Good morning bloggers and Happy Chanukah!
Tis the season to discuss what is going on with this weather pattern. While we watch video of snow falling in Seattle, Boston, Houston, Las Vegas, New Orleans, Chicago, Minneapolis, and many other places it makes one wonder what is going on? This weather pattern is just fascinating, frustrating, exciting, and yet leaves us wondering what is really going to happen this winter. Will we have a big winter storm, or will they all be small and quick moving? I still believe it will all come together at least one or two times this winter where we see significant snow either in this cycle or the next one as described by the LRC.
Jeremy posted this satellite picture from yesterday afternoon. This shows that I-70 is right near the cut off for significant snow on the ground and it was a factor with the low temperatures this morning as KCI airport dropped to 3 below zero, but it was just above zero south of I-70.
There are two storm systems and a fast moving disturbance that will affect us this week. We believe we are in around a 50 to 53 day cycle give or take a few days. In October into November when the LRC was just setting up these storm systems were a bit larger and more organized than they are showing up in this second cycle. This doesn't mean that this disorganization in our part of the nation will continue. Let's look at this next storm heading our way. We are going to look at some complex maps this morning at the 500 mb level. Just look for the big X located just south of Dodge City on this 48 hour GFS forecast valid mdignight Tuesday night:
There will likely be a band of 3 to 5 inch snowfall amounts along and north of this upper level storm track. The X is what we call a vorticity maximum, or "vort max". This vort max is a fast moving shortwave in the flow. When vorticity is increasing along the flow we call it positive vorticity advection or PVA. There is some strong PVA approaching the area Tomorrow night, but it will be fast moving. Along and north of the vort max is where most of the lifting to produce precipitation will be located. South of the vort max will likely be a strong dry slot and the precipitation will be shut off and the air will sink. So, this is why the track of this vort max is so important. And, can you see how hard it will be to forecast whether or not we will see snowfall accumulation on Christmas Eve morning. Look where this is forecast to track on the next map:
This GFS model run is forecasting the vort max to track right near Kansas City. If it is correct then we would have snow accumulate on Christmas Eve early morning, but some of you may miss this if it tracks just north of you. Let's look at the new data this morning and see what the trend is on the track and other features that are trying to come together.
And, now, let' look ahead to Saturday's storm system. Again, look at the bix X or vort max forecast for noon Saturday. This is oriented a bit differently than the earlier in the week storm, but still somewhat related at the same time.
Happy holidays everyone. This is going to be another rather wild and crazy week of weather. I will try to update the blog later this afternoon after we analyze all of the data.
Gary