There was a good comment in the blog yesterday broaching a subject that often comes up during periods of dry weather – is there a geologic feature in the area that makes storms split? Delahny asked it this way:
“We live between Rudolph and Versper. We have watched storm after storm and radar image after image create a virtual bubble around us – storms to each direction but overhead. Is there some geologic feature, some meteorological reason, something which causes this phenomena?”
The short answer is no. If Rib Mountain, or Bruce Mound, or Powers Bluff caused storms to split up then thhose areas near the geologic features would be very much like a desert because there would hardly be any rain during any year. The hills around Northcentral Wisconsin are not big enough to have any significant effect on storms or storm systems. The Great Lakes, of course, DO exert some well-known effects on weather patterns around the Midwest, but even they are far enough away from most of the viewing area to not affect thunderstorms very often. The only features in the landscape that I would attribute to very slight changes in storm paths and/or rain patterns is the gradual elevation change from low sandy open areas of Adams and Juneau counties up to the higher forested areas north of Marathon county. This gradual change in elevation and land character seems to affect the weather a slight bit. I don’t have any scientific data to back this up. It is just an observation based on my years of forecasting around here.
The longer answer is that this topic usually comes up every time there is a drought. It is the nature of most droughts in Wisconsin that there is some rain that occurs periodically every month – but this rain is very hit-or-miss. If the rain was more widespread, there wouldn’t be a drought in the first place. So many locations end up missing out on the few chances of rain during a drought and it certainly seems like something is keeping the rain away, but it is mostly bad luck. Here in Marathon county and Wausau we were lucky for the early part of the Summer. I only had to water my gardens once in June. Unfortunately, the last 2 weeks have not been so great and the storms are missing my gardens. So. it looks like I will have to water this afternoon.
There is a chance of storms on Saturday, so I could maybe wait to water, however, I am not 100% certain the rain on Saturday will be widespread. There will be high humidity and the storms could be strong but they might also be fast moving. I figure if I water today, then any rain on Saturday will be a bonus.
Another drought related discussion that has bubbled up nationally is whether the current heat and drought is being caused by anthropogenic global warming (AGW). The latest US Drought Monitor shows about the same drought conditions across the nation as last week, although in Wisconsin we have seen some small improvement. Repeated rounds of thunderstorms have caused the areal extent of extreme drought in southern Wisconsin to shrink.
The question remains: Is the the drought being caused by AGW? I have to give credit to environmental reporting and climate scientist statements for being more true to science lately in stating that, yes, according to theory, this type of event is what one would expect in an AGW world, but what really matters is the trend throughout many years and decades. It is more likely that AGW theory is on solid ground if we see an increasing trend in heat and droughts. And, that is why there is sometimes some bitter disagreement about the instrumental record. A few of these disagreements have made headlines recently.
I blogged about Richard Muller’s recent findings a while back. He was formerly a bit more skeptical about AGW theory but now he is more confident that it is true. First, he looked at the instrumental record in order to filter out possible bad data (such as thermometers affected by the urban heat island effect – which is dramatic). He found that there was not too much difference when the potentially “bad” temperature data was filtered out. There was still solid evidence that temperatures increased noticeably during the 20th century. He recently also looked at the correlation between CO2 emissions and the temperature rise and found a very good correlation, therefore he is now very confident of AGW theory.
Then you have some citizen bloggers and scientist who are more skeptical of the temperature record and don’t trust the data being released by government sources. Here Steven Goddard shows some of the differences in temperature trends over the years and suggest there might be fraudulent manipulation going on by the scenes. Even I, a person who accepts that humans are affecting the climate and temperature trends to a certain extent, had to go hmmm? after looking at the data. James Delingpole and Anthony Watts have also recently jumped on some of these changes in the “official” temperature record.
At first glance, this of course looks very suspicious. However, I suspect there are some logical valid reasons relating to statistical filtering of the data that have caused these changes in the official record (and the graphs). Sometimes there are even honest mistakes. I can assure all the readers that any changes in statistical methods, tabulation, and modelling are usually very open and transparent. Almost all of the data you see reported in mainstream sources has been through a robust peer review process. If I (or you) had enough time, we could dig through all the published papers and find the reason why each change was made and how this led to changes in the temperature trend/graphs over the last couple of decades. The odds that there is fraud is fairly low.
Have a swell Thursday! Meteorologist Justin Loew.
This post was written by jloew on August 2, 2012