177
FXUS63 KMQT 080857
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
457 AM EDT Wed May 8 2024

.KEY MESSAGES...

- Rain showers this afternoon and tonight to bring half an inch
  to an inch of rainfall to the area. Thunder chances are low,
  but are most likely (15-30%) along the MI/WI state line.

- Multiple passing low pressure systems will keep rain chances
  in the forecast into early next week along with thunderstorm
  chances both Sunday and Tuesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 242 PM EDT Tue May 7 2024

GOES-16 Day Cloud Phase imagery shows high cirrus over the eastern
UP and east half of Lake Superior while a cumulus deck moves over
the remainder of the region along with weakly convective shower
activity along the MI/WI state line. RAP analysis shows a 984
mb low pressure over the ND/SD state line that is vertically
stacked and not moving much over the past 3 hours. Rotating
around the upper low are shortwaves that are supporting a now-
occluded front which is pushing into the UP and causing the
shower activity. CAMs show this shower activity overspreading
the UP throughout the afternoon and evening. The QPF forecast
has gone up a bit with the most recent run of the HREF, with the
central UP now seeing slightly over 50% probabilities of an
inch of rainfall compared to around 2/3 of an inch at the same
probability the last couple of runs. Mean MUCAPE values are
still meager, peaking at only around 100 J/kg along the MI/WI
state line so the ~15% chance of thunderstorms remains the
prevailing forecast along with no severe weather expected. RHs
fell into the 20s and 30s ahead of the occluded front in the
central and eastern UP this afternoon along with wind gusts
around 25 mph, but with cirrus overrunning the region preventing
RHs from falling further, expected reductions in wind with
time, and the arrival of showers within the next 6 hours, fire
weather concerns are low.

&&

.LONG TERM /TONIGHT THROUGH TUESDAY/...
Issued at 452 AM EDT Wed May 8 2024

Periodic rain chances will be common throughout the extended period
as a series of low pressure systems pass through Upper Michigan.
Initially though, the period will start in a bit of a lull as a
Northern Plains closed mid-level low continues to slide
southeastward while opening up and drifting around the Lower
Midwest.  Meanwhile, the associated surface low ahead of it will
drift through the Ohio Valley.  So, what this means for much of the
UP is a dry forecast Wednesday night through Friday morning. Earlier
model runs were originally taking more of a northern track with the
aforementioned disturbance.  But, the southern track has come to
fruition, thus rain chances have been removed from the south and
east from Thursday.  And strengthening subsidence/ridging will keep
the forecast dry through Friday morning.

By Friday afternoon, mid-level ridging will begin to break down as
the next shortwave dives southeast from northern Saskatchewan.  With
an uptick in isentropic ascent after Fri 18Z, rain showers will
overspread the UP from west to east through the evening, quickly
tapering off after Sat 06Z with loss of dynamics.  In additiion,
will briefly carry thunderstorm mention over the west-southwest
portions of forecast area Friday evening with that sector falling
under the left exit region of a weak upper level jet, but that is
low to moderate confidence at this point.

After some lingering 10-20% rain chances through Saturday afternoon
(central and east) in association with departing shortwave, there
will be a lull in activity Saturday night as brief ridging once
again builds over the UP.  Again though, the dry weather will be
short-lived as focus turns to a series of systems traversing first
northern Manitoba and then southern Saskatchewan/Manitoba.  Showers
and thunderstorms will accompany both systems on Sunday and again
Tuesday.  And, it is still a bit early, but instability and vigorous
cold fronts could be enough to generate some strong thunderstorms
both days.  These will be targets of opportunity to monitor,
especially Tuesday afternoon/evening as high temperatures climb into
the low to mid 70s.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
Issued at 125 AM EDT Wed May 8 2024

Main band of showers rotating back into the area from the east
for the overnight with only SAW probably seeing steady rain from
these showers. Expect conditions to lower to MVFR and then IFR
overnight at SAW and IWD in showers as an upslope n-ne flow
develops on the backside of the associated sfc low moving toward
the Straits later tonight. CMX also has a good chance to see a
period showers and MVFR cigs early overnight, but then expect
CMX to improve to VFR late tonight (08Z or after) and continuing
into Wednesday as a downslope ne flow develops there.
Conditions will be slower to improve at IWD and SAW during the
day on Wednesday under the n-ne wind onshore flow with
improvement to MVFR by late morning and then to VFR in the
afternoon.

&&

.MARINE...
Issued at 307 PM EDT Tue May 7 2024

Easterly winds diminish to below 20 knots tonight before becoming
northeast and increasing to 30 knots on Wed into Wed night. North to
northeast winds drop below 20 knots on Thu and stay that way into
Sun.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
  Small Craft Advisory from 11 AM EDT /10 AM CDT/ this morning
     to 8 PM EDT /7 PM CDT/ this evening for LSZ240>242.

  Small Craft Advisory from 11 AM this morning to 5 PM EDT this
     afternoon for LSZ243-244.

Lake Michigan...
None.

&&

$$

SHORT TERM...GS
LONG TERM...TDUD
AVIATION...Voss
MARINE...07