339
FXUS63 KMQT 040520
AFDMQT

Area Forecast Discussion
National Weather Service Marquette MI
120 AM EDT Thu Jun 4 2026

.KEY MESSAGES...

- Elevated fire weather conditions this afternoon across much
  of Upper Michigan due to relative humidity values around 20%,
  warm temperatures, and wind gusts of 15-20 mph.

- Scattered showers and thunderstorms return on Thursday, with
  another round likely Friday afternoon and evening. Uncertainty
  remains regarding precise timing and rainfall amounts in
  storms. Additional chances for showers and thunderstorms
  linger into Saturday.

&&

.DISCUSSION...
Issued at 255 PM EDT Wed Jun 3 2026

Afternoon GOES-East Day Cloud Phase RGB imagery shows scattered
cirrus and some fair weather cu along the spine of the Keweenaw but
otherwise clear skies over Upper Michigan and the surrounding area.
RAP analysis shows expansive high pressure near 1026 mb spanning
much of the eastern CONUS with a near-stationary ~1015mb low over
southern Saskatchewan extending a cold front and unsettled weather
to its south. Aloft, the omega block is breaking sown, with a closed
low over southern Saskatchewan and another over the North
Carolina Coast with the ridge between them flattening over time.

RHs across much of the UP have already fallen into the 20s percents.
Thus far, the highest recorded gusts coincident with these dry RHs
are around 19 mph with most sites at 10 mph or less, limiting the
wildfire spread potential. Little change in the wind pattern is
expected today, with the CAMs showing the lake breeze remaining very
close to shore along Lake Superior. Clear skies and warm southerly
flow will lead to temperatures climbing into the upper 70s to mid
80s today, with the coolest spots being downstream of Lake Michigan.

Tonight into Thursday morning, with the ridge breaking down aloft,
the stacked low over the Canadian Prairie will be able to move east
and intensify to near 1008 mb over northwest Ontario by 12Z Thurs.
This will bring cold frontal showers to the western UP around that
time. Euro ensemble mean MUCAPE grows to 500-1000 J/kg throughout
the day Thursday, giving fuel for showers to have some thunderstorm
development, with 0-3km SRH values of around 125 to give some
ability for the updrafts to organize and sustain. However, CAMs show
significant placement and intensity differences for Thursday, so the
threat remains similar to the SPC Outlook - Marginal. Those looking
for a relief from the dry weather are not guaranteed a wetting rain,
as chances of 0.1" of rainfall on Thursday are only sporadically
above 40% and almost entirely west of the US-41/141/2 corridor
(Crystal Falls, L`Anse/Baraga, Houghton/Hancock).

The low will only make slow progress eastward along the northern
shore of Lake Superior through Friday, keeping rain shower and
thunderstorm chances in the forecast. The best chances for thunder
will be in the interior west to southern UP, especially east of the
US-41/141/2 corridor where it is less likely that the previous
day`s storms will have worked over the atmosphere. LREF mean
SBCAPE grows to around 500 J/kg with little to no CIN with 20-30
kt of deep layer shear. Another SPC Marginal Risk day appears
warranted. One big difference in the forecast on Friday is the
precipitation potential, as some training signal in the showers
is seen. LREF chances of over a quarter inch of rain on Friday
ranges from around 25% in the north to 75% in the south, which
will be a welcome reprieve from the dry soils and vegetation.

Saturday morning, showers and thunderstorms depart to the east, with
the exception of up to 30% chances (NBM) of the south seeing some
diurnal afternoon showers/thunder in the afternoon. Ridging then
sets up, leading to a dry Sunday. Models diverge on the details of
the forecast into next week, but the general pattern is ridging over
eastern North America and troughing over the west, setting up a warm
and moist flow pattern that will allow NBM high temperatures to
climb to the 90s in the west half and keep daily 15-30% shower and
thunderstorm chances in the forecast.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 120 AM EDT Thu Jun 4 2026

VFR flight conditions likely prevail through the duration of the 6Z
TAF period at all sites (70% chance). High pressure continues
shifting southeast away from the Great Lakes, giving way to a weak
low pressure system northwest of Lake Superior. This brings back
chances for showers and storms this morning. Confidence in timing
and coverage remains low and forcing to begin with is weak, thus
only -TSRA mention is via PROB30 groups at IWD/CMX. Only changes
from the previous package were to push back TSRA mention a few
hours. Similar chances arrive right at the end of the period at SAW,
so mention altogether was left out. Expect south to southeast winds
around 10 kts for much of the period. Isolated gusts up to 20 kts
are possible.

&&

.MARINE...
Issued at 255 PM EDT Wed Jun 3 2026

Winds will be mostly light throughout the period. Besides a brief
period of wind gusts near 20 kt in the west in response to a LLJ,
the next chances for widespread 20+ kt gusts will be Monday as the
gradient tightens with various low pressure elements in the western
US and a building high to the east of the lake.

&&

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

&&

$$

DISCUSSION...GS
AVIATION...77
MARINE...GS