Winter Weather — Southeast St. Tammany Parish, Louisiana

2024-01-15 to 2024-01-16 · Southeast St. Tammany Parish, Louisiana

Event narrative

Nearby mesonet and ASOS observations showed temperatures dropping below freezing around 11pm on the 15th. Rain switched over to freezing rain around this time and persisted for several hours, resulting in around 0.1 to 0.2 inches ice accumulation. It can be assumed similar amounts fell across the parish as radar reflectivity was relatively similar over that area. All interstates, including the Twin Spans were shutdown due to icy roadways.

Wider weather episode

A very amplified longwave upper level trough situated west of the Mississippi River Valley drove an arctic airmass well into the Gulf of Mexico. It's position, west of the Mississippi River, is common for previous events of very cold airmasses and frozen precipitation locally. Temperatures locally began to plummet from west to east on the evening of January 15th and into the morning hours of January 16th. A layer of mid-level of moisture riding over the colder surface was able to precipitate to the ground. Although temperatures aloft were too warm to support snow, subfreezing surface temperatures resulted in freezing rain and some sleet, even as far south as coastal Louisiana. Accumulation amounts ranged from a slight glazing to around one quarter of an inch. All local interstates, many state highways and local roads with bridges were shutdown due to icy roadways.

Source: NOAA Storm Events Database, event_id 1159990. Narrative written by the NWS forecast office that issued the report.