560
FXUS63 KGRR 271735
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
135 PM EDT Mon May 27 2024

.KEY MESSAGES...

- Shower chances and cool air linger into midweek

- Dry Thursday and Friday

- Low risk for showers returns next weekend; warmer

&&

.UPDATE...
Issued at 1030 AM EDT Mon May 27 2024

The winds and waves continue to increase this morning and most
sites were seeing waves in the 3 to 4 foot range. They are
projected to go up another foot or so. As a result, we will
maintain the Small Craft Advisory and Beach Hazards Statement for
today.

We did lower the thunder risk for this morning. Projected
instability plots have little support for thunder in our CWA over
the next few hours. The risk looks better tonight as the potent
mid level wave in the Upper Plains moves into MI.

&&

.DISCUSSION...
Issued at 335 AM EDT Mon May 27 2024

- Shower chances and cool air linger into midweek

Though the upper level low will open up with predominately zonal
flow the mid to low levels will be positively tilted allowing for
a strong gradient across Lake Michigan. That gradient will cause
downsloping flow which coupled with cold air advection will bring
gusty winds through the day. Expect gusty winds of 20 to 30 mph
today.

Latest CAMS soundings show further evidence of moist low to mid
levels. That should correlate to mostly cloudy skies through the
daytime. While some breaks in the clouds aren`t out of the
question, this Memorial day should be cloudy and windy. While the
best moisture is through northern lower peninsula there is enough
PWATs that coupled with NW flow across the lake to allow for light
showers and perhaps some storms this afternoon into early
evening, especially through far southwest Michigan near the
lakeshore.

Models continue to show a shortwave diving southeast through the
base of the longwave trough overhead Tuesday into Tuesday night.
This brings more showers across the area then departs early
Wednesday. However lingering sfc troughiness and cold air aloft
could result in a few widely scattered diurnally driven showers
redeveloping Wednesday afternoon and evening, especially over srn
sections.

- Dry Thursday and Friday

Then a couple sunny/pleasant days are in store for Thursday and
Friday as the center of a cool/dry Canadian sfc high passes
overhead. Wednesday night and Thursday night will be fairly chilly
nights and can`t even rule out some patchy frost across far nrn
sections.

- Low risk for rain returns next weekend; warmer

Fcst confidence currently low regarding rain chances next weekend as
model solutions diverge. The ECMWF is more progressive and is
sending showers/storms back into the picture by Saturday whereas the
GFS is holding on to ridging aloft and keeping things dry through
late Sunday. At this point will have low end 20-30 pct pops next
weekend with temps returning to slightly above normal values.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 135 PM EDT Mon May 27 2024

We are looking at an extended period of impacts via low clouds
through much of this forecast period. Low pressure nearby with
plenty of low level moisture is responsible for this. We haven`t
had many showers this morning, but more drizzle with a lack of
deep moisture. The drizzle may diminish a bit, but the MVFR to
LIFR ceilings will persist. There may be some local fluctuations.
Overnight, ceilings should tend to drop with night time cooling
taking place with cloud heights lowering some as a result. Winds
will also be diminishing a bit.

Ceilings should improve on Tuesday morning after sunrise with
diurnal mixing taking place, and somewhat drier air moving in. A
few showers could be possible about anytime at all terminals. It
might take a while, but conditions should go MVFR at all sites,
and then VFR toward the end of the period.



&&

.MARINE...
Issued at 345 AM EDT Mon May 27 2024

No changes as far as the  Small Craft Advisory and Beach Hazards
for Memorial Day. High confidence exists for winds to increase to
20 knots or higher and waves to reach 4 feet for much of the area.
Areas north of Whitehall should have a delay in the onset of
hazardous conditions as the surface low will be in that region
this morning. However by noon conditions will deteriorate across
all zones.

&&

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

&&

$$

UPDATE...MJS
DISCUSSION...Meade/Ceru
AVIATION...NJJ
MARINE...Ceru