477
FXUS63 KMQT 101225
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
825 AM EDT Fri May 10 2024

.KEY MESSAGES...

- Showers move in from the west this afternoon, mainly after 2
  PM EDT, progressing eastward into tonight. There is a slight
  chance for thunderstorms in the far western U.P. and along the
  WI/MI state line.

- Dry conditions are expected ahead of the showers with minimum
  RHs in the 20s to low 30s. That being said, there are no major
  wildfire concerns with light winds and showers on the way.

- 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 TONIGHT/...
Issued at 436 AM EDT Fri May 10 2024

The rest of tonight will stay quiet with cooler than normal temps.
RAP analysis shows a 1015mb high pressure over the UP, Lake Superior
and the eastern half of northern Ontario. A positively tilted and
somewhat compressed mid level ridge is analyzed over MN and northern
Ontario with a shortwave over the far eastern portion of Lake
Superior. Nighttime microphysics is already showing this shortwave
forcing some mid level clouds over the water and far eastern UP,
this looks to continue as the shortwave drops south the rest of the
night, however significant cloud cover is not expected as model
soundings only show a thin layer of moisture available around the
7kft level. This subsidence and mostly clear skies will allow for
good radiative cooling, especially over the west. Lows are expected
into the mid 20s to upper 30s, warmer near the lakeshores and
coolest in the interior west; I would not be surprised if a few spots
dip into the low 20s before sunrise.

Moving on to the daytime, a shortwave currently over Manitoba dives
southeast into Upper MI and WI mid to late afternoon. Mixing ahead
of the showers is expected to result in lower RHs into the mid 20s
to low 30s. Even though min RHs are below critical thresholds, there
are no major fire weather concerns as highs for the day are expected
in the 50s to mid 60s (cooler near the lakeshores), winds are
expected to remain light (mainly below 15 mph), and precip is on the
way. CAMs are really picking up on the lake breezes expected already
late this morning into the early afternoon off both lakes, stronger
in the east. This should help RHs recover a bit and result in some
variable winds, especially in the east where the two breezes
interact. Some convective cloud development is likely over the east.
Even though the CAMs reflectivity shows some isolated showers
developing along these two colliding lake breeze boundaries,
confidence in any shower development off the Lake breezes is low as
available moisture ahead of the cold front is lacking. If any precip
is able to develop, some sprinkles would be the high end scenario.
PVA and the associated clipper system`s cold front bring showers into
the far west mainly after 2 PM EDT. As the pair of forcing
mechanisms move east over the UP, showers move east with it. Low and
mid level lapse rates ~7-8C/km and bulk shear is around 40-45 kts
along the passing frontal boundary which would be supportive of
storms. That being said, energy is lacking: the 5/10 0z HREF mean
MUCAPE is around 100j/kg  with individual models plotting up to 200-
400j/kg on the high end. Putting this all together, there is a
slight chance for thunderstorms over the far western UP and along
the WI/MI state line late this afternoon into the evening hours, but
severe weather is not expected.

Chances for showers continue east across the UP tonight, but
thunderstorm chances end this evening as loss of daytime heating
diminishes any lingering instability. As the front departs from the
UP, precip looks to be primarily driven by PVA with some support
from northerly upslope flow. This means the best chances for showers
tonight are expected over the north central and eastern UP. Overall
accumulations through tonight are a trace to 0.15"; a few spots may
see up to 0.25" with thunderstorm development. Lows tonight are
expected in the upper 30s to mid 40s.

&&

.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 /12Z TAFS THROUGH 12Z SATURDAY/...
Issued at 824 AM EDT Fri May 10 2024

VFR conditions are expected to prevail at the terminals through this
morning and potentially through the afternoon. A clipper low
pressure system moving through the area will bring in some isolated
to scattered rain showers as well as MVFR cigs from west to east
across the UP. With high pressure and lake breezes earlier in the
day, winds will stay light and somewhat variable ahead of the
showers. Showers arrive first at IWD around 19Z, next at CMX around
21Z, and last at SAW around 23Z. Some thunderstorms are possible at
IWD late this afternoon into the evening hours, however were left
out of the TAF for now due to low confidence. As the clipper system
moves southeast into Lower MI tonight, light north to northwest
winds are expected. The northerly upslope flow will result in cigs
lowering at CMX and SAW to low end MVFR, possibly IFR with best
chances for lower cigs at SAW. Winds becoming stronger into Saturday
with some gusts nearing 20 kts at SAW by the afternoon.

&&

.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...Jablonski
LONG TERM...TAP
AVIATION...Jablonski
MARINE...TAP