The first day of significant rain after a long dry period can be very dangerous on the roads. Why?
During the dry period oil, dust and other debris collect on roadways and the addition of water produces a slippery emulsion. After a few days of rain, it washes off. The other issue is that people are used to dry-road driving and driving habits (like taking that corner slower) are slow to change. There is in fact a literature on this first-day-after-a-long dry spell issue--check out: http://www.drivers.com/article/652/ as one example.
So be really careful driving today...I have already received a number of reports of significant local accidents.
