Challenges of snow forecasting this week

 Hope you had a terrific Thanksgiving week. We are about to begin the month of December with a chance for some snow, HOWEVER, temperatures aren't going to be all that rough on us just yet. 

Snow forecast challenges ahead:

The hardest thing to do ahead of a winter system is pin down where the heaviest accumulations of snow will fall. Every storm presents its own unique challenges, and this one will be no different. The last 4 or 5 days, one model showed snow while another model had nothing at all. We are finally seeing some agreement that snow WILL setup in the Plains, but determining where the storm will wobble around is tough.

Here's what one model shows on accumulation for Wednesday/Thursday:

As you can see, it focuses more of the snow central and east. The amounts aren't huge, and at this time, I would doubt this storm would have anything record setting with it anyway. But what we want to take away from this is where the snow accumulations might be.

Another model has this:

Suggests that much of the snow will end up in southern Kansas and northern Oklahoma. Similarities between the two models are that the amounts of snow are up to about 5 inches but not much more. That is still a pretty good snow for the Plains and given the temperatures, would likely have some good moisture content to it. This is a storm where 10 inches of snow would equal about 1" of liquid precipitation. However, nobody is expected to come close to 10".

No Arctic air invasion! 

Don't like winter temperatures? This midweek system will have no Arctic connection. It does get cold enough to snow, but the air that will be in the Plains show no connection to the bitterly cold areas of Canada or the Northwest Territories. What does that mean? It should mean a quick rebound in afternoon highs at the end of the week. Just look at the map for Thursday afternoon. Areas north of Kansas will actually be a bit warmer, so we should warm and melt the snow quickly by Friday and the weekend.

Winter Forecast 2020-21

I never know if you'll be excited when you read this or disappointed (maybe that's with every storm we discuss here), but we have released our winter forecast. This has been a record year for lack of tornados in Kansas, but in the Atlantic basin, a record number of hurricanes and tropical storms. A total of 30 named storms - almost made it halfway through the Greek alphabet.

So what does all of this mean for the winter? There are always several challenges when coming up with these predictions, but here are some things we are taking into consideration.

La Nina: 

Located in the Pacific, near the Equator, this is where the water temperatures are colder than average. This change in the water temperatures does have an influence on the patterns across the United States. Look at the latest image above - shows the colder water that has built up along the equator (as indicated in the blue and even purple colors) We know that La Nina summers are notoriously hot and dry for Kansas - so let's hope this weakens before summer 2021. Winters are more of a wildcard for the Plains. Some La Nina winters are quite cold, but others are near normal. Most recent La Nina winters (2017-18, 2010-11, 2011-12) had near to above normal snow and several cold outbreaks. That's strongly considered in this prediction. La Nina is forecast to stay through spring of 2021. 

What kind of weather pattern normally sets up in La Nina? Take a look:

It will remain strong enough to be a contributor to our weather patterns in the months ahead. Colder than normal weather is likely in the northern Plains, with expanding drought potential across the southern states. Wet weather is typical near the Great Lakes in a La Nina setup. 

Arctic Oscillation: 

During the month of October, it dipped into the negative, but then we saw it go positive in November (resulting in a milder month). It's not uncommon at all to see these wild swings, but when it dips negative, we should prepare for our big cold snaps. It's likely going to be near neutral into the first half of December, so it will be chilly, but not crazy cold. Where it might go negative is late January and February, so that would be when I'd expect the strongest Arctic outbreaks. 

Patterns: Given the La Nina influence, the jet stream winds will likely come down over the northern Rockies and right over the central Plains. That could mean a BIG temperature contrast from east to west. And if the jet shifts by a hundred miles or so, could be the difference between Arctic cold and somewhat milder weather.

However, I do expect a few decent storms to develop over the Rockies and then push into the Plains. We saw this in late October and most recently with the storm that dropped mainly rain (and a little bit of snow in central Kansas). Classic, major winter storms come in from the desert Southwest, but I think the storms this winter will form closer to Kansas. That will be something to watch as we continue on into winter. 

Summary: 

I think we should have near normal snowfall this winter around much of Kansas. I don't think the drought conditions are going to improve; that's very hard to do in the heart of winter. But maybe the drought won't get any worse if we get some decent snows periodically throughout winter. We've already had some icy weather (back before Halloween), and my concern is that may show up again this winter. If the jet stream stays in more of a northwesterly pattern, we might escape the threat. 

I'm also expecting some of our coldest weather to arrive in February this winter. There will be plenty of chilly days before that, but that might end up being our coldest month this winter. January may have some surprising warmth for the Plains.

Weekend storm is coming & a preview to Thanksgiving travel

Just days away from another November storm that should bring rain to the Plains. We hear the requests daily for moisture and confidence is increasing this will be a statewide event. As we have said before, it will not be a drought ending rain, but helpful in whatever we get. At a glance, heaviest amounts should end up east of a line from Hays to Garden City, but even areas out near the Colorado line should get something. The rest of the week continues to be quite warm and will be leading up to the rain chance.

Timing: Not much rain expected at daybreak Saturday, but chances go up quickly into the afternoon. This is NOT a big storm for the Plains and the amount of cold air is severely lacking, so we aren't spending . 

Best chances: 5pm - 3a.m. Sunday

The rain will keep pushing east Saturday night. 

Forecast amounts:

Should be safe to set expectations around .50", but I am fairly certain amounts will go higher than that, especially over the eastern half of Kansas. This would be very helpful for next years wheat crop, along with diminishing the fire threat for a bit. 

Next week - Thanksgiving travel:

Considering the setup across the country for next week, I think the weather looks good (finally a WIN in 2020, right?) There should be some rain moving across the southeast US, and maybe some messy weather in the Pacific Northwest (rain and snow), but I don't think a big storm will setup next week. Much of the Plains will likely have sun and above normal temperatures once again. Most of us are probably limiting our travel, but getting around the immediate area won't be much of a challenge. 

Our winter forecast comes out Saturday night on the KWCH at 6:30pm. I will also have a write up here on the blog so you can read more about what our thoughts are for the season. Have a great day.