Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 191540

Area Forecast Discussion
National Weather Service Gaylord MI
1040 AM EST Fri Jan 19 2018

Issued at 1040 AM EST Fri Jan 19 2018

Not much of an update needed. A quiet day in store for the region
with a continual feed of weak vorticity originating from troughing
off the pacific coast, which will be plowing through the
increasingly more zonal fast flow aloft. Another shallow
shortwave trough is seen in srn Canada, which is trying to dig a
little toward Lake Superior. At the sfc, low pressure was
associated with the srn Canada wave, with a west to east oriented
stationary boundary that stretches north of the Great Lakes into
New England. 12z APX sounding reveals quite a bit of dry air below
roughly 500mb, but quite a deep depth of higher level moisture
from the pacific brought in by the feed of weak energy. This will
just result in mostly cloudy skies/filtered sunshine.

From a temperature standpoint, a strong inversion due to
impressive WAA seen mainly aloft, has resulted in strong low
level stability. This will make it tough to mix any of the
stronger SW winds and warmer temperatures aloft down to the sfc.
Thus, temperatures will remain well below their potential. Add in
the higher level clouds, and am finding it difficult to raise
temps much higher than what was in the forecast. This despite
these type of events typically resulting in warmer than thought
temperatures. Some areas have been mixing a bit into the better
winds/warmer temps aloft, and thus did raise readings to where
more areas will be in the lower 40s today. Will be watching for
stronger gusts and potential to go even higher.


.NEAR TERM...(Today through Tonight)
Issued at 329 AM EST Fri Jan 19 2018

...Temperatures continue to trend upward...

High impact weather potential: Minimal.

Pattern synopsis/forecast: Mid level heights on the rebound early
this morning as shortwave trough races off to our east and deep
troughing digs in off the Pacific into the West Coast. Surface
response features a weak stationary front layed out across southern
Canada into Lake Superior, while elongated high pressure stretches
out from the Ohio Valley into the northern Gulf. Above has resulted
in a rather mild, quiet night across the Northwoods, with current
temperatures only in the 20s and lower 30s (warmer than normal highs
for this time of year). Large area of stratus slowly thinning from
southwest to northeast as warm air advection continues through the
cloud-bearing layer.

Upper level flow regime becomes quite zonal across the Northern
Plains into our area by later today and tonight, forcing a much
modified Pacific originated airmass into the region. Passing wave
and attendant area of low pressure racing across Ontario this
afternoon and evening may provide the impetus for just a bit of
light precipitation across eastern upper Michigan.

Primary forecast concerns/challenges: Cloud/temperature trends and
addressing potential for a bit of very light precipitation.

Details: Warm air advection process go full tilt today, spiking H8
temperatures into the high single digits by this afternoon. This
will no doubt continue to steadily erode current stratus deck, last
across eastern upper Michigan. Plenty of high clouds to our west
will definitely filter the sun some, especially by this afternoon.
Primary forcing from that Ontario wave remains well to our north,
and model derived soundings really struggle to reach full
saturation, even for areas north of the big bridge. May carry a
small chance for rain/snow showers, but definitely nothing
significant. Now, on to those all important temperatures. Of course,
greatest warming will occur aloft, with strong low level inversion
capping just how much surface temperatures respond. Still,
increasing southwest winds and attendant mechanical mixing through
the shallow boundary layer easily supports highs well above
freezing. Will go full bore toward the warmer end of the guidance
spectrum as these type of warming events always seem to overachieve
a bit. Expect highs well up into the upper 30s, with at least a few
locations topping 40 degrees across northern lower Michigan.

Subtle cooling aloft expected tonight as mid level heights fall just
a bit. Stationary front remains well off to our north, and expect
that`s where greatest precip threat will remain. Plenty of high and
mid level clouds expected to linger overhead, and will need to watch
for additional early morning stratus development as today`s snowmelt
adds a bit of water vapor to the low levels. Another well above
normal temperature night, with lows by sunrise Saturday in the upper
20s and lower 30s.


