098
FXUS63 KMQT 022240
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
640 PM EDT Thu May 2 2024

.KEY MESSAGES...

- A Plains low pressure system moving through the Upper Great
  Lakes will bring widespread rainfall from this afternoon into
  tonight of .2 to .5 inch, highest west half.
- Active pattern continues through next week as a series of low pressure
  systems track across the U.S. and affect Upper MI. Above
  normal precipitation expected, including chance of
  thunderstorms at times.
- Mostly above normal temperatures expected, generally 5 to 10 degrees
  above normal on the majority of days thru the middle of next
  week.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 311 PM EDT Thu May 2 2024

Tonight, a vigorous shortwave now over the central/eastern Dakotas
will lift east-northeast and reach western Lake Superior Fri
morning. Main surge of waa/isentropic ascent and strong 850-700mb
moisture transport ahead of this shortwave advances across Upper MI
this afternoon/evening, as widespread showers now over west and
south central spread east across the rest of the fcst area late this
afternoon/early evening. There isn`t much elevated cape (basically
less than 200 j/kg), but this may lead to a few rumbles of
thunder over the east half later this evening into the early
overnight where models peg weak elevated CAPE values. Occluded
front associated with shortwave will reach western Upper MI
around 06z, will extend roughly thru Munising to Manistique by
12z Fri and will exit Luce County by 15z. Showers will abruptly
end with the passage of the occluded front as model soundings
show sharp mid-level drying surging into the area. Lower levels
will dry out quickly as well on Fri as daytime heating builds
mixed layer and taps very dry air aloft. Expect skies to trend
sunny Fri morning over the w half and early to mid aftn across
the e. Expect lows tonight to range from the lower 40s west to
mid to upper 40s south central and east.

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 354 PM EDT Thu May 2 2024

Rain showers quickly wrap up into Friday morning as the occluded
front moves through the eastern UP behind the exiting shortwave.
Sunny skies are looking likely, but there is reason or uncertainty
across the eastern UP, particularly nearer to the Great Lakes.
Following this round of rain, there will likely be some marine fog
and low stratus, which may be advected over the eastern UP under a
weaker wind regime and potential lake breeze development. This would
limit the potential for mixing. Where skies do remain sunny, daytime
heating will contribute to a building mixed layer that will in turn
help us tap into very dry air aloft. Dewpoints in the interior-
western UP drop into the lower 30s and even upper 20s.  With
temperatures area-wide well into the 60s and even the lower 70s,
relative humidity plummets into the 20s. Winds across the western UP
should be on the gusty side, closer in proximity to the surface low
centered over the Ontario/Manitoba border region and with better
mixing. Expect widespread gusts up to 20-30mph. This would all pose
some concern for fire spread, were it not immediately following the
ongoing round of widespread rain.

Dry weather will continue Fri night. Then, next shortwave will
already be approaching by Sat afternoon, resulting in a quick round
of showers spreading in from west to east for the afternoon and
evening hours. Showers quickly taper off from west to east into the
night behind the passing cold front. Showers are most likely across
the western UP as the right entrance region of the upper jet streak
will be draped over the area, lending some divergence aloft, but
rainfall amounts are still favored. PWATs are only topping out
around 0.75in, and soundings indicate only a brief window of deeper
moisture as the wave passes through. Though deterministic guidance
remains sort of all over the place, ensembles are still showing
around a 30-50% chance for totals in excess of 0.10in. Will continue
to lean towards the NBM solution keeping most of hte area at around
0.10 to 0.20in.

In the wake of the shortwave, dry weather returns for Sunday and
continues Monday with a ridge amplifying over the area. Then, expect
wet weather to continue through the work week. For the time range,
agreement is good for the next shortwave swinging out of the Rockies
on Mon to result in a mid-level low over the Dakotas for Tue. In
response, strengthening waa/isentropic ascent directed into the area
will touch off our next round of showers late Monday night into
Tuesday. Anchored by the mid-level low, mid-level troughing will
then expand across the Rockies and Plains to Great Lakes during the
midweek period, resulting in additional shortwaves tracking into the
Upper Great Lakes with additional rounds of showers through Thursday.

&&

.AVIATION /00Z TAFS THROUGH 00Z SATURDAY/...
Issued at 639 PM EDT Thu May 2 2024

IFR/LIFR conditions will continue into tonight. Easterly upslope
flow at SAW and CMX will result in LIFR prevailing longer than IWD.
Expect improvement to VFR at all terminals as a west-southwest wind
develops in the wake of the system`s cold front moving across the
area. First will be at IWD by late tonight and by morning at CMX
and SAW.

&&

.MARINE...
Issued at 354 PM EDT Thu May 2 2024

Winds primarily our of the NE continue to come in below 15kts so far
this afternoon, but will soon be on the increase into the evening
hours as a surface low lifts northward into the Great Lakes. Expect
winds to increase to around 20-25kts across far western Lake
Superior for a brief period this evening, then as winds veer to the
east with the weakening low moving into WI, expect winds to briefly
fall below 20kts in western Lake Superior while increasing to 20-
25kts to the east. As the low lifts into northern Ontario on Friday,
winds will shift to the SW. While gusts up to 25kt will continue
over western Lake Superior, winds will fall off to mostly under 15kt
over the eastern lake in the afternoon as winds back around to the
SE. Over the weekend, expect winds mostly below 20kts across Lake
Superior under a relatively weak pressure gradient. High pressure
that arrives over the Upper Great Lakes late weekend will shift
eastward on Mon while a deep low pressure emerges over the western
Dakotas. This will result in increasing easterly winds Mon into Tue.
Expect winds up to 30kts by Tue.

With showers moving across Lake Superior through tonight, some fog
will likely develop, and it could become locally dense. Fog will
push mostly to Canadian waters for Fri due to the SW winds. If the
fog does not clear off of the lake on Fri, it may expand back across
eastern Lake Superior during Fri aftn as winds back to the E/SE.

&&

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

&&

$$

SHORT TERM...Voss
LONG TERM...LC
AVIATION...07
MARINE...LC