000
FXUS63 KMQT 200722
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
322 AM EDT Sat Apr 20 2024

.KEY MESSAGES...

- Elevated fire weather conditions Sunday and Monday, mainly in the
west and central.
- Showers return Monday night into Tuesday.
- Temperatures warming through Monday, then cooler Tuesday/Wednesday.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 233 AM EDT Sat Apr 20 2024

Upper air pattern consists of a closed 500 mb low in James Bay with
a trough across the upper Great Lakes and northern plains. This
upper trough remains through 00z Sun. Deeper moisture moves out
today, so flurries and light snow showers will come to an end.
Overall, did not make too many changes to the going forecast.

&&

.LONG TERM /TONIGHT THROUGH FRIDAY/...
Issued at 321 AM EDT Sat Apr 20 2024

To start the long term period, the 500 mb pattern will feature
anomalous ridging over western Canada and anomalous troughing
centered over Hudson Bay and encompassing the remainder of eastern
Canada. Some of this troughing will extend into the upper Great
Lakes, although with lower amplitude as the flow pattern trends more
zonal with southward extent. The height gradient tightens through
the day Sunday as ridging shifts east somewhat and a vort max along
the southern periphery of the Hudson Bay low tracks from southern
Ontario into southern Quebec. Although the forcing for ascent with
this feature will remain displaced northeast of the forecast area,
it will push the tail end of a cold front across the eastern lake
into the eastern UP through the day. This will allow surface winds
to assume a northerly component, keeping much of the north-central
and eastern UP on the cool side, especially along the Superior
shoreline, with highs only in the mid to upper 40s. Deep mixing is
forecast throughout the UP with forecast soundings suggesting mixing
up to around 800 mb. This will result in a blustery day, with wind
gusts around 25 mph. Due to the mixing and dry air aloft, relative
humidity is likely to be lower than NBM guidance, especially across
the interior west where temps will likely reach the low to mid-50s
and dewpoints falling to near 20, yielding min RHs in the 25-30
percent range. Combined with the winds and a few days of drying,
this setup will yield elevated fire weather concerns (although with
temperatures still a bit on the cool side). The cooler temperatures
over the north-central and east should limit fire weather concerns
there.

Ridging briefly builds over the area Sunday night, resulting in good
radiational cooling conditions and lows mainly in the mid to upper
20s. This ridge will quickly give way to return flow in advance of
an approaching shortwave. The warm advection should give temps a
nice boost with highs mainly in the upper 50s/low 60s, although
cooler along the Lake Michigan shoreline. Models once again depict
deep mixing, so we increased wind gusts and decreased dewpoints
relative to NBM once again. This could be another day with elevated
fire weather conditions with RH values 25-30 percent and wind gusts
20-25 mph over the central and west.

Surface low associated with the aforementioned shortwave will move
out of the southern Canadian prairies Monday and to the vicinity of
Lake Superior Monday night, although there is still uncertainty with
the exact low track. A band of showers is expected (80% chance)
Monday night as the low level jet strengthens ahead of this feature.
Strong cold advection ensues on Tuesday as the low moves off to the
east. There is considerable uncertainty on temperatures in the
Monday night/Tuesday timeframe owing to differences in timing and
track of the low. There could be a non-diurnal trend to the temps if
the cold advection is on the early side Tuesday with temps falling
from north to south through the day. Another band of showers is
likely along the cold front, and if the cold air slides in soon
enough, it could mix with or turn to snow (although impactful
accumulations appear unlikely at this time). High pressure building
in from the northwest should shut off precip rather quickly Tuesday
night. A dry stretch is favored Wed/Thu beneath this high, while a
warming trend to above normal is expected for the end of the week
into next weekend on the back side of the high. Rain chances enter
the picture as well Fri into the weekend, but confidence is low on
timing, so broad-brush chance (30-50 percent) exists for now.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1220 AM EDT Sat Apr 20 2024

Some light snow showers look to continue through the area the rest
of this morning as low pressure troughing slowly is pushed out of
the region by a weak ridge. This will likely (80+% chance) cause
cigs to drop into high-end MVFR conditions. However, chances seem
fairly low (20 to 30%) that we will get below 2 kft now. That being
said, in a "heavier" snow shower, we could see the vis drop down to
MVFR from time to time also. As ridging tries to build in from the
west during the daylight hours, expect the snow shower activity to
cease and for skies to scatter out by the afternoon. Otherwise,
expect gusty W to NW winds today. Some marginal LLWS is possible,
but unlikely (20 to 30% chance), over KSAW for the next couple of
hours. However, cold air advection should bring the stronger winds
to the surface instead of keeping them trapped aloft. We also have a
low chance of seeing some marginal LLWS over KCMX and KSAW this
evening too, but given the low 20 to 30% chance, I`m certainly not
confident enough to include it within the TAF.

&&

.MARINE...
Issued at 321 AM EDT Sat Apr 20 2024

West to northwest winds of 20-30 kt continue today into tonight,
strongest east half, although they will decrease for a bit to 20 kt
or less west half early tonight. More stable air building over the
west half will allow winds to decrease to less than 20 kt Sunday
afternoon, while instability remains over the east half with 20-30
kt northwest winds continuing. The next period of interest is
Monday night as southerly winds increase ahead of an approaching
low. Although stability is expected to keep these winds to 25
kt or less, a strong pressure gradient on the back side of the
low brings potential for gales especially over central/western
portions of the lake late Monday night into early Tuesday
(around 50 percent). The potential for brief gales has been
growing, but there is still uncertainty with the low track.
Winds will become northerly Tuesday with widespread 25-30 kt
winds as colder, unstable air overspreads the lake.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Small Craft Advisory until 2 PM EDT /1 PM CDT/ this afternoon
     for LSZ240-245-246.

  Small Craft Advisory until 8 PM EDT /7 PM CDT/ this evening
     for LSZ241-247>249.

  Small Craft Advisory until 8 AM EDT Sunday for LSZ242>244-250-
     251.

Lake Michigan...
  Small Craft Advisory until 8 AM EDT this morning for LMZ221-
     248-250.

&&

$$

SHORT TERM...07
LONG TERM...Thompson
AVIATION...TAP
MARINE...Thompson