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2019 Rain Thread

Biff Tannen

By Biff Tannen
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phdhorn
phdhorn

Figured I'd post this here, it's where you'd look for me. First, thanks very much for the concern (I had no idea), it's appreciated.  I mean, really?  Wow, that's been surprising. Second, I'm fi

DonnyKerabatsos
DonnyKerabatsos

is the excessive rain this year being triggered from the ash rising to the atmosphere from the concentration camps on our border?  Like volcanoes creating storms when the erupt? 

Patricio Swayze
Patricio Swayze

So after my company started sending people home, a coworker of mine who takes the metro in from cypress left to catch the bus. He got to the NW transit center at 610 and old Katy road and they decided

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clapclapclap

clapclapclap 9000

Posted
Posted (edited)

The weather gods do not look kindly on land theft:

D6-yy9_XkAEoACW.jpg

 

It's also the anniversary of one the deadly Moore mega tornadoes .  Torcon of 9, the setup is being compared to Tuscaloosa 2011.  State Dept is evacuating all non-essential personnel from Moore.

Edited by clapclapclap
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'stache

'stache 21729

Posted
Posted
1 hour ago, atomheartbevo said:

Surprised at all of the schools closing.  They scared.  

People are upset at school closings based on a forecast, but lets also remember that some elementary school kids  died in a tornado in Moore a few years ago, so with that fresh on the memories of many, I'm okay with being over protective. 

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irishtexan

irishtexan 11435

Posted
Posted
4 minutes ago, 'stache said:

People are upset at school closings based on a forecast, but lets also remember that some elementary school kids  died in a tornado in Moore a few years ago, so with that fresh on the memories of many, I'm okay with being over protective. 

And let's be honest, these are schools in Oklahoma. It's not like they are really learning anything anyway. 

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atomheartbevo

atomheartbevo 89304

Posted
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20 minutes ago, 'stache said:

People are upset at school closings based on a forecast, but lets also remember that some elementary school kids  died in a tornado in Moore a few years ago, so with that fresh on the memories of many, I'm okay with being over protective. 

Didn’t realize Moore was 6 years ago today.  

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phdhorn

phdhorn 6224

Posted
Posted (edited)
12 minutes ago, atomheartbevo said:

Didn’t realize Moore was 6 years ago today.  

You mean Moore VI of X.  Moore has had 10 tornadoes since 1998, 3 of them killers and major damagers.   There have been 20 tornadoes at least touching down in Moore or within 10 miles of its border (in then-uncorporated parts) since 1893.

Moore is not the best place to be in the spring, well ever. 

Austin may be the Pollen and Facepalming Hipster Capital of the United States, but thankfully it lies too far SE in the "tornado belt" to get all that many.

Edited by phdhorn
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Brisketexan

Brisketexan 104227

Posted
Posted
You mean Moore VI of X.  Moore has had 10 tornadoes since 1998, 3 of them killers and major damagers.   There have been 20 tornadoes at least touching down in Moore or within 10 miles of its border (in then-uncorporated parts) since 1893.

Moore is not the best place to be in the spring, well ever. 

But back in the 80s, I knew a really pretty brunette with significant attributes who lived in Moore. So, 14 yr old brisket thought Moore was awesome.
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Okie State

Okie State 3747

Posted
Posted
Not sure what's safer... kids being home alone during a tornado or crouched in a school hallway/wind tunnel generally sanwiched between glass doors.  Though, iirc, the kids that died six years ago during the tornado actually drowned.
I believe a wall collapsed on them in the school. Several people drowned in the additional tornadoes just a week or so later.
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atomheartbevo

atomheartbevo 89304

Posted
Posted (edited)

From wiki - walls collapsing killed 7 students 

https://en.m.wikipedia.org/wiki/2013_Moore_tornado

Quote

On the afternoon of Monday, May 20, 2013, a large and extremely powerful EF5 tornado ravaged Moore, Oklahoma, and adjacent areas, with peak winds estimated at 210 mph (340 km/h), killing 24 people (plus two indirect fatalities)[2][3] and injuring 212 others.

Quote

At Plaza Towers, the second school to be hit, parents had been allowed to collect their children early in preparation for the oncoming storm, as by the time the tornado struck only about 75 students and teachers were in the building. Many students and teachers took shelter in bathrooms and closets, but in a newer addition to the building which housed the school's second and third grade classrooms, seven fatalities occurred. Third grade teacher Jennifer Doan was taking shelter with eleven of her students in a hallway when the tornado struck. Doan and her students were trapped when the walls of the corridor collapsed on top of them. Doan, who was two months pregnant with her third child at the time, suffered severe injuries to her back, but did not lose the baby. She and five of her students were pulled out, with the children suffering only minor to moderate injuries. Tragically, six of her students along with a student from another third grade class died

 

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Sandman

Sandman 3401

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9 minutes ago, Knoxtnhorn said:

I thought they'd taken cover in a basement, couldn't get out, and water filled the room.  I could be mistaken.  Either way, absolutely horrible to consider.

