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Convective Thread


weatherwiz

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36 minutes ago, eekuasepinniW said:

Got a ton of photos.  It always amazes me how much "more" there is to your typical lightning strike. Your eyes see the main channel, but photos reveal all sorts of finer stuff, often stuff that is way far away from the main bolt.

post.JPG

This is sick!  What shutter speeds were you using for the exposures?

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7 minutes ago, powderfreak said:

This is sick!  What shutter speeds were you using for the exposures?

Most were 10-15 seconds at F12, IIRC.

It was absolutely infuriating how every time an exposure would end, there would be a great strike centered right in the frame.  Once I began another exposure, I'd then get: 

bad1.JPG

lol

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10 hours ago, eekuasepinniW said:

This one is pretty cool.

Definitely kicking myself for not realizing the ISO was set too high.  They could have been nice buttery smooth images, but are instead rather grainy.  It was my first time using a DSLR and was busy freaking out trying to determine if it was even in focus or not.

I used to do this all the time when I worked at DVN, back when I used to see real thunderstorms.

The tip I had heard was to keep it on auto-focus and try and get it to focus on the farthest light source you can see. Once it does that, flip the focus back to manual and leave it there. Alternately if your lens was old enough and actually had the infinity mark on it.

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Everything stayed north of us last night, but got a surprise TS this morning, with some fairly close strikes though only 3-4 booms per minute.  Precip estimate shows a stripe of 0.6-1.0" just north of my place and another with some 1.5"+ pixels just south.  The mile-wide stripe of <0.3" between the heavier stuff is centered on my place.  (Why am I not surprised?)

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1 hour ago, OceanStWx said:

Just went back through our lightning detection, and over the hour ending 10 PM on average there were about 10 CGs per minute and a little more than an IC every second.

My observations seem to jive well with this.  I was counting flashes per minute.  For a period around dark I was seeing about 40 per minute along the back side of the line.  I'm sure there were more on the front side so 60 per minute makes sense.

I am still kind of awe struct with my drone video looking at the cell that passed over me and produced the heavy rain and hail.  Got the drone up as it was east.  Sure looks like a well defined wall cloud.  Here is another video.  I'm looking east so rain and hail is leading the cell.  At the SW part is the wall cloud.  Towards the end of the video watch the left side of the cloud.  Incredible upward motion.  I don't ever think I have seen such rapid motion.  Wish I had been closer.  Surprised no wind or damage reports.

 

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6 minutes ago, wxeyeNH said:

My observations seem to jive well with this.  I was counting flashes per minute.  For a period around dark I was seeing about 40 per minute along the back side of the line.  I'm sure there were more on the front side so 60 per minute makes sense.

I am still kind of awe struct with my drone video looking at the cell that passed over me and produced the heavy rain and hail.  Got the drone up as it was east.  Sure looks like a well defined wall cloud.  Here is another video.  I'm looking east so rain and hail is leading the cell.  At the SW part is the wall cloud.  Towards the end of the video watch the left side of the cloud.  Incredible upward motion.  I don't ever think I have seen such rapid motion.  Wish I had been closer.  Surprised no wind or damage reports.

It used to be a pet peeve of mine to use the term "non-rotating wall cloud" because we always used to teach that they needed to rotate to be a wall cloud. In reality they are just a local lowering of the updraft base. If you don't have a lot of low level shear, they won't rotate or at least won't appear to rotate to the naked eye. The cause is pretty simple. The forward flank is rain cooled, and inflow from that region has a lower temperature and higher moisture content than air coming from the south or southwest. Cooler temps and higher dew points mean a lower cloud base when the air rises. That is why the wall cloud is usually tucked in close to the leading edge of the updraft base, it's near the forward flank inflow.

Yesterday we had a decent mid level meso in that storm (hence the large hail to your east), but the low levels were not showing much rotation. So a non-rotating wall cloud is a fair description.

 

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21 minutes ago, OceanStWx said:

It used to be a pet peeve of mine to use the term "non-rotating wall cloud" because we always used to teach that they needed to rotate to be a wall cloud. In reality they are just a local lowering of the updraft base. If you don't have a lot of low level shear, they won't rotate or at least won't appear to rotate to the naked eye. The cause is pretty simple. The forward flank is rain cooled, and inflow from that region has a lower temperature and higher moisture content than air coming from the south or southwest. Cooler temps and higher dew points mean a lower cloud base when the air rises. That is why the wall cloud is usually tucked in close to the leading edge of the updraft base, it's near the forward flank inflow.

Yesterday we had a decent mid level meso in that storm (hence the large hail to your east), but the low levels were not showing much rotation. So a non-rotating wall cloud is a fair description.

