Hot July
In a few days the Weather Service in Tucson will issue a summary specifying, to the nearest tenth of a degree Fahrenheit, exactly how much the average high temperature this July exceeded the current 30-year average. While that number alone should make eyeballs pop, consider also the frequencies of the highs that will have contributed to this month's average. At the Tucson Airport through July 28, the number of days with high temperatures: 1-110, 1-109, 3-108, 1-107, 3-106, 4-105, 2-104, 6-103, 1-102, 3-101, none exactly 100, and only 3 days less than 100. That distribution occurring in June would still be a bit on the warm side for that month, but not so unusual. And in June it is a dry heat, with a good cool off at night. In contrast this month's humidity has been at monsoon levels for the last few weeks. But the rain amounts have not.
When averaged over the years the monsoon daily rainfall peaks this week, and then begins to taper off, slowly at first and then more rapidly toward the end of August. But this July when the upper high has been in its good position to the north it has been too broad--too warm aloft and on most days not enough vertical wind sheer to support organized lines of storms sweeping across the area. Things may change for the rest of this week.
The fact that on average the monsoon peaks about now may not be entirely coincidental with the fact that today, July 29, is Rain Day in Waynesburg (where I was born), Pennsylvania. Don't think they've had any rain yet today. But a sprinkle just before midnight tonight would count, and they may get that.
