388
FXUS63 KGRR 081738
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
1238 PM EST Fri Nov 8 2024

.KEY MESSAGES...

- Typical Autumn Weather Through Saturday

- Rain Saturday Night into Monday

- Another Period of Rain Next Wednesday/Thursday

&&

.UPDATE...
Issued at 1107 AM EST Fri Nov 8 2024

A batch of lake effect strato-cu clouds has developed over
Northwest Lwr MI in response to some chillier H8 air and cyclonic
flow which is sweeping in behind a cold front. Some of those
clouds will flirt with the area north of M-20 for a time today and
will make a slight modification to the sky fcst in nrn sections
to account for that. Otherwise rest of fcst unchanged with mostly
sunny, breezy conditions and highs in the mid to upr 50s.

The Small Craft Advisory end time was extended to 7 PM north of
Holland to match the start time in the southern zones as well as
the end time north of there in APX`s marine zones.

&&

.DISCUSSION...
Issued at 225 AM EST Fri Nov 8 2024

- Typical Autumn Weather Through Saturday

It will feel like fall both Friday and Saturday. Mid-level height
ridging slides into the Upper Great Lakes today as a closed low
over the desert southwest ejects to the northeast. This combined
with surface high pressure keeps weather tranquil. With forecast
soundings showing little to no moisture in the profile sunshine
will be plentiful today. Mid to upper-level moisture increases
Saturday ahead of our next system causing increasing mid to high
clouds. Expect highs in the 50s both days with lows tonight in the
mid 20s to low 30s.

- Rain Saturday Night into Monday

Heights will lower in advance of an upper level trough Saturday
night with positive vorticity and warm air advection. Low level jet
convergence picks up around midnight which is when rain is expected
to develop and move in. A few rumbles of thunder are not out of the
question but the best potential will be toward the I-94 corridor.

We could see a break in precipitation late Sunday morning into early
Sunday afternoon before the vorticity maximum associated with the
upper level trough moves over the area through Sunday night. Monday
chances for light showers continue (20 to 30 percent) with the best
chances along the lakeshore. Another shortwave trough and front
moving through Monday will help spread chances across the area
during the afternoon. Total rainfall amounts of a couple tenths to a
half an inch are possible.

- Another period of rain next Wednesday/Thursday

Ridging and high pressure will bring dry and pleasant conditions for
at least Tuesday with highs in the upper 40s to 50s. As previously
mentioned there is some uncertainty with how our next rain maker
will play out. There are timing differences along with how the upper
level trough evolves as it moves across the CONUS. These variations
can be seen in each ensemble`s individual members. That being said,
there is high confidence in rain, but lower confidence in the exact
timing of the rain along with the intensity and potential for
thunderstorms.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1237 PM EST Fri Nov 8 2024

Minimal concerns and impacts for this forecast period. VFR
conditions should prevail through the period.

Skies are mostly clear early this afternoon, with just some thin
cirrus floating overhead. Some clouds around 2500-3000 ft agl are
trying to drop down from the north, but feel these will not reach
the terminals as they seem to be mixing out. Skies will go mostly
clear this evening toward sunset. Slightly gusty winds early this
afternoon will diminish to around 5 knots or so overnight. Some
high clouds will try to move in late in this period, but that will
be it. Winds will not be as gusty on Saturday as today.



&&

.MARINE...
Issued at 225 AM EST Fri Nov 8 2024

Shoreline observations show that the current Small Craft Advisory
is verifying well as gusts up to 30 knots and 3-5 foot waves are
being reported. High pressure moving in will cause winds and waves
to fall in the afternoon and evening hours today. Winds and waves
stay below small craft advisory criteria Saturday with high
pressure overhead. Our next chance for conditions hazardous to
small craft is Sunday as winds increase with the approach of our
next system.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for LMZ844>849.

&&

$$

UPDATE...Meade
DISCUSSION...RAH/Thomas
AVIATION...NJJ
MARINE...Thomas