429
FXUS63 KGRR 301754
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
154 PM EDT Tue Apr 30 2024

.KEY MESSAGES...

- Dry Through Wednesday

- Above Normal Temperatures into Next Week

- Best Chance of Showers and Storms is Friday

&&

.DISCUSSION...
Issued at 324 AM EDT Tue Apr 30 2024

- Dry Through Wednesday

A surface cold front continues to sweep through lower Michigan
early this morning with high pressure filling in on the backside.
Clouds exit from west to east this morning and the timing of the
cloud exodus will be the largest deciding factor in how cold
temperatures drop this morning. The edge of the cloud deck is now
clearing east of our western CWA where temps look to drop in the
low to mid 40s. Lows in the mid 50s are expected further east
where the cloud shield overhead will exit a little later.

Tuesday stays dry under high pressure, then a low chance for rain
Wednesday morning as a surface low traveling through Wisconsin
diverts northeast into the UP and Lake Superior. A weakening cold
front will bring chances for light rain Wednesday morning, but
forcing dwindles as the front moves into lower Michigan. Cloud
cover will increase as the front travels through while any
appreciable rainfall stays north of the CWA. High pressure fills
in Wednesday leading to continued dry weather.

- Above Normal Temperatures into Next Week

Positive height anomalies prevail into early next week as the
primary area of upper level troughing favors the Northern Plains
region. Seven day total QPF progs would indicate that the most
active/wet weather stays west of Michigan closer to that trough.
High temperatures will be 70s each day although it will be cooler
at times near Lake Michigan.

- Best Chance of Showers and Storms is Friday

While pops are currently contained in numerous forecast periods
through early next week due to a wavering baroclinic zone, the best
chance of showers and storms currently looks to be on Friday. This
is when a more humid warm sector air mass with PWATs over one inch
will be in place as a sfc cold front and shortwave comes through.

In later updates we may be able to trim out some of the 20-30 pct
pops beyond Friday. It`s doubtful that there will be shower chances
as frequent as what is currently indicated by the NBM.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 139 PM EDT Tue Apr 30 2024

VFR conditions will dominate for the most if not all the forecast
period. Expect the winds to slacken this evening and then increase
and mix out early Wednesday morning. A front will bring gusty
winds beginning around 09Z with a strong LLJ which will cause Low
level wind shear 2KFT and below until around 13 to 14Z. The
timing for this shear is reflected in the TAFs. As the LLJ exits
expect lower cigs, after 15Z.

&&

.MARINE...
Issued at 324 AM EDT Tue Apr 30 2024

Winds have shifted westerly this morning following the passage of a
cold front. Winds turn southerly later in the day and will stay
fairly light thanks to the typical spring-time stable marine
layer over Lake Michigan. Conditions will stay quiet through the
end of the work-week with no marine hazards to note.

&&

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

&&

$$

DISCUSSION...Meade/Thielke
AVIATION...Ceru
MARINE...Thielke