Lansing, Michigan 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

407
FXUS63 KGRR 161840
AFDGRR

Area Forecast Discussion
National Weather Service Grand Rapids MI
240 PM EDT Thu Jul 16 2026

.KEY MESSAGES...

- Air quality concerns remain through Friday with slightly cooler air

- Shower and storm chances Friday p.m. and first half of Saturday

- Better rain chances late Monday into Tuesday; then much cooler

&&

.DISCUSSION...
Issued at 240 PM EDT Thu Jul 16 2026

- Air quality concerns remain through Friday with slightly cooler air

Bottom line upfront is: In coordination with Michigan Environmental,
Great Lakes, Energy (EGLE), the smoke is expected to remain
prevalent an very unhealthy to hazardous through most of Friday. The
smoke has spread across the entire state now behind the weak cool
front that dropped through late yesterday. The wind fields remain
weak, and what wind there is continues to draw down better smoke
concentrations from the north for the time being.

We do not see a major change in the situation until likely later
Friday. At that time, we see a large scale increase in the wind from
the SW ahead of the next incoming front poised to move through
Saturday. Smoke models that have had a clue with this smoke event
indicate that these winds will try to push the smoke out Friday
evening. Whether that is it for the smoke for this event is very
uncertain due to what happens with the fires over NE MN and Ontario,
what smoke plumes do, and then how the smoke plumes move with the
passage of the system.

- Shower and storm chances Friday p.m. and first half of Saturday

Back to the actual weather, we look to remain dry through tonight,
before rain chances arrive Friday morning across Central Lower, and
Friday afternoon for the southern half of the area.

We see a weak short wave traverse from Northern Minnesota and to
over Lake Superior and the U.P. tonight. The tail end of the few
showers/isolated storms could clip our far northern portion of the
area Friday morning. Obviously with a lack of diurnal heating, there
will not be much of a threat of anything strong.

We will then see the shower/storm chances shift from the north
early, to the south later in the afternoon. We see the front that
moved through yesterday return northward as a warm front Friday
afternoon/evening. The southern half of the area away from Lake
Michigan will see MU CAPEs increase to over 2000 J/kg. Deep layer
shear is quite limited, to less than 20 knots, so any storms will be
pulse type in nature.

We will lose the diurnal heating and rain chances Friday evening,
until Saturday morning with the approach of the front. This front
will be accompanied by the tail of a short wave. However, the timing
is not very good as it looks to move through most of the forecast
area by 18z Saturday. We do expect showers and storms to develop
ahead of the front, but probably won`t get going to halfway through
the forecast area. The much better chance of more widespread
showers/storms, and severe weather will be further SE where better
heating can take place before it moves through.

- Better rain chances late Monday into Tuesday; then much cooler

Sunday looks to be mainly dry, and fairly warm again as there is not
much cooler air behind the Saturday system. Dew points/moisture will
tank a bit to limit instability.

We will end up under NW flow aloft by then, and into early next
week. This flow pattern will bring the next noticeable system to
approach the area by late Monday. There is a series of 2-3 short
waves that will drive a front down into the area. The first one will
help bring a warm front up into the area Monday night, and then a
cold front come in early Tuesday. Then, the next upper wave
approaches Tuesday afternoon. These will bring the better chances of
rain to the area from Monday night through much of Tuesday.

The upper trough axis then moves by late Tuesday, and a long wave
ridge builds well west of the area. This will bring much drier and
cooler air for mid-late week next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 149 PM EDT Thu Jul 16 2026

Local surface observations continue to indicate IFR and even LIFR
horizontal visibility restrictions in smoke along with MVFR broken
"cloud" layers that are in reality associated with vertical
visibility restrictions in smoke. It is possible that terminals
experiencing LIFR visibility restrictions will temporarily rise
into the 1+ mile range this afternoon; however, predictability
with smoke and its light scattering effects are very limited. To
illustrate: our chief guidance source for these situations, the
HRRR-smoke model, has been under-forecasting the severity of visibility
restrictions thus far, which does not bode well for significant
improvements in the short term, or even for the full valid period
of this TAF package.

The only change of note was to introduce a period of northwest
winds this afternoon. But even this could be affected somewhat by
atypical diurnal heating effects (and subsequent surface pressure
responses) associated with the smoke.

&&

.MARINE...
Issued at 240 PM EDT Thu Jul 16 2026

Main marine issue initially is the wildfire smoke over the entire
area. The current thought is the smoke will remain largely unchanged
through Friday, until winds from the SW increase a bit and
potentially push the smoke to the NE. This was the reasoning for
extending the Dense Smoke Advisory earlier over the entire nearshore
through Friday evening.

Speaking of the increase in wind late Friday, right now it looks to
remain just below Small Craft Advisory criteria ahead of the cold
front. The better chance will be behind the cold front as slightly
cooler air moves in along with the ridge pushing in.

&&

.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Air Quality Alert until midnight EDT Friday night for MIZ037>040-
     043>046-050>052-056>059-064>067-071>074.
MARINE...Dense Smoke Advisory until 8 PM EDT Friday for LMZ844>849.

&&

$$

DISCUSSION...NJJ
AVIATION...TJT
MARINE...NJJ