Many cities in the east and central will be reporting top 5 or ten coolest June and July periods in the next few days and we will summarize them. Here is one – New York City’s Central Park.
With an average daily temperature of 72.7...3.8 degrees below normal... This is the sixth coolest July on record at Central Park.
Daily average temperatures have been at or below normal every day but two this month (the 28th and 30th)...for 46 of 48 days dating back to June 13th...and for 54 of the 60 days since June 1st.
Central Park has had only one day reach above 85 degrees so far this summer (86 on July 17th). This is the fewest number of days above 85 on record at Central Park since records began being taken in 1869. The old record was 7 in 1996.
Central Park has yet to reach 90 degrees this summer…for only the second time on record. The only other year not to have at least one 90 degree day in June or July was 1996.
For the months of June and July...the average temperature in 2009 is 70.1 degrees, making this the third coolest June and July on record in 151 years at Central Park.
It is also the second wettest June and July on record and on track to become perhaps the wettest summer in history. Also Boston's Logan ended with the fourth coldest June/Julys since records began in 1872. It averaged 69.15 in June/July ranking it behind only 1903, 1881 and 1902. Notice all the other years came from the 1800s and early 1900s.
Also note the record cold July in Rockford, IL. Also in other areas of central and northwest IL and northeast IA.
July 2009 will go down as the coldest in recorded history for Madison, Wisconsin (records go back to 1869). The previous record was July 1891. The highest temperature recorded in July 2009 was 82 degrees. This is also a record. The previous record was 84 in July 1869. It was also the coldest ever in Rhinelander, Appleton ands Stevens Point, WI. It was the coldest ever in International Falls, MN.
It was one of the coldest in Indianapolis, IN, and coldest in several other locations in northern Indiana including Fort Wayne. It was the coldest ever in Grand Rapids, MI. It may be the coldest July ever statewide in Iowa. It was the third coldest summer in Kansas City.
It was a cold July in western New York - #2 in Rochester and at the Buffalo Airport. It was the coldest ever in Jackson, KY and Huntington, WV.
The cold was associated with a persistent trough in the eastern and central states with a blocking ridge in northeast Canada and in the Gulf of Alaska.
With high pressure in the Polar Regions, the Arctic and north Atlantic Oscillations were persistently negative in both June and July which locks in the cold trough.
This is the correlation in June and July of temperatures with the NAO, colorized for the negative NAO with blues where it should be cold, and yellows and reds warm.
The AO and NAO are forecast to become less negative or even turn positive, which could leave to more warmth come mid August.
By the way, the South Pole had an average temperature of minus 86.8 degrees F, breaking the July record set back in 1965.