Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 02/18/24

Area Forecast Discussion

National Weather Service Detroit/Pontiac MI

 708 PM EST Sat Feb 17 2024

.KEY MESSAGES...

- Gusty winds and cold temperatures bring blustery conditions through Sunday
  with wind chills in the teens and single digits.

- Light snow showers possible tonight mainly north of I-69.

- Warming trend expected early to middle next week.

&&

.AVIATION...

A broad area of low pressure in northern Ontario powers SW wind
gusting in the 20 to 30 knot range this evening until stabilizing
slightly late tonight. The wind pattern and associated cold air mass
keep lake effect clouds and snow showers activated mainly north of
PTK while light system snow brushes MBS. The air is cold but also on
the dry side noted by surface Td in the single digits to teens
extending well upstream into the upper Midwest. This prevents a more
robust lake effect response while allowing ceiling to hold low end
VFR until a few hours during Sunday morning when borderline MVFR
ceiling is possible. West to NW wind continues a 30 knot gust
trend through Sunday afternoon.

For DTW... Clear sky along the DTW terminal corridor allows wind
gusts to subside toward midnight. Clouds return late tonight and
Sunday, mostly VFR below 5000 ft.

.DTW THRESHOLD PROBABILITIES...

* Moderate for ceiling aob 5000 feet late tonight and Sunday.

&&

.PREV DISCUSSION...
Issued at 349 PM EST Sat Feb 17 2024

DISCUSSION...

Following an extended period with temps averaging some 10+ degrees
above normal since Feb 1, a longwave trough over the eastern Great
Lakes has delivered the first below-normal temps of the month so
far. 850mb temps have settled down to near -16 C per the 12z DTX
RAOB and regional ACARS soundings, translating to high temps in the
20s F with blustery west wind holding wind chills in the teens.
Steady height/thickness rises commence this evening with a low
amplitude surface ridge holding mainly dry conditions. Surface temps
will fall to the lower 20s to upper teens tonight, bringing wind
chills back in the single digits. A strong jet streak traversing
around the Hudson Bay upper low pushes south into the local area
overnight with a surface reflection strengthening and tracking from
northwestern Ontario southeastward into far southern Quebec by
Sunday.

This deepening system will tighten the pressure gradient
considerably with winds shifting to southwest and remaining gusty
through the night as a 45-50 kt LLJ descends to near 900mb and into
the still mixed boundary layer. This will result in surface winds of
15 to 25 mph with some gusts of 30 to 35 mph overnight. Light snow
will also accompany the system, mainly across the Tri-Cities and
Thumb which will see a glancing shot of better ascent tied to the
jet`s left exit region. Moisture depth will remain shallow with this
clipper and model QPF remains light at a few hundredths of liquid
equivalent. So any areas that do see snow are most likely to receive
a dusting up to around a half inch.

Cold cyclonic flow is maintained across the state on Sunday as the
system departs to the east, though the better cold air advection
will be held well to the north of SE MI. Expect temps to rebound
into the mid to upper 30s by the afternoon, but continued gusty
winds to around 30 mph will hold wind chills in the 20s. The
environment may support occasional flurries or light snow showers at
times as model soundings show lingering supersaturation with respect
to ice in the cloud bearing layer that flirts with the DGZ through
the day. Some briefly higher intensity snow showers may brush the
Thumb by the late afternoon or evening as a surface trough shifts
the wind direction to northwest, sending a Lake Superior moisture
plume south across Lake Huron.

The eastern Canada longwave trough flattens on Monday and largely
lifts out of the Great Lakes, helping open the door for a
substantial warm advective pattern that will characterize the first
half of next week. An developing split flow pattern places SE MI
within a dearth of forcing resulting in mainly dry conditions Monday
and Tuesday. Low level southwest flow during this period advects in
a warmer air mass and a fair amount of sun boosts highs back into
the 40s. The next chance for showers arrives on Wednesday as a quick
hitting shortwave tracks in from the Midwest. Mild conditions look
to hold through Thursday but then a stronger push of cold air is
expected to send temps to more seasonable values by next weekend.

MARINE...

A low pressure system is strengthening over Ontario today before
passing east into Quebec Sunday morning. Pressure gradient is
tightening this afternoon with winds now out of the southwest. Cold
air advection continues even with the southwest flow as the cold
airmass extends down the Midwest into the Mid MS Valley. So winds
have responded already with gusts approaching 25 knots across the
region. Winds should peak around 30 knots this evening into the
overnight with a few gusts to around Gales in vicinity of Saginaw
Bay. Small Craft Advisories are in effect for all nearshore waters
and Lake St Clair to account for these winds and resultant waves.
The strong winds will also lead to low water conditions in Lake Erie
so a Low Water Advisory is in effect tonight. As the low passes
eastward Sunday, winds will increase out of the northwest again
which will produce a period of Gales so there is now a Gale Warning
for the north half of Lake Huron Sunday morning through the evening.
Northwest flow behind the exiting system will keep the cold airmass
and elevated winds around through Monday but warmer more stable air
will slowly work into the region Monday night.

&&

.DTX WATCHES/WARNINGS/ADVISORIES...

MI...None.

Lake Huron...Small Craft Advisory until 4 PM EST Sunday for LHZ442-443.

     Gale Warning from 10 AM to 10 PM EST Sunday for LHZ361-362.

     Small Craft Advisory until 10 PM EST Sunday for LHZ421-422-441.

Lake St Clair...Small Craft Advisory until 4 PM EST Sunday for LCZ460.

Michigan waters of Lake Erie...Small Craft Advisory until 4 PM EST Sunday for LEZ444.

     Low Water Advisory from 1 AM to 7 PM EST Sunday for LEZ444.

&&

$$

AVIATION.....BT
DISCUSSION...TF
MARINE.......DRK


You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.