792
FXUS63 KMQT 021726
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
126 PM EDT Sun Jun 2 2024

.KEY MESSAGES...

- Patchy fog expands until sunrise and will become locally
  dense. Fog will burn off within a couple of hours after
  sunrise. Marine fog on portions of Lake Superior may be an
  issue through the day.
- Isolated afternoon showers possible interior eastern Upper MI
  due to converging lake breezes.
- Frequent opportunities for showers and thunderstorms over the
  next 7 days.
- Above normal temperatures through the first half of the week,
  then turning cooler for the last half and next weekend.

&&

.UPDATE...
Issued at 930 AM EDT Sun Jun 2 2024

The forecast remains on track this morning. Patchy morning fog is
mixing out, though satellite does show marine fog over Lake Superior
beginning to seep southward towards the Picture Rocks shoreline.
Thus, will not rule out some patchy fog along the beaches of Alger
county, and possible Luce and even eastern Marquette counties.
Otherwise tranquil weather continues, with just a slight chance for
a few showers to pop on the lake breeze over the eastern UP this
afternoon.

&&

.SHORT TERM /THROUGH THIS AFTERNOON/...
Issued at 323 AM EDT Sun Jun 2 2024

Water vapor imagery and RAP analysis show a deep mid-level low
centered over northern Manitoba. To the s of this feature, flow is
zonally oriented along the U.S./Canada border from the Pacific NW to
Lake Superior. Upstream, the next shortwaves of interest are over
the northern Rockies. Shortwave that was over far northern ND 24hrs
ago has lifted ne and is nearing James Bay. This wave has helped to
drive a drier air mass aloft into Upper MI. At the sfc, a weak high
pres ridge is over the Upper Mississippi Valley. Weak pres gradient
over the fcst area is leading to light/calm wind at many locations
early this morning. Where skies are clearing and where rainfall
occurred yesterday and last evening, the light wind is allowing
radiation fog to develop. So far, coverage is limited. Current
temps range thru the 50s F.

Expect fog to expand thru sunrise as areas of lingering cloudiness
clear out. The fog will likely become locally dense. As we are just
under 3 weeks from the summer solstice, fog should quickly burn off
within a couple of hrs of sunrise as insolation rapidly increases,
leaving behind sunny skies. Aforementioned sfc high pres ridge will
shift to the western Great Lakes today, allowing lake breeze
circulations to rule the day. Over the eastern fcst area, the
converging lake breezes from Lake MI and Lake Superior raise the
prospect for a few -shra to develop. Models suggest at least a few
hundred j/kg of MLCAPE developing, but as is often the case, the NAM
is greatest. The NAMnest has upwards of 1000j/kg of MLCAPE and will
be discounted. Based on fcst soundings, it appears there will be cap
to sfc based convection somewhere in the 10-15kft range, so cloud
depth should be sufficient for isold -shra development, but not
thunder unless the outlier higher MLCAPE solution occurs. Fcst for
the aftn will reflect schc pops, around 20pct, centered across
southern Luce County where signal from models is most consistent,
but isold -shra could occur as far w as northern Delta/adjacent
Alger counties. To the w, building mixed layer will tap drier air,
driving dwpts down to the upper 30s/lwr 40s F interior w half. With
aftn temps in the 75-80F range, RH will tumble toward 25pct. Winds
will be very light in that area today, not much more than around
5mph, limiting fire wx concerns.

&&

.LONG TERM /TONIGHT THROUGH SATURDAY/...
Issued at 323 AM EDT Sun Jun 2 2024

Mostly clear skies this evening give way to rain showers and a few
thunderstorms over the far western U.P. by Monday morning as a cold
front begins pushing into the area. With clouds moving in tonight
over the west half in particular, expect lows over the west half to
be in the 50s to near 60 over the far west. Meanwhile, with less
cloud cover overhead, expect lows to get down to around 50 in the
east. No severe weather is expected Monday as the cloud coverage
will limit CAPE and lapse rates; in addition, bulk shear values look
to generally be less than 30 knots. That being said, it is still
possible that we could see a stronger cell or two that could produce
gusty winds and small hail. With the NAEFS and European ensembles
showing PWATs above 1.25 inches (which is above the 90th percentile
of modeled climatology), we could see some heavy rainfall at times
over the western half of the U.P. Monday. While the heavy rainfall
looks to be very sporadic in nature, there is a chance (30-50%) that
we could see some isolated spots get above 1 inch of liquid before
the sun sets; hopefully, this will alleviate the remaining moderate
drought concerns over in the western U.P.. As the front slowly makes
its way into the central and eventually eastern portions of Upper
Michigan late Monday afternoon into Monday evening, CAMs show
convective activity dwindling as frontogenesis weakens. Therefore,
lighter rainfall amounts are expected across the eastern half of the
U.P. late Monday.

