Area Forecast Discussion
Issued by NWS Gaylord, MI

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS63 KAPX 270901
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
501 AM EDT Wed Mar 27 2024

.KEY MESSAGES...

- Precipitation chances as cold air arrives today.

- Gusty winds persist today but not as strong as Tuesday.

- Lingering lake effect Thursday...rain/snow returns Friday
  night into Saturday.

- A break Sunday with additional active weather for early next
  week.

&&

.NEAR TERM /THROUGH TONIGHT/...

Pattern Synopsis/Forecast: Full-latitude long wave trough has mostly
taken up residence across North America this morning...height
rises/ridging along the west coast with a more zonal/progressive
pattern over the Pacific.  Short wave trough that brought Tuesday`s
unsettled weather is lifting through the Great Lakes this morning...
another short wave trough was tracking into Minnesota.  Colder/drier
air was spread into the upper Lakes in the wake of the departing
short wave trough.

05z surface analysis shows a 992mb low over the north shore of Lake
Superior...cold front arcing southward across Lake Huron/far
southwest Ontario/central Ohio.  Secondary surface trough was across
central Upper/Lake Michigan/eastern Illinois.  Bulk of the
precipitation from Tuesday well east of the area...moisture wrapping
around the low still producing some snow/rain showers across
Upper/northern Lower Michigan.  Some narrow southwest-northeast
oriented precipitation bands across northern Lower likely helped out
by shallow instability (925mb temperatures around -4C over a Lake
Michigan water temperature of 4C).

Surface low crossing Lake Superior will pull away from the upper
Lakes this morning...leaving cold/cyclonic flow behind in its wake.
Secondary short wave trough over Minnesota will cross into Lake
Superior/western Upper/northern Wisconsin this afternoon and
eventually across northern Michigan tonight.

Primary Forecast Concerns:

Precipitation chances as cold air arrives today: Will probably rely
on shallow instabilty being generated in southwest flow over Lake
Michigan.  Inversion heights forecast to barely poke up above 850mb
and at temperatures near or a bit colder than -10C.  Looks like more
nuisance light snow showers or flurries through much of the
afternoon.  But approaching short wave trough and resultant
forcing/synoptic moisture should improve the thermodynamic situation
as inversion heights climb to or a little above 800mb and a little
higher into favorable DGZ temperatures this evening.  But despite
what the OBM (Old Brain Model) thinks about an improving window for
snow showers off northern Lake Michigan...having a heck of a time
finding guidance willing to even have a decent looking PoP.  Tried a
myriad different combinations of guidance to at least get the PoP
trend in the right direction...centered mainly on the Straits
tonight.  Potential accumulations on the order of an inch or less
for now.

Gusty winds persist today but not as strong as Tuesday: While the
pressure gradient is not as strong as it was Tuesday... winds are
expected to remain gusty due to cold advection/mixing/ downward
isentropic momentum transfer.  Expect wind gusts today in the 20 to
25 mph range...and closer to 30 mph along the northwest Lower
shoreline as well as the southeast shore of Upper Michigan.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...

Anomalous upper trough over the Upper Midwest...as cold pool aloft
oozes southward into the central US (850mb temps below -12C). 700mb
trough centered over northern MN as of 3z...and 991mb surface
reflection over northern Lake Superior...as a beautifully wound-up
system swirls over the region per satellite imagery. Shortwave
trough axis stretches from this toward PA...including a punch of PV
on strong southerly flow with occluded part of the system sliding
northeast through Lake Huron. BCZ with this stretches all the way
down into the Gulf of Mexico and wraps back up into the Lee of the
Rockies, up into Alberta...ahead of ridging building into the West
Coast. Secondary cold front stretching down from aforementioned
991mb low through Lake Michigan...with a little redevelopment ahead
of this. Deepest moisture departing eastward ahead of this (pwats
still around 0.6 inches at 0z, with cooler/drier air upstream).

