Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 250002
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
702 PM EST Tue Jan 24 2017

.NEAR TERM...(Tonight through Wednesday)
Issued at 414 PM EST Tue Jan 24 2017

...Patchy freezing drizzle tonight giving way to snow on
Wednesday...

High Impact Weather Potential...Patchy freezing drizzle may result
in a light glaze of ice across eastern Upper by Wednesday morning.
Minor wet snow accumulation will be possible during the day on
Wednesday, impacting the morning and afternoon commutes.

Pattern Synopsis/Forecast...Northern Michigan remains within a split
flow pattern aloft as a weak shortwave lifts to our north and
mid-level ridging builds in from the south. This ridging is finally
bringing an end to the showers across our eastern CWA, but areas of
fog and drizzle will still persist through late this afternoon and
perhaps into the early evening as well. Drier air is building into
the area above 800mb today, but moisture will increase again later
tonight into Wednesday as the next system moves in from the
southwest. This system will bring the next shot at some snow during
the day on Wednesday, but potential accumulations are looking minor.
Snow is expected to move into our southwest between 09-12Z Wednesday
morning with the arrival of isentropic lift. The snow will
overspread the rest of the forecast area during the day, with the
best forcing and heaviest snowfall rates expected Wednesday morning.
Under WAA, temperatures will rise into the mid to upper 30s, which
will allow for some rain to mix in by around midday, with some
locations perhaps seeing a changeover to all rain for a period of
time.

Primary Forecast Concerns...A few forecast concerns for tonight and
Wednesday. First, how much longer will this afternoon`s fog and
drizzle linger? Drier air is building in aloft, but forecast
soundings show the low levels will remain nearly saturated
through this evening. Second, forecast soundings look favorable for
patchy drizzle later this evening and overnight, but there is some
uncertainty as to whether this afternoon`s patchy drizzle will
simply linger into tonight or if it dissipates this evening and
then redevelops overnight. The best chance for drizzle overnight
looks to be around and north of the Straits, but it is not out of
the realm of possibility that parts of northern Lower are impacted
as well. Low temperatures tonight will be a degree or two on either
side of freezing, so if drizzle does materialize overnight, there
could be some patchy freezing drizzle that results in a light glaze
of ice (most likely around and north of the Straits) by daybreak
Wednesday.

The final forecast concern revolves around snow amounts through
Wednesday. Model QPF for this event looks respectable, but the
best QPF will coincide with warming daytime temperatures and
rain potential. Ground temperatures must also be taken into
consideration given the recent mild stretch. Expect much of the snow
will melt (at least initially) on contact with the wet main roads,
unless a burst of heavier snowfall rates develops. Also, snow ratios
will be around 10:1 or perhaps a little lower through this event, so
the snow will be rather wet and compact easily. All told, we`re only
talking about perhaps an inch or two of accumulation through the
daytime hours, but if snowfall rates are heavy enough (especially
in the morning) it could lead to some slick roads for the commutes.
Given we`re not expecting much in the way of accumulations and the
rain that will mix in, have decided against issuing an advisory but
will consider an SPS and continue mention in the HWO.

&&

.SHORT TERM...(Wednesday Night through Friday)
Issued at 414 PM EST Tue Jan 24 2017

High Impact Weather Potential...Lake Effect snow showers return.

Pattern Synopsis/Forecast...Surface low tracks across southern MI
Wednesday night and into Ontario Thursday. Pattern transitions to
lake effect in NW to W flow behind the storm system.

Primary Forecast Concerns...QPF for storm system generally forecast
to be around 0.30" through Thursday morning...with slightly higher
amounts southwest of GLR...less north. Question is how much falls as
snow. WPC and forecast plumes indicating wide range of snowfall
values with 2-4" totals falling in the middle...but amounts as high
as 8" over the higher elevation interior. Seems overdone based on
model QPF. Temperature profile will be critical but BUFKIT soundings
show cooler air works in enough Wednesday night so that most areas
will be all snow to end the event. Looks like most areas will be in
the 1-3" range with a little more over the higher elevations where
precipitation remains mostly snow.

Pattern then transitions to LES as core of first shot of cold air
moves through Friday night. Inversion heights top out around 6-7kft
Friday night with temperatures near the top of the inversion around
-12C. 1000-850mb winds do not get locked into any one direction for
very long...going from NW to W between Thursday and Friday. So right
now not seeing large snowfall accumulations.

.LONG TERM...(Friday night through Tuesday)
Issued at 414 PM EST Tue Jan 24 2017

High Impact Weather Potential...Yes as much colder air, more
seasonal temps, remain centered over the Great Lakes through the
period. This pattern will increase lake snows thru the weekend.

At upper levels, the 500mb trough which settled into the state and
northern Plains earlier in the week, will remain anchored over the
Great Lakes into the upcoming work week. 850mb temps in the pattern
will be between -12c and -17c through much of the period, which will
generate seasonal afternoon temps in the mid 20s across much of
northern Michigan. At the surface, cyclonic flow on the backside of
a system stalled near Greenland, will enhance lake effects to
generate chances of snow over nrn Michigan through the weekend. A
clipper dropping over the Great Lakes early next week will generate
another round of snow over northern Michigan Monday and Tuesday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 702 PM EST Tue Jan 24 2017

Fog and low stratus remain the primary issues with continued thick
low level moisture engulfing northern Michigan. LIFR/IFR
conditions to persist with no improvement seen over the TAF
period. Periods of drizzle and very light snow will be common
before more robust rain and snow arrives Wednesday. Light winds
through the period.

&&

.MARINE...
Issued at 414 PM EST Tue Jan 24 2017

Patchy fog will linger into this evening but is expected to
dissipate overnight. Winds will remain light through Wednesday
morning, increasing out of the NNE Wednesday evening and becoming
gusty at times as low pressure moves through. Flow then turns NW
for the remainder of the week with SCAs possible for some
nearshore waters during the period.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

NEAR TERM...MEK
SHORT TERM...KJF
LONG TERM...SWR
AVIATION...SMD
MARINE...MEK



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