447
FXUS63 KMQT 101938
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
338 PM EDT Fri May 10 2024

.KEY MESSAGES...

- Showers increase in coverage from west to east this evening, with
rain continuing overnight into Saturday morning for the central and
eastern UP.

- Winds could briefly gust to 30-40 mph in the WI border counties
this evening with these showers.

- Chances for thunderstorms return on Sunday. There is a low (2%)
chance for some marginally severe hail and wind.

- Dry weather returns for the early part of the next work week.

&&

.SHORT TERM /THROUGH SATURDAY/...
Issued at 338 PM EDT Fri May 10 2024

Early afternoon water vapor imagery shows a vigorous, compact, and
strengthening shortwave trough now pivoting near the Twin Ports.
DCVA forcing bands of clouds and showers from the western UP back
into NW WI/western LS. Initial band appears to be mainly
virga/sprinkles as it interacts with the antecedent dry airmass. 12
minutes of light rain was observed at IWD as this activity passed.
Successive bands of showers should allow for gradual moistening and
more widespread showers with time this afternoon and evening for the
west and central, but totals will be hydrologically insignificant
(although there could be a few brief heavier downpours). Some gusty
winds could occur due to evaporational cooling with these showers,
with a couple upstream automated observations recording 30 kt gusts.
Thunder potential is still low, but cannot be ruled out mainly over
the WI border counties this afternoon/evening.

Surface reflection of this wave will strengthen late tonight into
Saturday morning over northern Lower MI as the midlevel wave goes
negatively tilted. This will result in the eastward progression of
the showers slowing down as a mesoscale pivoting band develops along
the NW flank of the low. This will keep rain in the forecast
overnight for the eastern UP, while coverage gradually decreases in
the central. Some of these showers will likely linger into Saturday
morning for the eastern UP and possibly for the higher terrain of
the north-central due to moist upslope flow. A good soaking rain
could occur where the band pivots, as HREF 90 percentile shows a
0.75 to 1" area over Alger and Schoolcraft Counties. Otherwise,
a high pressure ridge builds in from west to east through the day
with an associated clearing trend (which may not be until in the
afternoon for the central and east). Highs expected to be in the
upper 50s/low 60s, except low/mid 50s along Lake Superior due to
onshore flow.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 347 AM EDT Fri May 10 2024

Rain showers end across the area Saturday as a small high-pressure
ridge moves through the area from the northwest to the southeast.
However, more rainfall returns late Saturday night into Sunday as a
second shortwave drops across the area; while the chance is low
(2%), some marginally severe wind and hail is plausible,
particularly over the south central Sunday afternoon. While high
pressure ridging brings dry weather back over Upper Michigan during
the first half of the next work week, additional rain chances look
to return for the latter portion of next week to end the extended
period. Expect above normal temperatures and precipitation amounts
to continue through the extended period and next weekend. Additional
details follow below.

The shortwave low originally from far northern Manitoba gets pushed
out of the Upper Great Lakes Saturday as shortwave ridging moves
through from the northwest to southeast throughout the day. As this
occurs, the light rain showers associated with the low end across
the U.P. from west to east, with skies becoming mostly sunny across
the region by the late afternoon hours. With cooler air aloft
remaining over the area Saturday, expect temperatures to be around
or slightly below average, with highs getting into the 50s to low
60s in the south central.

The reprieve from the rainfall looks to be a fairly quick one
though, as another shortwave low dropping down from the Northwest
Territories brings showers and thunderstorms back across the area
late Saturday night through Sunday; with cloud cover increasing
Saturday night, expect low temperatures to be in the mid 30s in the
interior east to mid 40s in the west. However, with warm air
advection increasing across the area Sunday, expect the high
temperatures to be in the 60s, with the mid 70s being seen in the
interior west near the Wisconsin border. As the shortwave`s cold
front goes through Upper Michigan during the afternoon hours, there
is a low (2%) chance that we could see some severe weather as
MUCAPEs approach 1000 J/kg and 0-6 km bulk shear is around 30 knots.
With the NAM model soundings showing SBCAPE in the south central by
the afternoon hours, we could see marginally severe hail and wind,
particularly over the south central; we will have to see if the
chances for severe weather increase as we approach this weekend.
Otherwise, outside of possibly some locally heavy rainfall in a few
of the cells, expect light rainfall amounts across most of the area
late Saturday night through Sunday.

Dry weather returns by next Monday and remains for the first half of
the work week as high pressure ridging moves overtop us. While we
could see min RHs approach 30% Monday through Wednesday, with fairly
light winds and around normal temperatures predicted, no elevated
fire weather concerns are expected at this time. Rainfall looks to
return late next week as a troughing pattern moving through the
Central CONUS brings a shortwave pattern back across the area. Model
guidance seems to be pushing the timing back on the return of the
precipitation; while the NBM brings rain chances back over us
Wednesday afternoon, it seems like the latest deterministic runs in
the differing medium range model guidance suites hold the rain off
until late Wednesday night/Thursday. Therefore, I wouldn`t be
surprised if the rain chances get pushed back in subsequent NBM runs
(and thus our extended forecast). The rain chances look to continue
to the end of the period. Beyond the end of the period, the CPC has a
slightly higher chance of above normal temperatures and above normal
precipitation in the 6-10 day period; in the 8-14 day period, there
is an equal chance for above, near normal, and below normal
temperatures whereas there is still a higher chance for above normal
precipitation in the 8-14 day range.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 130 PM EDT Fri May 10 2024

VFR conditions in place to start the TAF period. Band
of showers is approaching IWD from the west, moving in around 19Z,
then reaching CMX around 21Z and SAW around 23Z. Unlikely this
initial band will result in any flight category reductions due to
the dry air in place and quick speed of the showers. The parent
system will slow down and strengthen to the southeast of the UP
tonight, which will result in moistening at lower levels and
continued showers at times. Expect IWD to remain VFR through the TAF
period, but CMX/SAW will fall to MVFR in cigs/vsby overnight (likely
01-03Z), and IFR cigs will become likely at SAW (60% chance) roughly
between 08-13Z. Cigs will gradually improve toward the end of the
TAF period as the system drifts off to the east.

&&

.MARINE...
Issued at 347 AM EDT Fri May 10 2024

Light winds of generally 20 knots or less dominate the period as
stable conditions prevent the mixing of higher wind speeds down to
the water`s surface.

&&

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

&&

$$

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