Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 01/19/24
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1026 PM EST Thu Jan 18 2024
.SYNOPSIS...
A low pressure system arrives from the west tonight and crosses the
region, bringing a wintry mix to the mountains tonight and Friday.
Very cold air comes into the area behind the system and settles over
the region through the weekend. Warmer temperatures return early
next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
As of 1000 PM: Band of rainfall now seen on radar mosaic from
eastern KY to NE AL, within warm advection preceding a shallow
shortwave and cold front. Echoes have a convective look over
the I-75 corridor of E TN, and FZRA or FZDZ have recently been
reported on ASOS and mPING obs from that area. If that isn`t
sufficient proof of a warm nose, recent RAP soundings reveal a
fairly stout one, and one ACARS sounding from Knoxville backs
that up. Meanwhile within the CWA, sfc temps have proven warmer
than almost all guidance, perhaps as low clouds moved in a little
earlier than expected. Dewpoints have rebounded but depressions
still are 25-35 degrees in many spots. It thus may come as no
surprise that recent hi-res models have largely come in drier
east of the mountains tonight. Likely to categorical PoPs remain
in the forecast for the mountains, but values in the Piedmont
are 5-10% lower. Temps eventually will wet-bulb down but still
think mins were too cold in these areas. Confidence in an all-rain
forecast remains high for areas near and southeast of I-85. Sfc
temps look to be the biggest impact on p-type tonight overall,
and especially in the Piedmont these should remain above freezing
thru the precip. It appears rain may mix with sleet as it tapers
off in the NW NC Piedmont, but this is not expected to be more
than a novelty, having little to no impact. For the mountains,
the changes were a little more notable. QPF came down a bit per
the hi-res models early on, and more of the QPF went into freezing
rain instead of sleet/snow. Thus, ice accum went up a little bit,
and snow down. These changes were not enough to warrant change
to the Winter Wx Advisory extents. Over the mtns, there should be
some pockets of sub-freezing air to support ice accum, but still
the amts will NOT be enough to reach warning criteria ice accum
in all likelihood. The first round of precip moves out quickly by
daybreak Friday outside of the wrn side of the mtns.
By sunrise Friday, we quickly pivot to a W/NW flow of low level
residual moisture getting forced up the west slopes by cold NW
wind. Temps fall steadily thru the day as the colder air moves
in behind the system, thus any remaining precip from this point
onward should be snow showers. Mid/upper forcing is relatively
weak as a following vort looks channelled. However, the upslope
flow looks good as the 850 flow becomes more NW into Friday
afternoon. Guidance suggests the Great Lakes connection will miss
to our N higher up the mtn chain in WV/VA. However, the moisture
should extend well up into the dendritic growth zone and the column
is so relatively cold that snow-to-luquid ratio climbs up into the
realm of 20-to-1 by late in the day. The upshot is that any snow
showers will probably be quite efficient at making a coating of
light/fluffy stellar dendrites. Most of the accumulation will be
close to the TN border, but some will spill outward away from the TN
border. The fcst snow amount has increased over the high terrain,
but not to the point where we are ready to bump up to a warning
or split any of the higher terrain off to its own Warning. This
could change with later fcst packages if the duration of the NW
flow snow production goes far enough into Sunday.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
As of 120 PM EST Thursday: Broad cyclonic flow aloft will continue
to churn overhead as a stout Arctic High (1040+mb) slides down
the leeside of the Rockies. Stout CAA will continue to filter
in as the pressure gradient tightens across the mountains as
the leading edge of the high pushes into the region. With very
cold air settling in the wake of the near-term system to go
along with gusty winds, expect wind chill advisory values across
the mountains Friday night, with overnight lows expected to be
15-20 degrees below-normal. Ongoing NWFS will continue along the
NC/TN border, especially in the northern mountains. Low-level
moisture will become more shallow from Friday night to Saturday,
but lingering light snow showers will last into Saturday night
and even Sunday morning as northwest flow will be maintained by
the Arctic High. The Arctic High will be in control through the
weekend as temperatures in the CFWA will struggle to get out of
the 30s, while the mountains and I-40 corridor struggle to get
above freezing for highs Saturday afternoon despite mostly sunny
skies. Winds will gradually subside as the pressure gradient relaxes
