travel impacts. Localized heavier snow
showers could significantly reduce visibility for a short time, and
commuters Wednesday evening could encounter drastically changing
conditions over short distances. After sunset, as temps drop toward
and then below the freezing mark, slick conditions will become more
likely on the roads. Temperatures Wednesday night and early Thursday
are forecast to tumble through the 20s.
&&
.SHORT TERM /THROUGH THURSDAY/...
Issued at 238 PM EST Tue Dec 10 2024
Afternoon mesoanalysis reveals our surface cold front exiting the
LMK CWA. The cold front is evident via the wind and temperature
fields. Behind the front, temperatures have cooled into the upper
40s to the lower 50s, but east of the front, much of eastern KY is
the low-mid 60s with some filtered sunshine coming through. Some
partial clearing is occurring out to our west along our border with
PAH. We may see a little clearing this afternoon across our far
west, but more clouds will push into the region this evening. Still
may see a few showers east of I-65 and north of the Bluegrass
Parkway for the next few hours. However, by evening most of the
region will be rain free. Temperatures will start to fall off from
west to east later this afternoon. By sunset, temps will likely be
dipping into the upper 30s over southwest IN with mid-upper 40s
along and east of I-65.
For this evening, dry and quiet weather is expected and by midnight
temperatures are expected to be in the upper 30s across much of the
region, with our far northwest sections dipping close to freezing.
Overnight, a sharp 500mb shortwave trough axis will approach from
the west/northwest. For the past few days, the models have been in
good agreement with a stronger band of mid-level frontogenetical
forcing resulting in a streak of clouds/snow developing across the I-
65 corridor and then pushing east. Model time-height and proximity
soundings still show a bit of drier air aloft that may prevent
initial snow from reaching the ground. However, deeper saturation
occurs later in the night, east of the I-65 corridor where a SW-NE
oriented band of light snow will move across portions of east-
central KY in the pre-dawn hours. While forcing is decent here,
moisture is marginal, but enough for snow production. However,
little if any accumulation is expected and should be limited to
elevated decks/rooftops.
Given the recent warmth and 4 inch soil temps running in the upper
40s to near 50, road temps over ground surfaces will likely only
drop into the mid-upper 30s tonight. Surface winds may remain
strong enough overnight to help dry out any residual moisture on the
roads. While temperatures will dip into the upper 20s prior to
sunrise, the light snows east of I-65 may result in some scattered
road impacts. The key problem areas will likely be
bridges/overpasses which are exposed and cool off faster. For this
reason, we'll cover these impacts with a Special Weather Statement
and continue to monitor impacts overnight.
Moving into the daytime hours on Wednesday, initial light snow
expected to be in progress across the Bluegrass region will continue
shift eastward during the morning hours. Across the rest of the
region, we'll just see dry and cold conditions during the morning
hours with brisk northwest winds. During the afternoon hours,
another mid-level impulse is forecast to drop into the region from
the northwest. Model proximity soundings show rapidly steepening
lapse rates in the low-levels which should result in snow showers
developing. The lapse rates are particularly steep here and snow
squall parameters suggest that a few snow convective snow
showers/squalls will be possible. In general, the highest risk of
snow squalls will be in areas along and north of the WK/BG Parkways
in the afternoon. Farther south into southern KY, there may be
enough warm air to produce a mix of rain/snow showers. While
surface temps from early-mid afternoon look to be in the middle 30s,
there is particular concern that we may see temps dip into the lower
30s by late afternoon where the snow squalls could lead to localized
accumulations in spots/streaks. This could result in impacts to the
evening commute, especially in areas that get under these convective
snow showers. For this reason, we'll cover this impact in the above
mentioned Special Weather Statement. We will continue to monitor
Wednesday afternoon's conditions. It is possible that a short lived
Winter Weather Advisory could be required in a portion of the area
if a more concentrated area of snow showers/squalls develop.
&&
.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
Issued at 238 PM EST Tue Dec 10 2024
Wednesday Night - Friday... Deep troughing will swing through the
region on Wednesday. Wednesday afternoon-evening snow showers will
begin to dissipate and move off to the east, chasing the best
forcing. CAA and high pressure will build in behind this system. Low
temperatures on Thursday morning are expected to be in the upper
teens and low 20s. With cold temperatures and recent precipitation
overnight, slick spots may develop leading to minor impacts to the
Thursday morning commute. Although we will see mostly clear skies on
Thursday, CAA will prevent temperatures from rising out of the 30s
on Thursday.
As the high pressure moves northeast of the region, slowly veering
southerly flow will bring moisture, increased clouds, and warmer
temperatures into the region.
Friday Night into the Weekend... Troughing originating from the
southwest CONUS will swing through the central Plains and into the
Midwest, bringing another surface low pressure system with it over
the weekend. Ahead of the system, ridging and southerly flow will
increase temperatures and dew points into the region to near normal
or slightly above normal values. In the warm sector of the system
and along the cold front, widespread showers will move through the
area. Most likely timing for this will be Saturday night through
Sunday. Amongst ensembles, there is a 10% chance of exceeding 0.9
inches of rain and an 80% chance of exceeding 0.4 inches of rain.
Early Next Week... Troughing moving along the northern CONUS will
deepen as it moves into the Midwest. This system will send a cold
front through the Ohio Valley with yet another chance for precip
along and ahead of the front. Temperatures through early next week
are expected to stay near normal or slightly above normal before the
front moves through.
&&
.AVIATION /06Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1250 AM EST Wed Dec 11 2024
MVFR to VFR CIG will be over the area for the start of the forecast
as low stratus clears from west to east this morning. Radar shows a
very light band of precipitation stretching from Indianapolis
towards Memphis sliding eastward into central KY. Currently, most of
this activity is not reaching the ground but models continue to show
some light snow development this morning from between 08z to 12z for
BWG to SDF with higher confidence of snow development for LEX around
10z. This wave won't last long and is not expected to have much of
an impact. There will be a break in precipitation but winds will be
on the increase later today with gusts increasing to around 20 to
potentially 25kts later this afternoon. A second cold front will
work into the region later this afternoon into the evening.
Scattered snow showers, with some being convective and cellular in
nature could produce quick but potentially moderate to heavy bursts
of snow for SDF to LEX between 20z to 24z. Decided again to go with
a PROB30 due to the very scattered nature of this activity. Mid
level clouds will clear out overnight with quieter weather into
tonight.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.
&&
$$
UPDATE...EBW
SHORT TERM...MJ
LONG TERM...SRM
AVIATION...BTN
Source:
LMK issues Area Forecast Discussion (AFD) at Dec 11, 12:51 AM EST ...Updated Aviation Discussion...---------------
If I'm using your data in a way that is against your terms please email the team at "threatweb@pupswoof117.com"! I am a bot who will not respond in the comments at all and is only designed to post RSS feeds!
