3:20 PM Update- Jay Trobec
The blizzard continues in western, central, and most of eastern South Dakota. Sioux Falls has finally had the persistent flooding rains change over to snow. North or northwest winds averaging 20-40 mph are causing blowing snow and diminished visibilities. Almost all of KELOLAND has experienced wind gusts over 50 mph. Where the snow is blowing across roadways, it is melting and re-freezing, which could cause additional travel difficulties through the evening.
Conditions should improve overnight from west to east, but travel will still be difficult in open areas due to lingering blowing and drifting and slipperiness. The clouds will clear overnight in most of KELOLAND, and winds will diminish to 10-20 mph from the northwest during the early morning hours.
Tomorrow will be partly cloudy, with only a northwest breeze keeping temperatures near the freezing mark. Afternoon highs will be in the low 30s.
With all the rain and melting snow, flooding is now a big issue in the southeast. Numerous roads are blocked due to flooding in south central and southeast KELOLAND. Here’s a look at our Falls Park skycam. The area shown is where you can stand and read about the history of the falls.
Blizzard Warnings now extend into parts of southeast KELOLAND. Rain will continue to switch to snow in the southeast during the late morning hours. Strong northerly winds will accompany the snow to lead to blizzard conditions.
Winter Weather Advisories continue in southeast KELOLAND as rain changes to snow around around noon and after. Northerly winds will also gust to over 50 mph to create reduced visibility and poor driving conditions. Snow amounts of 1-3″ will be possible in this area.
Wind gusts this afternoon will still get over 50 mph for many in central and eastern KELOLAND. The winds will die down late this evening and tonight.
Roads are blocked from blizzard conditions in much of central SD at this hour.
Take a look at our skycams this morning in Huron and Chamberlain. The video tells the story well.
24 hour rainfall totals are beyond impressive in the southeast with nearly 2.5″ in Sioux Falls.
Rivers are rising quickly, including the Big Sioux and the immediate runoff in the city of Sioux Falls. Take a look at this graphic.
We now see a shift to snow and wind to the east the next several hours. Please watch the developing weather carefully, with strong winds blowing snow around even in Sioux Falls this afternoon.
5:45 am Update-
We have many, many stories to follow this morning. Here are some of the big weather stories developing at this hour.
Thick ice has covered the Wessington Springs area. Here’s a picture from uSHARE@keloland.com sent to us overnight.
Many roads are flooded in eastern KELOLAND, including streets in Sioux Falls. Here are the water hazards in southeast SD.
March 12, 2019 1 PM UPDATE – Jay Trobec
Rainfall totals as of 1 PM. Big problems in Yankton, where runoff has washed out gravel roads, and there is street flooding and lots of wet basements. With snow pack and frozen ground, there’s no place for the water to go, and it’s still raining there.
Here’s our forecast for four major cities in South Dakota for tomorrow. Note the wind speeds – gusts high enough to qualify as a severe thunderstorm:
While it’s quiet as of 9:39 in Rapid City, the radar will fill in and north winds will start to increase. Blizzard conditions are still on track for western KELOLAND.
It’s a different story in eastern KELOLAND. We’ve been watching rain in south central and southeast KELOLAND. As that moisture moves north, it’s moving into colder air. Air temperatures are in the upper 20s and lower 30s where you see the pink color on the image above. This is an area of concern for freezing rain. This moisture will continue to move north into Aberdeen and Sisseton during the late morning hours. Be aware of very slick conditions through the afternoon and evening in eastern and northeast KELOLAND. Plain rain is expected to continue through the afternoon and evening in southeast KELOLAND. Rain amounts for the day will exceed an inch in some areas with more rain tonight.
Check out this video for the latest headlines on our developing storm across KELOLAND.
5:45am Update, March 13th
New this morning. Winter storm watches have been expanded into the Sioux Falls area for tomorrow for a potential blizzard switch with strong winds and blowing snow.
Ice Storm– This will be a complex forecast today, but the ice threat is significant. If icing of 1/4″ to 3/4″ happens with the expected strong winds, significant power outages and damage to trees and powerlines can be expected in the hardest hit areas. The spots highlighted in pink are at most risk, but keep in mind freezing rain could easily fall outside the indicated zone the next 24 hours.
Blizzard Threat– A major blizzard is still likely West River, no change on this forecast. Plan on 10″-18″ or more of snow in the heaviest band of snow near Pine Ridge, but those amounts could radiate into parts of central SD.
Flooding- Heavy rain is going to fall in much of the east. Here are some of the latest rainfall forecast estimates. We think 1-2″ of rain will be common, but some amounts may surpass 2″
March 12, 2019 10 PM UPDATE – Jay Trobec
Ahead of the incoming storm, there is a Dense Fog Advisory along and east of the James River, including Sioux Falls and the I-29 corridor. Just a few hours ahead of the storm, here is the patchwork quilt of warnings and advisories that are in effect:
March 12, 2019 3 PM UPDATE – Jay Trobec
Tomorrow we will see rain come up to Sioux Falls from the south during the morning hours. Western South Dakota will have snow that will quickly spread into the central part of the state. In between the two areas, in a line from south central SD to the NE, we could have rain, freezing rain, or show depending on exactly where the boundary sets up. Winds will become northerly, and pick up in intensity – especially in western South Dakota, where wind gusts over 50 mph will be possible.
