FXUS63 KGRR 260822

Area Forecast Discussion
National Weather Service Grand Rapids MI
322 AM EST Sat Nov 26 2022


.DISCUSSION...(Today through next Friday)
Issued at 322 AM EST Sat Nov 26 2022

Ensembles remain settled on the likelihood of two low-pressure
systems affecting our area in the coming week: one on Sunday and
one around Tue night / Wed morning. Ahead of each of them, there
will be fairly mild (warmer than normal) temperatures today and
Tuesday. A brief dip into colder than normal temperatures will
likely flow in behind the second low for late Wednesday into

-- Sunday into Sunday night --

The upper-level cutoff low over Texas will be reintroduced into
the midlatitude westerlies as it traverses toward the southern
Great Lakes, developing a surface low that will track near Lake
Erie by Sunday afternoon. Deformation zone precipitation northwest
of the low will make for a soggy Sunday in the southern third of
the lower peninsula. HREF probability matched mean places 0.5 to
0.75 inch QPF south of Saugatuck, Ionia, and Alma toward the state
line, and amounts tapering down to less than 0.1 near Ludington.

Just prior to precip ending Sunday evening, northerly cold air
advection below 850 mb may be sufficient enough for some wet snow
to mix in from central Mich to about I-96 near and east of Grand
Rapids. It appears any accumulation would be minor and probably
won`t impact travel. Can`t rule out some lingering drizzle or
very light freezing drizzle late Sunday evening, but again it
doesn`t appear to be very impactful other than some water freezing
into icy patches Monday morning as temperatures dip below
freezing. Lake effect behind the low will be negligible given
inversion heights below 5,000 feet.

-- Tuesday night into Wednesday night --

A more coherent Rossby wave trough propagating through the CONUS
midweek will feature sharper baroclinicity and consequently more
intense mid to upper level jet kinematics over the Great Lakes.
This will be a rain changing to light or moderate lake-enhanced
snow kind of event, though there is still quite a spread in QPF
among ensemble members. Some models within the ensembles point
toward a potential wind advisory especially for the lakeshore,
behind the cold front on Wednesday.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1225 AM EST Sat Nov 26 2022

VFR conditions will continue into Saturday night. Winds generally
from the southwest will become a little gusty during the middle of
the day. Between 09Z and 14Z, low level wind shear of nearly 30
knots between 2000 feet and the ground is expected at GRR and
LAN, as winds at 2000 feet will be approximately 25033KT.


Issued at 322 AM EST Sat Nov 26 2022

A pressure gradient between high pressure over Appalachia and low
pressure over Hudson Bay will strengthen southwesterly winds over
Lake Michigan today, and waves will be hazardous to small craft.
By Sunday morning, winds will relax and shift northeast as low
pressure from Texas moves through Indiana. Winds then strengthen
and shift more from the north Sunday afternoon as the low moves
east away from Michigan, and this could kick up another brief bout
hazardous waves for small craft until about daybreak Monday.


LM...Small Craft Advisory until 3 AM EST Sunday for LMZ844>849.




NWS GRR Office Area Forecast Discussion