328
FXUS63 KGRR 210646
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
246 AM EDT Mon Apr 21 2025

.KEY MESSAGES...

- Windy With Morning Showers Monday

- Several Chances For Showers Mid to Late Week

- Late Week Warmup Expected

&&

.DISCUSSION...
Issued at 243 AM EDT Mon Apr 21 2025

- Windy With Morning Showers Monday

Isolated showers and storms have developed over the region this
morning with more widespread precipitation and scattered storms
arriving shortly. A low pressure system moving into Wisconsin
today is the driver of our precipitation, with a cold front
crossing the area this morning bringing the more widespread
precipitation. Satellite shows a pronounced dry slot behind this
front that will keep the afternoon dry. Increased mixing behind
the front will lead to 30 to 40 mph gusts Monday as well.

- Several Chances For Showers Mid to Late Week

Our next chance of rain is Tuesday Night into Wednesday as we see a
warm frontal boundary lift north through lower Michigan. What
follows is quasi-zonal flow with small embedded shortwaves. Periods
of showers cannot be ruled out Wednesday/Thursday, but these setups
feature low predictability so timing, occurrence, and placement
of showers is not certain.

Rain chances increase again Thursday Night into Friday as a low
pressure system moves into the midwest. This will bring the
potential for both showers and thunderstorms into the region.
Conditions then dry out for the weekend as high pressure and ridging
move into the Upper Great Lakes.

- Late Week Warmup Expected

Highs are expected to climb into the 60s through Wednesday and well
into the 70s Thursday and Friday as ridging arrives. Some cooling is
expected behind the late week system, but it only drop highs into
the 60s for the weekend.


&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 135 AM EDT Mon Apr 21 2025

LLWS will continue through the morning with rain and a few
thunderstorms pushing slowly east across Lower Michigan between
about 12Z to 15Z. MVFR conditions can be expected much of Monday
with ceilings from 1200 to 2000 ft AGL. VFR conditions should
arrive during the evening as the stratus clouds scatter out.

&&

.MARINE...
Issued at 243 AM EDT Mon Apr 21 2025

No changes to the going forecast this morning. Winds have increased
ahead of a cold front with gusts of 25 to 30 knots ongoing. Better
mixing behind the front will lead to a period of gales around 35
knots during the day today before winds fall tonight. A period of
winds and waves hazardous to small craft are expected after the gale
warning expires. Conditions subside below small craft advisory
criteria by daybreak Tuesday and remain there through midweek as
gradient winds weaken.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 8 AM EDT this morning for LMZ844>849.
     Gale Warning from 8 AM this morning to 8 PM EDT this evening for
     LMZ844>849.

&&

$$

DISCUSSION...Thomas
AVIATION...Ostuno
MARINE...Thomas

NWS GRR Office Area Forecast Discussion