While it looks like some weak high pressure ridging moves over the
area Monday night into Tuesday, model guidance has trended up rain
chances slightly over the past 24 hours. Therefore, the predicted
cloud cover has increased a little since yesterday morning, with
partly to mostly cloudy skies now expected across the area as a weak
shortwave is expected to precede a second cold front approaching
from the Northern Plains. The shortwave could bring some light rain
showers and a couple of thunderstorms across the area early Tuesday,
particularly over the south central and east where the chances are
highest (15-25%). Warm air advection moving over the area Tuesday
will allow for high temperatures to get well above normal, with
spots in the interior west and possibly east getting above 80
degrees. Given the moisture from the Gulf and somewhat cloudy skies
overhead, we could see dewpoints get into the mid to upper 60s in a
few places, mainly over the interior west (a.k.a. it may feel a bit
muggy). With the cold front looking to arrive during mainly the
overnight hours, severe thunderstorms aren`t expected. However, with
the exact timing of the front`s arrival not pinned down quite yet,
some model guidance showing MUCAPE over 1000+ J/kg during the early
evening hours (and 100s+ J/kg in the overnight hours), and bulk
shear values in the 30 to 40 knot range, severe storms cannot be
completely ruled out, even though the chance right now is very small
(<2%); the location with the best chance for severe weather late
Tuesday is currently the far west. The cold front continues through
the U.P. through Wednesday, as the rainfall marches eastward with
the front. As the showers and storms associated with the front are
exiting the eastern U.P. Wednesday afternoon, a secondary shortwave
moving into the western U.P. behind the front could bring additional
showers and thunderstorms back across the area behind it.

The above normal temperatures we`ve been enjoying look to come to an
end for the last half of the week as a low pressure settles over
northern Ontario and sends cold air advection and multiple weak
shortwaves across our area from late Wednesday through this next
weekend. As this occurs, expect highs to drop into the 60s and for
lows to get into the 40s, which is below normal for this time of
year. In addition, light rainfall chances are expected from Thursday
onwards due to the shortwaves rotating over our area; while we may
see a rumble of thunder here or there during peak heating hours,
given the cooler temperatures, thunderstorm activity should be less
common.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 125 PM EDT Sun Jun 2 2024

VFR prevails at all terminals the rest of today into tonight with a
ridge over the area. An approaching disturbance tonight may spread
some -shra into IWD and CMX late tonight, but there is higher
confidence in shower activity after 12Z Monday with ceilings
lowering to MVFR. VFR holds on at SAW into tomorrow morning. Ahead
of the disturbance, low-level jet will reach western Upper MI late
tonight, resulting in LLWS at IWD/CMX. Otherwise, expect winds to
remain below 10 knots, of variable direction today due to lake
breezes but turning over to the SSE into Monday.

&&

.MARINE...
Issued at 323 AM EDT Sun Jun 2 2024

Light winds of 20 knots or less continue today into tonight as weak
surface high pressure continues over Lake Superior. However, as a
cold front moves through late tonight into Monday, southerly winds
look to gust up to 20 to 25 knots Monday, particularly over the
central lake and possibly near the south shoreline (especially near
the tip of the Keweenaw, where higher wind gusts could be seen).
Once the cold front moves through, the winds die down to 20 knots or
less yet again by Monday evening as weak high pressure ridging
sprints through the region. The light winds continue until a cold
front from the Northern Plains passes west to east across the lake
Tuesday night through Wednesday. Behind the front, expect southwest
winds to gust up to 20 to 25 knots over the western half of the lake
on Wednesday as a secondary shortwave quickly moves through the
region. As a parent low sets up shop in northern Ontario for the
latter half of the week, expect cold air advection and multiple
shortwave lows rotating around the parent low to bring higher west
to northwest winds across Lake Superior throughout the rest of the
work week and into this next weekend; we could see westerly gusts up
to 30 knots as soon as Thursday.

As for other marine hazards, the fog over Lake Superior looks to
burn off a few hours after the sunrise this morning as the sun
warms the air. A few thunderstorms could be seen over the lake
tonight through Monday night from west to east as the first cold
front pushes through. The second cold front pushing through
looks to bring a few more thunderstorms across the lake from
west to east from Tuesday afternoon through Wednesday. No severe
weather is expected at this time, although there is a very low
chance (<2%) that we could see some severe weather over the far
western lake Tuesday afternoon and evening.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.

&&

$$

UPDATE...
SHORT TERM...Rolfson
LONG TERM...TAP
AVIATION...LC
MARINE...TAP