Area Forecast Discussion Issued by NWS Grand Rapids, MI
000
FXUS63 KGRR 180200
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
1000 PM EDT Sun Mar 17 2024
.KEY MESSAGES...
- Lake Effect Snow Tonight Into Monday Morning
- Winter Isn`t Over Yet
&&
.UPDATE...
Issued at 954 PM EDT Sun Mar 17 2024
Convective lake effect snow bands continues to stream across lower
Michigan this evening. While the snow is light at times some bands
have reduced visibilities to below a mile. The bands continue to
weaken in the east and are more focused along and west of US 131
The winds have slacked a little but gusts of 15 to 25 knots
remain probable overnight, especially along the lakeshore. The
northerly flow will increase towards morning increase showers just
in time for the morning commute.
&&
.DISCUSSION...
Issued at 247 PM EDT Sun Mar 17 2024
- Lake Effect Snow Tonight Into Monday Morning
The ongoing scattered snow showers will continue over the next few
hours as the 500mb positive vorticity advection and trough axis
move through. There is some surface based instability allowing for
stronger winds to mix down with the more intense snow showers.
Brief visibility reductions down to a quarter mile and quick
accumulations of a tenth or two are possible within these showers.
As the trough axis passes we transition more into northerly flow
along with some colder 850mb temperatures working their way over
the lake. This will transition the scattered showers into more
focused bands along the lakeshore. With water and 850mb
temperature differences around 17 Celsius and the fetch across
the lake around 100 miles expect to see some additional
accumulations of 1 to 3 inches along the lakeshore through Monday
morning. Some isolated spots could get up to 4 inches with the
best potential in southwest Michigan. This will likely result in
some slick conditions for the Monday morning commute so make sure
to give yourself extra time and take it slow!
Light snow will gradually taper off through the day as 850mb
temperatures warm and we lose our low level moisture.
- Winter Isn`t Over Yet
A couple of opportunities exist next week for some snow...but likely
not until the end of the week.
A clipper will move across Lake Superior Tuesday. Precipitation
associated with the warm air pattern ahead of it will likely remain
just north of the cwa. However, we`ll see cold air move south behind
the clipper Tuesday night and Wednesday. That will help to keep
temperatures much of the week below normal.
Ensembles are congealing around the possibility of light snow
thursday night and Friday as low pressure rides east along the
aforementioned cold front. At this point, ensemble mean accums are
around an inch. However, ensemble probabilities of greater than 3
inches are 15-20 percent and considerably higher north of the cwa.
So this system will bear watching.
An even more impressive system may be lurking toward the end of the
weekend. A southern stream system is showing up in the models that
would tap into Gulf moisture and move north toward the Great Lakes.
The track trend has been farther west in recent runs which would
eventually put us in the warm sector. However, ensembles still
produce some snow and/or freezing rain, then rain. Thunderstorms
could be a player at some point in this evolution too.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 734 PM EDT Sun Mar 17 2024
Latest radar continues to show numerous snow showers moving across
lower MI from the northwest. Periods of MVFR cigs and vsbys will
continue especially at JXN...BTL and AZO. The NW flow will feed
the lake effect showers overnight. The convective snow showers
will bring periods of IFR to BTL and possibly AZO and JXN between
now and 06Z. AZO could have IFR at times overnight though the low
clouds and strongest snow showers should remain West of US 131.
While MKG will have MVFR cigs and vsbys currently the flow regime
isn`t orientated enough to give them IFR cigs. Gusty winds will
continue through Monday morning before conditions slowly improve
Monday afternoon into evening.
&&
.MARINE...
Issued at 247 PM EDT Sun Mar 17 2024
Gusty northwest winds continue hazardous conditions for small
craft through Monday. Winds turn a little more west to southwest
Monday night into Tuesday. Another extension of the Small Craft
Advisory is likely as we continue in this windy pattern until
Thursday.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT Tuesday for LMZ844>849.
&&
$$
UPDATE...Ceru
DISCUSSION...04/RAH
AVIATION...Ceru
MARINE...RAH