and the center of the Arctic high settles over the TN/OH Valley
Saturday night. As a result, good radiational cooling conditions
will be in store and expect temperatures to run 15-20 degrees
below-normal once again for most locations. Needless to say,
it won`t take much wind to support wind chill advisory criteria
across the mountains, and possibly the NC foothills for Saturday
night. The cyclonic flow aloft will be disrupted by an emerging
upper ridge that will allow for the trough axis of the cyclonic
flow to finally push east of the CFWA by Sunday morning. Heights
will recover as the ridge builds in from the west and the Arctic
High will reside over the central/southern Appalachians by the end
of the period. Expect a slight rebound in temperatures on Sunday
as a result, with highs still ~10 degrees below-normal.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 235 PM EST Thursday: Last real cold night will be Sunday
night as good radiational cooling conditions remain in place as
overnight lows remain ~10 degrees below-normal with the Arctic
High in place. The airmass will modify considerably next week as
upper ridging amplifies over the region in response to a digging
upper trough over the western CONUS. The former Arctic High will
reside just offshore the North Carolina Coast and gradually bring
in a nice moisture flux into the southeastern CONUS. Timing and
uncertainty in QPF response still makes this a low confidence
forecast, but the general consensus is that temperatures will be
well above-normal by the middle part of the week with an active
pattern in place. Thus, expect rounds of good rainfall starting
some time during Tuesday and sticking around through the end of
the forecast period, possibly beyond.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
At KCLT and elsewhere: At issuance time low VFR clouds were
impinging on KAVL and KAND, with other sites to follow before
06z. Deeper moisture remains upstream nearer main shortwave, and
will eventually bring cigs near if not below the MVFR threshold
along with a chance for light precip near cold fropa. Per high-res
models timing is similar to 18z TAFs, if not slightly later. With
relatively rapid moistening evident upstream, confidence on
precip impacts is a little better, so TEMPO was warranted at all
sites. Moistening will occur from the top down, and restrictions
become possible with any precip, lingering at the SC sites and
KCLT until post-frontal downslope winds can erode cigs near or
after daybreak. Regarding precip type, KAVL and KHKY will be
slightly colder during the precip and stand the best chance of
a wintry mix overnight, although confidence is only high enough
to mention at KAVL. Developing NW flow at KAVL in the morning may
result in changes between MVFR and low VFR cigs thru the remainder
of the period; a few flurries could be seen but accumulating snow
not expected and thus no mention in TAF. Winds will remain SW`ly
and fairly light but flip to NW and gust once front passes in the
morning. By afternoon mixing, gusts above 25 KT are likely at KCLT
and above 30 at KAVL.
Outlook: NW Flow moisture will continue to bank along the TN/NC
border and produce -SHSN there into Friday night, with flurries
perhaps seen at KAVL at times. Very cold and dry VFR conditions
return for the weekend and last into early next week.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...Winter Weather Advisory until 7 AM EST Friday for GAZ010.
NC...Winter Weather Advisory until 7 AM EST Friday for NCZ053-059-
062>065-501-503-505.
Winter Weather Advisory until 7 AM EST Saturday for NCZ033-
048>052-058.
SC...None.
&&
$$
SYNOPSIS...CP
NEAR TERM...PM/Wimberley
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...Wimberley
Area Forecast Discussion
National Weather Service Indianapolis IN
928 PM EST Thu Jan 18 2024
.Key Messages...
- Winter Weather Advisory expanded to include I-70 corridor and
Indianapolis Metro Area 9 PM Tonight to 10 AM Friday
- Total snow accumulations ranging from 1-3 inches along the I-70
corridors, with 2-4 inches for North Central Indiana and Eastern
Indiana
- Arctic air returns this weekend, lows near or below zero Friday
and Saturday night with wind chills below -15F
- Warmer with multiple rounds of rain mid next week. Watching
out for river flooding and ice jams during this period.
&&
.Forecast Update...
Issued at 928 PM EST Thu Jan 18 2024
No significant changes were made to the forecast.
Forcing continues in the mid levels of the atmosphere this evening
with the first surge of forcing. The issue, as has been lately, is
the very dry low levels.
Radar, observations, and ACARS soundings show some moistening is
occurring, but slowly. Most ceilings were in the mid levels, with
northwest areas getting lower. Surface observations show some snow
reaching the ground in east central Illinois at 02Z.
