The historical chance for an October 100° day is a mere 0.7%. Tucson comes awfully close to cashing in on these slim odds this week.
Highs today reach the mid 90s. Temperatures rise to the upper 90s tomorrow through the weekend, courtesy of high pressure building in from the east. Daytime temperatures Thursday into Saturday come a degree or two within reaching 100°.
Since 1894, there have been only 28 October days at or above 100° in the Old Pueblo.
As Tucson heats up, areas east of the metro may see a few storms Wednesday and Thursday. A storm system north of the state taps into enough moisture to trigger the mid-week thunder threat.
This weekend and early next week features high pressure loosening its grip on the Grand Canyon State. Sunshine prevails, but temperatures drop to the low to mid 90s by Monday.