However, while my tweet referenced udders, the National Weather Service, on their Facebook page, responded to my post to them with the following:
The "utter" looking clouds ... appear to be mammatus from this picture. The overall weather pattern and atmospheric stability would support this type of cloud today. Thanks for sharing.The word in quotation marks stands out. Of course the writer meant udder. How could such a mistake be made? Utter and udder are two different words with very different meanings. British English speakers must be particularly puzzled by this. The key here is pronunciation.
In the U.S., we are what those of us here at TOWFI like to call non-tauic (this is not a technical term; it's just one we made up based on an existing technical term). To explain this, we must start with the term non-rhotic (this is, in fact, a technical term and not one that we made up). Most British English speakers are non-rhotic, that is, they do not pronounce r if it is followed by a consonant. To go with that, they have the linking r, where the r is pronounced if it is followed by a vowel (in the word roaring, British English speakers pronounce both r's, and in "far and away" the r in far is usually pronounced) . In fact, many British English speakers also insert an r between vowels where one doesn't exist, and that is called the intrusive r. An extreme example of this, for Americans, occurs with the Mike Myers character Simon, from Saturday Night Live. This character is a child who likes "to do drawRings" (see the character on YouTube). The r is inserted between draw and -ings. Canadian Mike Myers' parents were both from Liverpool, England, and this may explain his fascination with accents of the British Isles (he also did a Scottish accent occasionally on SNL; his voice for the animated character Shrek was done in a Scottish accent, as well). A less extreme example of the intrusive r would be a British English speaker calling someone named Amanda "AmandaR."
That's all well and good, eh? What about utter and udder? In America we are non-tauic, in that we often do not pronounce our t's as t's. We sometimes pronounce a t within a word as a d, or we don't pronounce it all and substitute it with a glottal stop. Mountain is a good example of a word where we substitute a glottal stop. What is a glottal stop? An example of a glottal stop is the sound made when we say "uh-oh." The dash can be said to represent the glottal stop. Many Americans say "mao-un" (or "mao-in") where the dash again represents the glottal stop. Utter, on the utter hand (sorry), is a case where the t is pronounced as a d. This is so common that it leads to some misspellings, such as in the case of the NWS Facebook post. The poster was apparently more familiar with the spelling of the word utter than that of the word udder, two different words that are pronounced exactly the same by many in the U.S. Others make the same mistake: perform a Google image search for utter and you will get a few images of cows (along with many images of otters!).
Now, back to mammatus. One of the tweets in the screen shot above tells you that this cloud formation is so named because of the pendulous shape of the cloud, resembling hanging teats or udders. You can read a previous TOWFI discussion of mamma-related words here. Interestingly, back in Texas, I most often saw mammatus clouds in association with severe weather, which sometimes included tornadoes. Here in California, tornadoes are rare (though they do occur), but mammatus does turn up here from time to time, without any accompanying severe weather. However, it is an indicator of some pretty good atmospheric instability, a requirement for (but not always a producer of) severe weather. (Here are some terms and definitions related to severe weather, from the National Weather Service.)
Utter means, etymologically, "outer" and is, not surprisingly, cognate with outer. Utmost is another relative. Utter and utmost have the sense of "outermost," and the sense shifted to "going to the most outer (or utmost) point; extreme" (from the OED). Thus, an "utter fool" is the most extreme of fools. Calvert Watkins suggests that the Indo-European root here is ud- "up, out", which also gave us ersatz (via Old High German) "substitute or imitation," the sense being of putting something "out" and replacing it with something else.
And with that, I am utterly exhausted and will now retire to catch up on True Detective.