I have heard radio talk show hosts and politicians make all sorts of jokes about Global Warming as much of the United States get slammed by snow storms. They could be right but, then again, it might be a good idea for them to check out the facts before they speak. See, our opinions are limited on what we know and for people in the eastern United States, what we know is that it has been colder and snowier than normal which runs counter to what most people consider global warming. Philadelphia, Washington DC and Baltimore all have not only exceeded their average annual snowfall totals but also have broken annual records. The midpoint of winter was just passed about 10 days ago and spring time often produces big snowstorms. Louisville is probably fairly representative of much of the northeastern quadrant of the US if not parts of the South as well in regard to temperatures.
According to the National Weather Service’s National Snow Analysis, the snow cover of the United States as of February 11 was about 63.5% of the nation with an average depth of over 8 inches. If you look at the Louisville archived climate data, you find that Louisville has been much cooler than average going back to July 2009 when for the first time in recorded history, Louisville did not have a 90 degree day. Keep in mind, that 3 years ago Louisville moved the official recording site from the National Weather Service to the airport after over 30 years and the airport routinely has higher temperatures. There were bureaucratic reasons for the change but it generally will skew temperatures warmer and unless a climatologist is aware of the switch, then they might conclude that Louisville is a great example of global warming. Nevertheless, in spite of the switch, no 90 degree temperatures in July 2009. every month since then has been colder than average except for September 2009 and November. In most cases, the degree of colder monthly temperatures has been pretty dramatic, such as the July 2009 departure from normal coming at at negative 5 degrees. January 2010 featured 13 days of consistent below freezing temperatures but a week long warm up resulted in January’s departure from normal only coming in at negative 2.9 degrees. So far, February has been some 5-6 degrees below normal with no real warm ups in site for at least 10 days.
What is going on is that the long wave pattern has been generally stuck. There has been a consistent ridge over the Atlantic extending all the way to Greenland. The result has been the eastern part of the US has been in a generally persistent trough that allows the Arctic air to spill down at times to the Gulf of Mexico and there are not the normal fluxuations. Now, this is an El Nino year so we expect some variations to the norm. But, here’s the interesting thing: According to the Univeristy of Alabama at Huntsville’s data, January 2010 was the warmest month globally was the warmest January since they began making records using satellite sourcing. How can this be? Europe has also been in the grips of a deep freeze and heavy snow all winter. Dr. Roy Spencer of UAH has never been accused of being a Global Warming chicken little. He has worked tirelessly to analyze the climate from a non-political view and so he has been the target of much criticism from the left. So, his January report should not be dismissed by anyone. Spencer explains that the long wave pattern has been such that the cold pattern has been over land masses while the oceans have largely been dominated by a warmer pattern. The North Atlantic ridge I described is an example.
I have been critical of “pro global warming” news reports based on data from the National Sea and Ice Data Center (NSIDC) in recent years that always say that the Arctic ice was the 2nd or 3rd lowest when, in fact, the sea ice at the North Pole has been growing. Yes, it’s low but it has been coming off its recorded historic lows so the headlines could say that its growing but instead they take the negative angle. I’ve been tagged derisively as a “denier” when, in fact, I am looking for truth not trying to join a team. In that spirit, I should note that the ice growth trend seems to be slowing for the moment. In January, the total ice cover was greater than the lows of 2006 but, it is less than 2009 which is a break in the trend of growth since 2006. To be sure, one month does not a trend make and nothing can be construed one way or another from this single month. But, it is interesting in that the Pacific side of the Arctic really has an ice extent beyond the long term average. But, it’s the Atlantic side that has come in low. That same ridge that has given Louisville and the rest of the east colder and snowier conditions has resulted in warmer conditions, thus reduced ice growth.
What does all of this mean? I dunno. And, as I’ve pointed out before, the correct response should be I Don’t Know rather than taking a position one way or another. Because no one does know. The earth temperatures have been rising in recent years, but they’ve done so in the past. Is man contributing to the warmth? It’s so hard to say especially after revelations that some of the books have been cooked. If man is the cause can we do anything about it? And perhaps more importantly, should governments try to do something about it? Would the amount of difference from any treaties really make enough of a difference to justify the costs and could that money be used better for a fight against disease or world poverty? I have suggested that perhaps we are neglecting a bigger and real threat, which is the pollution of our oceans, waterways and water sources. But, the lesson here is to recognize that the world is a big place and just because you are having a tough winter doesn’t mean that the world is going into an ice age. It’s the weather…and it changes.
Weather Bottom Line: Global Warming or not, as you can tell from the data above, Louisville has been colder than the 30 year average every month but two since last summer and most of those anomolies have been fairly significant on the down side. I don’t see much of a change. In fact, I still don’t see how we get above freezing Friday and Saturday or even Sunday as some forecasts suggest. We will be close and if we do get above 32, it wont be for long and unless you are a thermometer, it won’t matter. I think we’d get more snow loss from sublimation than from actual melting. And it still looks like we’re going to add to our snow totals. The models continue to be consistent with bringing a shorwave down thorugh the flow on Saturday bringing snow for us Saturday night through Monday with most data suggesting the best accumulations coming on Monday. Some want to carry flurries and light snow into Tuesday. The range in snow totals generally are from 3-6 inches.
If you examine the NAM and GFS graphical snow depiction you can see a striking similarity. The NAM only goes out 84 hours to Sunday evening but you can see what looks like a finger painted line of snow pointing straight to Louisville with about 3 inches or snow pointing to Kentuckiana. The 84 GFS map looks almost exactly the same but we have the benefit of going out 120 hours on the GFS and you can see how it carries out the scenario. As with recent storms, there is a tight snowfall gradient from south to north. What is interesting is that the GFS takes a sharp turn higher in Southern Indiana just north of Louisville with totals up toward 8 inches whereas louisville is in the 4-5 inch range. As I’ve said for several days, I do think that we will get some decent snow but it’s tough to get 8 inches from a storm coming from the northwest. Typically, you need a moisture source like the Gulf of Mexico involved or a storm coming from the Southwest to get some really good snow totals. But, then again, if the shortwave is cold enough aloft it will squeeze whatever moisture it can find right out. So, we’ll see. And I still don’t see how we get above freezing anytime soon.