Area Forecast Discussion
Issued by NWS Gaylord, MI

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000
FXUS63 KAPX 281338
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
938 AM EDT Thu Mar 28 2024

.KEY MESSAGES...

- Nuisance light snow showers/flurries in spots today/tonight

- Chances for precipitation Saturday, starting as snow and possibly
  mixed precip in the early morning then mostly rain by midday

- Large uncertainty for weather system early to mid week next
  week

&&

.UPDATE...
Issued at 938 AM EDT Thu Mar 28 2024

Low-level flow is veering just a touch this morning, as low
pressure on Hudson Bay gradually fills. Though Lk Superior
activity remains north of Whitefish Pt, flurries/light snow
showers off of Lake MI have moved south toward Boyne Falls/
Indian River/Vanderbilt. Have adjusted morning pop grids. Only a
coating of new snow expected.

Otherwise a quietish day. Partly sunny outside the main
snowbelts, though with winds picking up a bit again with some
mixing. Temps will reach the low- mid 40s closer to Saginaw Bay,
but mostly mid- upper 30s elsewhere.

&&

.NEAR TERM /THROUGH TONIGHT/...
Pattern Synopsis/Forecast: Long wave trough axis that has been working
its way east across North America this will now lined up along the
Mississippi River...as a deepening upper low approaches the Pacific
Northwest coast with short wave riding building into the Rockies.
Upper low and associated dynamic PV anomaly (dynamic tropopause down
to nearly 600mb) lifting northeast past Lake Superior this morning.
Drier air has overspread most of southern Wisconsin/Lower Michigan
but deeper moisture continues to wrap around the upper low from
northwest Ontario across the western Lake Superior basin.

998mb surface low over southern Hudson Bay this morning...mesoscale
trough axis across western Lower Michigan. Mixed skies across northern
Michigan with some light snow/flurries across northern Lower...mostly
ahead of a short wave trough axis crossing Lower Michigan. There are
breaks in the clouds over northwest Lower and eastern Upper though
additional Sc and light radar returns across central/western Upper
and northern Wisconsin...which should be helped by boundary layer
instability over northern Lake Michigan as sub -10C 850mb
temperatures cross the 3-4C lake waters.

Overall pattern is quiet in the near term...general height rises
across the Great Lakes with a weak short wave trough sliding across
the area tonight.  Persistent cyclonic boundary layer flow finally
relaxes as a weak high pressure ridge builds into Wisconsin/Lower
Michigan.

Primary Forecast Concerns:

Nuisance light snow showers/flurries in spots today/tonight:  Best
chance for light snow/flurries today looks to be north of the M-72
corridor and especially focused through the Straits and out toward
southeast Chippewa county/Drummond Island with the most persistent
trajectory of low level moisture and upstream cloud cover will be
enhanced by a trip across Lake Michigan.  Farther north of the
Straits indications are of an uptick in flurries/snow showers during
the afternoon mostly driven by boundary layer processes. Tonight low
level flow slowly starts to veer toward a more west- northwest
direction...best thermodynamics expected to be around/ downwind of
Whitefish Point with inversion heights around 800mb and cloud top
temperatures poking up into the DGZ. Some stronger low level forcing
won`t hurt the cause either... for now have kept accumulations an
inch or less around Whitefish Bay. Veering winds will likely bring
clouds southward again into much of northern Lower with lake induced
snow showers/ flurries probably increasing in coverage as well in
favored northwest flow areas.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Pattern Synopsis / Forecast: Light snow flurries will diminish Friday
morning over eastern upper as ridging moves overhead. Temperatures
will warm around 5 degrees more than today with winds remaining light
and skies clearing up in the afternoon. Friday night into Saturday
morning, two weak surface lows will approach MI (one from the NW and
one from the SW). As they meet over MI, precipitation chances will
spread across the state from W to E Saturday morning and linger
through the day. Winds aloft remain zonal, which allows an elevated
warm layer (2.5 - 5kft) to linger over northern lower. Model soundings
depict chances for mixed precipitation, including non-zero chances
for some freezing rain, where surface temperatures are able to remain
below freezing Saturday morning (which will likely be near the tip
of the mitt). At this time, precipitation accumulations remain light
no matter how it falls (rain or snow). Temperatures should warm
across the CWA to above freezing by mid day, allowing all precip to
fall in the form of rain for Saturday midday and afternoon. Light
snow will be possible Saturday night for eastern upper as
precipitation moves out of the region.

Primary Forecast Concerns: There are a few areas of uncertainty for
precipitation chances Saturday. As for areas of confidence, timing
and moisture availability are stronger signals (around 89% of GFS/ECM
ensemble members began precip between 12 and 18Z Saturday, and PW
values only range around 0.2" with the mean around 0.5"). The
uncertainty lies in precip type. Box plots of the aforementioned
ensemble members 850mb temps over KGLR depict the median line right
over 0C, and tails reaching evenly to +/-4C Saturday at 12Z. This
means most guidance hovers right around freezing Saturday morning
around Gaylord, leading to the non-zero chance of brief freezing
rain. More of the box plot shifts below freezing for KPLN, and is
totally below freezing for KANJ. This leads to more confidence in
snow over eastern upper. As mentioned before, accumulations should
remain light, which should lower potential impacts, however a few
spots could become slick Saturday morning. Most precipitation should
become rain by the afternoon hours as temperatures are forecasted to
reach into the low to mid 40s Saturday.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Zonal flow will be seen Sunday through early next week. Afternoon
temperatures will continue a gradual warming trend for Monday and
Tuesday. Winds near the surface become E/NE by Monday as a surface
low over the central plains strengthens. At this time, there is high
uncertainty for what weather northern MI will see mid week next week.
The strengthening surface low gets carried northward with a mid
level trough/closed low, potentially tracking anywhere from central
MI to OH/PA/NY. Not only is the track up for debate, but the timing,
intensity, and available moisture are all depicted differently in
deterministic and ensemble guidance. This results in wildly large
ranges of ensemble values for 24hr QPF and snow.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Mainly VFR conditions expected through the day today with continue
lake and diurnally induced cloud cover though ceilings should remain
above 3000 feet.  Better potential for MVFR conditions developing
tonight as winds shift around a little more to the west-northwest
and allow lake convection to kick up its heels again...mainly with
ceiling heights but can`t rule out some lowered visibilities in
some of the snow shower activity around KCIU and KPLN.

&&

.MARINE...
Pressure gradient will continue to relax today as high pressure
builds into Lower Michigan.  But winds will remain gusty on Lake
Michigan and through the Straits into far northern Lake Huron...and
waves still 5+ feet within Lake Michigan nearshore zones outside of
Grand Traverse Bay.  So Small Craft Advisories will continue in Lake
Michigan nearshore zones and will probably expand east into the
Straits of Mackinac.  Straits to False Detour zone as well as
Whitefish Bay will probably flirt with small craft winds today.
Winds/waves should settle down by this evening...and not expected
the need for additional headlines through Friday night.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LHZ345-
     346.
     Small Craft Advisory until 8 PM EDT this evening for LMZ341-
     342-344>346.

&&

$$

UPDATE...JZ
NEAR TERM...JPB
SHORT TERM...ELD
LONG TERM...ELD
AVIATION...JPB
MARINE...JPB


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