Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 210444

Area Forecast Discussion
National Weather Service Gaylord MI
1144 PM EST Fri Jan 20 2017

Issued at 1005 PM EST Fri Jan 20 2017

Short wave trough continues to lift thru Northern Lower Michigan
late this evening...with area of light precip along and north of
this trough mainly confined to Eastern Upper Michigan attm. Radar
returns appear to be more impressive than what is actually hitting
the ground per regional obs...and intensities are rather light.
This area of precip will continue to lift northward out of our CWA
over the next couple of hours. Main issue for the overnight will
be continued development and expansion of dense fog across our
entire CWA as mid levels dry but ample low level moisture remains
in place. Certainly light winds and a gradually melting snowpack
will lend to continued fog development. Areas of drizzle and
possibly some freezing drizzle are also expected...and latest
radar images suggest this is in the process of developing. All in
all...a rather soupy night with the possibility of some slippery
spots developing on roadways and walkways as this dense fog and
drizzle freezes on some surfaces with temps falling to overnight
lows in the low to mid 30s.


.NEAR TERM...(Tonight and Saturday)
Issued at 409 PM EST Fri Jan 20 2017

...Periods of dense fog into Saturday...

High Impact Weather Potential...dense fog at times.

Pattern Synopsis/Forecast...Dampening mid level shortwave trough
continues to swing up through the state this afternoon with a
stretched out axis of precip lifting up through northern Michigan.
Precip really thinned/fell apart across this part of the state
over the last several hours producing only minor QPF. Precip is a
bit more robust just to our west across Lake Michigan and
Wisconsin where apparently stronger shortwave forcing resides and
some orographic lift may be helping the cause.

Meanwhile, we did manage to lose a good bit of the fog this
afternoon. But, there is still some rather dense fog across
eastern upper Michigan and parts of NE lower Michigan.

Primary Forecast Concerns...drizzle and fog. Shortwave trough and
axis of precip will continue to lift up through northern Michigan
this evening ending the main precip threat. Then, forecast
soundings show respectable drying aloft later in the evening and
overnight while low level saturated layer deepens to a few
thousand feet overnight through Saturday morning, a strong drizzle
and fog signal. Have trended the forecast to include more along
the lines of drizzle later tonight through Saturday, possibly a
little freezing drizzle in the higher terrain.

Fog concerns: Fog did manage to thin/clear over a good part of
northern lower Michigan today, still holding on across eastern
upper Michigan and NE lower Michigan. Fog likely to return again
tonight and plan on issuing another dense fog advisory for a good
portion of the CWA.


.SHORT TERM...(Saturday night through Monday)
Issued at 409 PM EST Fri Jan 20 2017

...Continued cloudy and mild with rain chances...

High Impact Weather Potential...Minimal, but a brief period of
freezing rain can`t be ruled out late Sunday night into Monday

Pattern Synopsis/Forecast...A warm front over Lower Michigan
Saturday night will make it about as far north as our southern CWA
border by Sunday morning before it stalls out. Meanwhile an upper
low over northwest Wisconsin will shear out as it slowly wobbles to
north of Lake Superior on Sunday, and a strong surface low will move
eastward from the southern Plains, reaching the Mid-Atlantic Coast
on Monday. Ongoing WAA will persist across much of the area Sunday
into Monday, with isentropic lift and an inverted surface trough
leading to an increased chance of rain showers Sunday afternoon and
evening. Split upper level flow will develop over the Midwest Sunday
night into Monday as a blocking ridge becomes highly amplified off
the East Coast. This ridge will cause the sheared out upper low over
southern Ontario to lift further north while a deep cutoff low
meanders over the Mid-Atlantic. This will translate into continued
surface troughing over northern Michigan during the day on Monday,
providing continued rain chances.

Primary Forecast Concerns...Ongoing WAA and dewpoints in the mid to
upper 30s will allow for efficient melting of the snowpack through
the weekend, resulting in a rich supply of low level moisture and
persistent low level cloudiness. Also of concern will be the
potential for lingering fog across the area Saturday night into
Sunday morning. Southerly low level flow will back to easterly on
Sunday as the inverted surface trough noses into northern Michigan.
This will cause a westward propagation of isentropic lift during the
day on Sunday with rain chances increasing as the best lift arrives
during the afternoon and evening. Temperatures are expected to drop
to right around freezing over eastern Upper and higher elevations of
northern Lower late Sunday night into Monday morning. This may
result in a brief period of freezing rain for some, but NAM forecast
soundings show only a shallow saturated layer aloft suggestive of
drizzle. The GFS has a deeper, colder saturated layer more
supportive of light snow. The ECMWF and Canadian are more middle of
the road for temperatures aloft. This will bear watching, but
at this time impacts are expected to be minimal.

.LONG TERM...(Monday night through Friday)
Issued at 409 PM EST Fri Jan 20 2017

The big picture in the extended period will be unsettled weather
with a general cooling trend from Tuesday to Friday.  The 500mb
pattern shows the conus dominated by broad troughing that begins in
the rockies and widens eastward by Thursday.

On Tuesday, a closed low develops in the central plains and sets it
sites on the great lakes. This low will move across Michigan on
Wednesday and of course it`s track will dictate exactly how Northern
Michigan is effected.  At present, The euro and GFS are tracking
this low through the straits of Mackinac. Of course that being day
5, this can still and likely will, change...but will remain the main
forecast challenge in the long term. The temperature regime and this
storm track would indicate we`ll be dealing with P-type
least across the lower peninsula.

Colder air begins to infiltrate on it`s looking like
it could be cold enough, with favorable wind fields and enough
moisture to generate some lake effect snow for Thursday and Friday.
It is still too far off to be confident in this call...but will
warrant chance pops at least.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1145 PM EST Fri Jan 20 2017

Mainly IFR conditions due to the development and expansion of
dense fog and areas of drizzle will impact all Northern Lower
Michigan TAF sites overnight into Saturday as ample low level
moisture remains in place across the Western Great Lakes region.
Light/calm winds overnight will become east under 10 kts on


Issued at 409 PM EST Fri Jan 20 2017

Overall light winds and waves anticipated through the weekend. No
headlines anticipated.


MI...DENSE FOG ADVISORY until noon EST Saturday for MIZ008-015>036-


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