504 FXUS63 KGRR 011048 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 648 AM EDT Wed Apr 1 2026 .KEY MESSAGES... - Threat for Freezing Rain tonight into Thursday morning - Chance for Severe Weather Thursday afternoon/night - Another round of Strong Storms Possible on Saturday - Rain totals add up as we move into the weekend && .DISCUSSION... Issued at 400 AM EDT Wed Apr 1 2026 - Threat for Freezing Rain tonight into Thursday morning An upper trough swinging through California this morning will zip through the Rockies today, the Plains tonight and into the upper midwest on Thursday. This upper trough will aid in bringing the front that moved through yesterday back as a warm front on Thursday. Some residual cold air will linger across interior Central Michigan late tonight and into Thursday morning as the warmer air surges in aloft. This will set the stage for a period of freezing rain late tonight and Thursday morning. Feel the freezing rain will mainly be confined to Osceola and Clare counties where some of our highest ground is found in the GRR forecast area. From roughly 200am through 1000am or so there is a threat for some icing. We are not thinking this will be heavy, up to a tenth of an inch at most. Warm air will be surging in so what does accumulate will begin to melt. That said, it does not take much ice accumulation to cause issues with travel and it will likely be ongoing for the morning commute up there. Bottom line, a Winter Weather Advisory has been issued for Osceola and Clare Counties from 200am Thursday to Noon on Thursday. - Chance for Severe Weather Thursday afternoon/night The SPC has placed the entire forecast area in a Slight Risk for severe weather on Thursday. Threats will exist with both the warm front moving in during the afternoon and the cold front sweeping through Thursday night. Instability in the models is modest on the order of 500 to 1,000 j/kg, but that could be a little underdone as surface dew points are forecast to hit 60F, while 850mb dew points reach 50F/10C. That is more than enough moisture to work with in combination with a shortwave upper trough swinging through and both a warm frontal and cold frontal passage. Winds are fairly unidirectional and strong (850mb LLJ on the order of 50 kts and the 500mb mid level jet around 60 kts) so damaging winds are certainly a threat. All threats are in play given the strength of the wind fields. Rounds of convection are expected during this time frame with plenty of clouds and showers around, so the details may not become clear until tomorrow. - Another round of Strong Storms Possible on Saturday Another low will move through the area on Saturday associated with a stronger upper trough. Wind fields with this system are even stronger aloft with a 60kt low level jet and a 70kt mid level jet. The question is how much instability we will have before the cold front sweep east during the day. If the timing of the front slows up just a bit it will place a portion of our area in the warm sector at max heating. We will be watching this time frame closely for another round of potential severe weather. - Rain totals add up as we move into the weekend We are likely looking at a fairly widespread 1 to 2 inches of rain between today and Sunday. The rain will come in a couple main rounds... Thursday/Thursday night and Friday night into Saturday. Both rounds of rain will be driven by a warm frontal and cold frontal passage so good forcing will be driving the rain. Precipitable water values with both systems will be near 1.5 inches which will certainly result in periods of heavy rain. We will be monitoring river forecasts as we head through the next few days. Some short term aerial flooding is possible given the convective rains driven by multiple fronts. We may also see some localized river flooding as well, but that will come into better focus as the QPF makes it into the river models. We will know more today and Thursday. && .AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 644 AM EDT Wed Apr 1 2026 Widespread MVFR ceilings are in place across the TAF sites at 12z. The MVFR ceilings will remain in place this morning, but some improvement to VFR will be noted this afternoon. Between 16z and 20z there is potential for all TAF sites to become VFR. Overnight, the warm front that went through yesterday will come back north as a warm front and aviation conditions will deteriorate once again. MVFR will work north with both ceilings and visibilities trending down with rain. IFR is even possible by 12z on Thursday in most areas. Northeast winds of 10 to 20 knots today will veer to the east tonight. && .MARINE... Issued at 400 AM EDT Tue Mar 31 2026 We will maintain the Small Craft Advisory (SCA) for the remainder of the night as some residual wave action continues from the north flow that ramped up behind the cold frontal passage yesterday. The WaveWatch3 shows some 3-5 foot waves likely occurring up near the Points and down towards South Haven. Today and into tonight the flow goes more off shore, first northeast today and east tonight. We will decide today whether the offshore flow is worthy of a Small Craft headline mainly for winds. Thursday and into Thursday night the winds veer to the south and increase making SCA conditions likely. The typical caveats apply though with a spring time warm air advection wind. The models may be mixing down too much wind during this time frame and the winds and waves may not be quite as high as advertised. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory from 2 AM to noon EDT Thursday for MIZ039-040. MARINE...Small Craft Advisory until 8 AM EDT this morning for LMZ844>849. && $$ DISCUSSION...Duke AVIATION...Duke MARINE...Duke

NWS GRR Office Area Forecast Discussion