#weather terms

[rank-sentimentalist]

Weather Terms

Weather story included two terms I had not yet encountered:

"wet microburst"

and

"backdoor cold front"

Feel free to discuss.

[your-featherbrained-weather-vane]

taken from our plane to Orlando — GORGEOUS and arguably textbook examples of anvil clouds, or cumulonimbus incus

I couldn’t get a good picture of the messier left one as suddenly the schmutz on the window kept getting in the way of my phone focus. but with the help of my window seat friend I did get a nice picture of the right one. this is a weather first for me, I’ve never seen proper anvil clouds from the ground where I live and now I got to see them perfectly, thousands of feet up, far enough away to not cause any trouble. and to see two in succession, that was really amazing!

cumulonimbus incus clouds form when they reach the tropopause, where the troposphere stops and the stratosphere begins. the cool rising air at the top of the anvil spreads out as it hits that boundary between the layers, in which the temperature stops decreasing with rising altitude.

[your-featherbrained-weather-vane]

Not sure if you're the correct person to ask this but like, do you know what the exact 'magic eight ball' terms were for chances of rain before we were given percentages were? Like I could have sworn early weather reports gave us like a standard list of 'Highly likely chance of rain' or 'not very likely'. Is there like a graph or a chart somewhere to translate that into numbers and back?

heya, sorry for being late! unfortunately I don’t think I’m the best person to ask — @tornadology may be of assistance? even so, I did try searching into what you mean because I’m curious myself. I couldn’t find any information on early standard lists of probability of precipitation expressions, but I did see modern usage of qualifiers translated to / from numbers by the NWS. I saw “slight chance”, “chance”, and “likely”. NWS Portland on Twitter also made use of “definite”.

I didn’t see things such as “highly likely” or “not very likely” or any early charts as I said, but maybe they’re out there and I’m just not looking in the right places 🤔

[your-featherbrained-weather-vane]

Term of the day!

3/24/22

isobars

WW2010, Isobars: lines of constant pressure

isobars are lines on a weather map that join places of equal atmospheric pressure at a given time, reduced to sea level to ignore altitude differences

they are isolines, or contour lines, similar to those on topographic maps that can never touch each other

BBC Bitesize, Weather systems

isobars are typically drawn at intervals of 2 or 4 millibars (mb), a unit of air pressure in the metric system — 992mb, 996mb, 1000mb, 1004mb, etc.

the usual worldwide range in sea-level pressure is 970mb – 1040mb — anything lower towards 890 would be a strong Low like a hurricane, and anything around 1030 and higher would be a strong anticyclone High

isobars closer / tighter together on a map indicate stronger winds and turbulent conditions, while isobars spread far apart mean light winds and calmer conditions

[your-featherbrained-weather-vane]

Term of the day!

3/20/22

Brocken spectre

Deadline News, Allan Donald / Mountain & Flood Landscape Photography

also known as a Brocken bow, “mountain spectre”, or simply a “spectre”, a Brocken spectre is the magnified shadow of an observer cast on clouds like fog or mist when the Sun is behind them

Brocken spectres are commonly accompanied by a glory, halo-like rings of colored light — sometimes more rarely seen with a fog bow, or white rainbow

Weather Underground

this enormous shadowy figure can appear on any misty mountainside or cloud bank, though the Brocken spectre gets its name from the Brocken peak of the Harz mountains, where mist is frequent

the Brocken spectre phenomenon is a possible explanation for the so-called Big Grey Man (Am Fear Liath Mór) — a creature or entity rumored to haunt the summit and passes of Ben MacDui, highest peak of the Cairngorms of Scotland

Met Office

[your-featherbrained-weather-vane]

Term of the day!

3/19/22

snow rollers

World Atlas

also known as “snow donuts”, “snow bales”, and “wind snowballs”, snow rollers form when wind pushes chunks of snow along the ground, picking up more snow on the way to end up as cylinders

because the inner layers are thinner and weaker the wind will often punch them out, leaving a hollow center & more donut-like appearance (great, now I’m thinking of delicious glazed donut holes…)

Flickr, Washington State Department of Transportation

most snow rollers are on the smaller side, from a few centimeters to inches wide, but some become as big as you!

these donuts are usually found around hilly areas, due to one condition of formation being gravity pulling a snowball downhill — they can be found elsewhere if the wind is just strong enough, but not too strong, to push snow along. and then the snowy conditions have to be just right, otherwise creation is doomed from the get-go

it’s because of the highly-dependent nature of their creation that snow rollers are a meteorological rarity

Weather Underground

[your-featherbrained-weather-vane]

Term of the day!

(3/18/22)

ball lightning

Ball lightning kills Richmann, 1753, A travers l’Électricité (c. 1900)

also known as globe lightning, ball lightning is a phenomenon reported to occur during electrical storms & has been hotly debated over the centuries

perhaps the most notable report of ball lighting was from 1753, when physicist Georg Richmann was apparently struck dead by ball lightning while conducting a lightning experiment

there have been widely-varying descriptions of ball lightning, but a couple things are agreed upon:

commonly present as glowing, fuzzy spheres of various colors

seem to appear within range of a recent cloud-to-ground lightning strike

can be small or as large as a grapefruit, some say even larger

lifespans generally range from a few seconds to over a minute

often enter through open windows and doors, some people claim they can phase through glass and wood with no issue or generate right beside windows

has erratic, wandering trajectories

may explode violently, often knocking back people and objects & causing burn damage, or quietly dissipate

upon explosion they may leave behind a nauseating odor of burning sulfur, overheating, or ozone

can be lethal or harmless (difficult to tell what your fate is between the two, good luck with that)

there are recent claims of taking photos or videos of this weather phenomenon, but with the elusive, unpredictable, and rare nature of ball lightning, no one can verify anything just yet

red sprites (a type of transient luminous event) and St. Elmo’s fire (luminous plasma created by corona discharge) have been mistaken for ball lightning

Vox, illustrations by Elizabeth Galian

[your-featherbrained-weather-vane]

I’ve been monitoring this cyclonic activity happening over the southeastern U.S. the past few days and upon checking weather news, I did find out that severe storms are sweeping the area

and remember, low-pressure systems have cyclonic flow but that doesn’t make them tropical cyclones, so nobody get spooked!

strong low-pressure centers with inward spiraling air are called cyclones — of the three main surface-based types of cyclones, extratropical cyclones, or mid-latitude cyclones, are weather systems that carry along stuff like rain and severe storms and they are completely normal

low-pressure systems like this one are often just called “lows”, and just like anticyclonic “highs”, these systems are normal conveyors of weather on Earth — it’s just how stuff gets around

despite the jankiness of that warm front line coming off the pressure system, it isn’t connected to that stationary front beside it — you can tell zoomed in!

speaking of stationary fronts, they are ALL OVER Canada and the U.S. today

and just LOOK at all those high-pressure areas! unbelievable

3/16/22