-- Discussion containing changed information from previous version are highlighted. --
640
FXUS63 KGRR 072003
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
403 PM EDT Fri Jun 7 2024

.KEY MESSAGES...

- Clearing tonight, showers Saturday

- Mostly Dry Through Mid-Week

- Starting Cool Monday then Warming

&&

.DISCUSSION...
Issued at 300 PM EDT Fri Jun 7 2024

- Clearing tonight, showers Saturday

Quite a bit of cu on regional visible imagery this afternoon,
courtesy of cooler temperatures aloft via the upper low. That low
is beginning to move east and warmer air aloft coupled with some
ridging is resulting in clearing skies across the lakeshore.
Clearing will continue this evening, but will be short lived as an
area of low pressure aloft moves southeast from south central
Canada. HRRR/Nam3km/FV3 all show showers developing with this
feature over the upper MS Valley tonight and crossing the cwa
Saturday afternoon and evening. Models also show a few hundred
j/kg MUCAPE as well, so it`s not out of the question we could see
a few lightning strikes.

HREF local probability matched mean suggests a quarter to half
inch of rain possible north of I-96 and a tenth to quarter inch
south of there Saturday. We`ll see some clearing after midnight
Saturday night as drier northwest winds develop.

Lows tonight will range from 45-50 degrees and highs Saturday from
the upper 60s north to mid 70s south.

- Mostly Dry Through Mid-Week

The last remnants of upper troughing slide east Sunday with ridging
building on the backside. Very isolated diurnally driven showers are
possible Sunday afternoon as a last ditch shortwave and cold front
move through the state leading to a cooler start to the week.
Building high pressure will maintain dry and quiet weather through
mid week before a cold front brings chances for showers later in the
week.

- Starting Cool Monday then Warming

850mb thermal trough settles in Monday then slides east as high
pressure builds in from the west. Monday will be the coolest day
with temperatures starting off in the upper 60s to near 70 the and
gradually warm into the rest of the week. Warming temperatures are
expected as zonal flow advects warm from the Plains into the Great
Lakes, but there remains a question on how hot we get. The Canadian
still favors the hotter scenario with highs in the upper 80s to 90,
while the GFS and Euro ensembles are more tame with highs in the low
80s. Highs in the at least in the low to mid 80s seem likely by mid
to late week.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 116 PM EDT Fri Jun 7 2024

Breezy winds continue this afternoon with widespread gusts to 25
to 30 knots. Meanwhile VFR prevails as a scattered to broken
diurnal cumulus deck to 4 to 6kft pivots through lower Michigan.
VFR will persist through the forecast period and winds will
weaken late this evening as mixing subsides.

&&

.MARINE...
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Issued at 403 PM EDT Fri Jun 7 2024

Marine web cams and buoys show waves slowly subsiding and are now
about 2 to 4 feet. A moderate swim risk will continue along a
portion of the shore through this evening. The Small Craft
Advisory and Beach Hazards Statement has expired at 4pm. Wind and
waves will not be hazardous to small craft Saturday.
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&&

.GRR WATCHES/WARNINGS/ADVISORIES...
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MI...None.
MARINE...None.
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&&

$$

DISCUSSION...04/Thielke
AVIATION...Thielke
MARINE...04/CAS