181
FXUS63 KGRR 181733
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
133 PM EDT Thu Jul 18 2024

.KEY MESSAGES...

- Fair weather through Friday

- Dry/pleasant weather continues through the weekend

- Widely scattered showers and storms return next week

&&

.UPDATE...
Issued at 1045 AM EDT Thu Jul 18 2024

Minimal change to forecast today, just increasing the cloud cover
a little (no longer completely sunny) now that cumulus clouds have
developed over much of the area. The story of the day remains a
potential increase in Lake Michigan swimming risk later in the
afternoon especially between Muskegon and Holland, perhaps
Saugatuck and South Haven as well, as northerly winds on the east
side of a high pressure center over Iowa are augmented by the
daytime lake breeze circulation.

&&

.DISCUSSION...
Issued at 313 AM EDT Thu Jul 18 2024

- Fair weather through Friday

High pressure will continue to build in from the northwest today
and bring fair and pleasant wx with high temps in the 70s today
and comfortable humidity levels. It will be clear and cool tonight
with mins mainly in the low to mid 50s along with a few upper 40s
readings in typically cooler locations over our north/ne fcst
area.

Short range guidance time height rh progs and fcst soundings
suggest skies will become partly cloudy Friday with sct-bkn fair
wx cu developing late morning and afternoon. It will be several
degrees milder Friday as winds become southwesterly. Max temps
will reach the upper 70s to lower 80s.

- Dry/pleasant weather continues through the weekend

Continued sfc ridging and dry air mass keeps the fcst dry/partly
cloudy through the weekend although guidance continues to suggest a
few isolated pop-up showers are possible Sunday afternoon in mainly
northeast Lwr MI but including the Clare/Mt Pleasant areas.

- Widely scattered showers and storms return next week

For next week the general theme looks to be for daily, mainly
diurnally driven, pop-up showers and storms-- peaking in the late
afternoon/evening hours. This is due to weak troughing aloft and a
slight increase in sfc dew pts and PWATs.

Coverage on Monday and Tuesday still looks isolated (and mainly
inland from Lk MI), but pops eventually creep up a bit by Wednesday
and Thursday as an upper low drops in from the northwest (40-50
pops/scattered coverage). Deep layer shear remains on the low side
so storms should be mainly of the pulse type and favoring any low
level convergence zones such as the lake breeze during pk heating.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 133 PM EDT Thu Jul 18 2024

Cumulus clouds with MVFR bases/ceilings earlier today have become
VFR, on average around 4,500 feet. Have found the HRRR model to be
too dry today, and the NAM-3km has had a better handle so far on
dew points and thus cloud cover/height. As high pressure moves
overhead tonight, winds go light or calm, skies clear, there is a
chance of MVFR to IFR mist/fog especially between 06z and 12z.

&&

.MARINE...
Issued at 313 AM EDT Thu Jul 18 2024

A small craft and beach hazards statement remains in effect
through early this morning. We then expect a brief lull in winds
and waves for the rest of the morning. However a consensus of
latest CAMs suggest winds will ramp back up a bit to around 10 to
20 kts with gusts to near 25 kts by mid to late aftn from around
South Haven northward to near KMKG.

Therefore once the early morning marine headlines expire we may
potentially need another sca/bhs for several hours this
afternoon/early evening. Otherwise conditions will become more
tranquil going forward tonight and Friday as high pressure builds
overhead.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 8 PM EDT this evening for MIZ050-
     056-064-071.
MARINE...Small Craft Advisory until 8 PM EDT this evening for LMZ844>847.

&&

$$

UPDATE...CAS
DISCUSSION...Meade/Laurens
AVIATION...CAS
MARINE...Laurens