Wednesday, December 8, 2010
Lake Erie Is Falling On Paris
Yes you read that correctly Lake Erie is falling on Paris...well the Paris of Appalachia anyhow. Lake effect snow. I have been watching the radar now for about 3 days and it always looks exactly the same, winds from the northwest blowing across Lake Erie and dumping snow on the areas south east of the lake. Even the weird patch of snow-freezing rain-rain south of Long Island has been in the same place for days. It is like the radar broke down so they just keep showing the same image from 3 days ago.
This is pretty much an annual event in December. For we Parisians Of Appalachia, lake effect snow is somewhat of a nuisance but certainly not the ordeal for which the Mistake On The Lake (old Steeler fan term for Cleveland--not a fan myself...so I see nothing particularly mistaken about Cleveland) or Buffalo must contend. Being on the very south eastern reach of the lake effect snows, we will receive on the order of an inch or two a day verses an inch or two hour for the snow belts. What amazes me is the persistence of the winds that drives lake effect snow. The winds can remain precise in their path for days, resulting in weird bands of places with heavy snow fall bordered by places with little or no snow. The effect is much more dramatic in the snow belts on the lee side of the lakes, but we get it down here as well.
There seems to be a tendency for strong low pressure systems to park their asses over Labrador, gain strength, and sit and twirl in a counter clockwise direction. It then creates these remarkably persistent strong winds which cross the lakes from the northwest. Looking at the Current Systems map, note the two low pressure systems one east of St Johns, Newfoundland, and the other in far northern Quebec. Due to the fact that I am still waiting for my degree in meteorology to come from that off shore university that you have never heard of, I am not quite sure which of these two system is the source although I suspect it is a combination of both.
Incredibly it turns out that lake effect snow requires a number of factors or it does not happen. I read about this in Wikipedia and I was surprised at what it takes to get lake effect snow. The simple version, strong winds, cold air and a warm lake. That warm lake is relative to the air temperature, no one is swimming in Lake Erie right now. The more complex answer which involves a lot of 50 cent words can be found here:
Wikipedia, Lake Effect Snow
What I did find interesting is that there is an altitude component to this. The air needs to be 13 Celsius degrees cooler than the lake at altitude of roughly 4,900 feet. Apparently that altitude is the ideal barometric pressure for the formation of the snow. A lot can go wrong and the snow won't form--what a pity. So the fact that we get so damned much of it seems to indicate that much does go right for the creation of lake effect snow.
There is an old adage about Pittsburgh, "if you hate winter, you will hate Pittsburgh, but if you like winter, you will hate Pittsburgh." We get a lot of what a friend from Georgia calls "typical Pittsburgh shit weather" half rain, half snow, snow on the ground from mid-November to early March but not enough to make a snow man. It is usually over cast all winter long and it turns out that much of the cloud cover is lake effect clouds. It seems that we who live close to the Great Lakes are more likely to suffer from S.A.D.--seasonal affective disorder, a name seeming contrived to fit the acronym. It is very prominent in Russia and the common cure is vodka. There is some sort of fancy light that you can sit under that is supposed to counter the affect. My own cure for S.A.D. is to insist that we leave the Christmas tree up all winter. It doesn't come down until Easter, and I find that it cheers me up. I am not sure what it does for my wife who earlier in our life together would want me to bring the boxes down from the attic in mid-January. I always found some half assed excuse and would put it off. Finally one year she became insistent and I refused claiming that I suffered from S.A.D. and wanted the tree up. She seemed to accept that in the odd way that people who have been married for a long time will know what battles not to fight. Some time around the vernal equinox, I will forget to turn the lights on the tree for a couple of days and she then states with some authority that the boxes are coming down this weekend.
One advantage that we shovelers of Lake Erie have over the other Great Lakes is that Lake Erie, due to its shallow depth, will eventually freeze over. No more lake effect snow, although the clouds persist at least here in Pittsburgh.
Pittsburgh is blessed with a lack of natural disasters. We don't, for the most part, have tornadoes, hurricanes, droughts, extremes of heat and cold, horrendous rains, mud slides, floods, fires, Santa Anna winds, or earth quakes. If we do have an occasional event, it is usually very moderate compared to Oklahoma City, New Orleans, or Los Angeles. I suppose in payment for our blessed lack of natural disasters, what we do have is a whole bunch of mediocrity. Pittsburgh shit weather in the winter, and not a lot of nice days in the summer. It is usually uncomfortably warm and humid in the summer but not excessively so. I suppose one could say that Pittsburgh is a rather dreary place but not a particularly dangerous place.
Every so often Pittsburgh wins some sort of Most Livable City rating. I am not sure who decides this, but I am almost dead certain that they don't live here.
Here is this morning's radar map. The two tendrils coming off Lake Erie into Western Pennsylvania have been constant for the past 24 hours. There is evidence on the one wind stream up in Lake Huron.
1. & 4. Screen print of radar.
Intellicast.com Current Radar, Binghampton NY
2. Canadian Current Systems.
The Weather Network
3. Warm moisture rising to 850 mbar to create lake effect snow.
Wikipedia, Lake Derived Snow