]]> http://www.thunderstruck.com/beautiful-storm/feed 0 http://www.thunderstruck.com/weather-word-wednesday-glory http://www.thunderstruck.com/weather-word-wednesday-glory#comments Wed, 19 Jan 2011 18:00:10 +0000 GoNorthWest http://www.thunderstruck.com/?p=305 Have you ever been out hiking and looked down on a waterfall, surprised to see a round, rainbow colored halo? Or perhaps you’ve looked off towards a bank of clouds, with the sun at your back, and seen the same colored halo? If so, you’ve seen what meteorologists call a Glory.

Essentially, a Glory is “one or more sequences of faintly colored rings of light that can be seen by an observer around his own shadow cast on a water cloud (a cloud consisting mainly of small, uniform sized water droplets). It can also be seen on fog and exceptionally on dew.”  The glory can only be seen when the observer is directly between the sun and cloud of refracting water droplets.

Solar glory at hot springs

Glories are not completely understood. The colored rings of the glory are caused by two-ray interference between “short” and “long” path surface waves – which are generated by light rays entering the droplets at diametrically opposite points (both rays suffer one internal reflection). Glories are often seen in association with a Brocken spectre, the apparently enormously magnified shadow of an observer, cast (when the Sun is low) upon the upper surfaces of clouds that are below the mountain upon which he or she stands. The name derives from the Brocken, the tallest peak of the Harz mountain range in Germany. Because the peak is above the cloud level, and the area is frequently misty, the condition of a shadow cast onto a cloud layer is relatively favored. The appearance of giant shadows that seemed to move by themselves due to the movement of the cloud layer (this movement is another part of the definition of the Brocken Spectre), and which were surrounded by optical glory halos, may have contributed to the reputation the Harz mountains hold as a refuge for witches and evil spirits.

The next time you have your back to the sun and clouds at your front, or are up high with clouds below, try and find a Glory on your shadow. If you have a camera with you, and see a Glory, send us a snapshot!

Source : Wikipedia

Water vapor satellite imagery depicts moisture content in the middle and upper layers of the atmosphere. Lower level moisture is not depicted in these images. Moisture transport over large distances generally happens through the middle and upper layers of the atmosphere. Hence these images will depict moisture coming into the Southwest from the Gulf of Mexico or across Texas. Additionally, weak disturbances from the east are best tracked through water vapor imagery.

The imagery looks like this when viewed online. The is a screen capture of one frame of data:

Water Vapor Imagery

Basically, what this shows is the amount of moisture that is in the upper atmosphere. This may be in the form of clouds that you see, but often it is not. Water vapor literally surrounds the earth, but is unevenly distributed due to things like oceans, lakes, rivers, deserts, arid areas, etc. For instance, in the image above, you can see a lot of water vapor coming up from the southwest into places like Arizona and New Mexico, which are traditionally dry regions. Areas like the Pacific Northwest, which are usually wet, have much less than normal. This is all due to seasonal shifts in winds and weather patterns, which change the flow of moisture around the planet. By looking at an image like this, you can get an idea of how much moisture is available in your area…moisture that could turn to rain or snow!

Quick Storm Development

Since this picture was taken, our area has seen multiple Severe Thunderstorm alerts, along with several Flash Flood warnings! It absolutely amazes me how quickly the weather can turn in our area of the wood, and why it’s always important to keep an eye on weather when outside doing fun things. Dry washes and rivers can turn into raging torrents without a single drop falling in your particular area. Always know the weather!