Tweaked hourly PoPs to reflect a slower start to the snow. Upstream
obs in Missouri and Iowa show decent snows still headed our way,
which may make up for anything lost early this evening. Thus, don`t
believe that this initial slower start will have a significant impact
on amounts. Will continue to watch closely though.
Adjusted hourly temperatures but forecast low temperatures look good
given the strong cold advection behind the cold front.
&&
.Short Term...(This evening through Friday)
Issued at 312 PM EST Thu Jan 18 2024
A round of accumulating snow is expected tonight into Friday along
with another arctic blast Friday night.
Upper troughing deepens over the Great Lakes region with a 160 kt
jet streak rounding the base of the trough through the Ohio Valley
tonight. Upper troughing interacting with a weak surface feature
lifting northeast through Kentucky will promote lower level and
surface cyclogenesis Friday morning. 850mb trough axis becomes
centered over Indiana tonight before closing off over Ohio Friday
morning as the main low level and surface low strengthens. As this
system becomes better organized tonight, moisture advection through
the column will continue to increase with BUFKIT profiles showing
saturation reaching the surface by the 03-06z timeframe. Steeper mid
and upper level lapse rates and deep saturation within the dendritic
growth zone may lead to heavy snow bands through the night. Also
with the development of a closed 850mb and surface low, hi-res
guidance is hinting at the possibility of a deformation band setting
up on the backside over portions of Central and East Central Indiana
Friday morning. If this occurs, periods of heavier snow could
persist for a few hours longer, leading to higher snowfall totals.
Best chance of this happening is around the I-65 corridor and points
eastward. Have gone ahead and expanded the Winter Weather Advisory
southward to include the I-70 corridor and much of Eastern Indiana
for the potential of overachieving snow amounts and impacts to the
morning commute in the Indy Metro area. Still thinking a general 2-4
inches is expected across North Central Indiana from Lafayette to
Kokomo to Muncie and 1-3 inches along the I-70 corridor including
Indianapolis. Will have to watch where banding sets up and where the
potential deformation band sets up as those specific areas will get
higher amounts than forecasted. Will update the forecast accordingly
during the event to highlight these areas.
One forecast concern is how much low level dry air is present
currently with dew point depressions still 15 to 25 degree. Upstream
observations do show low level saturation and rising dew points. But
such dry air in place may delay the start time of snowfall a few
hours. Still have the Winter Weather Advisory starting at 9 PM for
all areas, however heavier snow rates may not begin until after
midnight further south along the I-70 corridor.
Surface low pushes eastward during the day on Friday, however the
upper trough holds back with multiple upper vort maxes rotating into
the region. At the same time, low level arctic air rushes into the
state with 925-850mb temps dropping to -15 to -20C by Friday evening
lowering the Dendritic Growth Zone to the surface. BUFKIT profiles
show enough saturation within the DGZ and PBL to keep snow showers
and flurries in the forecast along and north of I-70 through Friday
evening. Little to no additional accumulation expected from
lingering snow showers.
With a 1040mb high approaching, the northerly pressure
gradient and low level jet increase during this time period. As cold
air advects in, expect low level lapse rates to steepen and stronger
winds to mix to the surface. Winds increase to 15 to 20 mph at the
surface with gusts upwards of 25-30 mph Friday around sunrise
through Friday evening. Temperatures will likely struggle to rise
Friday with temperatures steady in the teens through the day and
then dropping into the single digits after sunset. Wind Chill values
will likely be at or below zero all day Friday, falling below -15
after sunset. Have gone ahead and issued a Wind Chill Advisory for
the northern 75 percent of Central Indiana beginning Friday night at
7 PM EST.
&&
.Long Term...(Friday night through Thursday)
Issued at 312 PM EST Thu Jan 18 2024
Friday night through Sunday...
The impactful winter weather system expected across central Indiana
in the short term will be departing Friday night. Arctic air will
surge back into the region behind this system over the weekend with
the greatest concern being the potential for dangerous temperatures
and wind chills once again. Expect lows to drop well into the single
digits and near zero across the north Friday night into Saturday
morning. This combined with elevated winds overnight will lead to
the potential for dangerous wind chills below -15F. A wind chill
advisory has been issued for all of central IN. Broad cyclonic flow
still in place combined with flow off of Lake Michigan should
support scattered light snow showers or flurries. Minor
accumulations around a few tenths of an inch are possible, mainly
across east/northeast portions of the area.