That's what happened. They got trapped and the water poured in on them. Plaza Towers Elementary. Horrible.

We're up to a 45% chance of tornadoes. It's getting serious up here.

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phdhorn

phdhorn 6224

Posted
Posted

So for this thing tomorrow ff...:|

Pretty strong low sweeping on in but again, the Jets (not the team, the winds) are moving pretty strongly SW→NE and once again it'll be too far north to drop much heavy rain and/or severe weather (which is going to get pretty nasty up there the next 2 days).   A line of storms, almost certainly not severe, probably broken here/there, coming through Tuesday morning.  Maybe an inch in spots, then clearing.  The thing you'll notice though is that this front will sweep out the mugginess (for at least a day) although it'll get up to near 90°.  Mugginess slowly returns through the week.  Dry as well for the rest of it.

That's really about it for our area.

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Brisketexan

Brisketexan 104227

Posted
Posted
So for this thing tomorrow ff...:|

Pretty strong low sweeping on in but again, the Jets (not the team, the winds) are moving pretty strongly SW→NE and once again it'll be too far north to drop much heavy rain and/or severe weather (which is going to get pretty nasty up there the next 2 days).   A line of storms, almost certainly not severe, probably broken here/there, coming through Tuesday morning.  Maybe an inch in spots, then clearing.  The thing you'll notice though is that this front will sweep out the mugginess (for at least a day) although it'll get up to near 90°.  Mugginess slowly returns through the week.  Dry as well for the rest of it.

That's really about it for our area.

Supposed to fly out of here to dallas tomorrow 10:30-11:30...should the weather have passed by then?
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InkaUtexas

InkaUtexas 25289

Posted
Posted
2 minutes ago, dingleberryswitzer said:

What are those schools made of?  Seems like every school I've been inside of is made of cinder block walls and concrete beams and floors.  I'd feel safer in there than my house made of 2x4s.

Yeah, but Okie engineering. So you know that shit is crooked! 

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Okie State

Okie State 3747

Posted
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According to Wiki:

Among the hardest hit areas were two public schools: Briarwood Elementary School and Plaza Towers Elementary School. A preliminary study of Briarwood Elementary School conducted in September 2013 by a group of structural engineers found some structural deficiencies that led to its collapse during the tornado. Chris Ramseyer, a structural engineer and an associate professor at the University of Oklahoma determined that the building's walls that were not reinforced with concrete, there had been a lack of connection between the masonry walls and support beams in several portions of the building, and anchor bolts were pulled from the ground by the tornado. Another engineer that was involved in the study stated that the deficiencies that Ramseyer pointed out were not uncommon building practices at the time, and that current building code standards would not ensure that Briarwood would have withstood winds in excess of 200 mph.[42]

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atomheartbevo

atomheartbevo 89304

Posted
Posted
1 hour ago, dingleberryswitzer said:

What are those schools made of?  Seems like every school I've been inside of is made of cinder block walls and concrete beams and floors.  I'd feel safer in there than my house made of 2x4s.

Sustained 200mph winds.  Cheapest contractor.  

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phdhorn

phdhorn 6224

Posted
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Looks like a big motherfucker is forming north of Stillwater, near Marshall.  Warnings issued, we'll see how long it lasts, so far they're not lasting too long/touching down longer than a min. or two...  But I think they'll get worse as they hit the moister/warmer air points S and E of OKC.

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Assman

Assman 1830

Posted
Posted (edited)

@phdhorn

I've had the Radar Scope app for a couple years and use the velocity tilt often to check out the wind speeds and direction to try to spot rotation, so I have a handle on that. However, can you explain to me some of the parameters shown in the pic here. I mean, most of them seem self explanatory, but at what point does someone smart look at these numbers and say oh shit this is serious?  I know what a TVS is, and it seems the max delta velocity it just basically the max wind speed within the rotation?  What about the shear numbers?  What else would a trained meteorologist or storm chaser be looking at?

463311cf40362f10ea6565ba853b6ab9.jpg

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phdhorn

phdhorn 6224

Posted
Posted
42 minutes ago, Assman said:

@phdhorn

Here's the parameters of a mesocyclone. Can you explain the "storm relative depth", "strength index" and what triggers a TVS true/false?

ea7e30a44c085abd9537909b85c4cb21.jpg

Oh man, these aren't quickie answer questions... but...
... I'll make 'em quick (for now).

- Some of these features have been around for years, some now just cropping up on "radar packages"... most are good descriptors of what's going on but should not be used to make decisions per se.  It's more during/after the fact.  Plus, you can easily have a tornado (especially a weak one) without some of these factors.

