Portage, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

126
FXUS63 KGRR 261036
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
636 AM EDT Thu Mar 26 2026

.KEY MESSAGES...

- Brief Window for Strong to Severe Thunderstorms Today

- Below Normal Temperatures Friday and Saturday

- Potentially Unsettled Weather Next Week

&&

.DISCUSSION...
Issued at 225 AM EDT Thu Mar 26 2026

- Brief Window for Strong to Severe Thunderstorms Today

There is a brief window where we could see strong to severe
thunderstorms between 12PM to 5PM. This will be largely south of
I-96 with the best chances (SPC Slight Risk) along and south of
I-94. The 700mb jet moves in early this afternoon providing some
mid level lift along with elevated instability. With the stronger
winds aloft hail will be the primary concern. The wind and tornado
threat will largely be south of the area. This is due to the cold
front moving through this morning and afternoon. Areas along and
south of I-94 have a brief window for any surface based storms
between noon and 5PM before the cold front moves through.
Instability however is limited and looking at the Max SBCAPE
values on the HREF, there a tight gradient along I-94. Overall
odds are low, hence the SPC Day 1 outlook adjustment shifting the
wind and tornado threat south of the area.

Otherwise expect some scattered showers as the front shifts south
this morning and afternoon. Winds will pick up from the north
behind the front this afternoon and evening with gusts around 20
to 25 mph. Dry conditions return across the area this evening.

- Below Normal Temperatures Friday and Saturday

Colder temperatures move in for Friday with 925 mb temperatures
around 6 to 8 C below zero. Highs are only expected to be in the
mid to upper 30s with some spots potentially hitting 40. Colder
temperatures are expected Friday night with lows in the mid teens
to mid 20s. A shortwave trough moving through Friday night may
have enough moisture for some snow, any accumulations would be
light. Warm air advection brings slightly warmer temperatures for
Saturday with highs in the upper 30s to mid 40s.

- Potentially Unsettled Weather Next Week

Global ensemble data is in good agreement regarding a synoptic
pattern change by the early to middle portion of next week.
ECE/GEFS/CMC ensemble mean 500mb heights and vorticity indicate a
shift from a dominant ridge across the SW U.S. to an orientation
more across the SE U.S. as deep upper troughing begins to set up
across the West Coast. This places the Great Lakes in a region of
deeper southwest flow and already there are signs of anomalous PWAT
values surging into the region by Tuesday or Wednesday. Depending on
frontal positioning, this could lead to a rather wet pattern heading
into the midweek period.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 636 AM EDT Thu Mar 26 2026

VFR conditions are expected this morning before ceilings
gradually lower to MVFR as the front moves south and scattered
showers develop. A brief period of IFR ceilings is possible
especially toward JXN where there is a better potential for
thunderstorms. Depending on how fast the front moves through
lightning could remain south of the terminals. There will be a
potential for large hail between 17Z to 21Z but the wind and
tornado risk is expected to remain south of the area. Behind the
front winds will shift to the north, northeast. Gusts toward 20
knots is expected this evening. Ceilings will gradually lift late
tonight into Friday morning.

&&

.MARINE...
Issued at 225 AM EDT Thu Mar 26 2026

A brief lull in Small Craft Advisory conditions is expected today
before north to northeast winds pick up behind the front late this
afternoon into tonight. Even with the offshore flow, waves are
expected to rise to 3 to 6 feet. Waves may linger into Friday
morning before subsiding.

Scattered showers are also expected along the front, although the
potential for thunderstorms is low with the best chances south of
South Haven this afternoon.

Winds Friday turn to the northwest and increase briefly during
the afternoon. We could see Small Craft Advisory conditions return
for areas south of Grand Haven for a few hours before sunset
Friday.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory from 4 PM this afternoon to 6 AM EDT Friday
     for LMZ844>849.

&&

$$

DISCUSSION...Hoving/RAH
AVIATION...RAH
MARINE...RAH