Dry conditions are expected over the weekend as a strong arctic high
builds in. This leads to increasing concerns for dangerously cold
temperatures Saturday night into Sunday. Prime radiational cooling
conditions with the arctic high directly overhead Saturday night and
expected snowpack will allow for temperatures to quickly plummet
from highs in the teens. Due to this potential, went well below
guidance for overnight lows. The current forecast calls for
temperatures to bottom out around -5F to -10F, mainly near and north
of the I-70 corridor where the greatest snowpack will be. The
potential is there for even colder temperatures. However,
confidence is not high enough at this time to lower temperatures
further. Wind chills may not be as much of a concern for this period
since winds will be light, but temperatures will still be very cold.
Expect temperatures to then quickly warm up during the day Sunday
with return flow and upper level ridging building in.
Sunday night onward...
Dry conditions will likely continue through much of the day Monday
under the influence of large scale subsidence before the weather
pattern becomes more active. Ensemble guidance is in good agreement
that deep troughing will setup from the southwest to the southern
plains with multiple embedded shortwaves expected to move across
central IN. Increasing warm-moist advection and multiple shortwaves
expected to traverse the region will bring the potential for
multiple rounds of rain through the week. In addition, southerly
flow should help temperatures warm up through the week. The first
round of precipitation is expected to move in late Monday into
Tuesday. Surface temperatures will be hovering around freezing which
may support areas of freezing rain. It`s hard to determine if or how
much ice accumulation is expected this far out since temperatures
are marginally supportive.
&&
.Aviation...(00Z TAF Issuance)
Issued at 559 PM EST Thu Jan 18 2024
Impacts:
- Snow will bring IFR conditions overnight
- Gusty NW winds up to around 25 knots Friday
Discussion:
Snow will develop this evening and continue into the overnight.
Conditions will fall to MVFR near the start time of snow then
quickly fall to IFR as snow intensifies. Snow intensity will
diminish from west to east toward 12Z, allowing some improvement.
Colder air moving in behind the main push of snow will bring
northwest winds gusting up to around 25kt, and these winds will
continue through the daylight hours Friday. Questions remain on how
much blowing snow will occur, but the potential exists for some
reduction in visibility on Friday, especially at the northern sites.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 10 AM EST Friday for INZ021-
028>031-035>049-054>057-065.
Wind Chill Advisory from 7 PM Friday to 10 AM EST Saturday for
INZ021-028>031-035>049-051>057-060>065.
&&
$$
Update...50
Short Term...CM
Long Term...Melo
Aviation...50
Area Forecast Discussion
National Weather Service Louisville KY
856 PM EST Thu Jan 18 2024
...Forecast Update...
Issued at 855 PM EST Thu Jan 18 2024
Light wintry accumulations have started to come in across the region
tonight. Over south-central Kentucky where precip has mainly been
freezing drizzle/mist, light glazes of ice have been reported in
several locations. Farther north, particularly in the Bluegrass
region, snow has been the pre-dominant p-type and light
accumulations (1 inch or less) are common.
While snow banding is evident via obs and radar across north-central
Kentucky into the Bluegrass, recent trends would suggest that mid-
level dry air is becoming more prevalent over central Kentucky, and
that we may see more areas periodically switch over to freezing
drizzle/mist for a short time after a snow band passes by. The
window for freezing rain/drizzle may be short-lived, though, as KLVX
is starting to show an uptick in reflectivity to our northwest as
our next wave approaches... and while much of this activity is not
reaching the ground in southern IN/IL, it could provide enough mid-
level moisture or act as a `seeder-feeder` to where everything will
transition to snow from west to east over the next few hours.
Issued at 611 PM EST Thu Jan 18 2024
Radar echoes have `blossomed` over the last several hours as
forcing/lift has begun to support the development of wintry
precipitation. Most reports of wintry precip reaching the ground
have primarily been along and south of the Western Kentucky and
Bluegrass Parkways, and have varied from snow, to sleet, to freezing
rain/drizzle.
The p-type forecast could be a bit of a challenge tonight for
portions of central Kentucky, and we may see p-types bounce around
several times at any one given location, but AMDAR soundings and
radar trends will be key for identifying near-term areas of concern.
