Marine Weather and Tide Forecast for Fair Plain, MI

DISCUSSION
Issued at 158 PM EDT Sat Jun 21 2025

A significant early season heat wave remains the primary concern over the next several days as a 594+ dam H5 ridge anchored over a large portion of the eastern US. Ensemble data still strongly favors H85 temperatures of 20+ deg C through at least Tuesday, although guidance has backed off slightly in the last 24 hours.
Nonetheless, the anomalously warm profiles (as indicated by the 95th-99th percentile of H85 temperatures per the NAEFS) and deep subsidence beneath the thermal ridge will support multiple days with daytime highs in the lower to middle 90s F. Widespread dew points around 75 deg F are leading to excessively humid conditions and widespread heat indices around 100 deg F already this afternoon. The extreme moisture levels will also create a scenario where overnight low temperatures may struggle to drop even below 75 deg F, with the potential for record warm lows for multiple nights in a row. NBM mean wet bulb globe temperatures are expected to be near 86-88 degrees each afternoon through at least Tuesday, and NWS Heat Risk products continue to suggest the potential for major to extreme heat related impacts across the entire CWA during this same time period. It is worth noting that models have backed off a bit with the overall quality of the thermal environment especially into Monday and Tuesday, which may indicate some flattening on the northern periphery of the ridge which could potentially introduce some cloud cover and low end chances for precipitation early in the week which leads to uncertainty with maximum heat index values. While the numbers from a criteria standpoint are fairly marginal, the cumulative impact to the public over several days could be significant. There is still justification to potentially upgrade the Extreme Heat Watch to a Warning, especially considering current dew points running 3-5 deg higher than forecast and resultant heat indices more solidly reaching Heat Advisory criteria than earlier expected. However, given the down trend in NAEFS and more uncertainty on Monday and Tuesday, prefer not to upgrade at this time but also fully acknowledge the concerns for cumulative heat related impacts. As such, did not make any changes to the inherited heat headlines.

Overall, precipitation chances are expected to remain on the low side through Tuesday, though any ridge runner short waves could contribute to a couple of showers earlier in the week in the presence of sufficient moisture. Long range models do hint at the complete break down of the ridge by Wednesday through Friday of next week, supporting a shift toward a wetter pattern with more tolerable temperatures.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
Issued at 1258 PM EDT Sat Jun 21 2025

Windy conditions will prevail through the entire TAF forecast period. South/southwest winds will be sustained between 15 to 20 knots this afternoon and evening with gusts around 30 kts (and maybe a few isolated higher gusts to 35 kts possible). Expect winds to diminish to around 10 kts overnight some stronger gusts of 15 to 20 kts still possible. Winds ramp up once again on Sunday by late morning. Skies will be mostly to completely clear over the weekend with VFR ceilings as high pressure builds over the area.

IWX WATCHES/WARNINGS/ADVISORIES
IN...Heat Advisory until 8 AM EDT /7 AM CDT/ Sunday for INZ005>009- 012>015-017-018-020-022>027-032>034-103-104-116-203-204- 216.
Extreme Heat Watch from Sunday morning through Tuesday evening for INZ005>009-012>015-017-018-020-022>027-032>034-103- 104-116-203-204-216.
OH...Heat Advisory until 8 AM EDT Sunday for OHZ001-002-004-005-015- 016-024-025.
Extreme Heat Watch from Sunday morning through Tuesday evening for OHZ001-002-004-005-015-016-024-025.
MI...Heat Advisory until 8 AM EDT Sunday for MIZ078>081-177-277.
Extreme Heat Watch from Sunday morning through Tuesday evening for MIZ078>081-177-277.
Air Quality Alert until midnight EDT Sunday night for MIZ078- 177-277.
MARINE...Small Craft Advisory until 4 AM EDT Sunday for LMZ043-046.