Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 122309

Area Forecast Discussion
National Weather Service Gaylord MI
709 PM EDT Mon Mar 12 2018

.NEAR TERM...(Tonight through Tuesday)
Issued at 324 PM EDT Mon Mar 12 2018

...Lake enhanced snow thru the near term...

High Impact Weather Potential...A few inches of lake enhanced
snow in some areas.

Low pressure nearing ne Lake Huron is starting to lose its identity,
as it gets absorbed into the much larger circulation around the
developing east coast storm. Some leftover synoptic-scale moisture
and light snow continues in ne lower MI, while lake effect/enhanced
snow showers are on Superior and n central lower MI. Snow trends are
the main concern.

With a digging shortwave carving out a 500mb low over the eastern
lakes, reasonably deep moisture will remain in place over northern
MI thru Tuesday. Inversion heights of 7-8k ft are impressive, and
the DGZ is well-placed in the unstable layer (though a bit above the
layer of max ascent). However, the push of coldest 850mb air will be
directed over western Superior and juuuuust west of Lake MI. 850mb
temps of -14/-15C here are not outstanding for lake effect, given
how cold/icy the Great Lakes are (1/2C where there is open water).
In addition, our present nnw 1000-850mb winds are about as backed as
they will get over the next 30 hours; we will spend that time with
an almost N fetch for most of the period. When combined with ice
cover, that doesn`t expose a lot of northern MI to long-fetch lake
effect potential.

This is a disconcerting forecast, with a lot of the near-term
guidance spitting out QPF in places one would not expect (such as
GLR). But with the upper low developing just to our ne and e, and
associated lowering of 500mb heights, there`s more going on to
generate precip than just the lakes. It`s also disconcerting because
that near therm guidance is doing very poorly right this second, not
handling the current uptick into nw lower MI at all.

Will generally continue to bump up pops/QPF in places favored by a
north fetch (near and w of TVC, APN/Rogers, far western Chip/Mack),
and reduce elsewhere. 24 hour accums will be in the 2-4" range for
TVC/CAD and west, and around 2" for APN/Rogers and Paradise/Curtis.
Two inches or less elsewhere.

Min temps around 20 to the mid 20s. Max temps upper 20s to lower 30s.


.SHORT TERM...(Tuesday night through Thursday)
Issued at 324 PM EDT Mon Mar 12 2018

...Lake Effect Snow Ending then Possibly Restarting...

Primary Forecast Concern...Pops through the period.

Marginal over lake instability/lingering upper level troughing
should prolong northerly flow lake effect snow showers into Tuesday
night. Instability is marginal and waning as the night goes on so
additional accumulations are expected to be under an inch. As the
upper level trough slowly pushes off to our east and weak warm
advection kicks in Wednesday, activity should finally end in the
morning. A short wave moving through the flow will bring a chance
for a few mainly nuisance snow showers Wednesday night. The ECMWF
and to a lesser degree the GFS are now bringing in another
reinforcing shot of cold air into the region Thursday. If this ends
up being the case it will likely be cold enough to fire up the lake
effect snow machine once again with the flow out of the north
northwest or northwest. Will not totally buy into this quite yet but
will lean toward this possibility and lower highs a bit while
introducing chance pops. Temperatures are expected to be a few
degrees below normal for the middle of March. It looks like a long
time before spring weather makes it this far north as long range
models look a bit chilly.

.LONG TERM...(Thursday night through Monday)
Issued at 324 PM EDT Mon Mar 12 2018

Models have come into some agreement for at least the first part of
the long range forecast...with high pressure and much drier air
building into the Great Lakes region through the day Friday...ending
any lingering snow showers. As the previous forecaster
mentioned...this weekend through the beginning of the work week is
up in the air, with models differing from high pressure and a series
of low pressure systems. Any precipitation that may develop however
appears to be minimal. Highs will be in the 30s to low 40s, while
low temperatures will be in the mid teens to low 20s.


.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 702 PM EDT Mon Mar 12 2018

Challenging forecast with regards to snow shower intensity and
coverage. Trends still support heaviest and steadiest snows
targeting areas closer to Lake Michigan and Lake Huron through
tonight into Tuesday. No completely sold on this idea as low level
flow veers a bit northeast before coldest air arrives (especially
off Lake Michigan). Will tentatively have lower vis restrictions
for KMBL and KAPN, holding off any lower vis for KTVC until
better radar trends are realized. Otherwise, expecting just some
passing light snow showers and mostly VFR/MVFR cigs. Gusty
northwest to north winds will develop overnight into Tuesday. Snow
to liquid ratios will remain elevated, averaging around 18/20-1.
Any blowing snow concerns should remain minimal.




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