719
FXUS63 KGRR 221141
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
741 AM EDT Wed May 22 2024

.KEY MESSAGES...

- Quiet through Thursday

- Cold Front Brings Showers/Storms Friday night into Saturday

- Low Moves in From the South WIth Rain Showers on Sunday

- Upper Trough Results in Showers Monday into Tuesday

&&

.DISCUSSION...
Issued at 352 AM EDT Wed May 22 2024

- Quiet through Thursday

A cold frontal boundary will move through lower Michigan this
morning as the upper low progresses further north into Ontario. Some
light shower activity will be possible this morning, but most areas
should stay dry. Temperatures drop closer to normal with highs in
the 70s this afternoon and Thursday. Humidity values decrease as
dewpoints fall into the 50s behind the cold front.

- Cold Front Brings Showers/Storms Friday night into Saturday

A cold front will move into the state from the west Friday night
with an increase in moisture and instability. Surface dew points
will push into the 60s with MUCAPE values approaching 1000 j/kg. We
are currently carrying 60-70 pct chances for precipitation as the
cold front sweeps through. Chances will begin late Friday afternoon
and linger into Saturday morning, but the bulk of the rain will fall
Friday night. Rainfall totals will likely be in the quarter to half
inch range in most areas. SPC currently has a marginal in the
southwest cwa. Any severe threat would likely be confined to the
afternoon and evening as stronger storms advect in from the west.

- Low Moves in From the South With Rain Showers on Sunday

A surface low moves in on Sunday from the south bringing chances
for mainly rain showers. We currently have 30-50 percent chances
for rain Sunday into Sunday night as an upper system moves in as
well. The low will be deepening as it moves in with plenty of
moisture to work wit. Can see needing to up chances for rain
Sunday into Sunday night.

- Upper Trough Results in Showers Monday into Tuesday

The upper trough and low linger into the early portion of next
week. We actually have chances for rain from Monday night right
through Wednesday. Can see needing to up our chances from the
current 30-50 percent values with time as well. Also, we may need
to lower temps as there will likely be clouds and showers around
each day.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 741 AM EDT Wed May 22 2024

A cold front is sweeping through Southwest Lower Michigan at 700am
stretching from near HTL to AZO. By late morning the front should
be east of the TAF sites. We do not expect any further
precipitation with the front.

Some lower ceilings near and just behind the front will move into
the western TAF sites of MKG, AZO and GRR this morning for a time.
MKG will be the most impacted, with MVFR ceilings persisting into
the early afternoon most likely.

VFR weather should be the rule from late afternoon through
tonight. Gusty southwest winds of 15 to 25 knots can be expected
all day today (through about sunset).

&&

.MARINE...
Issued at 419 AM EDT Wed May 22 2024

Strong southwest flow lasts through this morning leading to
hazardous winds and waves. Gusts to 25 to 30 knots are expected
through this morning before winds weaken during the afternoon.
Waves will peak at 7 to 8 feet and will drop from south to north
late morning and afternoon. Conditions will remain hazardous to
small craft through this evening, with conditions improving from
south to north. Marine conditions remain quiet through Friday
before waves begin to build to 3 to 4 feet Saturday morning with
westerly winds.

Beach Hazards season begins today and we will be issuing a Beach
Hazards Statement for a High Swim Risk. The waves will take much
of the day to subside so expect dangerous waves and currents at
all beaches through the day. The south sides of south piers will
be most dangerous given the southwest flow. Water temperatures are
in the 50s this morning, so not expecting too many swimmers
today.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through this evening for MIZ037-043-050-
     056-064-071.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>849.

&&

$$

DISCUSSION...Duke/Thielke
AVIATION...Duke
MARINE...Duke/Thielke