- One more quick context:  for several decades, but especially the last 15 or so, one "breakthrough" that seems to have occurred with understanding tornadoes is that sorta somehow, a wind "gets going" on the surface, a circular type of thing, kind of like a "sideways tornado" only the wind isn't (yet) nearly as fast.  That "sideways wind" gets picked up in a supercell as updrafts increase (i.e. air going up into the cell and becoming vertical).  Then that air cools as it rises, gets faster, and begets all kinds of hell (hail, electricity... and spinning vertically).  So the idea is that a tornado usually (well, educated guess) develops when 2 factors are present, and usually both must be present - only one doesn't cut it.  The factors are:  1) velocity of the column of air begins to show a great contrast (usually the upper part in mid-level atmosphere spins a lot faster than the lower part).  And: 2) there needs to be sort of a continual 90° "bend" of horizontal inflow air, which gets pulled up, gets vertical, and spins faster.  Again, this seems to be a reliable factor, but it's the tip of an otherwise non-really-well-understood deal.  So what some of these values are, are measures of the strength of the differences in velocities through the air at lower levels (LLRV in the graphic above), maximum difference between velocities measured at various levels (MRV), and the greatest difference in the lowest clear level of rotation (LLDV).  What all this boils down to is that tornadoes like 1) "bent" wind coils, and 2) different velocities (shear) up the column.  

Basically this is akin to sabermetrics in baseball... a lot of newfangled measurements that might mean something significant... but might not.  Fun stuff to play with, but not supposed to be at this point anyway the Ten Commandments of Tornado Formation.

So I'm gonna skip over the very long links between this idea and the metrics for the most part (lots of calculus there), so I'll just answer the others you named:

- Storm relative depth - this is a general number derived by calculating the distance between the storm's inflow (usually at or near ground level) and the height of the storm's most pronounced shear point (greatest difference in velocities in the column) within the lower levels of the storm (something called effective bulk shear, or EBS).  These are complex calculations, with readouts that would stymie Einstein, but it's sort of boiled down here to the percentage of the column where these extremes take place; i.e. the distance is about 62% of this column in the lower part of the storm.  It is not a simple measurement of the storm's height or whatever.  The idea here is that the larger the % in this figure, the more likely a storm is to have tornadic potential - but again, it doesn't mean it'll happen.

- Strength index is again a fancy calculation of measured points in the lower level of the storm.  The idea here is that it seems that storms that might go tornadic often have strong rotation, often the strongest in their lower levels (makes sense, a storm with higher speed rotation in the upper levels might not touch down and so there's no tornado).  Storms with higher lower-level rotation get the higher number... so a storm with say 2,304 is going to be "less likely" to go tornadic as one with say 6,403.  In this case, 4392 is about lower-mid severity on the scale.  Storms with 6500 or above are most often associated with tornadoes.

- TVS signature - this is a 1/0 terminology determined by a bunch of calcs (duration, depth of shear/column, speed, etc. a figure that covers the speed of rain moving to/from the sample point, etc.) that all gets boiled down to a "true" or "false".  However, again, 1) storms that show "true" might be rotating higher up, so it's not a given that it's going to be a touchdown, and 2) there have been tornadoes, especially weaker ones (EF0-2) that might not even have this signature because the vertical column of shear might be very shallow or so discombobulated that the signature hasn't shown up.  You often see these signatures in the well-known "red/green -yin/yang" Doppler signatures air/rain moving toward the sample point shows up green, moving away red).  Usually when you see that popping up, you tend to ignore the "true" or "false" determinations (it's right there before your eyes, though 99% of the time it'll be "true).  This is more for less-developed shear storms.  In this case it says that it's not  (yet?) picking up the traditional to/from diversity in a rotating storm.

The calculations themselves are way out of my league, but I sort of understand what they mean.  Good enough for now, I guess.

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Hate

Hate 20095

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Posted
That thing looks like it’s been on the ground for 45 minutes, and they are saying it’s still being observed.  
Moving 50mph and just about to Arkansas.  


I was just about to Arkansas too, but it was just a fart.
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Assman

Assman 1830

Posted
Posted (edited)
36 minutes ago, phdhorn said:

Oh man, these aren't quickie answer questions... but...
... I'll make 'em quick (for now).

- Some of these features have been around for years, some now just cropping up on "radar packages"... most are good descriptors of what's going on but should not be used to make decisions per se.  It's more during/after the fact.  Plus, you can easily have a tornado (especially a weak one) without some of these factors.

