Winter Storm Watches Posted: Friday morning forecast discussion with Brant

The potential for very heavy snow and gusty winds is expected to bring significant impacts to the Black Hills Region, with a workable timeline starting to come together

The National Weather Service in Rapid City has issued Winter Storm Watches across the Region, with elements of the forecast still coming together at this hour.

  • Significant impacts are becoming more likely for the Black Hills, particularly along and South of I-90 starting late Saturday going into Sunday morning
  • The highest impacts look to be along the South Dakota/Nebraska border – where over a foot of heavy wet snow will be possible combined with gusty NE & E winds
  • The potential for upslope snow along the I-90 corridor put Rapid City and the Eastern foothills in the running for snow totals pushing 6″-12″
  • The Central and Southern Black Hills could see over a foot of snow.
  • Dry air from the Northwest could significantly cut down overall snow totals for Northeast Wyoming, the Western Hills and the Northern Hills.
  • Rain could significantly cut down on snow totals for areas of the SD plains, including areas North and East of Rapid City.

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Lets further break down timeline and impacts expected across the Black Hills Region

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  • The next 36 hours will be relatively uneventful, save for a few rain showers pushing North from Nebraska.
  • These are not expected to amount to much.

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  • Temperatures expected to push the 40s and 50s North of I-90
  • Cooler temperatures in the 30s and 40s expected in the Black Hills

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  • Friday night expected to be relatively uneventful, with temperatures in the 20s and 30s across the area.

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  • By Saturday morning and afternoon, areas South of the Black Hills will start to feel significant impacts from the advancing winter storm.
  • In contrast, the Black Hills themselves should stay relatively mild – save for a few rain/snow showers creeping in from the South towards the afternoon.

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  • Winds will start to pick up from the northeast by Saturday evening, with southern portions of our area starting to see moderate rain/snow bands move in from the South.
  • Eastern Wyoming and areas of the Nebraska panhandle will become difficult for travel during this time period.
  • Overnight, Fall River and Oglala Lakota County will start to see impacts to travel as snow bands move in.

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  • By midnight, conditions are expected to start deteriorating from South to North.
  • A distinct Rain/snow line will form just North and East of the Black Hills – this could push into the Eastern foothills and muffle overall snow totals.

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  • Sunday morning and afternoon will feature continued moderate to heavy snow bands – with the rain/snow line creeping in from the North and East.
  • Rain could mix with snow periodically along the I-90 corridor and the SD plains.

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  • Winds will begin picking up from the East and Northeast by Sunday afternoon.
  • This is the period of time where heavy upslope snow could quickly add up for Rapid City and the I-90 corridor.

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  • By Sunday evening, Dry air from the Northwest begins to undercut snow from west to east.
  • Stubborn snow bands will still exist along the Eastern foothills – so long as easterly winds remain in place.

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  • By Monday morning, most snow will have pushed East of the area and improvements to overall conditions can be expected.

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  • Specific snow totals are still too far out for our short range models given the multi-day nature of this event.
  • However, the areas of greatest and least impacts are becoming clear as surface winds/Low locations becoming more solidified.
  • The Central Hills, Southern Hills and portions of Fall River/Oglala Lakota County are expected to see the heaviest impacts – with over a foot of snow possible combined with blowing snow in the plains.
  • This would include Pine Ridge, Oglala, Hot Springs, Oelrichs, Ardmore and *possibly* Edgemont.

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  • The I-90 corridor by far has the most volatility in overall snow totals – but 6″-12″ seems reasonable for Rapid City, Sturgis, Piedmont, Summerset and Nemo
  • Upslope enhancement with heavy wet snow could push snow rates of 1″-2″ per hour at times – leading to difficult travel
  • Combine this with possible blowing snow – and travel could become dangerous.
  • Areas of New Underwood, Wall, Wasta and the Hermosa Foothills will see varying accumulations given the rain/snow mix potential… but winds will have a bigger impacts and could lead to blowing snow.
  • Even if snow totals are relatively low for the plains.. below the 6″ level… – blowing snow Sunday afternoon could lead to significant travel impacts.

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  • Spearfish, Lead, Deadwood and Belle Fourche will be right on the line for impacts… with aggressive dry air pushing in from the Northwest.
  • Expect significant changes in your forecast for the next 24 hours as short range guidance gets a better grip on the extent of this dry air.
  • Dry air could push as far East as Sturgis and Meade County, and as far South as Edgemont.
  • Newcastle, Gillette, Sundance and Hulett could see significant cuts to overall snow totals due to this undercutting dry air. Less than 6″.

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  • Areas north and East of the Black Hills will see a combination of dry air and rain cut into overall totals… so places like Philip, Union Center, Ekalaka, Bison and Buffalo could see little to no impacts out of this system.

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  • By Monday morning, most impacts will be pushing East River and our of our area.
  • Another potential quick moving clipper system will follow up Tuesday and Wednesday – but that’s not expected to bring large impacts to the area other than the potential for a few more inches of snow.

DISCUSSION

By far the toughest forecast I’ve had in my short career – The usual actors of dry air and rain/snow mix has endlessly complicated a forecast that features a potentially record setting winter storm for the front range. Bottom line – this is going to change… but if you live south of the Black Hills  and haven’t already started preparations for heavy snow, now is the time. We will be posting several forecast discussions over the next 24 hours as zero hour approaches – we appreciate you trusting us with this forecast… we understand the importance in hols when making critical preparations. Stay safe out there, and stay tuned. – Brant

Categories: Local News, Weather Daily