000
FXUS63 KMQT 211814
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
214 PM EDT Sun Apr 21 2024

.KEY MESSAGES...

- Elevated fire weather conditions today and Monday, especially in
the west and central.
- Showers return Monday night.
- Temperatures warming through Monday, but becoming much colder and
breezy Tuesday with rain showers turning to snow showers.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 241 AM EDT Sun Apr 21 2024

Upper air pattern consists of a broad 500 mb trough across the Great
Lakes region with a ridge in the northern and Canadian Rockies. This
ridge moves into the northern plains by 00z Mon. A dry and weakening
cold front moves through the area today. Rh`s get down to around 25
percent this afternoon. This is some concern with winds being gusty,
but with recent wet trends, this should keep fire weather concerns
down for now. Will mention in the hwomqt product and also send out
an email to our fire weather partners to let them know about the low
rh values this afternoon.

&&

.LONG TERM /TONIGHT THROUGH SATURDAY/...
Issued at 359 AM EDT Sun Apr 21 2024

Midlevel troughing will pivot into eastern Canada tonight, while
shortwave ridging builds in over the local area through Monday.
Pressure falls over the northern Plains in response to an
approaching compact upper low will result in return flow building
into the UP late tonight into Monday. Surface ridge will be in place
initially Sunday night with good radiational cooling conditions,
although the commencement of return flow will put a floor on lows
and maybe allow temps to rise a couple degrees over the west.
Coolest temps should therefore be across the interior east with some
lower 20s possible. Lows range through the 20s elsewhere, low 30s
along the western Superior shoreline. Southwesterly winds combined
with deep mixing up to 800 mb will result in a nice boost in temps
Monday. Forecast went a bit above NBM guidance with mainly 60s, but
cooler in the 50s downwind of Lake Michigan. The deep mixing should
tap into very dry air aloft and result in low RH values mainly 20-
30% (lowest interior west and central). Winds aloft are not overly
strong, but the deep mixing should result in gusts of 20-25 mph
through the day. This, combined with a couple of good drying days
over the weekend, should result in elevated fire weather conditions
for most of the UP except for the area immediately downwind of Lake
Michigan. The gradient flow should keep the Superior lake breeze at
bay, so the mild temps should extend close to the shoreline.
Mid/high clouds will thicken through the day and eventually deeper
moisture will win out as low-level jet magnitudes increase, and a
band of showers is likely to cross the UP Monday night.

Low pressure will cross Lake Superior from west to east late Monday
night into Tuesday, pushing a cold front southward through the UP
through the day Tuesday. This front will pack a punch with
trajectories behind the front emanating from cold high pressure
centered over southern Hudson Bay. Highs will be in the morning with
temps falling from north to south through the day for most of the
UP, possibly around a 20F drop through the day. NBM guidance does
not have a good handle on the expected sharp temp drop, so a non-
bias corrected dataset was preferred. The frontal forcing and lake
enhancement should lead to a band of showers with rain turning to
snow behind the front. Amounts are expected to be a dusting up to
maybe an inch over the higher terrain. If it were a month or two
earlier, would be more concerned about icy road conditions
developing given the steep temp drop, but the late April sun angle
and temps not falling too far below freezing if at all during the
snowfall makes me skeptical that there will be issues. Still, the
temp drop will be a shock to the system with apparent temps falling
into the 20s and teens for most of the UP by the evening with strong
northerly winds gusting to 30 mph. Ahead of the front, it could be a
sneaky warm day over the south central with temps possibly reaching
the low 60s due to the later frontal passage there.

A chilly airmass will continue to reside over the area Tuesday night
into Wednesday with the Hudson Bay high building in. Skies will be
clear amid the dry and cold airmass, however. The airmass moderates
Thursday into Friday as the high shifts east, with temps rebounding
to near/above normal values. Indications are that moisture will
quickly increase Friday night into next weekend as the Gulf opens
ahead of a negatively tilted trough ejecting out of the central
Plains. Periods of rain are likely Friday night into Saturday.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 214 PM EDT Sun Apr 21 2024

VFR conditions expected to hold steady through TAF period despite
weak cold front dropping through the area.  Winds will, however, be
a bit breezy out of the northwest into this evening with gusts up to
22 kts at times. In addition, look for a wind shift to the
west-southwest this evening at the surface.

&&

.MARINE...
Issued at 359 AM EDT Sun Apr 21 2024

Winds should remain at or below 20 kt through Monday, except over
the far eastern lake this afternoon as a cold front brushes past and
maintains instability with northwesterly wind gusts to 25 kt. A low
pressure system will track west to east across the lake Monday
night, with strong northeasterly to northerly winds developing
behind it late Monday night into Tuesday. There is a brief window
for gales 35-40 kt mainly Tuesday morning along the Keweenaw up
toward the northern Lake Superior buoy, with 50-70% probabilities in
this area. Elsewhere, probability for gales are 20-50%, with gusts
more likely topping out around 30 kt through the day Tuesday. Winds
will gradually diminish Tuesday night as high pressure builds in and
results in light winds Wed/Thu.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Small Craft Advisory until 2 AM EDT Monday for LSZ250-251.

Lake Michigan...
None.

&&

$$

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