487
FXUS63 KAPX 061509
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1109 AM EDT Sun Apr 6 2025

.KEY MESSAGES...

- Accumulating snow returns tonight into Monday

- Unseasonably cold again Monday into Tuesday, then temps
  gradually rebound

&&

.UPDATE...
Issued at 1108 AM EDT Sun Apr 6 2025

Current forecast in good shape and plan few changes. Increasing
warm air advection aloft this afternoon will spread clouds and
eventually snow chances into parts of Chippewa/Mackinac Counties
toward evening. Much better snow chances will come tonight.
Current forecast has this handled well. Otherwise, lots of
sunshine but still below normal temperatures in many areas, with
highs ranging from the upper 30s north to middle 40s south.

Clipper system brings snow to the area tonight, with the biggest
accumulations over eastern upper.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 340 AM EDT Sun Apr 6 2025

Pattern/synopsis: A surface ridge axis folds over across the
western and southern lakes today. This ridge axis is suppressed
southward by a prominent and amplifying nnw-flow shortwave trof,
circulating around the deep Hudson Bay stacked low. Surface
cyclogenesis occurs in northern WI today, and the gradually
deepening low cross far northern lower MI tonight. This results
in the unwelcome return of wintry wx.

Forecast: Most of today is fairly quiet. Some nw flow lake
effect is ongoing into parts of Chippewa Co early this am,
thanks to 850mb temps dipping to -11C. A little of this activity
could persist past daybreak, but precip coverage is and will
remain low, and thus any impacts will be small. Respectable
amount of sunshine elsewhere this morning. By afternoon,
increasing warm advection well aloft will increase cloud cover
over the eastern UP and far nw lower MI. There is a chance for
synoptic snow to emerge in Chippewa/Mackinac Cos west of I-75
before 8 pm, but much better chances wait until just after.

Tonight, rapidly increasing dynamic forcing ahead of the
sharpening upper trof will amp up precip coverage and intensity.
F-gen forcing and deformation will be greatest just to the north
of the surface low track. Model consensus argues for that being
along the M-32 corridor, but the range of solutions is still
somewhat broad. Given where the shortwave trof is now (w of
Hudson Bay), it is not being well sampled yet. A swath of snow
will develop eastward this evening into eastern upper and far
northern lower MI. This swath will make gradual southward
progress early overnight as the system transits, then faster
southward progress in it`s wake, as the surface cold front
accelerates southward. Along the southern periphery of the
precip shield tonight, a rain-snow mix may be briefly possible
at onset. However, evap cooling will push this toward being a
snow event for most of the area, most of the time.

The total snowfall accum maximum (including Monday morning)
remains the same as the inherited forecast, 3-5". However, where
that falls has moved about 60 miles northward compared to the
forecast from 12 hours ago. It`s squarely over the eastern UP,
grazing northern Emmet and northern Cheboygan Cos. Totals are
1-3" elsewhere, highest nw and lowest se. With a more
consistent model placement of the higher snowfall totals, I`d be
happy to issue an advisory for some areas at this time. But
lacking that, will hold off on a headline at this time.

Max temps today upper 30s north to upper 40s far se. Min temps
tonight 20f north to 30f se.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 340 AM EDT Sun Apr 6 2025

Pattern Synopsis and Forecast:

Midlevel shortwave troughing will have its axis centered over the
Great lakes region and a jet maxima over the northeast. Cold
temperatures from the north will be drawn into the region at the
start of the long term along with H8 temperatures remaining well
below freezing (at times in the minus teens). Surface level low
pressure will continue ongoing synoptically driven snowfall
across the CWA. Current ensembles and probabilistic products
depict a quick hitting system that will be departing this
Monday. QPF solutions remain around a general tenth or two for
eastern upper along with the "tip of the mitt" and with snowfall
ratios in the high teens, most parts of Mackinac and Chippewa
counties could expect a general 3-5 inches of moderately
dry/light snow. Concerns for a different solution however remain
possible with a stronger, more narrow band of frontogenesis to
develop across the upper peninsula. If this solution does come
to fruition, the region could expect accumulations starting to
approach a half foot for parts of the region.

Conditions begin to overall dry across the region Monday night, but
northwest flow along with delta T`s strong enough to support lake
effect will kick off a quick and short lived response through Monday
for the classic snowbelts. Overall subsidence building will keep
these amounts low, with only a few light showers or flurries
expected to linger Monday night and possibly into the morning hours
of Tuesday.

The remainder of the long term is relatively quiet as midlevel
heights rise and return a more mild air mass to the region.
Temperatures climb later this week with highs reaching the 50s this
Thursday and Friday. Another wave of energy tracks south of the CWA
Thursday night, but the majority of rainfall will be over the Ohio
Valley. A few rogue showers remain possible, but overall dry
conditions are expected through the remainder of the forecast
period.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 639 AM EDT Sun Apr 6 2025

VFR today. Tonight, strengthening low pressure will cross
northern lower MI. Snow will develop, initially at CIU, then
PLN, then TVC. IFR vsbys likely for a few hours at the above
sites.

Light westerly winds today.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory from 6 AM Monday to midnight EDT Monday
     night for LHZ345.
     Small Craft Advisory from 11 AM Monday to 8 AM EDT Tuesday for
     LHZ346>349.
     Small Craft Advisory from 6 AM Monday to midnight EDT Monday
     night for LMZ323-341-342-344>346.
     Small Craft Advisory from 11 AM Monday to midnight EDT Monday
     night for LSZ321-322.

&&

$$

UPDATE...JK
SHORT TERM...JZ
LONG TERM...SJC
AVIATION...JK/PBB/JZ