- One more quick context:  for several decades, but especially the last 15 or so, one "breakthrough" that seems to have occurred with understanding tornadoes is that sorta somehow, a wind "gets going" on the surface, a circular type of thing, kind of like a "sideways tornado" only the wind isn't (yet) nearly as fast.  That "sideways wind" gets picked up in a supercell as updrafts increase (i.e. air going up into the cell and becoming vertical).  Then that air cools as it rises, gets faster, and begets all kinds of hell (hail, electricity... and spinning vertically).  So the idea is that a tornado usually (well, educated guess) develops when 2 factors are present, and usually both must be present - only one doesn't cut it.  The factors are:  1) velocity of the column of air begins to show a great contrast (usually the upper part in mid-level atmosphere spins a lot faster than the lower part).  And: 2) there needs to be sort of a continual 90° "bend" of horizontal inflow air, which gets pulled up, gets vertical, and spins faster.  Again, this seems to be a reliable factor, but it's the tip of an otherwise non-really-well-understood deal.  So what some of these values are, are measures of the strength of the differences in velocities through the air at lower levels (LLRV in the graphic above), maximum difference between velocities measured at various levels (MRV), and the greatest difference in the lowest clear level of rotation (LLDV).  What all this boils down to is that tornadoes like 1) "bent" wind coils, and 2) different velocities (shear) up the column.  

Basically this is akin to sabermetrics in baseball... a lot of newfangled measurements that might mean something significant... but might not.  Fun stuff to play with, but not supposed to be at this point anyway the Ten Commandments of Tornado Formation.

So I'm gonna skip over the very long links between this idea and the metrics for the most part (lots of calculus there), so I'll just answer the others you named:

- Storm relative depth - this is a general number derived by calculating the distance between the storm's inflow (usually at or near ground level) and the height of the storm's most pronounced shear point (greatest difference in velocities in the column) within the lower levels of the storm (something called effective bulk shear, or EBS).  These are complex calculations, with readouts that would stymie Einstein, but it's sort of boiled down here to the percentage of the column where these extremes take place; i.e. the distance is about 62% of this column in the lower part of the storm.  It is not a simple measurement of the storm's height or whatever.  The idea here is that the larger the % in this figure, the more likely a storm is to have tornadic potential - but again, it doesn't mean it'll happen.

- Strength index is again a fancy calculation of measured points in the lower level of the storm.  The idea here is that it seems that storms that might go tornadic often have strong rotation, often the strongest in their lower levels (makes sense, a storm with higher speed rotation in the upper levels might not touch down and so there's no tornado).  Storms with higher lower-level rotation get the higher number... so a storm with say 2,304 is going to be "less likely" to go tornadic as one with say 6,403.  In this case, 4392 is about lower-mid severity on the scale.  Storms with 6500 or above are most often associated with tornadoes.

- TVS signature - this is a 1/0 terminology determined by a bunch of calcs (duration, depth of shear/column, speed, etc. a figure that covers the speed of rain moving to/from the sample point, etc.) that all gets boiled down to a "true" or "false".  However, again, 1) storms that show "true" might be rotating higher up, so it's not a given that it's going to be a touchdown, and 2) there have been tornadoes, especially weaker ones (EF0-2) that might not even have this signature because the vertical column of shear might be very shallow or so discombobulated that the signature hasn't shown up.  You often see these signatures in the well-known "red/green -yin/yang" Doppler signatures air/rain moving toward the sample point shows up green, moving away red).  Usually when you see that popping up, you tend to ignore the "true" or "false" determinations (it's right there before your eyes, though 99% of the time it'll be "true).  This is more for less-developed shear storms.  In this case it says that it's not  (yet?) picking up the traditional to/from diversity in a rotating storm.

The calculations themselves are way out of my league, but I sort of understand what they mean.  Good enough for now, I guess.

I can't rep this enough.  Thanks for the explanation...which of course leads to some follow up questions in which you can politely tell me to STFU if you wish.

1.  With the LLDV, since this is a delta, with a number like 108kts in the example above, does this mean that the max winds within the column of air are way above 108kts?  Or is it possible that the max could be 109kts and the min 1kt, hence the 108kt delta?  Also, since you're saying the more shear, the more likely a tornado, in general, can you say the higher LLRV, LLDV, and MRV are, the more likely a tornado, and/or the greater chance for a strong tornado?  Is there one value that is more indicative of a tornado than others?  I think I'm tracking that MRV + LLRV = LLDV?

2.  With the storm relative depth, you say the % is the total distance from the inflow to the max shear point, and that a higher % means a greater potential for a tornado.  However, wouldn't a low % mean a lower-level shear point (altitude wise) which might indicate more instability on the surface?

3.  On my first post on the previous page, I included a TVS readout.  One of the parameters is max shear (measured in m/s/km) and height of max shear.  Is there a scale for max shear?  What's considered a lot?  Also, if you look at that read out, the Height of Max Delta Velocity, storm base, and Height of Max Shear are all at 1.9K feet.  Does this mean the maximum shear is right at the cloud base?  This kind of ties into my second question about the "ideal" altitude for shear.  What's worse:  high altitude or low altitude shear?

 

Edited by Assman
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