THE HAIR OF MY CHINNY CHIN CHIN...
Another winter storm has come and gone. According to the Iowa Mesonet, this was the 13th to impact some part of Iowa this season. For the most part this one had minimal impacts in my area outside of the far NW where 1-2 inch snowfalls were noted along a line running from approximately Cedar Rapids to Dubuque. Much larger totals were found just to the west with a healthy 6-10 inch band blanketing much of the NW half of Iowa. We missed the big stuff by the hair of my chinny chin chin. Dang, we can't buy a good snow around here! Take a look.
This larger perspective shows as much as 23.7 inches in Merna, Nebraska with the snow band extending from Colorado to northern Wisconsin.
The path of Wednesday's storm through SE Iowa has been the preferred track all winter long. Look at the range in seasonal snow from NW to SE over the state. Some places in SE Iowa have not even had an inch, while Sibley in the NW has had 42.40 inches! Can you believe that? The spread from Le Mars, Iowa to Sibley, a distance of 58 miles is 36 inches...that's less than an hour's drive!
Here's the seasonal snowfall departures through January 19th. The majority of my area is 7-11 inches below normal. Sibly, is more than 30 inches above it.
By the way, my sister who lives north of Waverly, Iowa sent me this picture of the 7-8 inches of snow she shoveled Thursday morning. She knows I'm a snow freak so she rubbed it in good. If you love snow, don't live anywhere within 100 miles of me. I am the blackhole of white gold. Man, it gets frustrating! I can't even tell you the last time I saw more than 4 inches of snow in a single storm but it's been years in this area. Cry me a river...
AN ACTIVE PATTERN WITH RUMORS OF SNOW
Friday and most of Saturday remaon snow free but a minor disturbance Saturday night looks like it could kick up some light snow over most of the region. Moisture is marginal and so is any prolonged forcing so this appears to be another one of those systems that brings just enough snow (an inch or so at best) to be a nusiance. For now, here's what models are suggesting for snow accumulations.
Things get more complicated Tuesday of next week when another batch of energy is shown ejecting out of the southern Plains. The degree of phasing between the northern and southern branches of the jet will determine if this becomes a snow producer in my region. (For sure, rain is not an issue with this storm). Phasing and its ability to alter moisture and energy is something that models traditionally have a hard time with, especially at this distance. A more phased solution would be necessary for the surface and upper air features to track far enough north to impact any part of the area with snow. The deterministic GFS indicates that possibility and brings several inches of snow into eastern Iowa and the NW half of Illinois.
The EURO is the least phased and is too far east to allow for anything more than snow showers in far SE Iowa and WC Illinois. Basically a miss.
Finally there's the Canadian solution which is closer to the GFS bringing several inches of snow to mainly the SE half of the region.
It is absolutely too early to know if anybody shovels or we just watch this thing move harmlessly off to the east. The way things have gone around here this winter I certainly wouldn't hold my breath. However, the threat is out there and it's an issue that will be addressed in coming days.
There is no doubt that we are gradually transitioning to a colder pattern that will hold into the start of February. The most likely time for the coldest readings is around the period January 26th-February 2nd.
The Canadian is the coldest with 7 day mean temperatures like this.
The GFS has this.
The EURO is the wamest today with this.
It does appear that the cold will break again shortly after the first as a strong ridge builds over the SE U.S. That promotes SW flow and another upwards trend in temperatures in early February.
The last thing I will leave you with is this. I talked in a recent post about the stretching of the polar vortex in the stratosphere and how that can set the stage for Arctic outbreaks. I'm no expert on this subject so keep that in mind. What I have learned is that when the polar vortex is stable, the coldest air in north America resides near it, generally in the vicinity of the North Pole. Today at 10mb, the highest level of the atmosphere temperatures near the pole are minus 78. Brutally cold.
10 Days from now all the purple has been displaced to the south and readings are shown warming from -78 to -25.
The theory is that the rapid warming over a few days disrupts the intense circulation of the polar vortex descelerating the speed of the westerlies and in strong events reverses the flow entirely to easterly. The weakened flow allows air to descend into the vortex where it's compressed. That generates compressional heating which can warm the air 50 degrees in a matter of days. It also sets the stage for the warming to sink south reaching lower altitudes where our weather occurs. The cold air that previously existed within the polar vortex is forced elsewhere as the weakened polar jet buckles. That is how a strat-warm delivers Arctic