Marine Weather and Tide Forecast for Parchment, MI

UPDATE
Issued at 928 PM EDT Fri Apr 25 2025

Little if any instability remains over the cwa now that the front has moved through. As such, we removed the mention of thunder tonight. Radar shows the last band of showers poised to move across the lake shore. Once that moves through, the rest of the night will be dry. No changes to the remainder of the forecast.



DISCUSSION
Issued at 341 PM EDT Fri Apr 25 2025

- Evening storms then drying out for the weekend

Convection has commenced this afternoon, poised just off to our south across the far southern row of Michigan counties. MUCAPE values are on the order of 1000-2000 j/kg so we have plenty of instability. Deep layer shear is on the order of 30 knots, so we have had occasional cores aloft that have been worth monitoring, but nothing severe yet. Given solid instability and marginal shear there will be periods this evening where a stray core may pulse towards severe levels. Overall though, our severe threat is quite low. Storms will continue from now through 7-8pm before moving east and/or diminishing. There may be some wrap around showers on the backside of the departing low tonight, but scattered pops (30-40 pct) at best should cover that threat.

Otherwise, we are looking at dry weekend as high pressure slides east across the Great Lakes. Next chance for precipitation should not come until Monday night.

- Frost potential Saturday night

There will be the potential for some patchy frost in the counties we have active for frost/freeze headlines for Saturday night. The counties we are issuing headlines for are from the Muskegon/Kent/Montcalm/Gratiot row to the south. At this time though we are holding off on any headlines at all and we will assess the threat further tonight and into Saturday. As it stands now low temperatures look to be 34 to 36 degree range that would equate to an advisory if these forecast low temperatures hold. The Central Lower Michigan counties are colder, but the growing season has not progressed enough up there at last check to bring them into the fold. Bottom line is there is a chance of frost Saturday night but we will hold off for now and issue going forward if confidence increases.

- Thunderstorm Potential Monday night and Tuesday

The GRR forecast area is in a slight risk for severe thunderstorms both Monday night and again on Tuesday. Monday night the convection will be coming in likely in a decaying phase after generating early on Monday upstream. On Tuesday, the convection will go up on an advancing front in our south and east, so it will only be a portion of the area that will have a threat for severe weather. The upper wave driving the cold front looks fairly potent. Monday night convection looks elevated with marginal shear values so cannot rule out some near severe hail.

The time frame of concern will be Tuesday afternoon as the moisture consolidates along the front and instability jumps to in excess of 2000 j/kg. Deep layer shear on Tuesday is high around 50 knots per the GFS. The combination of CAPE/Shear is sufficient for all hazards. The question mark as is always the case in these events is whether or not the clouds and precip clear out enough on Tuesday to build the instability to forecast levels. Bottom line we are watch Monday night and especially Tuesday closely.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/
Issued at 743 PM EDT Fri Apr 25 2025

Showers will be largely east of the I-94 TAFs at the beginning of the period. However, another batch of light showers are moving in to west central Lower and may affect the I-96 TAFs. Don't think there will be much if any reduction to visibility as instability will continue to wane during the evening.

Ceilings will fall to MVFR tonight before climbing Saturday morning and eventually clearing out during the afternoon.

MARINE
Issued at 341 PM EDT Fri Apr 25 2025

North winds are beginning to fill in across Lake Michigan this afternoon. Low pressure consolidates this afternoon across the Southern Great Lakes and moves east this evening. Peak winds will occur this evening but a stronger north flow will persist into Saturday. North winds of 15 to 30 knots will be common tonight and Saturday morning. We have a Small Craft Advisory (SCA) in effect through 800pm which looks good. We may need to extend the SCA for an hour or two in the far south Saturday evening, but at this point thinking is it looks good.

Winds and waves will be below advisory criteria Saturday night and Sunday as high pressure drifts through the region. Sunday night into Monday south winds take hold and we may need headlines once again.

GRR WATCHES/WARNINGS/ADVISORIES
MI...None.
MARINE...Small Craft Advisory until 8 PM EDT Saturday for LMZ844>849.