textproduct: Grand Rapids

KEY MESSAGES

- Rain Showers This Morning

- Warmup Today into Saturday, Rain Saturday Night/Sunday

- Seasonable Temperatures Early Next Week, Mostly Dry

DISCUSSION

Issued at 251 AM EDT Fri Mar 20 2026

- Rain Showers This Morning

At this time, water vapor images show an upper PV max moving southeast across eastern Lake Superior while an extensive area of precipitation is moving across the UP and northern Lower MI ahead of this feature. Based on latest radar trends and guidance, have extended PoPs farther to the south and east this morning. Our northeast zones in central interior Lower MI should receive the greatest amount of precipitation. Surface observations there are reporting temperatures in the mid to upper 30s. Given that southeast to south winds will likely increase with the approach of the associated surface low, it is unlikely temperatures will be able to drop to freezing; hence, freezing rain is not expected. This is good news to central interior Lower MI, which has already had more than its share of ice accumulations recently. Precipitation should exit the area by late morning/early afternoon.

- Warmup Today into Saturday, Rain Saturday Night/Sunday

Aforementioned southerly flow today into Saturday will support a warmup ranging from near 50 north to lower 60s south. At Grand Rapids, this will equate to mid to upper 50s, which is about 10 degrees above normal.

A cold front is expected to push through Saturday Night into Sunday with mostly post-frontal precipitation that should be chiefly rain. This assumption of rain is based on warm antecedent temperatures and what appears to be a lack of deep cold advection with the system driving the front. Trends have been to slow this front, which is not surprising given what appears to be a deep layer of boundary-parallel flow. There is in fact some question about how soon this front exits the area, or whether it becomes stationary in the vicinity into Monday.

- Seasonable Temperatures Early Next Week, Mostly Dry

Running under the assumption (and majority report) that the post-frontal precipitation departs by late Sunday, 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 /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 143 AM EDT Fri Mar 20 2026

Key changes: - extended LLWS through late morning - removed morning mention of MVFR ceilings

Confidence for staying out of IFR restrictions through the period is around 90 percent. In fact, through 00Z tonight, we estimate a 80-90 percent chance of remaining VFR. Cloud bases should generally remain well above 10000 ft AGL. This is more optimistic than before, when we advertised ceilings of 2-3 kft AGL developing during the day.

Based on model guidance, we decided to keep LLWS until around 16Z. It's unusual to continue LLWS well into the daytime like this, unless there is a strong warm front in the vicinity (which is not the case here). It appears that wind speeds and gustiness will increase as we go through the late morning; however, there appears to be just enough speed and directional (winds veering clockwise with height) shear to keep LLWS going for a while longer.

As noted previously, it seems likely that terminals will remain VFR through 00Z. However, there are indications that ceilings around 2000 ft AGL could start affecting terminals not long after that.

MARINE

Issued at 418 AM EDT Fri Mar 20 2026

Based on latest wind and wave guidance, decided to issue a Small Craft Advisory for our central marine zones. Winds and waves will peak shortly after 8 AM, followed by a gradual decrease. The expiration time of 8 PM may end up being a bit too long, so wouldn't be surprised if later shifts decide to cancel this early.

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...Small Craft Advisory until 8 PM EDT this evening for LMZ845>848.