.SHORT TERM...(Saturday through Sunday)
Issued at 329 AM EST Fri Jan 19 2018

...Quiet weather before a wintry mix arrives Sunday night...

High Impact Weather Potential...Minimal.

Pattern Synopsis/Forecast...Zonal flow aloft for much of the weekend
over the Upper Great Lakes with the polar jet nudged northward into
southern Ontario. This will allow for continued mild late January
conditions across northern Michigan. Isentropic ascent across the
Ohio Valley early Sunday will gradually lift northward through the
day, spreading into northern Michigan by late afternoon. Meanwhile a
developing cyclone over the Southern Plains on Sunday will take aim
at the Upper Great Lakes heading into Sunday night and Monday.

Primary Forecast Concerns...Precipitation chances/types on Sunday.

Pretty quiet weather expected through Saturday night. Forecast
soundings show a shallow saturated layer from the surface to about
0.5 km with the moisture trapped below a sharp inversion roughly
above 925 mb. Little if any omega coincident with this moist
boundary layer, so not expecting any precipitation/drizzle to fall
from it. However, do expect it to result in a decent amount of low
stratus across the area (especially northern Lower) with SREF
ceiling probabilities offering strong support for that idea. Have
therefore increased cloud cover to mostly cloudy. Highs will take a
run at 40 degrees once again in many areas with everyone at least
climbing above freezing. Dewpoints will struggle to reach 32F,
however, so not expecting efficient melting of current snowpack.
Could be some areas of fog that develop Saturday night.

A weak front draped across northern Lower on Sunday may provide
enough support for some flurries between the Straits and M-32.
Isentropic lift nosing in from the south along with increasing
moisture may trigger some drizzle or perhaps light rain/snow showers
south of M-72 during the afternoon. The bulk of the precipitation
associated with the advertised potential winter storm will hold off
until later Sunday night into Monday, and that is when the forecast
starts to get somewhat messy for northern Michigan (see below for
more details).

.LONG TERM...(Sunday night through Thursday)
Issued at 329 AM EST Fri Jan 19 2018

High Impact Weather Potential...Potential for a wintry mix of snow,
freezing rain, and sleet Sunday night through Monday with some ice
and snow accumulation. Then accumulating lake effect snow for a
portion of eastern Upper and northwest Lower through midweek.

Significant differences still exist among model guidance in terms of
the track and intensity of a winter storm for the Upper Great Lakes
later Sunday night through Monday night. Consensus was taking the
storm from SW Iowa Monday morning through the Straits by daybreak
Tuesday. But...(dun dun duuuun) the 19.00Z run of the ECMWF now
takes the storm track farther south through the Thumb, obviously a
colder solution. So specific forecast details such as precipitation
types and amounts are still far from certain. Nevertheless, there is
continued moderate confidence that much of the APX forecast area
would lie within a transition zone, seeing the potential for a
wintry mix of snow, freezing rain, and sleet before warmer
temperatures Monday afternoon would support a changeover to just
rain south of the Bridge. That is, unless things trend towards the
colder ECMWF solution, which would increase the potential for snow
across at least the northern portion of the forecast area. At any
rate, looking like a respectable amount of precipitation from this
system with QPF in excess of 0.5" for the bulk of the forecast area.
This could result in moderate snow accumulation for the Straits
region and eastern Upper. Could be somewhat windy surrounding this
system`s passage as well. We will continue to closely monitor this
system over the next few days as forecast details gradually become
clearer, and you should keep tabs on the forecast for changes, too.

Beyond that, the rest of the long term forecast period looks colder
with renewed chances for lake effect snow across a portion of
eastern Upper and northwest Lower from Tuesday through Thursday
morning. Highs back in the 20s with lows in the teens to single


.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 623 AM EST Fri Jan 19 2018

VFR conditions expected today under some passing mid and high
level clouds. Increasing low level moisture below strong inversion
likely to kick off more MVFR producing stratus later tonight.
Southwest flow wind shear today into early this evening.




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