Measurable snow expected Thursday night

RAPID CITY, S.D. (KEVN) - A storm system in the Pacific will move ashore tonight and quickly move over the Rocky Mountains and up toward the central and northern plains. Snow is expected to fall for many locations, including parts of Wyoming, South Dakota and Nebraska.

This storm has shifted a few times over the past couple of days. The reasoning for that is that data collected over the Pacific Ocean is minimal, so the computer models use the limited information to computer a scenario of where the storm system will impact over its duration. As the storm moves closer to shore, more data is able to be collected and processed by the models, allowing it to get a better understanding of what the storm will do. This is why there is so much uncertainty with a storm 3 or more days out. Once the storm moves ashore, usually 1-2 days from impact, models have a firm grasp on the location, timing and impacts. We’re entering that time frame now and will gain confidence tomorrow, before the storm hits.

Snow is expected to develop and push into our region late Thursday afternoon and evening and fall Thursday night. The storm will pull away through the day Friday and snow will come to an end by midday for much of us. As of 4:30 p.m. Wednesday, December 8, Winter Storm watches are in place for Fall River, Custer, Oglala Lakota, Jackson and Bennett Counties. These begin Thursday evening and last through Friday. Updates will likely be issued to the watches Wednesday night or Thursday morning. I’d expect Winter Storm Warnings for those under the watch and Winter Weather Advisories for areas just to the north, including Rapid City.

The heaviest snow will fall Thursday night, where accumulations will be heaviest along the Nebraska state line. The farther north you travel, the lower the snow totals. Locations north of I-90 will likely miss out on the majority of the snow. Here’s a look at a preliminary snowfall map of what I am expecting as of Wednesday afternoon. This map can and will likely change as we fine tune our final expectations Thursday afternoon, before the storm hits.

Travel impacts are expected for areas along and south of I-90. If you have any travel plans to Denver or Sioux Falls/areas east of there, you will likely want to hold off until Saturday at the earliest. Sunday will likely be your best bet to travel due to improving road conditions. Locally, you will want to allow for extra time during your Friday morning commute to school or work. Roads will be slippery, so keep plenty of space between your vehicle and those ahead of you. Stay safe and check back in tomorrow, Thursday, for the latest updates on the storm.