In this blog I have frequently talked about summertime superior mirages over Puget Sound, in which warm air over cold water creates an atmospheric lens that makes objects near the water loom upwards in height. Here is an example of one provided to me by Skunk Bay weather cam master, Greg Johnson, in chich the coastal cliff's loom upwards.
But during the last few days, we have had the opposite situation in very cold air (15-25F) has moved over the relatively warm water of Puget Sound and adjacent waterways (all around 48-50°F). This warm water warms the air immediately above.
Cold air over warm produces a lens effect that results inferior mirages, in which objects are seen lower than they actually are (see schematic below).
A frequent example of an inferior mirage is on hot summer days, a very warm roads heat the adjacent air, with cooler air above. Light from the sky is bent down, giving the impression of water on the road, when it is actually light from the sky that provides the watery look (see below). Inferior mirages often invert objects as they push them downwards.
A close-up shows the action better.
An image of a ship (the Evergreen) shows a similar downward displacement and inversion of features.
Another "mirage" have been the suggestions of moderate snow over the Puget Sound lowlands. On Saturday, precipitation in some sea level locations will start as snow (Saturday evening), but will rapidly turn to rain.
I don't believe the bow appears inverted, we're seeing the wave over the bulbous bow at the waterline.
ReplyDeleteMirages are interesting. However, we've got all sorts of interesting weather happening in the U.S. right now. Not in the least, the forecasts for south of us in Oregon and California. Please give us your thoughts/predictions on these Prof. Mass.
ReplyDeleteNWS just issued a Winter Storm WARNING for the Hood Canal region. Your thoughts?
ReplyDeleteI live in Seabeck
The ~8" of snow we got in the SnoCo foothills on New Year's is still light & powdery, unusual but an excellent illustration of the low humidity.
ReplyDeleteUW Zone forecast predicts the freezing level rising to 2500' Sunday & I can't wait!! So tired of snow, ice & frozen water supply...
I believe the mirage phenomenon is called "fata morgana".
ReplyDeleteYes, would love if you discussed Oregon weather a little more..
ReplyDeleteThat kind of looks like a normal RO-RO (roll on roll off) car carrier, they are slab sided brutes. Bow looks kinda normal like Eric says.
ReplyDeleteIt always seems to me that mountains loom larger after a snowfall followed by clear air. Would love an explanation of that.
ReplyDeleteWill someone please help me see what Cliff describes in the final photo of the good ship Evergreen? Like where in the photo is a ship located? E.g., "halfway over from the left and 1/3 way up from the bottom".
ReplyDeleteAnd, without an "un-miraged" image of the ship in the previous image, I don't see what part of it is distorted/inverted as a mirage.
Anyone know what's up with Langley Hill radar? Been down more than up, the last several days. Since I live just SE of Cheahlis, this fairly new radar instillation has really enabled me to "see" what's coming at me. It is missed .... Lew
ReplyDeleteGary said: Will someone please help me see what Cliff describes in the final photo of the good ship Evergreen?
ReplyDeleteI assume it is the white hourglass shape (and the darker shape) at the bow of the ship. It looks like it is perfectly inverted from the midpoint of where it narrows. Eric and Alex say it is just the wave over the bulbous bow at the waterline but I'm not sure that would look so symmetrical.
After the blog, I put together an image that shows a little more detail. I took another picture of the ship as it went by out front that day. I cropped the original photo (taken 15 miles away) and then cropped the close-up and aligned them proportionally on one image. They are aligned at the deck level. This really shows the difference. http://skunkbayweather.com/InferiorMirageComparison.jpg
ReplyDeleteWe see these inferior mirages on the Columbia River from time to time. Happened today in a very limited area.
ReplyDeleteYears ago I saw something like this from the air, flying in to SeaTac in very cold weather. Looking across the Sound, the Olympics appeared to be raised on pillars, as if the foothills were stretched vertically. No photo, sadly. One of the weirdest things I've seen.
Have also seen the mirage of objects over the horizon appearing above the horizon and inverted -- once an island from Resolute, Nanuvut (Inuits call this mirage "bobbing up", and once a ship sailing upside down into the Golden Gate from Stinson Beach.