Marine Weather and Tide Forecast for Michigan City, IN

DISCUSSION
Issued at 334 AM EDT Fri Apr 17 2026

Marine air from Lake Michigan and a still very moist surface due to recent rains trapped beneath an inversion with decent radiational cooling conditions with the clearing skies has allowed for areas of fog to begin enveloping the area. Many locations already as of 07z have been reporting 1/4 mile or less. A dense fog advisory is in place through 8 AM EDT this morning to address this hazard. There was a bit of uncertainty as to how far south in the CWA this would spread but patches of dense fog will be likely in all areas so opted to include the entire CWA under the advisory out of an abundance of caution especially with the thicker fog during the morning commute. If travelling this morning, slow down and allow for greater following and stopping distances.

After 8 AM or so diurnal warming will begin and start to allow for winds to mix down and help to clear out the fog for most areas, however locations near Lake Michigan may take a bit longer to mix out.

The focus then turns to the approaching cold front from the west associated with a surface low moving through Iowa into south central WI later today. Ahead of the cold front, will be much above normal temperatures with highs across northern IN in the upper 70s to low 80s and surface dew points in the upper 50s to low 60s. Around 1500 J/kg of MUCAPE will be available and Bulk Shear Values around 35 to 45 kts. With the expected linear convective line pushing into the CWA around 11 PM EDT tonight a few pockets of Helicity with values around 200 to 300 m2/s2 ahead of the front may remain and allow for a few tornadoes along with the main wind threat but with the less than ideal diurnal timing may lack the better surface instability which will minimize the tornado threat. Will need to monitor this carefully later today to get a better idea of the actual environmental ingredients present. With the front moving through overnight into Saturday morning the remaining activity will move easterly through the rest of the CWA and would expect the activity to be on the decrease into the morning hours as the storms likely become more cold pool dominant. Will need to monitor for some nuisance type flooding possible with the very wet surface still in place and any additional rainfall will be quick to pool and pond.

A drier patter arrives this weekend along with cooler temperatures (highs in the upper 40s to low 50s) into the beginning of next week. Will need to monitor for the potential for some frost and even freeze conditions especially Monday morning with lows on Sunday morning in the 30s and colder yet on Monday with lows in the upper 20s to low 30s. By Tuesday, broad upper level ridging over the central CONUS will begin pushing eastward into the region and we will see a warming trend return with highs on Tuesday in the upper 60s to low 70s. Highs in the 70s will be expected through the rest of next week. A few showers and thunderstorms for Wednesday and again next Friday.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
Issued at 632 AM EDT Fri Apr 17 2026

LIFR/IFR cat vsby/cig reductions due to fog at the beginning of this TAF period will improve to MVFR/VFR around 14z Fri. Some residual low cigs may hang on a bit longer than expected and also KSBN may see a longer time frame for improvement but confidence is low on sticking around longer. Southerly winds will pick up today with the diurnal heating. Gusts around 20 kts expected through the evening. An approaching cold front from the west will increase precipitation chances in thunderstorms in which a few of the storms may become strong to severe after 00z Sat and spread eastward into Saturday morning bringing MVFR cigs/vsbys within thunderstorms and post frontal.

IWX WATCHES/WARNINGS/ADVISORIES
IN...Dense Fog Advisory until 8 AM EDT /7 AM CDT/ this morning for INZ005>009-012>015-017-018-020-022>027-032>034-103-104- 116-203-204-216.
OH...Dense Fog Advisory until 8 AM EDT this morning for OHZ001-002- 004-005-015-016-024-025.
MI...Dense Fog Advisory until 8 AM EDT this morning for MIZ078>081- 177-277.
MARINE...Dense Fog Advisory until 8 AM EDT this morning for LMZ043-046.
Small Craft Advisory from 8 PM this evening to 2 AM EDT Sunday for LMZ043-046.