In case you missed them…a 2008 full moon and, moving ahead, yesterday’s sunrise

The full moon of December 11, 2008. Thought maybe you'd like to see it again coming up over the Catalinas. — The full moon of December 11, 2008. Thought maybe you’d like to see it in case you missed it, or see it again if you did see it. Maybe you had a special memory with this moon.

7:09 AM. Altocumulus perlucidus with a little lenticular underneath.

7:43 AM. — 7:10 AM. Zooming and zooming.

7:14 AM. Iridescence is evident in the cloud ripples just above the mountain silhouette.

7:16 AM, Contrails were soon visible in our Altocumulus layer, the aircraft making it at the right edge of the photo. Appeared to be in a climb out going right to left. And, when you see these “high temperature contrails” in Altocumulus, you can be sure ice will form and rifts will develop as a little bit of light snow develops and falls out. The jillions of ice crystals in the contrail cause the droplets in the Altocumulus to evaporate, in a way, gutting it. An ice crystal is like a low pressure center when amid droplets; the droplets evaporate and those water molecules deposit themselves on the ice crystal, a process named after the discoverers, Wegner-Bergeron-Findeisen. Eventually the crystal is large enough to settle out and a clear streak results unless the air is rising rapidly and can replace the droplets (as generally happens in storms). Sometimes the lift in the Altocumulus layer is enough that a clear canal caused by an aircraft can fill back in after many minutes.

7:18 AM. Two aircraft contrails, about a minute old. After two or three more minutes, they will not be visible within the cloud, though ice is forming, decimating the droplets around the intense streamers of ice in the contrail.

7:28 AM. The small ice canal (the ice is hanging just below the Altocumulus clouds–kind of hard to make out, but its there.

7:42 AM. Those little clear streaks are hardly noticeable now, partly because they were quite narrow, and because of perspective and things bunching up in the distance.

From the Cowboys in Laramie, Wyoming, this TUS sounding for yesterday morning in the pre-dawn hours:

Suggested locations of cloud layers. The Altocumulus layer in which the contrails were embedded seems to be at -25°C, a "normal" temperature for this kind of "high temperature contrail". In general contrails are not supposed to occur until the temperature is below about -35° C and the air is moist, thus they are usually seen amid or near Cirrus clouds. not down in Altocumulus. — Suggested locations of cloud layers. The Altocumulus layer in which the contrails were embedded seems to be at -25°C, a “normal” temperature for this kind of “high temperature contrail”. In general contrails are not supposed to occur until the temperature is below about -35° C and the air is moist, thus they are usually seen amid or near Cirrus clouds. not down in Altocumulus. See usual contrail height at Cirrus levels in moon photo.

As the morning wore on, the Altocumulus deck faded away, moving east, and we were left with some Cirrus clouds, but what kind?

10:58 AM. Cirrus of some type, but notice there is absolutely no fibrous details (strands and such) as we normally see in Cirrus. Could be transverse waves in a Cirrostratus deck since Cirrostratus can be fog like, have no detail, in a version we call, Cirrostratus nebulosus. The up and down motions would cause clearings perpendicular to the wind up there. The lack of strands and uniformity in these bands suggests very tiny ice crystals, ones having very little fallspeeds.

2:34 PM. Some nice “hovercraft” clouds, Altocumulus lenticularis off in the distance SSW. Hung around out there for a couple of hours.

3:17 PM. This one appeared to be concave upward, which was a little odd. Zoomed view next.

3:17 PM. Looks like the inside is higher than the outside. Huh.

Well, that was it for photography yesterday.

Doesn’t seem to be any reliable indication of rain in sight. Oh, sure, rain here pops up in the models almost every day, but its about 12-15 days out. As the model gets closer to the day it predicted rain, it seems to go away like the “water mirage” on a hot paved road; always ahead of you, but you never get to it. We’ve had some major rains indicated in the models as of a few days ago, but spaghetti was never very high on those events (clustering those crazy lines in a trough over us), so it wasn’t even worth mentioning.

And, even that rain is a gonner in the model runs from last night!

The End

Author: Art Rangno

Retiree from a group specializing in airborne measurements of clouds and aerosols at the University of Washington (Cloud and Aerosol Research Group). The projects in which I participated were in many countries; from the Arctic to Brazil, from the Marshall Islands to South Africa. View all posts by Art Rangno

2 thoughts on “In case you missed them…a 2008 full moon and, moving ahead, yesterday’s sunrise”

Fantastic sunrise shots there, Art. We may be seeing a similar scene here tomorrow morning, as increasing clouds arrive to eventually give us snow later in the day. Quite the start to winter here. This morning was 19F, tomorrow morning even colder before the snow arrives, and it looks like snow is in the forecast for a few days after that too!

Hi, Roland.
Hope you enjoy your snow and cold.

Thanks for your comment!

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