Portage, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

072
FXUS63 KGRR 191820
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
220 PM EDT Thu Mar 19 2026

.KEY MESSAGES...

- Rain Showers North Tonight

- Warmup Friday into Saturday, Rain Saturday Night/Sunday

- Seasonable Temperatures Early Next Week, Mostly Dry

&&

.DISCUSSION...
Issued at 219 PM EDT Thu Mar 19 2026

- Rain Showers North Tonight

A mid-level wave drives a surface low north of the area tonight,
with the precipitation shield limiting the areal extent of showers
to areas north of M-46. The lastest probabilisitc guidance favors
conditions remaining warm enough for precipitation to fall as rain.
This is reflective of the latest high resolution model guidance
which allows temps to warm into the mid 30s before showers begin.

- Warmup Friday into Saturday, Rain Saturday Night/Sunday

Southerly flow Friday into Saturday will support a warmup into highs
in the 50s north and 60s south. This will be disrupted by a mid-
level wave driving a cold front across the area, though guidance
varies on when exactly this occurs. Robust moisture doesn`t arrive
until late Saturday Night/Sunday in the post frontal environment.
Latest guidance trends with the slowing of the front suggest
precipitation remaining rain for most if not all of Sunday.

- Seasonable Temperatures Early Next Week, Mostly Dry

As the low/troughing departs, Monday will see the advancement of
surface and mid-level ridging into the region. The forecast is
generally for dry conditions, however latest guidance suggests that
shortwaves (which are difficult to pin down at this forecast range)
may drive low precipitation chances. Highs will generally be in the
40s to low 50s, which is near normal for this time of year.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 143 PM EDT Thu Mar 19 2026

VFR cigs and vsbys will continue through the daytime and into the
evening hours. There is a chance for MVFR cigs to develop for
KGRR, AZO, MKG and BTL tonight between 05Z and 13Z. Have adjusted
the TAF`s accordingly. These are not expected to reach fuel
alternate status but there is a low chance so have put scattered
at 1KFT to show this potential.
 The other aviation concern is the chance for LLWS overnight.
There should be a low level jet that drops down overnight with
40kts as low as 010KFT between 07Z and around 12Z. While it will
slacken a little, a 35 to 40KT jet should continue until around
13Z tomorrow morning.
 This should lift and winds at the central TAF sites should
increase after 14Z.

&&

.HYDROLOGY...
Issued at 219 PM EDT Thu Mar 19 2026

Only one site remains at or above flood stage as of this afternoon.
The Grand River at Comstock Park is now cresting at minor flood
stage. The Maple River at Maple Rapids went below minor flood stage
this morning allowing the warning to be cancelled. With light
amounts of precipitation expected over the next few days, additional
flooding is not expected.

&&

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

&&

$$

DISCUSSION...Thomas
AVIATION...Ceru
HYDROLOGY...Thomas