919
FXUS63 KMQT 090848
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
448 AM EDT Thu May 9 2024

.KEY MESSAGES...

- Clipper system brings chances for thunderstorms to the far
  western areas of Upper Michigan Friday afternoon and Friday
  evening.

- Chances for thunderstorms return on Sunday for the west half
  of the Upper Peninsula.

- Multiple passing low pressure systems will keep rain and
  thunder chances in the forecast next week, but uncertainty on
  timing and track remains.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 325 PM EDT Wed May 8 2024

Water vapor imagery and RAP analysis show a broad mid-level low
centered over SD and troffing over se Canada back into the Great
Lakes. Into the latter trof, a shortwave is dropping toward Lake
Superior. Btwn the mid-level low and the eastern trof, a col is over
ne MN/NW WI. In the wake of the shortwave that brought rain to the
area last night, particularly the e half of Upper MI, it`s been a
dry aftn so far, but daytime heating has led to cu/stratocu
development inland from the stabilizing influence of Lake Superior.
Recent radar imagery indicates that these clouds are now building
enough depth for some sprinkles or a few -shra in eastern Gogebic
County. Temps currently range from the 40s near Lake Superior to the
mid 60s F in the interior closer to the MI/WI stateline.

Approaching shortwave from the n and weak diurnal instability will
support some -shra/sprinkles over portions of interior western
Upper MI near the MI/WI stateline for the next several hrs. Not
out of the question that a few sprinkles could develop over the
eastern fcst area as well given the buildup of clouds in that
area. A dry night will then follow with skies becoming partly
cloudy. 850mb thermal trof is currently supporting considerable
stratocu ne of Lake Superior. As this thermal trof advects sw,
stratocu will also advance sw. Some of this cloudiness may
appear in Upper MI around sunrise, but probably more so during
Thu morning. Expect low temps tonight in the mid 30s to lwr 40s
F.

&&

.LONG TERM /TONIGHT THROUGH WEDNESDAY/...
Issued at 447 AM EDT Thu May 9 2024

Starting tonight, a trough will be settling south while ever so
brief ridging and sfc high pressure builds in over the UP from the
northwest. While this trough settles south, some shortwave energy
passing over the eastern UP may give some additional forcing for
clouds. That said, q-vector divergence and dry model soundings
indicate dry weather will persist under mostly clear skies are
expected. With good radiational cooling, temps below normal are
forecast with lows in the upper 20s to 30s, coolest in the interior
west.

Dry weather ends Friday afternoon as shortwave over the
Manitoba/Ontario province line dives southeast into Upper MI and WI.
Mixing ahead of the shortwave is expected to result in lower RHs
into the upper 20s to 30s. That being said, there are no major fire
weather concerns as highs for the day are expected in the mid 50s to
mid 60s (cooler near the lakeshores), winds are expected to remain
light below 15 mph, and precip is on the way. Some lake breezes are
also likely late morning/early afternoon off both lakes which should
help RHs recover some and result in some variable winds. PVA kicks
off showers mainly after 2 PM EDT over the far west. As the cold
front moves east over the UP then, showers move east with it. With
mid level lapse rates ~7C/km and the 5/9 0z HREF mean MUCAPE around
100j/kg (individual models plotting up to 200-400j/kg) there is a
slight chance for thunderstorms over the far western UP. That said,
bulk shear is lacking (mainly below 25 kts) and the forcing
mechanisms do not appear as strong later in the day. Severe weather
is not expected. Chances for showers continue east across the UP
Friday night as temps fall into the mid 30s to mid 40s.

As the trough moves southeast toward New England on Saturday,
additional shortwave energy advects over the UP suppling enough
forcing for some slight chances of showers, mainly over the east on
Saturday. Chances for showers and thunderstorms return again on
Sunday as a sfc low over northern Ontario moves east, tracking a
cold front across the UP. As we move into next week, there are
discrepancies on precip timing and track and thus confidence
diminishes. The GFS has a weak shortwave for later in the day Monday
forcing some showers and potentially thunderstorms while the ECMWF
stays dry with sfc ridging extending over the UP through Tuesday.
The next best chances for showers and thunderstorms arrive mid to
late next week when a shortwave riding east along the U.S./Canada
border earlier in the week arrives at the Great Lakes. With current
spread in the guidance, opted to leave NBM chance PoPs as is.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 150 PM EDT Wed May 8 2024

Lower level moisture is mixing out and is being lifted by building
mixed layer. Advection of stabilizing marine layer off of Lake
Superior will also work to limit any cu/stratocu development closer
to the lake this aftn. For IWD/CMX, this stabilizing influence will
allow VFR to prevail this aftn, and VFR will continue tonight. At
SAW, expect stabilizing flow off of Lake Superior to result in MVFR
cigs scattering out to VFR in the next hr or two. VFR will then
continue at SAW tonight. Area of lower level moisture represented by
the stratocu per vis satellite imagery well ne of Lake Superior will
advect sw today and tonight. While some of this moisture will mix
out this aftn, it should contribute to cu/stratocu/MVFR cigs
developing at all terminals after sunrise on Thu. After a few hrs
or so, cloud bases will lift to VFR, or the clouds will scatter out
to VFR.

&&

.MARINE...
Issued at 447 AM EDT Thu May 9 2024

Northeast winds of 15-25 kts will diminish this morning, falling
back below 20 kts across the lake as high pressure builds over the
lake and stability increases. With this weak high pressure
maintaining over the lake through tonight, winds likely will remain
below 15 kts into the weekend as the stability remains. The
exception to this is Friday night behind the cold front when the
combination of cold air advection and downsloping off the
northwestern shores of the lake may result in some gusts nearing 20
kts along the lakeshore areas. Some thunderstorms over the far
western portions of the lake are also possible with the passing cold
front. Winds increase to around 15-20 kts on Sunday as another cold
front passes over the lake; some thunderstorms over the west half of
the lake are possible with this cold front as well. Winds
otherwise hold around 10-20 kts into the early parts of next week.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Small Craft Advisory until 2 PM EDT /1 PM CDT/ this afternoon
     for LSZ240-241.

  Small Craft Advisory until 11 AM EDT this morning for LSZ242.

  Small Craft Advisory until 8 AM EDT this morning for
     LSZ243>245-250.

  Small Craft Advisory until noon EDT today for LSZ248-249.

Lake Michigan...
None.

&&

$$

SHORT TERM...Rolfson
LONG TERM...Jablonski
AVIATION...Voss
MARINE...Jablonski