 

not to be a dink but I see them all the time -

 ... as an obsessive cloud watcher of the first order, spanning multiple decades of life ...I have come to identify with precision the various systemic structures of CBs - an know what is happening within them.  I have piled out of office buildings in late summer afternoons, looked to the west and said, "up - super cell"  ...Come to find, tor warning issued.  Just from observing the southern 'edge' of anvils being stenciled against blue, with scud moving underneath from south to north... automatic.   

anyway, being near the base of a CB and out of the obscuring effects of rain shafts, one can identify really quickly where the updraft entrance/elevator is taking place; and often where that interfaces with the air mass below the lcl there are these transient suspicious features ...even in completely benign pulse storms too.  

Fact of the matter is, these identifications and categorizations we make as science folk ...they are all kind of meaningless in a way?  Every event in nature exists on a spectrum really. Their content-attributes that are merely cousins to events that may happen to have more obvious features that fit the classification.  It's philosophical conjecture, but you get my drift - 

There used to be tropical and extra tropical cyclones.  Then there were sub-tropical this... Then Hybrid that... Now we have fanciful storm graphics that show off physical thermodynamic process types, on a colorized charts that describe the evolution of cyclones through those types as symmetric vs non-symmetrical phases over time...   

Classifications are entirely human distinctions (if not conceits) that sometimes bear resemblance to what is really taking place in Nature.  heh.   

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1 hour ago, Typhoon Tip said:

 

Fact of the matter is, these identifications and categorizations we make as science folk ...they are all kind of meaningless in a way?  Every event in nature exists on a spectrum really. Their content-attributes that are merely cousins to events that may happen to have more obvious features that fit the classification.  It's philosophical conjecture, but you get my drift - 

Classifications are entirely human distinctions (if not conceits) that sometimes bear resemblance to what is really taking place in Nature.  heh.   

The above is worth repeating, especially the part I bolded.  Though trees move more slowly than weather systems and rarely get involved with rise or descent, the forest is still a messy place that defies the textbook definitions we learned in college.  Even more the case when things are totally fluid, like our ocean of air.

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Thanks for all the expert input on my "wall cloud" video.  Sure,  I've seen lots of lowerings in CuB bases.  I don't remember seeing one with such defined edges and so low.  What was the most impressive to me is that if you watch the video towards the end you see in real time how fast that north side  edge is going up.  Even from miles away it was just rising so quickly that it was impressive to see from a "weather freak" perspective.  

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2 minutes ago, wxeyeNH said:

Thanks for all the expert input on my "wall cloud" video.  Sure,  I've seen lots of lowerings in CuB bases.  I don't remember seeing one with such defined edges and so low.  What was the most impressive to me is that if you watch the video towards the end you see in real time how fast that north side  edge is going up.  Even from miles away it was just rising so quickly that it was impressive to see from a "weather freak" perspective.  

The updraft was strengthening pretty quickly after it passed you (which is why I warned on it). I would guess typical severe updraft speeds around this part of the country approach 60 mph at times. You'll definitely notice that with the naked eye.

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Couple more images from the drone flight after last nights severe thunderstorm.  Went back and slowed the video way down.  Didn't realize I caught 2 lightning bolts.  Kind of interesting from the air.  Don't know how close the second one got to me as it was off the screen.  I was very aware there was still a lot of lightning close by but hey if a bolt hit the drone I probably would have caught a great video even if it would have cost me $1000!

Lightning 1.jpg

lightning 2.jpg

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Just learned from the home front that, shortly after I'd headed to Augusta in the midst of the surprise TS, a very close strike popped at least one circuit breaker down cellar, and left our poor dog shaking and panting.  My wife also saw a lightning-struck sugar maple a mile or so to the west of home, along Weeks Mills Road - branches and leaves on the lawn and folks looking up at the damage.

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6 hours ago, wxeyeNH said:

My observations seem to jive well with this.  I was counting flashes per minute.  For a period around dark I was seeing about 40 per minute along the back side of the line.  I'm sure there were more on the front side so 60 per minute makes sense.

I am still kind of awe struct with my drone video looking at the cell that passed over me and produced the heavy rain and hail.  Got the drone up as it was east.  Sure looks like a well defined wall cloud.  Here is another video.  I'm looking east so rain and hail is leading the cell.  At the SW part is the wall cloud.  Towards the end of the video watch the left side of the cloud.  Incredible upward motion.  I don't ever think I have seen such rapid motion.  Wish I had been closer.  Surprised no wind or damage reports.

 

Your drone has the ability to zoom?! Also great shot!

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