In areas where we`ve seen higher reflectivity values (~15dBZ or
greater), p-types have generally been snow. In areas where the
reflectivity returns are light (<10dBZ), reports have generally been
freezing rain/drizzle. The latest ACARS sounding data from the
Nashville airport (which happens to be in the lighter reflectivity
areas via radar) show that there has been a loss of deeper moisture
above 750mb, which happens to be below the ice crystal growth zone,
so it makes sense that there are no snow reports in these particular
areas.
So based on the data above, the best potential for the highest
accumulating snow amounts over the next 2-3 hours will most likely
be in a corridor from Bardstown to Horse Cave, points east-
northeastward. This is where the deeper moisture resides aloft for
ice crystal growth via radar trends. Outside of that corridor, we
may see p-types bounce around from snow to fzra/fzdz, though it`s
likely the northern side of the CWA would stay more snow given
slightly colder temperatures aloft. Forecast grids have been tweaked
to account for these trends.
.Short Term (Now through Friday)...
Issued at 337 PM EST Thu Jan 18 2024
=================================================================
Key Messages:
* Winter Weather Advisory in effect
=================================================================
There are few changes to the forecast. We are still expecting two
waves of wintry precipitation to pass through southern Indiana and
central Kentucky this evening through the afternoon tomorrow. The
first round of precipitation will bring a mix of rain and snow to
parts of of central Kentucky, south of the Interstate 64. North of I-
64, snow is expected to be more common. Around midnight, a break in
precipitation is expected before a second wave of snow arrives from
the northwest beginning in the predawn hours and lasting into the
afternoon.
Expected total snow accumulations from both waves to range from 0.1
near Bowling Green to 2.5 to 3" in the far eastern Bluegrass region.
This puts Lexington in the 2-2.5" range, Louisville 1-1.5" range,
Jasper, IN 0.25-0.5" range, Madison, IN 1.5-2" range, and Liberty,
KY 1-2" range. These numbers are fairly tight ranges. It`s likely
not exact, but it`s current thinking.
Freezing rain and icing isn`t expected to cause many negative
impacts. In the area south of a line from southern Perry County, IN
to southern Jefferson County, KY, and on to southern Garrard County,
KY total ice accumulations have fallen slightly from a maximum of
around 0.05" to 0.03". Usually ice in the 0.1" range will start to
cause problems, so will keep looking at ice potential but not too
concerned with it currently.
The first wave is already beginning to work into southern Kentucky.
This is being driven by weak isentropically lifted moisture in
southern flow ahead of a shortwave. With today`s high temperatures
underperforming slightly, many areas are within a degree or two of
freezing. This will favor more frozen precipitation over rain. Model
soundings in south central Kentucky keep levels below around 750 mb
saturated, but the dendritic growth zone (DGZ) remains unsaturated
much of the afternoon/evening. This lack of ice crystal formation
would lead to more drizzle and less snowfall, and if temperatures
are below freezing, it should produce freezing drizzle on surfaces
that below freezing. However, experience says there have been many
times when model soundings showed dry DGZ layers, and it still
snowed. Still believe there will be precipitation across southern
Kentucky. Activity is expected to increase in the coming hours and
will exit central Kentucky from 5-8z tonight. Many will experience a
break before the second wave of precipitation reaches their
location.
Tonight, around 6-7z, a strong upper jet will stretch southeast
along the backside of an upper trough from Montana, through the
Plains, and into western Tennessee. This will place our CWA under
the jet`s left exit region which will increase forcing over the CWA.
At the same time, northwest flow will bring a surge of deep layer
moisture to the Lower Ohio Valley. This moisture will fully saturate
the DGZ, and with a wind profile of northwest winds, there will be
plenty of cold air. All the precipitation with this system will fall
as snow. Believe this added forcing and the deep layer moisture will
help to produce better snowfall compared to the first system this
evening, but the quick moving nature of the system will limit dwell
time, limiting snow totals. Most of the moderate snowfall rates are
expected to end during the morning hours, but with low level
clouds/moisture and falling temperatures in the low 20s and teens,
flurries and light snow could linger later in the day.
With the expected winter weather the Winter Weather Advisory will
remain in effect through 0z Saturday.
.Long Term (Friday Night through Wednesday)...
Issued at 300 PM EST Thu Jan 18 2024
=================================================================
Key Messages:
- Frigid weekend
- Significant warm up next week with snowmelt and rain chances
=================================================================
Friday Night through Sunday Night...
