676
FXUS63 KGRR 051131
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
631 AM EST Thu Dec 5 2024

.KEY MESSAGES...

- Lake Effect Snow Continues Today

- No significant precipitation events this weekend into mid next week

- Temperatures warm this weekend and then fall into next week

&&

.DISCUSSION...
Issued at 333 AM EST Thu Dec 5 2024

- Lake Effect Snow Continues Today

Bottom line up front. Have ended the winter weather advisory for the
US127 corridor including Lansing and Jackson. Have transitioned
Osceola, Mecosta, and Calhoun counties into an advisory, and the
rest of the winter storm warning remains as is.

Radar shows that a notable lake-effect snow band is ongoing in the
northwest flow regime along a roughly Muskegon to Kalamazoo line.
This morning low-level winds veer to a more northerly flow
configuration with the passage of a surface trough. This leads to
the development of a lake effect snow band near and west of US131
enhanced by a Lake Superior connection that will lead to continued
moderate to occasionally heavy snowfall. East of US131, scattered
showers will occasionally impact the counties in the winter weather
advisory and isolated showers for the US127 corridor. This
translates to a general 4-8 inches with locally higher amounts
possible near and west of US131, 1-3 inches of additional snow
across the advisory counties, and up to an inch for the US127
corridor. Areas of heavier snow will likely see notable reductions
in visibility.

In addition to the snow, gusty winds persist today. Gusts will
generally be in the 30-40 mph range inland with gusts to 45 mph
towards the lakeshore. The gusty winds will also lead to patchy
blowing and drifting snow through this afternoon which may cause
localized visibility reductions, particularly in open areas. Use
caution on the roads today areawide, even where the advisory has
been dropped as lingering slick roads and possibly patchy blowing
snow will persist in this region.

Snow then diminishes tonight as surface ridging and mid-level height
rises move into the region. Light snow showers are then possible
across the area on Friday as a weak clipper tracks northeast past
the area to the northeast.

- No significant precipitation events this weekend into mid next week

The are no major systems that are set to affect Southwest Lower
Michigan in the Saturday through next Wednesday time frame. One
surface low moves into the Northern Great Lakes and fills this
weekend. Another follows that low and is deeper moving well off to
our north into Northwest Ontario on Monday.

As for the details, there may be some lingering light lake effect
snow showers Friday night into Saturday, but this looks to be mainly
flurries. Depth of moisture is a question with the DGZ being
unsaturated. There is a good chance we are dry during those two
forecast periods.

The next chance for precipitation comes Sunday night into Monday as
an upper shortwave ejects out of the Central Plains and through the
Great Lakes. This wave is moving quickly and does not have deep
moisture associated with it. Precipitation amounts look to be on the
order of a quarter of an inch or less. We will have warmed up by
this time and p-type looks to be rain.

Mid week an upper trough moves through the Great Lakes region with
air cold enough for lake effect snow once again. At this point we
only have 20-40 pct chances for snow showers, but this may need to
be bumped up as the upper trough does look fairly sharp with a solid
shortwave. All in all, the Saturday through Wednesday time frame
looks much quieter than the weather we have going on currently.

- Temperatures warm this weekend and then fall into next week

Temperatures will warm through the weekend with highs rising back
above normal into the 40s for Sunday and Monday. A cooling trend
back into the 30s for highs will occur as we head into mid week.
Normal highs this time of year are around 40.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 630 AM EST Thu Dec 5 2024

Lake effect snow will continue over Western Lower Michigan today
affecting MKG and AZO the most. Occasional IFR conditions will
occur at those TAF sites along with northwest winds that will gust
at times into the 30-40 knot range. GRR and BTL will be impacted
a bit less, but MVFR will certainly occur today. Inland areas will
see a mixture of MVFR and VFR today being further away from the
impetus of the lake effect snow, Lake Michigan. All areas will see
wind gusts towards 30 knots if not 35 knots, but the strongest
winds will be towards MKG with a wind off the lake. Snow shower
activity will diminish tonight with improving aviation conditions.

&&

.MARINE...
Issued at 333 AM EST Thu Dec 5 2024

Gale Warning has verified well with gales expected to persist
through the evening as strong mixing continues behind the arctic
front that passed through this evening. Have extended the Gale
Warning through 7pm EST due to persistence of gale force gusts
through the evening. Winds diminish overnight as ridging takes hold,
though waves remain elevated so a Small Craft Advisory will be
needed after the Gale Warning expires. Winds will also approach
small craft advisory criteria Friday afternoon as the gradient winds
increase from a nearby clipper system. Waves diminish Friday night
before increasing again Saturday to levels hazardous to small craft.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Storm Warning until 1 AM EST Friday for MIZ037-038-043-
     044-050-056-057-064-065-071-072.
     Winter Weather Advisory until 1 AM EST Friday for MIZ039-045-051-
     058-066-073.
MARINE...Gale Warning until 7 PM EST this evening for LMZ844>849.

&&

$$

DISCUSSION...Duke/Thomas
AVIATION...Duke
MARINE...Thomas

NWS GRR Office Area Forecast Discussion