Good morning bloggers,
NBC Action News Meteorologist Jeremy Nelson from Saturday, "If the model trends continue in the direction they are currently at, this buzz may become a roar by the end of the weekend". Well, what happened? The model trends went the other way! And meteorologist Jeff Penner goes into something that is worse than "modelitis" on www.LRCWeather.com. Let's go over this early week storm:
There are several somewhat disorganized parts to the storm heading our way. Part #1 is a wave of energy being ejected out from the southwest. This disturbance will pass by us overnight and be past Kansas City by Tuesday morning. Part #2 is the evolution of a middle of the nation trough, but as you can see below it is forecast to be positively tilted (tilted from northeast to southwest):
These maps are from the 06z GFS run. There is still a disturbance trying to separate and be its own entity, which is hard to do in a positively tilted trough. I pointed the arrow to the big X or vorticity maximum forecast by this model run to be over Oklahoma later tomorrow. But, because the trough is so positively tilted look at what it does to the other levels of the atmosphere. I am using the 850 mb flow to show the problem for our snow producing potential. Notice, below, that even this 850 mb trough is positively tilted. You can see this by the kinks in the lines stretching from Michigan to St. Louis to southern Arkansas. The flow is forecast to be north with temperatures cold enough to snow, but this is not a good flow for lifting and snow producing potential. Now, if the upper levels can be a bit more organized, then this level will also be better organized. This is not the trend though.
What does this all mean? Rain is likely tonight as the first disturbance tracks across the region, then it will be cold enough for snow on Tuesday aftenoon. There continues to be the question on whether there will still be any organization left to this storm where snow can be generated later tomorrow. We are going to go with up to around 1 inch of snow, and then as the new data comes in we will update this forecast later today. There is always the potential for this to organize a bit better and we could end up with more snow, and of course the other thing could happen and the snowflake contest may continue beyond Tuesday.
Let's look ahead to the end of the week. The ECMWF has been much more aggressive with blasting us with an Arctic air mass later this week. The GFS has been tame in bringing the Arctic air south. Look below at the GFS forecast valid at 6 PM this coming Saturday:
This GFS forecast is showing an Arctic front stalling and perhaps barely sagging south across Nebraska. It will be difficult for the front to stall as the Arctic air mass is growing in size and strength. We will talk more about this as the week progresses and on our newscasts today and tonight.
Gary