Fairly impressive 1040+mb high is forecast to drop into the Plains
Friday night and then drift right over Kentucky Saturday night. Low
clouds will likely remain in place across the region Friday night
and into Saturday morning and this will not allow radiational
cooling to allow temps to plummet. In addition, we`ll still have a
residual pressure gradient keeping winds up during the night.
Nonetheless, cold advection will allow temps to fall into the lower
single digits across the area with wind chills in the -5 to -10
degree range. We`ll see sky clear from west to east during the day
on Saturday with highs only warming into the teens.
Saturday night will feature clear skies with the 1040+mb high moving
directly over Kentucky by 12Z Sunday morning. Clear skies, very
light winds, and an expected snowpack will allow for a very good
radiational cooling night. Given this setup and based on what
happened earlier this week with a similar high (though weaker and
more south of us), I have gone ahead and went close to the bottom
5th percentile of the NBM guidance, which is still likely too warm.
The coldest temps will be found where we have the deepest snowpack.
Areas that have snow on the ground will likely be below zero in most
cases and where deep snow pack and ideal radiational cooling take
places, lows in the -5 to -15F range look attainable. After the
snow ends on Friday, we should be able to better define which areas
will see these dangerously cold temps. With the high drifting to
our east/southeast during the day on Sunday, we`ll start the warmup
process. Current guidance suggests highs in the mid-upper 20s,
which may be too generous over snowpack regions. Lows Sunday night
will be a bit warmer given the southwest flow and increasing warm
advection. So readings in the mid teens look good here.
Monday through Thursday...
A much anticipated warmup will commence on Monday as upper ridging
holds sway across the region and a continued low-level southwest
flow develops across the area. Highs on Monday look to warm into
the upper 30 to perhaps near 40 in some spots. Gulf moisture will
increase across the region late Monday night ahead of an approaching
trough. We may see precipitation break out after midnight and
depending on how fast precip develops, we could see a brief wintry
mix as precipitation starts as lows will be in the low-mid 30s.
Precipitation should continue through the day on Tuesday with
perhaps a late day break before another wave of precipitation moves
in Tuesday night. Highs Tuesday will continue to be milder with
upper 40s to lower 50s expected. Some additional rainfall looks
likely on Wednesday into Thursday before the moisture plume off the
Gulf moves eastward into the southern Appalachians and the Mid-
Atlantic. Highs Wednesday will be in the lower 50s with highs by
Thursday warming into the upper 50s to lower 60s.
As far as precipitation amounts go, total rainfall amounts of 1 to
1.75 inches will be possible in the Monday night through Thursday
time frame. Combine this rainfall with ongoing snowmelt given the
warm temperatures, we will see soils become quite saturated and
drought conditions will continue to improve. While area rivers and
streams are low and can handle water, there is a concern that we may
see some quick rises on area creeks and streams next week. Some
minor river flooding will be possible toward the end of the week on
the lower Green River basin (Rochester/Woodbury).
&&
.Aviation (00Z TAF Issuance)
Issued at 611 PM EST Thu Jan 18 2024
Wintry precipitation has moved into the region and is overspreading
much of central Kentucky. P-Types could be a challenge at times as
observations from several sites have bounced between snow, sleet, or
freezing rain/drizzle/mist. In general, the best chances for snow
will be across KLEX/KSDF, though can`t rule out periods of light
freezing drizzle at times. Cigs/Vis will likely be in the MVFR to
IFR range.
We may see a brief break in the activity shortly after midnight, but
another wave of wintry precip will be right on its heels along and
behind an arctic front. Precip is expected to be primarily snow with
this wave. Snow showers should taper down tomorrow morning after
sunrise, and winds will pick up out of the northwest. MVFR stratus
will likely linger through much of the day tomorrow.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
KY...Winter Weather Advisory until 7 PM EST /6 PM CST/ Friday for
KYZ023>043-045>049-053>057-061>067-070>078-081-082.
IN...Winter Weather Advisory until 7 PM EST /6 PM CST/ Friday for
INZ076>079-083-084-089>092.
&&
$$
Update.........DM
Short Term.....KDW
Long Term......MJ
Aviation.......DM
Area Forecast Discussion
National Weather Service Memphis TN
610 PM CST Thu Jan 18 2024
...New AVIATION...
