Tuesday Morning

Good morning from the northwest end of Augusta, Maine. This morning is another sunny day, what Mainers refer to as a "sunny & 60's day". Temps are not expected to rise above the mid 60's with the rain continuing to hold off. 

This morning's readings are:

a relative humidity of 73% with a Dew Point of 41.8ºF.

The temperature is 50.4ºF, with no wind chill at this temperature to speak of. 

What wind we have so far this morning is between 1.8 mph and 3.0 mph out of the Northeast.

Our Barometric pressure is 30.20 and rising.

There has been no rain in the past 6 days, with the only rain in our forecast arriving sometime thursday.

This time of year, particularly at the end of the month, "moon rings" become more visible in many locations. What causes them and some folk lore abot them appear below. Enjoy.

 

The moon can produce interesting optical effects when conditions are right. The most common of which are moon rings, moon bows, which are similar to rainbows, moon dogs and moon pillars. A rainbow is produced when sunlight is refracted through water droplets - A similar effect is produced when moon light refracts through ice crystals.

The ring around the Moon is caused by the refraction of Moonlight (which of course is reflected sunlight) from ice crystals in the upper atmosphere. The shape of the ice crystals results in a focusing of the light into a ring. Since the ice crystals typically have the same shape, namely a hexagonal shape, the Moon ring is almost always the same size.

Less typical are the halos that may be produced by different angles in the crystals. They can create halos with an angle of 46 degrees.

Moon Ring Weather Folklore

Folklore has it that a ring around the moon signifies bad weather is coming, and in many cases this may be true. So how can rings around the moon be a predictor of weather to come? The ice crystals that cover the halo signify high altitude, thin cirrus clouds that normally precede a warm front by one or two days. Typically, a warm front will be associated with a low pressure system which is commonly referred to as a storm.

It is believed that the number of stars within a moon halo indicate the number days before bad weather will arrive. Give it a try the next time you observe a moon halo.

Rings Around The Sun - The same phenomena that causes lunar halos can also be observed around the sun.

NOTICE: Never look at or photograph the sun directly.

Anatomy of a Moon Halo

The ring that appears around the moon arises from light passing through six-sided ice crystals high in the atmosphere. These ice crystals refract, or bend, light in the same manner that a camera lens bends light. The ring has a diameter of 22° , and sometimes, if you are lucky, it is also possible to detect a second ring, 44° diameter. Thin high cirrus clouds lofting at 20,000 feet or more contain tiny ice crystals that originate from the freezing of super cooled water droplets. These crystals behave like jewels refracting and reflecting in different directions.

Cloud crystals are varieties of hexagonal prisms, (6 sides) and range in shapes from long columns to thin plate-like shapes that have different face sizes.

Moon Dogs

Moon dogs are the paler version of sun dogs: bursts of light often in reds and blues that appear on both sides of the moon. Both phenomena are the work of almost invisible clouds that reside in the atmosphere where commercial airliners cruise, at about 30,000 feet. The clouds are composed largely of ice crystals, known as diamond dust. The official name for a moon dog is a paraselene if seen at 22 degrees. If the image is at 90, 120 or 140 degrees then it's known as a parantiselene.