000
FXUS63 KGRR 262333
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
633 PM EST Wed Jan 26 2022

LATEST UPDATE...
Aviation

.DISCUSSION...(This evening through next Wednesday)
Issued at 244 PM EST Wed Jan 26 2022

- Some impacts look possible Thursday due to the snow

A positively tilted mid level trough pushes eastward through the
CWA on Thursday. The moisture deepens up into the DGZ with the
best saturation over northwest parts of the CWA. During the
afternoon and evening the deeper moisture pulls away. As a result
we will see an area of mainly light snow moving in from the
northwest during the morning...which then pushes off to the
southeast for the afternoon. Models are generally showing an inch
of so of accumulation...primarily for the north half of the CWA
where the better saturation is progged. We will feature relatively
high POPs for Thursday. Most locations will see high temperatures
staying in the 20s. As a result a least local impacts look
possible.

- Lake effect possible Thursday night into Friday

Overall this setup does not look favorable for widespread
accumulations. Little and Big Sable Points are likely to see the
most snow shower activity as a north northeast flow tends to favor
those locations for the highest concentration of snow showers.
However at this time we do not see this as a major event because
the moisture depth remains mostly under 5k ft and the winds will
be shifting with time. We will go with likely or better POPs for
that region and 1 to 3 inches of snow.

- We will need to monitor the Sunday system for possible snow

There has been a trend in the models towards an increased
potential for snow later Saturday night into Sunday. This will be
another system featuring the passage of a mid level wave which
taps lake moisture to result in some snow. One difference with
this wave is that the dynamics and moisture alignment look
better. For now we will introduce some POPs for northern parts of
the region where the lift and moisture are shown to come together
for a possible snow event.

- Possible impactful pattern for mid week next week

It has been some time since we have seen a stronger surge of Gulf
moisture advecting into our area...but that is what the models are
showing for Tuesday into Wednesday. Thus an increased potential
for heavier qpf is shown to exist. Surface dewpoints may rise
above freezing here in the CWA on Tuesday. At the same time a
surge of arctic air will be dropping southeast out of the Upper
Plains. Precipitation will be developing along this frontal as one
or more waves lifts out of the Southern Plains. The onset of the
precipitation in Southwest Lower MI Tuesday could feature rain
given given the warmer temperatures in place...but as the arctic
air filters in a transition to snow looks possible as we go into
Wednesday. Again some of the precipitation could end up heavy so
close monitoring will be needed. If we end up with mostly
rain...we would have to consider the impacts to the
rivers...especially with the ice in place. If it ends up as mostly
snow...heavy accumulations could occur. Also a zone of freezing
rain is likely between the rain/snow line so those impacts are
another possible consideration.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 633 PM EST Wed Jan 26 2022

Most of our TAF sites are clear or close to clear this evening,
only MKG still have MVFR cigs due to lake educed clouds. It would
seem to me the dry air moving in from the south should clear the
sky at MKG by 01z. Otherwise overnight expect nearly clear skies
to continue but there will be a strong south southwest winds just
above 1000 ft AGL, so I have added LLWS to all but the MKG TAF
(wind aloft not quiet as strong there) for the overnight hours.

A frontal system will bring light snow back to the TAF sites by
early afternoon for MKG and LAN, by mid afternoon for the I-94 TAF
sites. This will bring IFR/MVFR conditions as the snow moves in.

&&

.MARINE...
Issued at 244 PM EST Wed Jan 26 2022

The winds and waves will increase tonight as a low level jet moves
in. Southwesterly values surface winds are likely to hit gale
force as the pressure gradient tightens up. The wave of low
pressure responsible for the stronger winds shifts east of the
area on Thursday which is when the winds will shift to the
north...by evening. Hazardous conditions are likely to linger into
Friday.


&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 10 PM EST this evening for LMZ845>849.

     Gale Warning from 10 PM this evening to 10 AM EST Thursday for
     LMZ845>849.

     Small Craft Advisory until 11 AM EST Friday for LMZ844.

&&

$$

DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS

NWS GRR Office Area Forecast Discussion