Rain will continue in Sioux Falls and eastern South Dakota on Thursday, and snow with blizzard conditions will continue in the central and west. Temperatures will be in the 30s, but all of KELOLAND has the potential to see wind gusts of 50 mph or possible. Sioux Falls and eastern KELOLAND, those areas that got primarily rainfall, could get an inch or two of snow before the storm exits Thursday night. Because of strong winds, it is possible that blizzard-like conditions could rapidly develop in open areas.
We still expect that the heaviest snowfall will be in a stripe from around Martin to Murdo to near Pierre. Those areas have a very good chance at a foot of snow – and two feet is not impossible in some locations in the SW quarter of South Dakota.
March 12, 2019 10:00 AM UPDATE – Grant Smith & Brian Karstens
After looking at the morning updates, some updates are needed to the snow and ice forecast. First off, the ice forecast needed to be expanded in northeast SD. Notice how the ice threat zone stretches along the east side of the coteau. That area will be highly dependent on the wind so it is highly susceptible to changes.
This next update comes from the short-term, high resolution computer models. It appears there will be a quick switch from rain to snow in the east and southeast areas on Thursday. This switch will happen in the late morning to early afternoon. So this area will go from strong winds and rain to strong winds and snow, which has all the ingredients to a blizzard. This will be a small weather feature that will need to be monitored closely.
March 12, 2019 5:15 AM UPDATE – Grant Smith & Brian Karstens
Some of the Winter Storm Watches from yesterday have been upgraded to Blizzard Warnings and Winter Storm Warnings. The Winter Storm Warnings are in the Black Hills where significant snow is likely but the winds won’t be quite as strong. But the plains of SD is looking at significant snow with very strong winds upwards of 60+ mph. These will be in effect Wednesday and Thursday.
In addition to the winter weather, there is a Flood Watch issued for the southeast. This is for heavy rain, upwards of 1 to 3″ of rain. Even embedded thunder is not out of the question in northwest Iowa. We got a glimpse of urban flooding last weekend and there’s no reason to think that won’t repeat only this time, river flooding is a concern.
Snow is still looking very impressive in the cold sector of this storm. There is over a 95% chance for more than 12″ of snow in the southwest and a near 70% chance for more than 18″ of snow in southwest SD. For those near I-29 and east, there is snow likely, but not near the amounts.
There is also a threat for icing. With the east in the warm sector of the storm and the west in the cold sector, the transition zone where temperatures go from above freezing to below freezing, is where the icing threat is.
In addition to the snow, rain, and ice, the winds will be very strong. Sustained winds up to, and over, 40 mph are likely with gusts easily over 60 mph. Below is just a screenshot of the winds Thursday morning but winds will be ramping up Wednesday, will stay strong Wednesday night, and last into Thursday.
March 11, 2019 10:35 PM UPDATE – Jay Trobec
Just looking at the probabilities of heavy snow in the southwestern quarter of South Dakota. The probability of a foot or more has actually been increasing. The latest forecast models have settled on an almost unbelievable 90% risk that the areas around Martin up to Murdo will get a foot or more of snowfall. I don’t think I have ever seen such a thing. Pierre’s risk of a foot has increased slightly, to about 60%. I called this storm a whopper on TV, and it appears that will be the case – and it doesn’t even include the punch that north winds exceeding 40 mph will provide.
March 11, 2019 3:50 PM UPDATE – Jay
A very powerful low pressure system moves into Kansas on Wednesday, and will push rainfall into areas along and south of I-90 during the morning hours of Wednesday. During the day on Wednesday, rain will increase from south to north – primarily along and east of the James River – while snow will begin in western and northern South Dakota. North winds will pick up dramatically with the snowfall, creating blizzard conditions. Temperatures will be in the 30s to low 40s, but probably fall during the day with those north winds. Sioux Falls and SE KELOLAND could see heavy rainfall of an inch or two, so it could be a repeat of the urban ponding we saw on Saturday – or even more significant flooding will certainly be possible. And in the area between the rainfall in the east and snowfall in the west, there could be a “few counties” wide ribbon of significant icing somewhere in central South Dakota.
(Green and yellow are rain, blue is snow, salmon color is a mix or freezing rain)
Snow and fierce winds will continue on Thursday, especially the first half of the day. Heavy snowfall will be possible, especially in western and central South Dakota. The probability of a foot or more of snow is staggeringly high… from 30% in Aberdeen to 50% in Pierre, to a bullseye probability of 80% that Martin, SD will get a foot or more of snow. Temperatures on Thursday will be in the 30s, although very strong winds will make it feel much colder.