Another April Storm Ahead...
April 15, 2013 8:22 PM
After 2 major storms have rolled through South Dakota over the last week bringing upwards of an inch of freezing rain to some and 1 to 2 feet of snow to others… another winter like storm is on the way. There are still many unknowns about this next storm, however enough cold air will exist to bring the possibility of all 4 precipitation types to the area; rain, freezing rain, sleet, and snow. There are some indications that this could be another major storm with heavy snow, ice, and rain… however at this time, it is just not known how large of an impact this storm will have. Below is a look at the latest estimates of what’s to come.
First off, it is just too early to know how big of an impact this precipitation will have on the area as forecasting computer models are far from agreement. Right now, the Hydrometeorological Prediction Center (HPC) has compiled a forecast for liquid totals from now through Thursday evening Nationwide.
The heaviest of the precipitation will stay to our south and east where thunderstorms are expected to form in what could be a large severe weather outbreak, especially Wednesday and Wednesday night. These thunderstorms though could have an effect on precipitation across our area. Remember that our moisture source is the Gulf of Mexico. Well, thunderstorms can act like a wall effectively preventing moisture from surging northward into our area. This would actually starve the northern part of the storm for moisture and end any precipitation that is falling across our area. Now the hard part is trying to figure out whether that is going to happen or not and the computer models are not helping. The following images are forecasted snow accumulation through Friday morning from two different computer models.
The first one is pretty light with generally just 1 to 3 inches of snow possible for many across our area with heavier amounts toward the Black Hills. The second image though paints a much different picture with widespread amounts of 6 to 12”+ across the area with nearly 2 feet possible from the Black Hills to the front range of the Rockies. The first image is the result of the “thunderstorm blockade” and the second image is the result of free flowing moisture from the Gulf. Dilemma?? I would say so.
Now here is what the HPC is predicting for snowfall from Tuesday evening through Thursday evening. The first image is the probability of receiving at least 2 inches while the second image is for the probability of receiving at least 8 inches.
Once again, much of the area has at least a chance at getting 2 inches of snow with this next storm while much of the north and west have at least an 80 percent chance. Far lesser chances for more than 8 inches of snow, however, considering that this is the middle of April… any probability at all is impressive. The HPC shows up to a 40 percent probability for those in central South Dakota of receiving 8 inches of snowfall.
Here is the KDLT forecast for snow accumulation. Right now it appears like we are in the middle. This happened for a couple reasons. First, it’s late enough in the year that it takes nearly perfect conditions to get several inches of snow…. Which there are too many questions still to know that for sure. Secondly, forecasting models are spread really far apart on snowfall totals which gives us forecasters no help in predicting the overall strength of this storm. That being said, a swath of 3 to 7 inches appears pretty likely, but it all comes down to temperature and storm track. If it moves one direction or another, or if it weakens or strengthens… then these figures could go up or down so you will have to stay tuned.
If you weren’t already depressed from the snowfall prediction, then you probably will be now. There are chances for more ice accumulation across areas of the east. Unfortunately though, we are even more uncertain about just how much ice could accumulate in some areas, however conditions are favorable for at least some minor ice accumulation in some areas.
Many of the areas that received significant icing from last week’s storm have the possibility of more this week, however conditions are NOT favorable for a widespread heavy icing event like we saw last week. The likelihood of another major icing event happening just days after a previous one is about one in a billion. That being said, if rain begins to fall Tuesday night with a brisk northerly wind ushering in cooler air from the north, then another quarter inch of icing will be a possibility. Stay tuned.