Sunday, June 14, 2020

The continued inanity of June 15th

Nine years ago I railed, twice in the same month, about the silly season of talk about the monsoon. In the second of those June 2011 posts I wrote (misspelling site for sight):

Suppose that someone had lived in Tucson for a couple of decades, then fell into a Rip van Winkle sleep for another couple of decades, and finally awoke last week. Rip van Winkle would be bewildered to hear that the monsoon starts Wednesday, and that, alas, despite the approaching start date there's no rain in site (as if rain in site would be normal for this date in June). As terrible as the wildfires have been this year, and as good as it would be to get enough rain to relieve the situation, that's not a realistic hope this early.

The difference this year is that June 15th arrives on Monday, not Wednesday as it did in 2011. It's still silly to talk about the monsoon starting on June 15th, despite a decade of the National Weather Service pretending otherwise.

At this point it might be enough to say, "See previous posts." But following after this April's remininiscing post, this post goes back forty-some years to the weather station at Davis-Monthan Air Force Base here in Tucson. Since the stations's weather radar and human eyes both had a relatively clear line of sight to the south, at this time of year it would not be uncommon for the weather observer to include in a late afternoon or early evening hourly weather observation an uncannilly precise remark that a thunderstorm cloud was being visibly observed 95 miles to the south. So there was no ignorance about moisture pooling in Mexico. But when a trough in the westerlies would briefly pull some of that moisture north and generate a thunderstorm or two, customers would be briefed that, "That was not the monsoon." Emphasis was on the long-term correlation between the north-to-south transition from dry to moist air and the north-to-south transition from westerly to easterly upper-level winds. Thunderstorms, at least scattered coverage, moving generally from east to west, day after day (or at least most days)--like pornography, Tucsonans know what they expect from the monsoon. And until recent decades forecasters understood how to tailor and communicate their monsoon call for locals.

I have no qualms about a firefighter labeling the entire difficult month of June as a nebulous and agonizingly long period known as "at the start of the monsoon." But I doubt a firefighter would insist that the lightning strike on the evening of June 5, which sparked the Bighorn Fire, was "not the monsoon" while at the same time insisting that a lightning strike tomorrow evening would be "the monsoon." That would be just silly.