Winter Storm Warning Issued: Periods of heavy snow starts tonight for the Black Hills

The National Weather Service in Rapid City has issued a Winter Storm Warning for the central and southern Black Hills, including areas of Weston County and Southern Campbell County in Wyoming. Winter Weather Advisories stretch along I-90 from Buffalo, Wyoming through Chamberlain, South Dakota and continuing Northeast through the State. Areas along the Nebraska border from Fall River county through Todd County are also under Winter Weather Advisories.

• This is a developing forecast and will be updated through the morning and afternoon hours
• This system is expected to move Southwest to Northeast, impacting Central Wyoming in the early evening before moving into the Black Hills Region tonight into Wednesday.
• Our week long weather of sunny, warm days will help mitigate road conditions for some areas – but snow rates will quickly overcome this barrier – particularly along SD-79 South of Rapid City and the central/southern Black Hills into Wyoming.
• The system will quickly push Northeast, with snow ending by Wednesday evening for most of the region.

Lets break down the finer details:

• We may have a few snow showers already strafing Wyoming by later this morning, but most of us will remain dry through the afternoon.
• Heavier snow bands will arrive in Central Wyoming by this afternoon, so any travel plans South should take this into account.

• By 6-8 PM, the overall system will be creeping into the picture from Southwest to Northeast.

• Some temperatures even at the 8 PM hour will be hovering in the upper 40s, but these numbers will slowly drop the farther into the evening we push.
• It’s possible some of the initial bands will be a mix between rain and snow – which will diminish overall snow totals.
• There is an expected across the board shift to all snow by early Wednesday morning, however.

• By 10 PM, portions of Fall River, Custer and Pennington County will start to see initial waves of light to moderate snow.
• Northeastern Wyoming will be pretty well socked in once you get past the 9-11 PM hour.

• After midnight, skinny bands of moderate to heavy snow will push into the Black Hills and the West River Plains.
• Notice there are distinct patches of dry pockets that could hinder overall snow totals – sharp accumulation cutoffs should be expected.

• 4-8 AM is expected to be the zenith of our snow accumulations across most of  Wyoming, with heavier bands still trying to push into South Dakota by this hour.
• This is the time frame where snow covered roads and visibility could become an issue – use caution.

• Temperatures across the area by 6 AM will be plenty cold for a full transition to snow.

• By the 8-10 AM hour, widespread snow bands are now pushing into areas along and North of I-90 in South Dakota.
• Snow is starting to let up across Wyoming by this time – with only light to moderate bands hanging on in isolated pockets.

• The Lunch hour shows good improvement for the Black Hills and areas West – but moderate to heavy snow bands will be strafing the region Southeast and East of the Black Hills.

• By 4-6 PM, most advisories will be ending across the area, with a few stubborn leftover snow bands sticking around in pockets.
• Pockets of upslope enhancement could throw snow accumulations into overtime, these are going to be the places where snow accumulations exceed projections.

SNOW ACCUMULATIONS:

• The initial bands of snow will be on the wet and heavy side, with temperatures hanging around the freezing mark. As temperatures drop, snow will transition to more of a powder. Road conditions will be very slick as melted snow will freeze overnight.
• Although advisories have numbers posted around the 3″-5″ mark for the SD plains, latest guidance suggests very heavy (small) pockets of snow could throw snow totals for a loop. This will be along a thin North/South line from the Nebraska border up through Faith, Dupree and Philip.
• Dry pockets are likely in the Black Hills themselves, so although the Winter Storm Warning calls for 5″-8″ of snow we’ll likely see pockets of 1″-3″ particularly in the Northern and Northwestern portions of the Hills.

This is exactly what the doctor ordered – let’s just make sure we still respect the limitations of travel that these conditions can inflict, even if it’s welcome! I’ll update this article through the day with any updates. don’t forget to send in your snow totals! Be safe out there.
– Brant