Profile photo of

other than thermometers and barometers that any of us can have

I should have mentioned that those two (particularly the barometer) could be very useful in the overall prediction process. An interesting exercise that would only take a couple of minutes every few days would be to go to Weather Underground (scary name for some of us old enough to remember, though I’ve been assured there’s no relationship to the original organization by that name). At the upper right, enter your zip code (if US) in the “Location” box and hit [Enter].

What comes up at the top is current conditions. Below that is the 10-day forecast. It not selected automatically, click the “Graph” tab (not the “Table” or “Descriptive” tab). Then notice what happens with temperatures, wind directions, barometric pressure, general weather (cloudy, sunny, etc.) as well as precipitation probabilities and amounts. After a while, you’ll begin to notice patterns. Wind direction and barometric pressure tend to be leading indicators of changes coming. If pressure is trending down (more than just the intra-day changes), you’ll notice that weather also tends to deteriorate shortly thereafter. In most areas, when there’s a distinct wind shift to where it’s coming from the 270-360° quadrant, or directly from the west up through directly from the north, you’ll tend to see clearing with colder temperatures almost immediately thereafter. Yet depending on where one is situated, just a few more degrees around the compass (i.e. wind out of the northeast), with dropping barometric pressure, that could spell considerable trouble (the famed “nor’easters” of the US east coast, for example). When winds trend out of the south and southeast in the US, and in some areas out of the southwest, moisture is generally being pulled into the area, with increases in cloudiness.

Those are all generalizations, but there are patterns that can be quite helpful. Clouds types can also be quite instructive, sometimes. We had a tornado siren go off in our area a few years ago, and I was shocked! I went outside, took a look around, noticed the types and extent of the clouds, and called “BS” on it immediately. I then came in and looked at the computer radar on Weather Underground (I particularly like the “Nexrad” radar at the top right of their local screens), and confirmed what I already “knew” – there wasn’t even a chance of a tornado in the area! Some idiot saw a very localized but heavy rain shower coming out the bottom of a small buildup (cloud formation that didn’t go particularly high), and by contrast with the surrounding blue skies, that heavy but localized downpour was dark grey. The uninformed do-good citizen called in a tornado on the ground report to our local emergency management office, and without bothering to check it out, they put out the tornado warning! (Or maybe they did “check it out” by looking out the window and seeing the same “tornado” – hah hah!) Sometimes idiocy known no bounds. There wasn’t even a chance of a thunderstorm that day, let alone one near enough to being capable of producing a tornado. But the “experts” in the area didn’t have any idea what they were talking about, and didn’t bother to check with the TV station meteorologists first before screaming “TORNADO” all through the area (and probably scaring a few little old ladies and school principals half to death). It was hilarious, just because of the idiocy of the “experts.”

On the contrary however, when you see very, very large buildups off in the distance, with what’s sometimes known as an “anvil” shaped extension at the top sticking off in one direction, that’s a mature thunderstorm, and out of that anvil can be coming hail, with the hail falling out in an area NOT in the middle of the storm activity on the ground. Pilots know not to fly in the nice pretty clear area just below an anvil, or they can be pelted with hail that is being spewed out the anvil. And note that we get to see tornadoes quite clearly on video, because they’re not embedded right in the middle of a storm, which would obscure the outline of the tornado. Instead, they tend to be on the edges of large storms, and therefore visible (if daylight of course).

So, there are some things that can be learned at least in the way of patterns to look for. If you don’t have a barometer, you might consider getting one – and watching it. Notice the patterns that develop following trending changes in the pressure readings, and practice on the Weather Underground “Graph” display 10 days out in the future. That could at least help you predict when serious weather might be coming, or significant temperature changes, etc. If you’re already within (or even near) the first frost date, for example, and the barometric pressure is really trending up, and the wind shifts distinctly to the northwest with a fair amount of speed, you might want to cover your plants that night if possible. No guarantees, but certainly worthy of consideration.

Hope that helps.