Tag: clouds

Drought Returning

“Enchanted Light | New Mexico” by Jim Crotty is licensed under CC BY-NC-ND 4.0


Since the last report where the drought level was easing due to low temperatures and wet conditions, things are picking up again. While Droughtman seized the opportunity to point out that the wildfire hazard was low, it didn’t last. We’ve had a few hot, dry days and the scale is back up to very high, just short of an extreme hazard. — Breaking news: it just went up to extreme. — July was the only month to exceed normal during this period when we expect to get a good share of our annual precipitation, and it didn’t even reach 115%.

It looks as if the jet stream might be thinking of moving into its usual summer position, which is well to the north of us. When that happens we settle in for that long period of summer heat that we’ve usually had, or at least begun by now. This year, though, the jet stream seems to have stalled with an arm of it looping down to the west of us. That means there’s an avenue for a series of weather systems to pass nearby or right over us. Hence the lower temperatures and wetter weather.

The fire suppression crews got control of the big fire that was threatening to come over the mountain and descend on us. Those people are champs.

One of these times I’m going to have to talk about the deep duff.

rjb

Drought Easing

“Enchanted Light | New Mexico” by Jim Crotty is licensed under CC BY-NC-ND 4.0

Already we have surpassed the average rainfall for July, at only the three-quarter mark. This has allowed the drought level to be reduced from 3 to 2. That means our conditions have gone from “very dry” to “dry.”

What has Droughtman got to say about this? He says that 2019 has been very rainy, even though July has been the only month this spring/summer to reach normal levels of precipitation. He reiterates that the big lakes have a lot of water. To his credit, this time he didn’t say that means there’s no drought. Maybe he forgot to mention it.

Here’s hoping this unusually cool and wet July continues and carries over into August. It has been a nice change and we can use it. The wildfire hazard is down, a relief after the last two years of big fires. If we keep getting rain, maybe the aquifers will have a chance to recharge. With higher temperatures in the forecast, it would be good to build up a bit of a buffer.

We had a splendid thunderstorm pass through last night, with near-continuous lightning and some rain. Hopefully the lightning-caused fires can be knocked down before they do too much damage.

Don’t stop now, rain.

rjb

The Great Cloud Conspiracy

Credit Craig Sunter – CC-BY


In the past week I’ve had a couple of visits from people who saw a link from another site to a post here. Being curious I backtracked them and found myself reading about the Great Cloud Conspiracy. Apparently when the International Cloud Atlas released a new edition with some added cloud types it meant that they were actually new clouds that didn’t use to exist. And of course that means that someone, probably the government, had done something that caused them to appear. Something about chemtrails? Note that my posts were linked to as a form of validation for their theories. In one case the author of the conspiracy post simply cut-and-pasted my post right off the screen. Any reasonable person who reads my posts will realize that I don’t subscribe to the conspiracy theories they’re supposed to support.

To be misunderstood is bad enough. To then be used as back-up for some wingnut’s conspiracy theory is going too far.

rjb

More Drought

“Enchanted Light | New Mexico” by Jim Crotty is licensed under CC BY-NC-ND 4.0


Droughtman is strangely quiet these days. It has been cool and cloudy and is forecast for more of the same, with the possibility of precipitation, and he hasn’t said anything snide about it. It might have something to do with the latest information from our water management people. They have raised the drought level to 3, very dry. Although that would normally trigger Droughtman to sneer at them and point out that there’s still water in the big lakes, they also mentioned that Okanagan Lake, the biggest, is low. His go-to proof that he knows more than they do has let him down, and he has gone quiet. In addition, the upper-elevation reservoirs, which Droughtman had failed to consider in his earlier claims, have failed to fill this year.

All this is giving water utilities cause for concern. Their supplies look as if they might not meet demand, so they are replacing voluntary measures with restrictions on their customers’ use of water. So far it’s just for outdoor use, such as watering lawns and gardens on a strict schedule, but if it continues dry the restrictions will escalate. Already the lakes are low, as are the reservoirs and some wells, and even with the cooler and damper weather recently, we’re well below average for precipitation. It could be that all this information has been enough to quiet even Droughtman.

Time will tell, I guess.

rjb

Jet Stream – Related Phenomena

Credit sleske – CC-BY-SA

Cloud of the Day – Other Phenomena Related to the Jet Stream

As promised in the original post on the jet stream, today’s post will cover related phenomena such as the polar vortex and the Southern Oscillation.

You will recall that jet streams form at the boundaries between major air masses, and at the boundary between the troposphere and the stratosphere. The Polar Jet, for instance, marks the boundary between the colder air mass to the north and the warmer one to the south. As a rule, the greater the difference in temperature of the air masses, the higher the wind speed in the jet stream. The Subtropical Jet is in addition affected by el niño and la niña. which are in turn affected by the Southern Oscillation. Whereas el niño and la niña are ocean events having to do with the warming and cooling of the surface waters of the eastern tropical Pacific Ocean, the Southern Oscillation is an equivalent atmospheric effect. When the two events synchronize they reinforce each other. During an el niño event the subtropical jet stream trends further south, and further north during la niña. When the periodic oscillations of the ocean waters and the atmosphere reinforce each other, the effect on the jet stream is greater and we experience more extreme weather modification. When they tend to cancel each other out, the weather events are less pronounced. This description is vastly simplified and once again I’m impressed by the persistence and attention to detail shown by meteorologists and other scientists.

The polar vortex has made it into the news recently as the eastern part of North America has been subjected to outflows of frigid arctic air. Strangely, people tend to blame the polar vortex, as if its existence were responsible for their frostbitten noses. The fact is, as you will see, it is the polar vortex that normally holds the cold air in, preventing their nasal misery.

Both poles have a polar vortex. They are persistent, large-scale low pressure areas generally lying poleward of sixty degrees latitude. These vortices are upper air phenomena, with their bases in the upper troposhpere and lower stratosphere, around the tropopause, where jet streams live. The strength of the vortex depends on the temperature differential between the equator and the poles. This is greater in winter, which is good for keeping that cold air in and saving our noses.

Unfortunately the vortices are more commonly ill- rather than well-defined. There is not always a strong jet stream wrapped around them. They can break up into two or more vortices, resulting in the flow of arctic air becoming disorganized, sometimes breaking out and spilling southward.

Climate change, for various reasons, is resulting in a decrease in the pressure and temperature differential between the equator and the poles, resulting in weaker vortices and less containment of arctic air. This causes the apparent paradox of localized cold snaps brought on by global warming. The atmosphere is dynamic and complex. There’s more to it than the nightly weather report.

rjb

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