139
FXUS63 KGRR 231139
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
739 AM EDT Sun Jun 23 2024

.KEY MESSAGES...

-Dry and cooler

-Strong storms possible late Monday night and Tuesday

-Dry Wednesday/Thursday; storm chances return Friday/Saturday

&&

.UPDATE...
Issued at 443 AM EDT Sun Jun 23 2024

Based on latest wave models, we included the all nearshore zones
in the Small Craft Advisory and also extended the Beach Hazards
Statement to include Mason and Oceana Counties. The headlines
will expire at 5 pm today.

&&

.DISCUSSION...
Issued at 330 AM EDT Sun Jun 23 2024

-Dry and cooler

Latest surface analysis shows a cold front extending from Traverse
City to Chicago. Radar showed rain falling south of I-96 ahead of
the front and the back edge of the precipitation moving across the
lakeshore.

Showers will exit the southeast cwa by 10am leading to dry weather
the rest of the day. IR loop shows extensive cloudiness west
through Wisconsin and HREF cloud progs point toward cloudy
conditions through early afternoon. Late in the day high pressure
will nose into the region and we`ll start to see some breaks in
the clouds which will set us up for a partly cloudy night.

H8 temps will fall to around 10c today which should result in high
temperatures in the lower 70s near US-10 to upper 70s near I-94.
Dewpoints in the lower 60s will still create humid conditions, but
it won`t feel as humid as the last several days.

Under partly cloudy skies tonight, temperatures will fall into
the 50s...a welcome relief from the very mild mid 70s earlier in
the week.

High pressure will settle over the region Monday yielding sunny
skies, less humid conditions and highs in the lower 80s.

-Strong storms possible late Monday night and Tuesday

Interesting summertime MCS pattern shaping up for Monday night, with
returning H8 20C thermal ridge and 50 kt low level jet aimed into
Wisconsin. Guidance indicates nocturnal tstms developing to our
northwest once mid level cap breaks then deep layer thickness progs
would suggest they`ll propagate southeast our way late at night into
early Tuesday, along the incoming instability gradient.

Should this develop into a mature MCS, it is possible we could see
some damaging winds crossing Lk MI toward dawn Tuesday. Those tstms
should weaken/exit by Noon, but new convective development looks
possible along the cold front in the late afternoon/evening Tuesday,
with guidance currently favoring a west-east oriented cluster of
storms near I-94.

-Dry Wednesday/Thursday; storm chances return Friday/Saturday

We dry out behind the cold front on Wednesday with cooler and drier
air flowing in from the north, then high pressure delivers fine
weather on Thursday. Guidance has been trending faster in the
departure of that sfc high, with tstm chances returning already on
Friday as the warm front lifts back north again. Storminess persists
into Saturday before the next cold front swings through and dries
things out for Sunday.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 739 AM EDT Sun Jun 23 2024

Cold frontal passage is bringing widespread IFR cigs early this
morning along with areas of light rain and drizzle. Conditions
gradually improving to MVFR later this morning then lifting to VFR
after 18Z. Skies clearing tonight. Northwest winds of 15 to 25
kts today, subsiding below 10 kts after 00Z this evening.

&&

.MARINE...
Issued at 445 AM EDT Sun Jun 23 2024

A Small Craft Advisory and Beach Hazards statement are now in
effect until 5 pm and include all nearshore zones and lakeshore
counties. 3-5 foot waves are expected until mid afternoon when
they will begin to subside.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 5 PM EDT this afternoon for MIZ037-
     043-050-056-064-071.
MARINE...Small Craft Advisory until 5 PM EDT this afternoon for
     LMZ844>849.

&&

$$

UPDATE...04
DISCUSSION...04/Meade
AVIATION...Meade
MARINE...04