Here it is in plain English: the longer you're out in the Plains the better your odds of seeing tornadoes. However, with each passing year we are finding that more and more folks simply cannot take off enough time to commit to a 10-day tour and our short tour formula has become, by far, the more popular. Hence, beginning in 2012 we will be offering only two 10-day length tours and will be greatly expanding our slate of 6 and 7-day length tours. While it is true that your odds of any given "short" tour witnessing tornadoes will correspondingly decrease, the data does NOT suggest that the probabilities will be dramatically lowered. And you'll still get the same great, genuine storm chasing tour experience that you've come to expect from Silver Lining Tours.

Here is a separate article explaining some of the trade-offs of chasing in the "early" versus "late" season storm chasing.

More about the 6-day summer tours:

Come chase the high plains and northern plains during their peak severe weather season of June and July. Your tour guide will be the legendary Roger Hill, widely recognized as one of the most experienced and successful chasers in the nation. Roger will be taking you through some of the most extraordinary scenic regions of the United States in search of severe weather of all kinds. Eastern Montana, the Dakotas, the high plains and upper Midwest experience a significant amount of severe weather, including supercells and tornadoes, during this time period. Each of these tours will begin and end in Denver, the heart of this chasing region. You will have 6 full days of chasing, with your tour beginning and ending on Saturdays, which are designated travel days arriving and departing Denver.  These tours are designed for those who cannot take off enough time for a 10 day tour, are looking for a later tour, or simply want a less expensive tour. Or, they are for you have always wanted to visit the northern and high plains and corn fields of the Midwest but haven't yet. Thus, if you're adamant about maximizing your odds of seeing great storms, go for one of the remaining 10-day tours or two consecutive 6-day tours (for which a fairly sizable multi-tour discount will apply). For more information please contact Dr. David Gold or Roger Hill . You won't be disappointed! Dr. Dave will be providing weather data to Roger as needed during all tours.