Marine Weather and Tide Forecast for La Porte, IN

DISCUSSION
Issued at 242 AM EDT Wed Mar 18 2026

Overall NW flow aloft will continue to send relatively weak clippers/disturbances into the region over the next couple of days before upper level heights increase sufficiently to allow a temporary shift NE of this active flow. The impacts of the first wave are already bringing some light snow to portions of SW WI/NE IA and NE MN with vsbys generally above a mile. As the isentropic lift increases over the next several hours, a lot of dry air needs to be overcome (00Z KILX sounding showed a very dry layer between 700 and 900 mb) before any snow can reach the ground. Have made some changes wrt timing and overall pops, which may need further revision in the coming hours as we see how this unfolds. Overall snow accumulations will be under an inch and most likely near/under a half inch (highest west), which could cause some slick spots for the morning commute. Any precip quickly exits by afternoon with temps climbing above freezing (40s SW).

Next, somewhat stronger, wave dives SE late Wed night into Thursday with another burst of isentropic lift. Trends suggest onset likely not occurring until after 9Z and possibly even closer to 12Z Thu.
Exact onset time may factor into ptype with air temps likely near freezing in NE areas. For now have removed any ZR mention and IF some occurred, it would be very brief in duration as WAA strengthens across the area. Overall QPF will be somewhat higher than today's system, maybe reaching a tenth or so in some areas.

More substantial low level WAA commences going into Fri and Sat with highs back into the 60s and possibly some 70s as the main train of waves is pushed NE (for a short period). A stronger cold front arrives late Sat night into Sunday, but so far appears to be lacking deeper moisture (sfc dewpoints struggle to 50 degrees Sat night)
resulting of lower overall QPF potential. In the wake of the front, more seasonable temperatures start the work week with some moderation back above normal to end the period.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/
Issued at 104 AM EDT Wed Mar 18 2026

A disorganized shortwave is dropping south through WI and IL this morning bringing a period of snow. Eastward progression into Indiana, against a 1027mb high over the Ohio River Valley, has been slow. However, ceilings are on the decline and dew point depressions are narrowing, if only slightly. Upstream, dew point depressions of about 5-7F are noted.

High confidence in a period of MVFR snow at KSBN but not enough confidence to remove the inherited TEMPO IFR. Upstream trends will be monitored closely. It is also uncertain how this wave presents at KFWA, where a brief period of MVFR snow could be the outcome. Here too, not enough confidence to remove the inherited PROB30 IFR. Upstream, there are instances of 1 1/2 SM.

Behind this wave, ceilings improve to IFR

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