July 2012 hits the record books at the hottest July in Louisville's history!
The average temperature for the month (July 2012) was 84.5°
The average temperature for the month (July 1901) was 84.1°
One other interesting point is that the past three July's rank among the warmest of the hottest five on record.
July 2012 - 1st hottest July in Louisville history
July 2011 - 3rd hottest July in Louisville history (tied with 1936)
July 2010 - 5th hottest July in Louisville history
Do you see a theme here?
POSSIBLE TORNADO IN SOUTHWEST INDIANA
National Weather Service officials will be surveying damage just West of the WAVE 3 viewing area, near Evansville in the town of Oakland City (Gibson County). According to ISP, a tornado touchdown caused damage that has shut down the city.
The severe thunderstorm came through Oakland City ten minutes before a parade started at the Sweet Corn Festival. Four people were injured. One of those injuries was a foot injury and the other three were minor cuts, nothing major. Baseball size hail sent people scrambling. Power was knocked out to over half the town when trees, power poles were taken down by the intense wind. The storm also knocked over grain bins, caused roof damage to several houses, and blew trees into houses. A few houses are destroyed.
RECORD LOW TWISTER COUNT IS DROUGHT'S SILVER LINING
There is at least one upside to the massive drought that covers more than half of the lower 48 states: a near-record low number of tornadoes. In contrast to last year, when swarms of tornadoes killed hundreds during the spring and early summer, this year has seen a flatlining of tornado numbers since June. Through July 23, there had been just 12 tornadoes recorded in the U.S. this month; a record low number. In fact, the U.S. may even break its record for the least tornadoes in any summer month.
The weather has been characterized by a sprawling area of High Pressure over the Central U.S., which has brought stifling heat and much below-average rainfall to a broad swath of the country. St. Louis, Mo., for example, has reached or exceeded 105°F a record 11 times so far this year, which is more than occurred during the Dust Bowl in 1934. During July this year, 3,908 daily high temperature records have been broken or tied in the U.S., and 169 of those records have been all-time high temperature records.
One might think that all of this heat would provide ample fuel for severe thunderstorms. After all, a warm air mass is a main ingredient in severe weather. However, for tornadoes to form, there also needs to be high humidity, strong jet stream winds, and wind shear, which is winds that change direction or speed with height. In July, those ingredients have not come together in the right amounts, at the right time.
The heat dome discourages storms by causing the air to sink, warming as it does so, and choking off any storms. The dry ground also discourages storms by releasing less moisture into the air, cutting down on the instability available for storms to form. The jet stream has been shunted well to the north, across the U.S.-Canadian border, depriving thunderstorms of the wind shear needed to form large hail and tornadoes.
Source: Climate Central