Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 231806

Area Forecast Discussion
National Weather Service Gaylord MI
Issued by National Weather Service Marquette MI
106 PM EST Mon Jan 23 2017

.NEAR TERM...(Today and tonight)
Issued at 316 AM EST Mon Jan 23 2017

...January thaw continues...

High Impact Weather Potential: More dense fog, especially this

Pattern Synopsis/Forecast: Northern Michigan largely in-between
systems at this early hour, with deep troughing and attendant
increasingly intense surface low pressure well to our south
(responsible for quite the severe weather outbreak the last few
days) and more broad troughing laying out to our northwest.
Inverted surface trough extends north from that southern low,
working its way slowly west across our area. Just off the deck
thermal gradient showing signs of ramping up along this trough axis,
with rather sharp h8 temperature gradient developing across northern
Lake Michigan. Not a ton of activity with the developing fgen
response just yet, with only a shallow detached moisture plume
working west along and just behind surface trough. Moist low levels
and an unseasonably warm airmass overspreading still cold and snow
covered ground has resulted in more drizzle and fog, some of which
has been locally dense once again.

Overhead mid and upper level pattern actually changes little heading
through today and tonight, with the area remaining largely centered
between storm riding up east coast and that broad troughing off to
our west. That surface trough becomes stationary across the area
tonight, all-the-while the fgen response via that tightening thermal
gradient becomes a bit more robust with time. Combine above with
arrival of deeper moisture/deformation and showers look like a
pretty good bet by later today and tonight (some of which may
attempt to mix with snow by later tonight).

Primary forecast concerns: Addressing dense fog concerns this
morning. Rain development today and eventual precipitation type
concerns tonight.

Details: Kinda an interesting forecast as that inverted surface
trough stalls overhead, with fgen/deformation and arrival of deeper
moisture looking to kick off a growing area of precipitation today
into at least this evening. First things first, and expect dense fog
and drizzle to persist into this morning, with arrival of tightening
pressure gradient and attendant east flow likely lifting the fog
heading through later this morning. Per obs showing widespread half
to quarter mile visibilities, will definitely let inherited dense
fog advisory runs it course through the morning. Chances for
legitimate showers definitely looks to ramp up, especially by this
afternoon. Showers continue into this evening, slowly fading
overnight as deeper moisture and forcing is lost. Deep surface based
melting layer looks to keep showers all liquid into at least early
this evening, with slowly cooling profiles introducing more of a
rain/snow mixture later this evening through the overnight. Arrival
of coldest profiles after passage of deepest moisture and marginal
surface temperatures should keep any snow accumulations minimal,
with perhaps a light coating of snow across eastern upper Michigan
by morning.


.SHORT TERM...(Monday through Tuesday night)
Issued at 316 AM EST Mon Jan 23 2017

...Storm to move into N Michigan Tuesday Night and Wednesday...

High Impact Weather Potential...Wet accumulations and possibly
freezing rain/drizzle Tuesday night and possibly Wednesday night.

Pattern Synopsis/Forecast...Rain leaves the forecast area on
Tuesday, as the 500 mb ridging pushes into the region by 00z, and
shuts off the precipitation, sometime in the afternoon. Then about
03z/Wed we start to bring rain back into the region as the warm
front from the main system moves into the forecast area. Model are
showing some issues for the Tuesday night into Wednesday morning
forecast with the rain moving into the region. It looks like it
should be a mix of rain and snow, but there is supposed to be some
below freezing sfc temperatures, especially in E Upper, which could
cause issues, by producing freezing rain. As the low moves through
the state on Wednesday we should see all rain/drizzle again during
the day as the sfc temperatures warm above freezing again. Then we
resaturate (if the GFS is right) overnight, and cool the 850 mb
temperatures. The rain in the evening will change to snow, as we
transition. Probably won`t see much in the way of LES overnight,
until we get closer to 12z/Thurs.

Primary Forecast Concerns...Both nights look mixy. With the Blends
and forecast builder pushing accumulating ice both nights. Scaled it
back, as the it seems that only one of three models is actually
showing that Tuesday night. Is there a possibility? sure. Not a high
confidence, possibility, but enough to keep it in the forecast.

.LONG TERM...(Wednesday through Sunday)
Issued at 316 AM EST Mon Jan 23 2017

High Impact Weather Potential...prolonged lake effect snow pattern
through the following weekend.

Extended (Thursday through Sunday)...Once the low on Wednesday moves
through, the cold air crashes into the region and it looks like that
we will see a prolonged pattern of NW to NNW winds through the
weekend, with synoptic moisture and -10c or colder 850 mb
temperatures and with lake temperatures still around +2C to +4C,
will see accumulations each day through the next weekend.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 102 PM EST Mon Jan 23 2017

Areas of dense fog have been sluggish to improve today, although
should see nearly all locations push above 1sm by early this
afternoon. Winds have remained light from the east/northeast
around 5-10kt. Expect IFR conds to flirt with MVFR cigs, but this
will be short-lived as IFR cigs are expected to return later this
evening and remain overnight possibly trending back towards LIFR
and VLIFR conds overnight. VSBYs will also dip back to around 1sm
and less overnight. Confidence is low on how many locations will
dip to 1/4sm VSBYs overnight, but may need to trend TAFs further
down. Forecast models continue to lean towards patchy
drizzle/lgt-rain overnight.


Issued at 316 AM EST Mon Jan 23 2017

East winds become a bit gusty today across northern Lake
Huron (although remaining below SCA criteria), with light winds
persisting elsewhere. Light winds return tonight, continuing through
Tuesday night. Fog, locally dense, will continue into this morning.




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