A weekend of possible thunderstorms, bad luck

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This is one of those weekends when the sky could mess with a good time.

Numerous events of the kind usually held in late spring – the Untapped Festival, University of Texas softball, the high school state track and field championships, Jmblya 2016 Austin – will be under threat of thunderstorms. Saturday will actually be mostly sunny, but it also carries with it a 40 percent chance of thunderstorms and rain, according to the National Weather Service’s forecast on Friday night. By Saturday evening the weather should be mostly cloudy, with a 30 percent chance of thunderstorms.

Those odds of rain and thunderstorms rise to 50/50 on Sunday. Remember, a 50 percent chance of rain means that there are even odds that rain will fall on a given place during the 12-hour period.

(I’m giving a 20 percent chance of headlines along the lines of, “Rain doesn’t dampen the spirits of festival goers …”)

This has been a weird last six months — we miss you, Mark Murray! — and State Climatologist John Nielsen-Gammon says there is some evidence that Texas weather has gotten more extreme. But the severe weather that could hit Saturday is not out of character for Central Texas this time of year. May is the month with the most severe weather: thunderstorms, hail and tornadoes. And remember, Mercury is in retrograde, which could means this weekend is going to be unlucky or could mean absolutely nothing at all, depending on whether you believe astrologers or scientists.

Sick of the rain? Well, that’s understandable. The Highland Lakes, primary reservoirs in the Austin area, area nearly full, and the ground is saturated. But don’t get too used to it. Summer is probably also going to be mild. But this fall, when the El Niño weather pattern in the Pacific gives way to a La Niña, we could slip back to the days of the hot and dry.

Mercury’s in retro what now? Will May turn out to be just the worst?

I hate to break it to you, Internet denizens, but if something goes horribly wrong this month, it probably is your fault, despite what the astrologers are telling you.

Yes, Mercury is in retrograde, and that is an interesting astronomical phenomenon, one that we’ll get into in a moment. But first: no, there is no scientific evidence linking that phenomenon to your flat tire, bad date or that lost Japanese satellite. Astrologyzone.com may claim understanding retrograde “can allow you to increase your productivity and avoid at least some of the frustration they can bring about,” as well as asserting that Mercury “rules all types of communication” including speaking, reading and negotiating contracts, but the web site cites no scientific source for why your May is going to be so messed up. You should, as they say, consider the evidence before blaming the Mercury retrograde for the next death of a prominent singer.

There is some good astronomical science here, though. Basically, Mercury will appear to be moving the wrong way across our sky until May 22. It looks, to casual observers, as if it reversed its orbit and now goes around the sun in the other direction.

That’s not actually the case. It’s an illusion caused by the fact that Mercury, being much closer to the sun, rotates around it faster than the Earth does. Several times a year, the relative position of the Earth and Mercury make Mercury appear to be going backward. NASA explains it with the following example:

“Start out standing side by side with a friend. Have a friend walk forward slowly. Now you walk forward at a faster speed. Watch your friend and think about how they are moving relative to you. At first, they move away, then as you pass them, they APPEAR to be moving backward relative to you – even though they are still walking forward.”

(A few years ago NASA put together a graphic about how this phenomenon

Imagine courtesy NASA. This is actually a depiction of Mars retrograde, but the general explanation holds.
Imagine courtesy NASA. This is actually a depiction of Mars retrograde, but the general explanation holds.

works with Mars.)

This particular Mercury retrograde — apparent retrograde, it should be emphasized — comes with another bit of interesting astronomical phenomena, said Keely Finkelstein, a research associate and lecturer in the University of Texas’ Department of Astronomy. Mercury will pass between Earth and the Sun on May 9, an event that occurs only 13 times every century.

“You’ll need decent equipment to view the transit, but this will be a real astrophysical event, where interesting science can be done,” Finkelstein said. Mercury will appear to be a small dot against a very bright object, so the naked eye won’t work, though NASA will be streaming a live program through its TV station and Facebook page.

This Mercury retrograde will last until May 22. Some people suggest waiting until the retrograde is over to move, apply for a new job or buy things. The advice is debatable. Until then, I guess it couldn’t hurt to follow one piece of #mercuryretrograde advice, if only because this is Austin: