As the spring semester of 2012 comes to an end, I am able to gather all the weather data collected throughout the semester and make climographs to illustrate the trends that took place. There were thousands of temperature records set this semester all over the United States as we experienced relatively warm weather throughout the semester. Also, numbers were down for precipitation numbers as well. I also constructed climographs of the averages for Eau Claire, WI as well as other major cities around the state to see if we had a "normal" year or if there were some anomolies. The first climographs are comprised of the data collected throughout the semester and the ones below are climographs which give the averages for the target city over a number of years as listed above the graphs. These graphs help to make comparisons which can uncover trends wether it be gradual warming or maybe more precipitation. Also, at the end, there is data from the NE for the month of March to see if other regions of the U.S. are experiencing the same trends that we are.
Semeseter Data
January
Right off the bat it is easy to see that the January temperatures do not look right. Look at how often the temperature was above the average January temperature in Eau Claire (11°F). We definitely experienced a very abnormally warm January with the highest noted temperature very close to 60°! Take note of the dominant wind direction throughout the month which was the SE which means that warm air was being brought our direction from the south. Precipitation was a bit below average as well, only receiving small amounts 5 times in January.
February
February was another abnormally warm month as temperatures were consistently above the normal range of 17°F for Eau Claire, WI. We did not record a max temperature as high as we did in January but it was overall, pretty pleasant. The dominant wind direction was from the west and then also the ESE which brought warm air into the region. Precipitation was very low as the only notable precipitation came on the last day of the month.
March
March was once again a relatively warm month with some temperature readings above 70°F! This is well above the average of 30° for the month of March. We got a little more precipitation but still below average for March and the dominant wind direction was out of the ESE which helps explain the warmer trend.
April
The warming trend continued into April but not as noticeable as it was in the previous 3 months. The average temperature for April is 50°F. April brought more showers but still below the average which led to a drought in the area for much of the month. The dominant wind direction was out of the ESE bringing lots of warm, moist air to the region which helped spark more storms.
May
Through 8 days of May, temperatures have been pretty normal for this month. We have gotten precipitation basically every day this month except for the 1st. The winds have mainly been out of the west.
There were a few anomalies which stuck out especially with the temperature. As far as temperature goes, this winter/spring displayed abnormally high temperatures and hundreds of records were set across the country this year in that category. Looking at the predominant wind directions, it seems like we were usually getting winds from the west, south or east in some aspect which the latter two were blowing warm air into the region vs. a northerly wind which would have brought on colder conditions like we are used to. As far as precipitation goes, very little was received between January and March. This could be from the air drying out by the time it reaches our region and not creating the necessary conditions for precipitation. As far as the jet stream goes, we were in a ridge for the majority of the winter/spring which did not allow cold air from the continental polar to descend on us. The months of April and May have seen more precipitation then January, February, and March which is not unusual because we start to get warm, moist air pushed our way vs. having cold, dry air hanging around which is not going to produce precipitation.
Madison, WI averages.
As far as trends go, obviously the warmer months were summer months, the mornings showed higher relative humidity, more rain in the summer months, and more cloudy days a year than clear days.
Milwaukee, WI averages
Milwaukee on average was a bit warmer than Madison with a lower number of extreme temperatures per month. Also, Milwaukee received more rain and had way less cloudy days than Madison. I think that since Milwaukee is close to Lake Michigan, the lake regulates the temperature so you don’t see major swings in temperatures like you might see in Madison.
Local data records for the month of April 2012
The graphs below are averages for the listed city from data gathered between the years listed above the graphs.
Data derived from 1949-1995
Data derived from 1948-1995
Minneapolis/St. Paul - http://www.worldclimate.com/cgi-bin/data.pl?ref=N44W093+2100+72658W
Data derived from 1837-1990
Data derived from 1931-1995
Data derived from 1931-1995
Data derived from 1948-1995
Data derived from 1946-1995
By comparing data to multiple locations, especially those around the same state, you can see how similar/dissimilar your city is to the other ones and can see on a geographical scale, what may be causing differences in the readings i.e. elevation, proximity to water, latitude, etc…Take for instance Superior, the graph displays relatively lower temperatures than the other cities which is because of their geographical location, further north. Milwaukee does not see very large swings in their temperatures because of their proximity to Lake Michigan which regulates the temperatures, and also because they are the furthest south. Minneapolis, Eau Claire, La Crosse, and Wausau all are pretty similar in both temperatures and rainfall throughout the year because they are away from large water bodies and their locations are not that far apart. Data collection techniques can also have an effect on these graphs because the time periods of data collection can impact the temperature readings i.e. coldest temps in the morning, hottest in the afternoon. Types of weather instruments and instrument height also have an impact. Missing data values on certain days can also skew the data.
The graph below is data collected from the Northeast between the years 1895-2012 for the month of March.
The top 5 wettest years were: 1936 (6.56"), 1899 (5.46"), 1913 (5.44"), 2010 (5.17"), 1994 (5.09").
The top 5 driest years were: 1915 (0.71"), 1910 (1.18"), 2006 (1.31"), 1981 (1.36"), 1924 (1.86").
The trend line rides right down the middle if not a very slight downward slope which means that over this period of time, precipitation is on the decline for the month of March.
The top ten coldest years: 1916, 1960, 1896, 1900, 1984, 1926, 1906, 1941, 1940, and 1950…The top ten warmest: 2012, 1946, 1945, 1921, 1903, 1973, 2010, 1977, 1898, and 1910
As a trend, the average temperature for the month of March in the NE is rising between the years 1895-2012. Notice some of the larger outliers (mostly above normal) where the highest average temperatures were: 41, 41, 43, 43, and 44. Some of the larger colder averages were: 25, 25, and 26. This is helpful to study other regions of the U.S. to see if similar trends are going on there as well. A warming climate is just not a localized phenomenon but a trend being witnessed all over.
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