047
FXUS63 KGRR 240728
AFDGRR
Area Forecast Discussion
National Weather Service Grand Rapids MI
328 AM EDT Thu Sep 24 2026
.KEY MESSAGES...
- Dry through Tuesday
- Chances for rain mid next week (Tues night through Wed Night)
- Slightly above normal temperatures through the 7 day forecast
&&
.DISCUSSION...
Issued at 328 AM EDT Thu Sep 24 2026
- Dry through Tuesday
High confidence in dry fall weather today through Tuesday. BUFKIT
overviews show little in the way of moisture through the depth of
the atmosphere through next Tuesday. Ensemble data from both the
GFS and ECWMF show no members with any precipitation into next
Tuesday, so 80 members indicating dry. That is an emphatic
statement that dry weather will continue into early next week.
- Chances for rain mid next week (Tues night through Wed Night)
Major model discrepancies arise mid next week when looking at the
GFS and the ECWMF. The GFS is bringing a deep fall low (989mb) right
through the western Great Lakes during the Tuesday and Wednesday
time frame, whereas the ECMWF has some weak surface troughing
(1012-1014mb). Interestingly, both bring locally heavy
precipitation to the area during this time frame. With the GFS the
rain is driven by the deep low and a strong cold front. In the
ECMWF the rain is driven by overrunning of a warm front. Low
confidence to say the least out at this range in the forecast, but
we will continue to monitor trends to see if we can get better
agreement.
- Slightly above normal temperatures through the 7 day forecast
Normal highs for this time of year are in the upper 60s for the
most part. MOS guidance and 850 temperatures around +10C indicate
that we will likely be a bit above normal for highs in the lower
70s. Lows will dip into the 40s into next Monday.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 152 AM EDT Thu Sep 24 2026
VFR weather is expected the next 24 hours with zero restrictions
to ceiling or visibility. There are some VFR cloud bases across
Southwest Lower Michigan (around 5,000ft) at 06z, but we expect
these to exit the state to the southwest before daybreak. Some
cumulus development will occur today but we are not anticipating
much more the FEW050 given high pressure firmly in control. Winds
today will be from the east at 5 to 10 knots.
&&
.MARINE...
Issued at 328 AM EDT Thu Sep 24 2026
Surface high pressure will remain entrenched across the Great
Lakes region through the remainder of the work week, the weekend
and into early next week. High confidence in lighter winds and
limited waves through that time frame. Waves are expected to be
less than 2 feet into at least Monday. The next chance for higher
winds and waves does not come until Tuesday and especially Tuesday
night next week. That said, the system potentially bringing us
wind during that time frame, in the GFS, is not handled the same
in the ECMWF.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...None.
&&
$$
DISCUSSION...DUKE
AVIATION...DUKE
MARINE...DUKE
NWS GRR Office Area Forecast Discussion