.SYNOPSIS...
Issued at 305 PM CST Thu Jan 18 2024
An arctic cold front will move into the Lower Mississippi Valley
later tonight into Friday bringing a return of colder air into
much of the weekend. Wind chill values below zero will be possible
both Friday and Saturday nights. A warming trend will begin next
week with a transition to rain showers and milder temperatures.
&&
.DISCUSSION...
(This evening through next Wednesday)
Issued at 305 PM CST Thu Jan 18 2024
Surface analysis this afternoon places an arctic cold front from
the Great Lakes Region back through northern Missouri and into
portions of northern Kansas and Nebraska. Meanwhile, a surface
low near the Arklatex and a warm front over Louisiana is
producing some overrunning precipitation/isentropic ascent across
portions of the Mid-South this afternoon. KNQA/KGWX/TMEM still
show some light returns occurring mainly east of the Mississippi
River across the Mid-South. The last ACARS sounding from near the
Memphis International airport around 1830Z indicated a warm nose
aloft with temperatures dropping below freezing at or below 2000
ft. Surface temperatures as of 2 PM CST range from above freezing
across north Mississippi and lower 30s elsewhere across the area.
Short-term models along with latest observational trends indicate
the aforementioned light precipitation producing light freezing
drizzle or drizzle will be coming to an end over the next few
hours as isentropic lift wanes and drier air filters into the
area. Not much improvement in temperatures are expected for the
remainder of the afternoon and will begin dropping into tonight as
the aforementioned arctic cold front drops into the Lower
Mississippi Valley later tonight into Friday morning. The Winter
Weather Advisory is in effect until 7 PM this evening and has
already been trimmed back to northwest Tennessee. This advisory
may be cancelled before expiration if the precipitation comes to
an end early. Short term high resolution guidance is indicating
the probabilities for fog and low visibilities to develop tonight.
Conditions will be monitored tonight for potential Dense
Fog/Freezing Fog Advisories tonight if conditions warrant.
Much colder air will arrive for Friday through Sunday morning. A
combination of elevated winds and cold temperatures will result in
wind chill values dropping below zero Friday night into Saturday
morning, and potentially Saturday night into Sunday morning. A
Wind Chill Advisory was issued for Friday night into Saturday
morning, and another one will likely be needed for Saturday night.
Long term models indicate a warming trend will begin late Sunday
and through much of next week as southwest upper level flow aloft
and milder air returns to the region. Precipitation will
transition to rain showers next week along with a potential for
perhaps an isolated thunderstorm late next week. Forecast rainfall amounts
towards the end of the period may average between 1 to 2 inches.
CJC
&&
.AVIATION...
(00Z TAFS)
Issued at 610 PM CST Thu Jan 18 2024
Dense FG and FZFG will develop at all sites over the next few
hours as winds remain weak and moisture pools ahead of an
approaching cold front. Prevailing LIFR CIGs and VSBYs will
persist throughout much of the overnight period. An arctic cold
front will move through all sites between 09Z and 12Z with strong
northwest winds behind it through the end of the TAF set. CIGs
will lift to MVFR behind the front and eventually to VFR near the
end of the period.
AC3
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Freezing Fog Advisory until 9 AM CST Friday for ARZ009-018-
026>028-035-036-048-049-058.
Wind Chill Advisory from 10 PM Friday to 11 AM CST Saturday for
ARZ009-018-026>028-035-036-048-049-058.
MO...Freezing Fog Advisory until 9 AM CST Friday for MOZ113-115.
Wind Chill Advisory from 10 PM Friday to 11 AM CST Saturday for
MOZ113-115.
MS...Freezing Fog Advisory until 9 AM CST Friday for MSZ001>017-
020>024.
Wind Chill Advisory from 10 PM Friday to 11 AM CST Saturday for
MSZ001>017-020>024.
TN...Freezing Fog Advisory until 9 AM CST Friday for TNZ001>004-
019>022-048>055-088>092.
Wind Chill Advisory from 10 PM Friday to 11 AM CST Saturday for
TNZ001>004-019>022-048>055-088>092.
Winter Weather Advisory until 7 PM CST this evening for
TNZ001>004-019>022-051.
&&
$$
PUBLIC FORECAST...CJC
AVIATION...AC3