Energy over the Dakotas/southern Canada to pinwheel in
today...exiting tonight, with continued northwest/west flow near the
surface. Lingering PV maxima along the backside of the trough should
keep generally nuisance clouds and perhaps flurries around
Thursday...but as upstream ridging builds in...will look for winds
to calm down Thursday into Friday as high pressure slips in for a
time. Attention will then turn to developing low pressure over the
central US...which looks to approach the Upper Great Lakes Friday
night into Saturday. Strengthening easterly surface flow ahead of
this could set up potential for p-type issues ahead of this Friday
night into Saturday, though low certainty in how this will evolve on
the front-side attm.

Primary Forecast Concerns:

LINGERING LAKE SNOW THURSDAY...As trough axis finally swings
through...expect some slight resurgence in lake effect, particularly
along and north of M-68 on west to perhaps slightly WSW winds.
Signals are not terribly strong for low-level convergence attm,
though...but will hold slight chance pops in the forecast. Better
shot of this will be across the EUP, where it should be colder...and
moisture should be a little deeper...though nothing impressive by
any means (pwats running at or even a touch below normal for this
time of year). For now, not expecting much more than half an inch
over the course of the day, but think we will be hard-pressed to
squeeze much more out of the atmosphere than that. Some potential
for NW flow lake bands to try to set up across the EUP going into
Thursday night behind a weak trough/pv maxima slipping through,
though not sure even this will produce much.

RETURN OF PRECIP FRIDAY NIGHT...warm advection ahead of the system
over the Plains should approach our area by late Friday into Friday
night. Primary focus for any precip Friday night should be across
our SW counties. Guidance soundings suggest a warm nose should be
trying to creep in late...which could lead to some p-type concerns,
particularly if low-levels end up dry enough Friday during the day
to allow for more substantial evaporative cooling Friday
evening/night with top-down saturation. A lot of uncertainty in this
attm, though...in whether or not it will happen, as well as
regarding timing...and will for now just call it "wintry mix"/"rain
and snow" in the forecast...and keep an eye on trends as we go
forward.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...

Aforementioned Plains disturbance slips through the Great Lakes/OH
Valley region Saturday. We should be on the northern edge of
this...which could leave us with some possibility of p-type issues,
depending on how long dry air is able to hold on in the low-levels
as warm air moves in aloft. Otherwise...expecting this to be a
relatively quick mover, with guidance hinting attm at a quiet
Sunday...with brief high pressure trying to move overhead. This,
too, appears to be short-lived...as impacts from the next system
approach the region potentially as early as Sunday night. Some
uncertainty attm in the position/track of this system for early next
week...as its track should be related to how far south the BCZ from
Saturday`s system gets...as well as how far north into the region
ridging is able to build going into early next week...with some
question as to the evolution of a northern stream niblet trying to
move through the region early. The quicker this moves across the
region...the cooler we are liable to be Monday across the region,
and the greater the potential for snow over us. (A less progressive
solution with a deeper trough could lead to a more dynamic system in
our area Monday/Monday night, which could shift further development
along this lingering BCZ southward for the end of the extended.)
Bottom line:  I have confidence in the idea of activity across the
Great Lakes region early next week...though low confidence in how
exactly it will evolve and what the timing will be. Stay tuned.

&&

.AVIATION /06Z TAFS THROUGH 06Z THURSDAY/...
MVFR to IFR producing cigs will continue to spread back west
into the region this morning, producing at times a few
insignificant sprinkles or very light snow showers. Slow
improvement expected to develop this afternoon, with more rapid
scouring out of the overcast this evening. Winds will remain
gusty as they slowly veer to a more west to southwest direction
today. Winds expected to become light this evening.

&&

.MARINE...
Wind and wave conditions will necessitate continuing Small Craft
Advisories on Lake Michigan...as well as through the Straits...far
northern Lake Huron nearshore zones...and the St. Mary`s River.
Looks like SCA conditions will continue through tonight and into
Thursday for the Lake Michigan/northern Lake Huron zones.

&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT Thursday for LHZ345>347.
     Small Craft Advisory until 8 PM EDT this evening for LHZ348-
     349.
     Small Craft Advisory until 8 PM EDT Thursday for LMZ323-341-
     342-344>346.
     Small Craft Advisory until 1 AM EDT Thursday for LSZ322.

&&

$$

NEAR TERM...JPB
SHORT TERM...FEF
LONG TERM...FEF
AVIATION...MSB
MARINE...JPB


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.