Marine Weather and Tide Forecast for Michigan City, IN

DISCUSSION
Issued at 1241 PM EDT Thu Jun 19 2025

Surface low with attendant cold front is working its way through Ontario this morning, with a breezy cool(er) airmass being ushered in under northwest flow. Clouds and light rain showers will continue to push east across the CWA through early afternoon before general clearing takes place. Thanks to this heating, CAMs suggest a few showers and storms might be able to fire off this afternoon/evening primarily along and south of US-30 (20-40% chance); lightning and some gusty winds will be the main threat with convection today. Highs will also remain pleasant today (mid/upper 70s) but that will be short lived...

Ridging will settle in over the eastern CONUS by this weekend, characterized by increasing 1000-500mb thickness values. Highs will max out on Saturday around 90 degrees, but it'll feel like it's in the upper 90s. A strengthening low pressure system moving into the Dakotas will result in a tightening pressure gradient. That, coupled with very efficient daytime mixing, will trigger gusty southwest winds in the afternoon. Common gusts will be in the 25-30 mph range, but there is a 20-40% chance of exceeding 40 mph across portions of the area.

Heat is on by Sunday, and good ensemble agreement provides us with confidence that highs of the low/mid 90s with overnight lows in the low/mid 70s will create hazardous conditions for vulnerable populations. Wet-Bulb Globe Temperature, which differs from Heat Index in that it factors in things like sun angle, incoming solar radiation, wind, etc. With values in the upper 80s Sun-Tue suggest a High Threat for heat illness for those exercising or doing physical activities outdoors (based on criteria used in our portion of the country). Wind is a slight limiting factor on Saturday. Regardless, expect at least Advisories will be warranted at some point in the near future.

Moisture return around the western side of the ridge will finally work its way into the area by Tuesday. GFS brings PWATs of 1.5-2.0 inches back into the area. While shear will be minimal and preclude any organized severe threat, our area will be under a warm and moist environment with steep low-level lapse rates. Consequently, some gusty winds wouldn't be surprising next week if showers and storms do pop off.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/
Issued at 1144 PM EDT Thu Jun 19 2025

Subsidence and drying in the low and mid levels should help keep VFR conditions through the TAF period. However, some patchy shallow dense fog had developed this early tonight over northern Indiana in the wake of the showers and storms from earlier today. At this time, have left fog out of TAFs as rain cooled air was not in the vicinity of the TAFs or METAR sites, but will continue to monitor for fog encroachment into the terminals. Kept a PROB30 for thunder at SBN for the arrival of storms associated with an upstream dying MCS.

IWX WATCHES/WARNINGS/ADVISORIES
IN...None.
OH...None.
MI...None.
MARINE...None.