Updated: Mar 31, 2020
Starting a new miniseries--"Sky Detectives". You could check your phone for the weather forecast, or you could just look up into the sky. It gives us all kinds of clues about what's coming down the pike, and it's beautiful, to boot. Plus, aren't most things more about the journey than the destination? Same with weather in my book. These days, I'm trying to see weather flowing by overhead like an old trout must look up and see what's floating down the river toward it from above. He knows it's ever-changing, and darned interesting. Like these cirrostratus clouds headed our way. Thin veils of ice crystals spread across the upper level of the troposphere, accented by two jet contrails. Could it mean change is coming? Why yes!
Part 2 in Sky Detectives, this time going low. Did you know the air above us moves in layers? Or that clouds show us where those layers are and what's going on in each of them? Not that there are strict boundaries between them, but it's an idea we can work with. Here, up high on the top of the Plateau, the land scrapes up against the bottom of a Stratus nebulosus. Yes it looks like snowy fog, or snog as my husband likes to call it, But as the plateau drops off, the clouds lift up above the ground, and they take on their regular appearance--big, flat, featureless, low level clouds that don't make a lot of weather. They just show what the lower level air is up to, a sure clue that a sheet of warm-ish, moist-ish air has just been lifting up across the region, depressurizing, cooling, condensing, and viola! the cloud appeared!
Part 3 in "Sky Detectives" miniseries. What do sun dogs like these two spectral pups have to tell us about the future? They're formed by cirrostratus clouds way up high at the top of the troposphere where they can see what's coming, metaphorically speaking, of course. A figment of ice crystals, sunlight, and our eyes, these sun dogs, faithfully follow their master the sun at 22° to the left and right of it. And being part of the cirrus family, they're precursors to weather fronts coming our way. That means the air mass that's here will be pushed out by another moving in. And with the changeover will come some kind of weather...probably something cold and precipitating. Woof! in anticipation of some moisture.
Part 4 in "Sky Detectives. Just because there're clouds doesn't mean there will be rain. Or snow. Or much if it does fall. We all know that from experience, but it's hard to take to heart when you live in a chronic dry spot. There's moisture up there, so why doesn't it fall?...dammit. Apparently, clouds mean one thing: that patch of air that is the cloud got cold enough for its vapor to condense to tiny droplets. Invisible to visible. Warm to cool. Unsaturated to saturated. It's just step one in the precipitation process. If there aren't some tiny particles for the droplets to coalesce around there won't be raindrops or snowflakes. If there aren't enough tiny droplets to coalesce, there won't be rain or snow. If the air isn't in some state of turmoil that cools down parts of it, don't expect precipitation. Were those conditions all met this cold, damp morning? Yes, to the tiniest extent. We got our millimeter of snow. Before the sun warmed it all up and turned the droplets and ice crystals back into vapor again. I don't get why that keeps disappointing me!
Part 5 "Sky Detectives". What else are you going to do anyway, in a time of pandemic? May as well look out your window at the clouds, read into them whatever messages of escape, movement, transcendence you're wishing for. Not long ago, we'd drive up to the top of the pass, directly into the mid-level winter clouds, and inspect them up close. Skis underfoot, heads in the clouds, the alto clouds. Altostratus, altocumulus, the clouds that hang out around mountains, or in the middle atmosphere in general, their bases situated anywhere between 6,500 to 23,000 feet up. They're largely made of ice crystals at these elevations, looking white when light bounces off them toward you, and dark when they get in the way of it. Not so much a sign of coming weather as a portal into what's going on with the air up here. How fast is the wind blowing, how much moisture has it got, how upwardly unstable is the air. From a "what good are they?" standpoint, they can rain, snow, or be purely decorative. Sometimes that's all we need.
Final shot at this theme of "Sky Detectives". This is the part where it's all brought together, in an effort to get beyond "the sky is so beautiful" to "the sky is so full of meaning if I take the time to look at it and think". As a species, we've always wanted to be up there among the clouds, weightless and soaring. Now that we've been, we know they're not piles of cotton candy and whipped cream, nor the portal to heaven. We've seen beyond their beauty to their real-world essence. It is beautiful, and it's our atmosphere, our oxygen source, weather-bearer, bringer of moisture, HVAC system for the globe. And it's a startlingly thin envelope of gases circulating around the earth. What happens up there matters in many ways. So,honor it by looking closely whenever it gives you a sign of what's going on. Whether it's high level cirrus or jet contrails, altocumulus, stratus, or cloudless skies, these are all clues. Here is one you can take to the bank. Where there are clouds, the air is cold enough to condense its water vapor. And where it's clear, the air's too dry, too warm, or both. Another clue--look at how high up the clouds are--low, mid, or high. There can be different things going on at different levels. Sometimes there's vigorous inter-level mixing, and fast, high level winds make their way down to our level, Sometimes the layers stay separate.
Here is a real winter cloud challenge, I'm going to give it a try, even with no meteorology background. There's moisture up high, ice crystals at elevation--a cirrostratus sheet, cirrocumulus in the puffs at its edges where a little convection is fluffing them up. The speed bumps and crazy shapes suggest strong winds up high..a nearby jet stream could be the reason. Looks like a sign of moisture to come. And there it is, in those mid-level clouds just starting to appear. You don't need to look very hard to see the culprit behind it all, and every other weather scenario we discussed. It's trying to hide behind that cirrus cloud, but not very effectively because it's so darn bright!