Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 131730
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1230 PM EST Mon Nov 13 2017

.UPDATE...
Issued at 1024 AM EST Mon Nov 13 2017

Still dealing with pesky drizzle out there, mainly in NW lower and
the higher terrain. It`s still freezing in spots in the higher
terrain where temperatures were right at 32F. Another hour or so
and there will be no freezing component to the drizzle. Across
Chippewa county in eastern upper, low level moisture depth was
hovering around -10C resulting in snow at times, mixed in with
drizzle. Just another cloudy, gloomy day.

Things will start to change heading through tonight. Did add some
more evening drizzle/higher terrain freezing drizzle. Shoved some
of this up into Mackinac Island and Mackinac county, as the weak
1000-850mb winds turn more WSW and press the moisture flux
component into these areas. However, more substantial WAA ensues
overnight with the passing of a shortwave trough and subsequent
mid level height rises. The inversion height lowers to the
point/moisture shallows out to where drizzle should completely be
out of the question. Roads can easily still be slick, mainly the
untreated secondary roads.

&&

.NEAR TERM...(Today through Tonight)
Issued at 305 AM EST Mon Nov 13 2017

...Areas of freezing drizzle throughout the morning hours...

High Impact Weather Potential...Freezing drizzle causing some slick
spots on untreated surfaces during the morning.

Pattern Synopsis/Forecast...Weak cold front remains stalled over
Upper Michigan early this morning...enhanced by lake aggregate
troughing. Strong high pressure remains centered just upstream along
the Mississippi Valley...with surface ridging poking into Lower
Michigan. Areas of drizzle/freezing drizzle continue to impact much
of our CWA as temps hold mainly in the low to mid 30s. Some very
weak over-lake instability is enhancing ongoing very light precip
across the western half of our CWA thanks to westerly low level
flow. Areas of fog are also impacting portions of our CWA...but
remains relatively light for most locations.

Ample low level moisture will remain over much of the Western Great
Lakes region today as the weak cold front slowly slides east. Dry
mid and upper levels with all low level moisture staying well below
the -10 C isotherm combined with some wind shear at the top of the
moist layer will lend to continued development of areas of
drizzle/freezing drizzle today into this evening. Upstream high
pressure center will build into Michigan by tonight...bringing this
light precip to an end...but some lingering low level moisture will
likely lend to the development of areas of fog. High temps this
afternoon will be mainly in the mid to upper 30s across our entire
CWA. Low temps tonight will cool back into the mid to upper 20s.

&&

.SHORT TERM...(Tuesday through Wednesday)
Issued at 305 AM EST Mon Nov 13 2017

...Wet midweek weather...

High Impact Weather Potential: Minimal.

Pattern Forecast: Surface high pressure will gradually press
eastward across northern Michigan Monday night into early Tuesday as
warm air advection ramps up over the Mississippi Valley into the
western Great Lakes. Strengthening southwesterly return flow
throughout the day Tuesday will aid in drawing moisture into the
region with upstream isentropic lift over Wisconsin gradually
spreading more mid/high cloud into the region, followed by
increasing rain chances as early as Tuesday evening. A pair of mid
level shortwaves will phase across the Great Lakes on Wednesday with
an attendant strengthening surface low trekking across southern
Ontario, ultimately dragging a cold front across the forecast area.

Primary Forecast Concerns/Challenges: Increasing rain chances
Tuesday evening into Wednesday...perhaps enhanced off of lake
Superior Wednesday afternoon.

As was alluded to by the prior shift, forecast soundings continue to
show a shallow layer of moisture trapped near the surface into early
Tuesday morning. Expectation is for low clouds and perhaps a bit of
lingering fog to dissipate through the midday hours as daytime
mixing gradually picks up. However, increasing mid-high clouds will
likely be spreading into the region from the west, so while some
breaks in the clouds look feasible...another mostly cloud day is
expected.

Moisture fields steadily increase throughout the day as WAA and
associated southwesterly winds continue to ramp up. PWs progged to
climb to 0.75-1.00" Tuesday night with rain becoming likely during
the evening across far northwest Lower/eastern Upper...eventually
spreading across the entire forecast area associated with modest mid
level forcing expected to arrive overnight. The majority of the
steadier rain still looks to exit by mid-late Wednesday morning;
however, scattered showers remain possible ahead of the cold front
expected to arrive later in the day. Total QPF on the order of a
quarter to half an inch through the event...highest across eastern
Upper as additional Lake Superior enhanced showers will become
possible as temps aloft steadily cool (-2 to -4 C at 850 mb) through
the mid-late afternoon. Wouldn`t be all too shocked to see
snowflakes mix in as well late in the day Wednesday across the far
north, but nothing expected to be of consequence.

High temps both Tuesday and Wednesday within a degree or two of
normal...in the low 40s area-wide.

.LONG TERM...(Wednesday night through Sunday)
Issued at 305 AM EST Mon Nov 13 2017

High impact weather potential: A potentially strong system arrives
this weekend with a myriad of possible issues including rain, strong
winds and eventually snow.

The extended begins with any lingering precipitation continuing to
diminish. Wouldn`t be shocked by a few snow showers Wednesday
evening into the early overnight hours as low level temps continue to
cool behind Wednesday`s cold front...perhaps allowing lake processes
to ramp up for a brief window into Thursday morning.

Otherwise, attention quickly turns to the Friday through the
Sunday/Monday timeframe as an impressive Pacific originated mid
level wave carves out troughing across the center of the CONUS with
attendant cyclogenesis underway lee of the Rockies. Said low
pressure is expected to rapidly deepen as it approaches and
eventually crosses the Great Lakes Friday night-Saturday. Noticeably
gusty winds and increasing rain chances will commence as early as
Friday afternoon (perhaps a bit of mixed precip early?)...continuing
into Saturday before the system`s cold front sweeps east across the
forecast area allowing for much cooler Canadian air to spill into
northern Michigan. Current trends suggest any low CAPE/high shear
severe weather threat ahead of the aforementioned cold front will
remain south of the CWA. By Saturday night, any lingering
synoptically driven precip may change over to wet snow with
northwest flow lake effect process ramping up as well. The combo of
rain, wind and snow make the upcoming weekend one to keep an eye on
moving forward.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1225 PM EST Mon Nov 13 2017

Mainly MVFR/low VFR cigs will continue into this evening with
drizzle becoming much more isolated with time. Do think that the
patchy drizzle/freezing drizzle will hang around into the evening
for PLN, while the low clouds are expected to erode through the
night from SW to NE. SSW low level winds do increase very late
tonight into Tuesday morning, which will increase moisture flux
off Lake Michigan into MBL for a potential return to MVFR CIGS.
Winds will remain light/variable thru tonight with speeds under
10kts Tuesday.

&&

.MARINE...
Issued at 305 AM EST Mon Nov 13 2017

Winds and waves will stay below SCA criteria thru Monday night as
high pressure gradually builds into the Western Great Lakes region.
Conditions will reach SCA criteria Tuesday afternoon and night ahead
of our next cold front moving into the Great Lakes region. Low
clouds and areas of drizzle/freezing drizzle will continue to impact
all of our nearshore areas today into this evening...along with some
areas of fog.


&&

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

$$

UPDATE...SMD
NEAR TERM...MR
SHORT TERM...MG
LONG TERM...MG
AVIATION...SMD
MARINE...MR



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