The first photo was sent to us by Chris Jense. Here, we are looking at an awesome convective process. The cumulonimbus cloud, commonly referred to as a cauliflower cloud, is built by a process of warm and cool air. The sun heats the earths surface and causes the air to warm and rise. The rising warm air is cooled by the atmosphere above and eventually it becomes a large cloud like the one above. At some point, the cloud can no longer hold the moisture. The result is a short, intense downpour that we see above. This specific cloud is still building. You can tell by the sharp edges of the top of the clouds against the blue sky in the middle of the photo. Notice the bands of rain pouring down over the Jack In The Box. That's some heavy rain and most likely some small hail mixed in as well.
Linda Sullivan got a sunset snapshot of a passing thunderstorm. Again, we see the cauliflower-style clouds that extend well up into the atmosphere. The higher these cloud tops bubble up, the stronger the "updraft" is from the surface. The updraft is that column of warm rising air from the surface into a cooler environment above. The stronger the updraft, the faster the air is rising. This style of cloud is typically associated with active weather. We had a few weeks of afternoon thunderstorms around the Portland-metro area towards the end of spring.
Another convective picture, this time sent in from a viewer along I-5. Love the contrasts in this picture. The lighter clouds against the blue sky on the right side shifts to the dark rain clouds and the rain shaft on the left side. That dark area is actually rain falling from the clouds. Again, we are looking at convective rainfall here. The rain falls when the updraft can no longer sustain the rain. The weight of the rainfall overtakes the updraft and the result is the rain core you see above!
Funnel clouds are not unusual for Oregon. Tornadoes are. A funnel cloud is just a rotating cloud in the air. It can't cause any harm unless it touches the ground, then it becomes a tornado. It can be difficult to identify a funnel cloud from a still photo. It needs to be visually confirmed or else it may appear to be a low-hanging cloud. This definitely has the look and structure of a funnel cloud, however. No tornadoes have been confirmed in Oregon for the 2012 spring.
A well-timed shot was sent to us from Estacada. That looks like an impressive bolt. Notice how it goes from cloud-to-ground. These type of strikes are the only ones that produce thunder. A cloud-to-cloud lightning bolt can put a nice charge into clouds, but no thunder is heard from it.
This winter weather wasn't limited to the winter season in Portland. This is a great shot from outside the station in the middle of spring! Portland saw near 5 inches of snow over the spring, making up for the usually dry first half of winter we had.
This tranquil photo was sent in by Barbra Lane from Parkdale, Oregon. An amazing, peaceful photo after a heavy dose of snow fell near Mt. Hood.The Cascades got plenty of snow this past winter and first half of spring. That should make for a great water recreation summer.
This photo wasn't sent in to the station and isn't even from Oregon. This photo was taken in McCalla, Alabama. I am really hoping that this is the actual photo and not photo-shopped in any form. If this is a true photo, WOW! It looks like the lightning is striking the street! The clap of the thunder was probably ear-piercing. Very powerful!
Finally, a little bit of astronomy. The west coast was treated to a solar eclipse on May 20th. A solar eclipse occurs when the moon travels between the earth and the sun and blocks the sun from view on earths surface. Above is the western satellite view that caught the dark spot on the earths surface. The next eclipse will be a partial eclipse on October 23rd, 2014.
Spring offers up some of the best weather and thus, weather photo ops. I'll be monitoring the summer photos and will be sure to share any interesting pictures!