Area Forecast Discussion
Issued by NWS Gaylord, MI

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FXUS63 KAPX 181447
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1047 AM EDT Sat Mar 18 2017

.UPDATE...
Issued at 1046 AM EDT Sat Mar 18 2017

KAPX 18.12Z sounding shows saturated low levels with moisture
extending up to about 2.5km and very dry air above. Hence the
areas of drizzle and fog across much of northern Michigan this
morning along with some isolated flurries. Temperatures are
starting to creep upward in a few spots, but very slowly. Still a
handful of areas hovering around freezing, including here at the
office where small tree twigs have nearly a tenth of an inch of
ice from ongoing freezing drizzle. Winter weather advisory slated
to run until noon, but will see how 11am temperatures respond
before deciding whether or not to cancel it early. We will stay
locked in by low stratus the rest of today, which will keep
temperatures in the 30s for most. Areas of drizzle will likely
persist for much of the day especially in higher terrain, though
probably focusing more east of I-75 this afternoon where low level
confluence will develop.

&&

.NEAR TERM...(Today and Tonight)
Issued at 322 AM EDT Sat Mar 18 2017

...Light nuisance precip today...

High Impact Weather Potential...Light icing/slick roads through
the morning hours.

Pattern Synopsis/Forecast...Water vapor imagery/surface map
reveals a pronounced mid level closed circulation and attending
surface low nearly coincident...sliding southeastward out of
Wisconsin into central lower Michigan this morning. Initial axis
of "warm conveyor" moisture and precip that slowly worked across
our area yesterday has pivoted up through eastern upper Michigan
and into Ontario, but did bring some light snow accumulations to
the northeastern part of the CWA through the course of the night
as anticipated. Secondary batch of moisture/light precip with the
closed low is also sliding out of Wisconsin toward central and
southern lower Michigan and will largely miss us. So with the
departure of deeper moisture to the north and a leftover
saturated low level, a hodgepodge of flurries/drizzle/freezing
drizzle and light icing has been prevalent through the night,
particularly across interior northern lower Michigan where a few
hundredths of icing has been reported per ASOS obs.

Closed mid level circulation and attending surface low will slide
through southern lower Michigan and across Lake Erie and into New
York/Pennsylvania by days. Upstream ridging and surface high
pressure build into the region tonight heading into Sunday.

Primary Forecast Concerns...Nuisance precip chances/type today as
deformation and deeper moisture axis rotate down and out of the
region.

Today: As mentioned above, mid level circulation and attending
surface low slides through central/southern lower Michigan this
morning...inverted sfc trough lingering back into the northern
lakes. Deformation axis/slightly deeper moisture will follow,
gradually pivoting down through northern Michigan through the
course of the day. Forcing is weak and saturated lower layers
barely reach the -10C level through the day. Thus once this last
bit of light snow rotates up and out of NE lower and eastern
upper Michigan early this morning, we`re probably left with a
hodgepodge of drizzle/freezing drizzle(early)/flurries/sprinkles
that slowly diminishes through the day.

Headline-wise: Light icing due to freezing drizzle and/or fog
will persist across the region until mid to late morning and temps
get solidly above freezing. Current winter weather advisory
(addressing the icing) runs until noon, which may be a little
long, but I think I will leave well enough alone for now. Day crew
can likely trim the advisory early.

Tonight: Some nuisance light precip may linger into the evening
hours. But an overall drying trend is anticipated as upstream
ridging/surface high pressure gradually builds into the region.

&&

.SHORT TERM...(Sunday through Monday)
Issued at 322 AM EDT Sat Mar 18 2017

...Quick hitting systems...

High Impact Weather Potential...minimal

Pattern Synopsis/Forecast...Sunday looks to remain dry as the sfc
high retreats to the east. The 500 mb ridge moves off as well
allowing for the chances of precipitation to begin to increase after
00z/Mon. The precipitation now looks to be all rain, even in E Upper
as the warm advection looks quite strong through the night as the
warm front moves through the region. The first cold front looks to
pass into the forecast area, around 12z/Mon, but the cold advection
doesn`t look that strong behind it so the main p-type looks to
remain as rain through the day. Through 06z/Tue, things look dry as
the a dry tongue moves through the region ahead of the next cold
front. After 06z, N lower looks dry, and it isn`t certain that E
Upper will see any snow.

Primary Forecast Concerns...Some of the models were giving some
subfreezing temperatures at the sfc for Sunday night, causing some
freezing rain issues in the interior of N Lower. Think this is
pretty low chance, as the warm advection is still going on, and the
model soundings for the center of the state look to show the lowest
25 mb above freezing. So have kept the mention of freezing rain to a
minimum, just to keep this in the back of our minds.

Timing on the cold front Monday overnight is a little less certain
as the GFS is now faster with the cold air than the 00z NAM and 12z
ECMWF. So a low chance that there is LES in Upper Michigan between
06z and 12z/Tues. Even if there is some it doesn`t look like much.
The better chances for LES look to be later on Tuesday when the
ECMWF and the GFS are in better agreement.

.LONG TERM...(Tuesday through Friday)
Issued at 322 AM EDT Sat Mar 18 2017

Extended (Tuesday through Friday)...Models are in decent agreement
with the colder air moving into the region by 12z/Tues, which will
bring about the chance for lake effect snow Tuesday, Tuesday night
and into Wednesday morning. Wednesday afternoon, the core of the sfc
high moves into W Upper and W Lower this will dry the region and cut
off the LES, except maybe some flurries. Thursday, the sfc high
moves off to the east. The models have better agreement on the speed
of the high moving out, so the precipitation onset Thursday night is
a little better than it was yesterday. Friday, the warm front moves
north through Michigan, and changes any snow thursday night into
rain. The GFS is still pushing the main sfc low up the Mississippi
Valley, while the ECMWF now centers the low near KTOP at 00z/Sat.
However, the models are in better agreement with sfc lows as they
each deepen the 500 mb trough in the Midwest by 12z/Sat. Will have
to watch this as the system moves in for the weekend.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 737 AM EDT Sat Mar 18 2017

Widespread IFR conditions across northern lower Michigan this
morning with low cigs...areas of drizzle/freezing drizzle and some
fog particularly across the higher terrain areas. CIGS/VSBYS
should tend to come up this morning and afternoon with daytime
heating...although no better than MVFR. Periodic nuisance light
precip (drizzle/sprinkles/flurries) will also continue through
much of today.

Nuisance light precip will end this evening. But lower CIGS
(probably lowering back to IFR) will stick with us through
tonight.


&&

.MARINE...
Issued at 737 AM EDT Sat Mar 18 2017

Winds will turn northeast to northwesterly across the region today
and increase a bit. A few gusts to 20 knots are possible. But
winds/waves under small craft advisory conditions are anticipated.
Winds remain relatively light through the rest of the weekend.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until noon EDT today for MIZ008-015>019-
     021>024-026>030-032>036.
LH...NONE.
LM...NONE.
LS...NONE.
&&

$$

UPDATE...MEK
NEAR TERM...TBA
SHORT TERM...JSL
LONG TERM...JSL
AVIATION...TBA
MARINE...TBA



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