Marine Weather and Tide Forecast for Harrisville, MI

UPDATE
Issued at 1121 AM EDT Tue Apr 29 2025

Strong cold front crossing the region this morning...temps in the upper 70s across much of NE Lower ahead of this, with dewpoints still in the 50s/60s...and behind, temps falling into the 30s with dewpoints in the upper 20s to lower 30s with some snow showers reported at Houghton-Hancock. A largely SW-NE line of convective redevelopment ahead of a dry slot poking in...with some gusty winds and hail possible in the strongest storms...where best instability is still located. Still possible that a few storms could bump up to severe levels this morning into this afternoon with the front shoving its way through. 700mb winds still up around 50kts aloft ahead of the front; 850mb winds around 30-40kts...such that even outside of thunder, have seen some of these stronger winds (esp the 850mb level winds) get mixed down with the dry slot as well as some early-morning clearing ahead of the cold front. Have opted, therefore, to go with a wind advisory for the area...generally through mid-afternoon west of I-75, and through the remainder of the afternoon for NE Lower. Have also included parts of the EUP in the wind advisory, particularly downwind of Whitefish Bay, as the pressure gradient is expected to tighten up on the backside of the low this afternoon up there. Will expect temps to fall quite dramatically through the remainder of the afternoon from W to E...though low-level clouds will likely build in and keep things feeling much more fall-like than summer like...particularly if a few flakes do manage to mix in (most likely across the interior higher terrain).

SHORT TERM /THROUGH TONIGHT/
Issued at 224 AM EDT Tue Apr 29 2025

Pattern Synopsis/Forecast: ~996mb low pressure is currently situated over Lake Superior/northern Ontario. Plenty of convection across parts of eastern WI, central/eastern U.P. and northern Lake Michigan out ahead of the system's cold front. Primary focus revolves around the next 6 or so hours as convection, albeit weakening, crosses northern Michigan with the trailing cold front clearing area-wide later this morning. Higher surface pressures build in from the west through the remainder of the day with high pressure becoming centered squarely overhead by 12z Wednesday.

Forecast Details: Quite the mild and windy night out there tonight with many areas across downsloping northwest lower still in the 70s at this early hour (78! at TVC). Latest trends continue to support ongoing convection across parts of eastern upper, northern Lake MI, far northwest lower and points upstream to make a run across across much of northern MI over the next several of hours. Noted diminishing trend over the last couple of hours on KAPX/KMQT/KGRB with latest suite of short term guidance continuing this trend as precip rolls across northern MI. THat said, some enhanced gustiness out ahead of this convection along the gusty front and certainly still some rumbles of thunder anticipated as decaying axis of instability folds across the forecast area. While chances for severe storms appear to be diminishing, they're certainly not zero. Any stronger storms that do develop will still be capable of all hazards simply given shear parameters. 925mb winds on the order of ~70 kts, 0-6km bulk shear values up over 50 kts with sfc-1km SRH nearly 300 m2/s2 and sfc-3km >400 m2/s2. The bulk of this threat is expected to be east of the area by 11-12z, however, the lagging cold front remains several hours behind. Additional isolated to scattered storms will remain possible ahead of the front, primarily northeast lower, through the late morning time frame with a continued low-end severe threat.

Quite the change anticipated for the second half of the day into tonight. Continued gusty winds turn out of the west post fropa and eventually northwest by late afternoon. Much colder temperatures to be ushered in (upper 30s and low 40s by late afternoon across much of eastern upper and northwest lower) with those gusty northwest winds leading to sub-freezing wind chills. Some light showers/patchy drizzle possible as well. Winds relax considerably this evening before turning calm in many areas after midnight. Clearing/clear skies and light winds should lead to excellent radiational cooling with lows tonight falling in the 20s across much of northern MI.
While the forecast won't reflect as such, there are even some low probabilities of localized teens showing up for the typically cooler/interior/icebox locales.

LONG TERM /WEDNESDAY THROUGH MONDAY/
Issued at 224 AM EDT Tue Apr 29 2025

High pressure holds through Wednesday evening leading to abundant sunshine and seasonable temperatures. Increasing clouds overnight Wednesday with showers expected to arrive Thursday morning as an area of low pressure moves up from the southwest. Showers continue through the day on into Thursday night with chances for showers on Friday as an upper level trough sits over the region. Temperatures are expected to be on the cool side. Increasing ridging at the surface and aloft this weekend with the ridge holding into early next week. Warming temperatures are expected as a result along with precipitation free conditions. This should make it feel and look more like true spring with flowers emerging and trees beginning to burst out in blossoms.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/
Issued at 618 AM EDT Tue Apr 29 2025

Cold front crosses northern Michigan this morning with some lingering isolated to scattered storms possible, primarily at APN.
Otherwise, a few post frontal showers possible amidst lowering CIGs expected. Some improvement anticipated by mid-late afternoon before clearing skies area-wide this evening. Winds remain gusty today, initially out of the southwest, turning westerly and eventually northwesterly post fropa. Calm winds tonight.

APX WATCHES/WARNINGS/ADVISORIES
MI...Wind Advisory until 3 PM EDT this afternoon for MIZ016-017- 020>022-025>027-031-032-099.
Wind Advisory until 8 PM EDT this evening for MIZ018-023-024- 028>030-033>036-041-042.
Wind Advisory until 5 PM EDT this afternoon for MIZ086-087.
MARINE...Small Craft Advisory until 11 PM EDT this evening for LHZ345.
Gale Warning until 11 PM EDT this evening for LHZ346>349.
Gale Warning until 2 PM EDT this afternoon for LMZ323-341-342- 344>346.
Gale Warning until 11 PM EDT this evening for LSZ321-322.