What Summer? A Recap of July.

Where has the summer gone, or rather, where was our summer and did we just skip it this year? July was abnormal with near and sometimes record cold for much of the Midwestern United States along with irregular precipitation patterns for summer. The year with abnormal weather patterns continues as summers upper atmosphere continues after irregular patterns in both winter and most notably, spring. The lack of severe weather for not only places like the plains but also the Midwest. The Athens area also saw a large decrease in the amount of thunder so far this year. June was an especially quiet month with thunderstorms down over fifty percent. This was because of the ridge/trough pattern that developed during the early part of July refused to give way to the typical early summer pattern but reinforced with a trough across the eastern United States.

Here are the temperatures and precipitation for July 2009 in Athens at Scalia Laboratory.

Temperatures

July was much below normal for the Midwest and Appalachian region including Athens. The average temperature for the month was 70.8 degrees. The average temperature for Athens is 72.7 degrees. That would make this year 1.9 degrees colder than average, which breaks the trend of warmer than average July’s. In 2008 the average was 74.2 and in 2007 the average was 74.3 both nearly 2 degrees warmer than the typical 30 year average. At the neighboring National Weather Service observation site across the border in nearby Parkersburg was much below average, in fact 3.6 degrees below average. The average temperature for the site is 74.6 degrees while 2009 was only 71.

The jetstream set up in the early part of the month was a major factor on the temperatures, clouds, and rainfall pattern for the month of July. Here is the pattern, very similar to one of late winter/early spring, that was in place:
The typical high temperature for a day in July in Athens should be 85.6 degrees. The actual average high temperature for July 2009 was 79.9 degrees, that’s -5.7 degrees below normal. Usually the 90 degree mark is hit several times throughout the month but this year was anomalous as the 90 degree mark was never hit. The closest Athens came to that mark was on the 16th when the temperature reached 88, still two degrees away. The second highest temperature recorded in July was 87 on the 10th. In July of 2008, the Scalia Lab’s instruments measured temperatures at or above 90 five times. Parkersburg hit 90 once in 2009 on the 16th (the same day as Athens July high of 88) with a high of 91.
The average low temperature for July was 61.7 degrees. This was actually 2 degrees above the normal of 59.7 degrees. While Athens did not set any record lows for July, Parkersburg set an all-time record low of 50 degrees on the 14th of July that broke the previous record of 52 in 2001. The lowest recorded temperature in Athens was 53 on the 15th.

Here is a map of the United States showing how the average temperature of each state compared to the normal average for July:
A more detailed look at the records set within July throughout the United States along with the above map can be found at NOAA's website located HERE

Solar

Clouds were very abundant with the trough that had established itself over the east United States as systems brought around more moisture to the upper levels of the atmosphere. Clouds keep the surface of the earth cooler during the daytime, but during the overnight they do the exact opposite. The clouds prevent the escape of radiational heating from the surface of the earth. They act as an insulator to the surface keeping the atmosphere warmer than it would be if it was a clear night and heat can escape into space. So while the clouds kept the daytime highs much cooler than normal, they kept the overnights warmer than normal. The large amount of cloud cover can be seen when looking at the solar radiation from this July compared to last July (2008). This year the average daily solar output was 1058.71 microwatts, while last year the average was a whooping 1168.67 microwatts. That’s down nearly ten percent from 2008, meaning many more cloudy days than the previous year. This can also be blamed for the decrease in afternoon temperatures. What is most surprising of July is that with the added clouds, decreased temperature, and spring-like pattern there was a lack of rainfall for the month.

Rainfall

Rainfall for the southeast Ohio region varied much like it does in summer from place to place remaining very isolated with steady normal amounts. Athens received 3.29” of rain in the month of July. This was .96” less than average. Nearly eighty-five percent of that precipitation occurred in the last nine days of the month when 2.83” of rain fell. This occurred as the trough in the eastern United States began to break down and typical July thunderstorms moved over the area. This rain came fast and within short amounts of time as the rain only fell on seven of the last nine days. To show the isolated type of summer precipitation, neighboring Parkersburg received 5.85” of rain in July, 1.65” above normal. The majority of the precip (4.19” of it) came within the last week with rain on five of those days. In 2008, Parkersburg only received 2.02” of rain while Athens got 2.49” in only six days of rain during the entire month.


Christopher Redmond
cr898005@ohio.edu