270
FXUS63 KGRR 091813
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
213 PM EDT Sun Jun 9 2024

.KEY MESSAGES...

- Patchy Fog Through Sunrise, Breezy Today

- Cool Monday night, then a warming trend

- Chance of rain Tuesday night through Thursday night

&&

.UPDATE...
Issued at 1225 PM EDT Sun Jun 9 2024

Very little in the way of weather concerns this afternoon. It will
be breezy with west to northwest winds of 15 to 25 mph. There will
be some clouds that advance in from the north as well, near and
behind a surface trough that is pushing southward. The trough
looks to extend from near Oscoda to Manistee at midday. There is
some CAPE in place to the south of the trough, but this looks to
be on the decline this afternoon and drier air is being advected
in.

&&

.DISCUSSION...
Issued at 259 AM EDT Sun Jun 9 2024

- Patchy Fog Through Sunrise, Breezy Today

Low stratus and patchy fog are currently affecting areas south of
M46. This will dissipate just after daybreak as winds increase and
solar heating takes effect. The main weather consideration today
will be the wind, as steep lapse rates (9-10 C/km) up to 700mb are
expected in combination with a 25-35 knot low-level jet. Gusts of 30-
40 mph are likely, with about a 10 percent chance of isolated gusts
exceeding 40 mph. Otherwise, mostly sunny skies are expected this
morning once stratus burns off. However, a weak shortwave and
associated deeper moisture will cause increasing clouds near and
north of I96 this afternoon. Highs will range from the mid 60s near
US10 to the mid 60s south of I94.

By Monday, the shortwave exits with approaching surface and upper-
level ridging moving into place. Northerly flow will advect dry air
into the area and by extension skies will be sunny. The northerly
flow keeps conditions cool like today so highs will be around 70.

- Cool Monday night, then a warming trend

Monday night will be the coolest night of the period. Lows will be
in the lower to mid 40s. However, across the northern cwa, upper 30s
will be common. As the center of the surface moves east Tuesday,
southwest winds will develop and we`ll see temperatures steadily
rise throughout the week. Highs in the mid 70s Tuesday will climb to
the mid 80s by Thursday.

- Chance of rain Tuesday night through Thursday night

Models are hinting at a couple of chances of rain during the period.
The first chance is Tuesday night, mainly over the northern half of
the cwa as a short wave moves across the UP and northern Lower. Chc
PoPs will cover this north of M-57 with little chance of seeing rain
south of there.
Stratus and some fog covers the terminals except MKG. It`ll likely
take until 14-15z to for the stratus to lift/dissipate. Once it
does, VFR conditions are expected the rest of the day. A cold
front will move through the region later this afternoon. MVFR cigs
are progd to move south across the terminals after midnight.An
approaching cold front Wednesday night and Thursday will provide
the best chance of rain for the week, but even that`s only chc
PoPs. A narrow ribbon of higher CAPE just ahead of the front may
help to trigger a few showers/storms. We`ll have to see how this
evolves, but it could end up being a fairly dry week.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 213 PM EDT Sun Jun 9 2024

Breezy conditions this afternoon while a MVFR cloud deck
approaches and sinks southwards with a surface trough. Wind will
weaken a touch this evening and tonight while staying mainly
northwesterly. MVFR clouds slowly move southwards out of the area
Monday morning between 06 to 12z.

&&

.MARINE...
Issued at 1225 PM EDT Sun Jun 9 2024

We leave more explanation for the afternoon discussion, but have
opted to add Muskegon into the Beach Hazards and have expanded the
Grand Haven to Manistee areas all the way through Monday evening.
So, Muskegon County is now in the Beach Hazards and the whole
lakeshore will be in it through the main portions of the beach day
on Monday. The HRRR, FV3, ARW and 3km NAM all have 20-30 knot
winds in the advancing high scenario in our nearshore zones (0-5
miles from shore) on Monday. We now feel that 3-6 footers will be
common up and down the lakeshore on Monday.

As for today, we are seeing some chop on the water with some
spilling breakers (white water) near the beach. All of our
nearshore buoys are reporting 2.6 or 3.0 feet at this time. So, we
will hold off with marginal conditions and not start the BHS/SCA
at this time. We will continue to monitor buoys and cams however
this afternoon.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 8 PM EDT this evening through
     Monday evening for MIZ037-043-050.
     Beach Hazards Statement from 8 PM EDT this evening through
     Monday evening for MIZ056-064-071.
MARINE...Small Craft Advisory from 6 PM this evening to 11 PM EDT Monday
     for LMZ844>849.

&&

$$

UPDATE...Duke
DISCUSSION...04/Thomas
AVIATION...Thielke
MARINE...Thomas