Cumulonimbus Cloud Anvil Strengths

[MikeD]

Question 1. Hey guys, I'm just asking for a quick question on the difference (in terms of storm strength) between CUMULONIMBUS CALVUS (CB with no anvil), CUMULONIMBUS CAPILLATUS (Fiber Anvil), and CUMULONIMBUS INCUS (Solid Anvil). I know that fiber-anvils and wispy looking clouds usually signal the development of ice-crystal formation, but it would be nice to gauge the storm's power from a distance instead of taking a peek at radar or driving up to the cloud base.




Question 2. I'm also kind of confused about these two types of anvils and which is more powerful...pictures below. NOTE: both these anvils are in the CUMULONIMBUS INCUS FAMILY. I know the left one has the infamous "puff" (it screams SUPERCELL at you) and the one to the right has more of a calm, thin, solid-looking anvil.

 

[Jeff House]

All else equal, the CB with an anvil is more mature and should be stronger than without anvil. Of course in weather it's usually not equal on different days. However same day, same airmass, same sounding, one could consider the more robust anvil is likely on the stronger storm.

Second set of pictures, it's possible the first is overshooting; but, it's not visible that angle. Second looks farther away (by the angle) but I could be wrong depending on cloud tops.

Hope I did not create more questions than I answered. I still love visuals in the field, from anvil to mid-levels down for cues, so I like the question.

 

[MikeD]

Okay, so I did research and answered my first question. The CB INCUS is the most powerful. Anvils with fiber-y edges are weaker than anvils with a solid anvil edge.

I’m still confused about the second question though. I just need someone to tell me which of the two clouds in the pictures is stronger.

Also, Jeff did create more questions than he answered.

 

[Jeff House]

Hello again! Yes I understand your first question better. The crisp anvil is better than the fuzzy one. Storm chasers often post about quality crisp updrafts. We should include crisp anvils too.

Question 2, these specific pictures, storm on the right is stronger. Has overshooting top confirmed. Rest of the anvil is symmetrical and crisp. One can discount the ice crystals off to the left; they appear to be ejected and not important.

Question 2 left storm convection does not look as deep/tall. I believe it is closer to the photographer; therefore, it's less tall/deep. It has potential, if still developing and in the Plains. If mature in Midwest/Dixie, it looks to disappoint, lol!

 

[Devin Pitts]

Yeah, when see fuzzy anvils I start to prepare to leave for another storm fairly soon. I'll let it cycle for a few updraft pulses and if it's still having fuzz issues with each one I generally call it quits for that particular storm.

I cant recall seeing a single supercell with a fuzzy anvil doing anything worthwhile. Personal bias obviously and I'm sure there's plenty of exceptions(as with everything), but just from my experience this has been one of my most used visual cues for deciding to stick with a storm or not.

Sent from my Pixel XL using Tapatalk

 

[MikeD]

Yep, so all this:



And none this:

 

[Richard Williams]

Most CB's I see in the UK are weak with wispy tops and would barely qualify as "Cumulonimbus Incus", more like "Cumulonimbus Extinctus".

However, I've also noticed that the glaciated "hairy" look doesn't seem obvious in very powerful storms. On the very rare occasion I saw the tops of intense known-severe thunderstorms in the UK (28th June 2012 and 1st July 2015), the upper parts of the cloud were solid like a rock, including the anvil cloud. Somehow the air motions of a violent storm produce what appears to be the usual bubbling appearance of cumulus clouds in the upper part of the cloud shaped like the anvil, and no wispiness. Obviously the cloud top is glaciated, so I'm not sure what the specific reason is for this. Maybe the up-draft force resisting the horizontal high altitude winds?

 

[MikeD]

Found it by accident. The fiber-looking anvils HAS NOTHING TO DO WITH ANVIL STRENGTH. They’re just ice crystals ejected from the cloud, through NATURAL STAGES OF A CB LIFE CYCLE.

 

[Marshall Stoner]

With supercells the look of the anvil is highly dependent on angle. If you are to the north or west of a storm and there's a strong wind near the anvil level, chances are the anvil will look wispy as it's spread far by the wind. If you're south or west of the storm it will usually look much thicker and more impressive. In extreme shear / low instability setups you get in late winter or early spring you don't always see a classic back-sheared anvil though. Sometimes the shear is so extreme you can't even see the anvil from the southwest, but that doesn't always mean the storm is weak and/or incapable of producing severe weather or a tornado.

 

[Lawrence Burkett]

Crisp anvils contain numerous liquid cloud droplets whereas fuzzy anvils contain numerous solid ice crystals. For an anvil to be made up of numerous liquid cloud droplets require a strong updraft to transport liquid cloud droplets from warmer air below up to (much) colder altitudes above where anvils form. Since updraft speed is a good proxy for convective storm severity, a crisp anvil versus fuzzy anvil is therefore a pretty good indicator of storm severity. Also, in general, the farther you are away from a storm's updraft the fuzzier the anvil will appear...this is because of the waning influence vertical transport of liquid cloud droplets by updraft with distance.