During much of last week, a heat wave built across areas from central Argentina into Uruguay with temperatures in some cities topping out near 42 C (108 F).
The clashing of the hot, humid air currently over the region with cooler, drier air to the south led to a round of thunderstorms Monday night into Tuesday across northeastern Argentina and Uruguay, including the cities of Buenos Aires and Montevideo.
In this Thursday, Dec. 26, 2013, photo, teenage girls cool off in a water fountain in Buenos Aires, Argentina. An intense heat wave was felt across much of Argentina last week as temperatures soared above 100 degrees. (AP Photo/Victor R. Caivano)
By Tuesday night and early Wednesday, the storms had shifted north of Buenos Aires and Montevideo.
The break from stormy weather for both cities will be short-lived as another front will quickly approach from the south.
This second cold front will cross central Argentina during the day on Wednesday then continue northward on Wednesday night.
Along and ahead of this front, strong to severe thunderstorms are likely to erupt with the strongest storms containing flooding downpours, damaging winds and hail. The severe thunderstorm threat will again include Montevideo and Buenos Aires.
Gusty storms with heavy rainfall will be possible from late Wednesday night into early Friday morning.
Rainfall amounts will average 25-50 mm (1-2 inches) with local amounts up to 100 mm (4 inches). Wind gusts over 80 kph (50 mph) will be possible in any of these storms.
People look at damage caused by the collapse of a building's roof in Buenos Aires, Argentina, Thursday, April 5, 2012. As many as 11 people were killed after thunderstorms brought strong winds and hail overnight. (AP Photo/Rodolfo Pezzoni, DyN)
The cold front will gradually march northward on Friday which will bring the threat of more heavy thunderstorms with flash flooding and damaging winds across northern Uruguay, southeastern Brazil and far northern Argentina.
Behind the second front, relief from the heat and humidity is likely as a push of cooler air penetrates deeper into central South America.
Meteorologist Eric Leister contributed to this story.
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Savannah, GA (1999)
6.60" of rain.
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Heavy and frequent rainfall continued. Oklahoma City had a 17th straight day of rain, with 10 inches total for the month. Normal is just over 4.5 inches for the entire month. Houston, TX had 19 days of rain so far in June totalling 5.47 inches, slightly ahead of the normal 5.35 inches. Dallas, TX also had 19 days of rain so far, totally 11.01 inches, normal for the month is 3.23 inches. Wichita Falls, TX had 21 days of rain, bringing 7.82 inches, the monthly normal is 3.69 inches.
Dramatic cooling behind a cold front from the 28th to the 29th. Philadelphia dropped from 89 to 77. Boston fell from 92 to 77, Providence from 92 to 74, and Portland, ME from 89 to 73. Atlantic City, NJ dropped from 93 to 76.