textproduct: Grand Rapids

KEY MESSAGES

- Severe weather potential this evening and tonight

- Freezing rain tonight into Wednesday over Central Lower MI

- Accumulating snow Thursday night/Friday over Central Lower MI

DISCUSSION

Issued at 358 AM EDT Tue Mar 10 2026

- Severe weather potential this evening and tonight

A stationary front is slowly sagging southward early this morning from Central Lower Michigan towards I-96. The southward progression of the front will continue today. A mid level shortwave will be working across the plains this evening, which will induce weak cyclogenesis at the surface. The low will be situated in Southeast Iowa at 00z with a developing/strengthening warm front stretching eastward across Northern Illinois to along the Michigan/Indiana line. The placement of the warm front will be critical to the mode of severe weather this evening and overnight. The SPC HREF, which is a trusted severe weather ensemble, has the warm front further north laying along the I-94 corridor. A low level jet will strengthen this evening to 40-50 knots which will set the stage for impressive low level wind shear. Corroborating the HREF is the HRRR which for several runs now is showing the warm front into the I-94 corridor as well with 40 knots of 0-1km shear and 60-70 knots of deep layer 0-6km shear. Given the shear in place rotating storms are certainly expected. The placement of the warm front will be pivotal in determining the tornado threat this evening/tonight but beyond that the rotating updrafts will likely produce a hail threat over a larger area including both the I-94 and I-96 corridors. The wind threat will likely be closer to I-94 as points north will be deeper behind the warm front into the cool air meaning more elevated storms.

In terms of the evolution we expect storms to initiate off to the west over Northern Illinois and Southern Wisconsin after 4pm expanding in area as they work east. It is after 8pm and especially 9pm when our threat increases. 9pm to 3am will be the likely window for severe potential tonight. Again, elevated hailers are the most likely severe mode. Both damaging winds and tornadoes cannot be ruled out down towards I-94. We will be watching the warm front location very closely as any storms that roll up from the south and interacts with it will have tornado potential.

Both the HREF helicity swaths and Nadocast tornado probabilities indicate the biggest tornado threat being south of our area (although its close) across Northern Illinois and Northern Indiana. Probabilities and helicity swaths are painted into our southern couple rows of counties too, just not to the intensity of those further south. Again, some of the parameters from hand picked soundings across our south via the HRRR indicate a very clear signal for tornado potential. The pivotal factor will be how storms evolve and whether the front noses up into the I-94 corridor like the HREF and HRRR indicate.

- Freezing rain tonight into Wednesday over Central Lower MI

We have issued a Winter Weather Advisory for Lake, Osceola and Clare counties for tonight into Wednesday. It is certainly spring in the midwest with a dynamic system in play when we have winter weather across Central Lower Michigan and severe storm potential across the south. It is testament to the strength of the warm front. Low level cold air will be pulled into the U.S. 10 corridor setting the stage for a period of freezing rain overnight and into Wednesday morning. The surface temperatures are marginal (around 32F) so the extent of the icing will likely not be significant. It doesn't take much icing at all though to create problems. There is some indication that the freezing rain could also affect Mason, Newaygo, Mecosta and Isabella counties but given the near to slightly above freezing air temperatures decided to issue for only the most confident counties.

- Accumulating snow Thursday night/Friday over Central Lower MI

The clipper that has been in the models now for days remains in the models tonight with a trend towards a deeper low. That trend has been going on for several days. The low will likely track just to the north of Central Lower, which will place the heaviest snow up across Northern Lower Michigan. That said, we are looking at several inches of snow with advisory/plowable snow possible. We will get by the storms and the ice first and then look deeper into this system for potential headlines.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 152 AM EDT Tue Mar 10 2026

A complicated next 24 hours is in store for aviation interests across Southwest Lower Michigan. A stationary boundary sits just north of the TAF sites at 06z stretching from near LDM to AMN. This front will sag southward today and set up as a strengthening warm front near I-94 this evening. What this means for aviation is developing fog and stratus the rest of tonight. A moist airmass with decreasing winds near the front are the reasons for the fog/stratus. Conditions will reach the IFR category at all locations this morning with pockets of LIFR as well. Some mist will be possible through the day with showers and thunderstorms developing this evening. The showers and storms will likely hold off until after 00z, at which time an increase in coverage and intensity is expected. By the time we get to the 02z to 06z period this upcoming evening and overnight the showers/storms should be widespread. Southerly winds this morning will gradually back to the east as the front sags south. Bottom line...the main concerns are low clouds and fog this morning switching to showers/storms this evening.

HYDROLOGY

Issued at 358 AM EDT Tue Mar 10 2026

The antecedent conditions are that we have wet soils in place which will aid in at lease some increase in runoff and elevated river levels from recent rain. We are looking at a rain event from this evening into Wednesday. Expected rainfall from the Weather Prediction Center is for around an inch of rain across Southern Lower Michigan including the Grand and Kalamazoo River basins. Operational models are showing higher swaths than that with the NAM indicating a band of 2+ inches of rain.

The meteorological setup is a typical heavy rain producer for us with a strong low level jet on the order of 40-50 knots impinging on a warm front draped across the area. Precipitable water values through the event are forecast to be around 1.3 inches which is above the daily max for the day (1.1 inches) per the SPC sounding climatology page. Given the antecedent conditions and the forecast rainfall a Hydrologic Outlook (ESFGRR) was issued from the I-96 corridor to the south yesterday to convey the chance for short term flooding/ponding of water and the potential for river flooding.

Given the forecast rainfall amounts around an inch we are expecting many sites to reach action stage/bankfull. Some locations may reach Minor Flood Stage, even with rainfall totals of around an inch. If the rain overperforms, which there is potential for, we will see an increase in the number of river forecast points going to Minor Flood Stage. We will be monitoring rainfall amounts closely via radar products and ground truth reports. If the rainfall trends towards 1.5 to 2.0 inches those are the values that will add more river flooding potential. Areas to the south and east of Grand Rapids are the locations most likely to see flooding from this event.

GRR WATCHES/WARNINGS/ADVISORIES

MI...Winter Weather Advisory from 10 PM this evening to 2 PM EDT Wednesday for MIZ038>040. MARINE...None.