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General Severe Weather Discussion 2018


weatherwiz
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54 minutes ago, ct_yankee said:

So... That supercell yesterday produced something like 4 tornadoes from just over the NY state line on out to Long Island, including one that tracked from New Canaan to Norwalk... And nobody comments?

Yeah, I get it that some people just want to move on to winter, but damn... I expected a little more excitement.

@CT Rain and I were chucking :weenie: at each other via text message, does that count?

Almost landed on the anniversary of Windsor Locks too. 

 

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Just now, CT Rain said:

Between text messages, twitter, and nws chat there were a lot of :weenie: chucked. What a day. 

I've been at this a long time now, and I still find myself fascinated by little things like what a razor's edge difference last night was compared to last Friday. 

We're talking maybe 50 J/kg difference in the low levels. That was all we needed to stretch the low level shear.

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1 minute ago, OceanStWx said:

I've been at this a long time now, and I still find myself fascinated by little things like what a razor's edge difference last night was compared to last Friday. 

We're talking maybe 50 J/kg difference in the low levels. That was all we needed to stretch the low level shear.

I mean literally everything on radar was spinning. 

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3 minutes ago, CT Rain said:

I mean literally everything on radar was spinning. 

And SBCAPE MUCAPE were more or less the same, and yesterday shear was about 100 m2/s2 and 20 knots weaker.

These high shear cases, you really need to balance that with enough instability for a robust updraft. Otherwise, it's shredded.

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3 minutes ago, OceanStWx said:

And SBCAPE MUCAPE were more or less the same, and yesterday shear was about 100 m2/s2 and 20 knots weaker.

These high shear cases, you really need to balance that with enough instability for a robust updraft. Otherwise, it's shredded.

It's finding that balance that is so often the challenge. Days that look good just can't seem to strike it. 

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5 hours ago, OceanStWx said:

I've been at this a long time now, and I still find myself fascinated by little things like what a razor's edge difference last night was compared to last Friday. 

We're talking maybe 50 J/kg difference in the low levels. That was all we needed to stretch the low level shear.

Yes, the razor's edge difference. Why does one day fizzle, and another go crazy? That is the key question. It often seems to me that shear doesn't behave as a linear continuum, but rather as a threshold, beyond which you get supercells and rotation, with nothing much happening until that threshold is reached. I've seen countless days out on the Plains where storms will go up and strengthen for hours without showing any signs of rotation, and then bam, suddenly every storm along the dryline will begin to spin and form a strong low-level meso, as if a switch was flipped... But it's almost as if we're not quite measuring the right things, because helicity values and the other parameters we look at don't seem to me to be able to predict exactly when and where that changeover to a supercellular regime occurs. Perhaps it's just that the numbers we look at via mesoanalysis and modeling aren't really reflecting the true state of the atmosphere, I don't know... But we're missing something, or we wouldn't keep getting surprised by these events. Not that Tuesday was a surprise, the SPC and others pretty much nailed it, but you know what I mean... Why was this event nailed, when so many others that looked pretty similar did not perform as expected?


 

 

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It was defintely an impressive event, especially in PA. Some of the things I noticed in this event that stood out, were better lapse rates aloft and shear. Overall you had higher MLCAPE and better shear aloft. I recall previous events having near 50kts or so around 850, but then dropped as you got near 500. The shear in this one was a bit higher and accompanied by a decent mid level s/w.  So this helps sustain mesos that do develop. Also winds screamed from the 200-230 direction just below 850mb. I think this event had winds more veered in that level compared to previous events.

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2 hours ago, CoastalWx said:

Records for tornadoes are tough since everything these days is caught on camera or reported. You can say most since so and so year or most ever, but can get an asterisk too.

An uptick in violent tornadoes would be more alarming.   Technological advancements, like dual pol, coupled with talented meteorologists are helping capture more of these events as well.  Which is really exciting to see from a public safety/emergency response standpoint.  

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3 hours ago, CoastalWx said:

Records for tornadoes are tough since everything these days is caught on camera or reported. You can say most since so and so year or most ever, but can get an asterisk too.

Debbie Downer....CT peeps should be popping the champagne and donning First Time to 8 t shirts.

 

 

but yeah....you are right.

more little spinups being captured on dual pol and cell cameras. 

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44 minutes ago, JJBASHB said:

An uptick in violent tornadoes would be more alarming.   Technological advancements, like dual pol, coupled with talented meteorologists are helping capture more of these events as well.  Which is really exciting to see from a public safety/emergency response standpoint.  

Yeah - and either way there's no real trend in tornado activity around here.

I could see in a warming world our severe weather season expanding some with more events happening in the spring and fall. Warmer waters off New England would certainly help that. 

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2 hours ago, HoarfrostHubb said:

Debbie Downer....CT peeps should be popping the champagne and donning First Time to 8 t shirts.

 

 

but yeah....you are right.

more little spinups being captured on dual pol and cell cameras. 

That wasn’t a downer comment at all. I mean look at Pittsburgh NH. That would have went undocumented even 3 years ago, if it wasn’t for a met friend of mine and OceanStWx. Chris forced the issue. Lots of rinky dink funnels could have been easily missed. On the other hand, some tornado damage could have been straight line winds too. 

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2 hours ago, CoastalWx said:

That wasn’t a downer comment at all. I mean look at Pittsburgh NH. That would have went undocumented even 3 years ago, if it wasn’t for a met friend of mine and OceanStWx. Chris forced the issue. Lots of rinky dink funnels could have been easily missed. On the other hand, some tornado damage could have been straight line winds too. 

Whoosh.   My attempt at humor. 

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14 hours ago, CoastalWx said:

It was defintely an impressive event, especially in PA. Some of the things I noticed in this event that stood out, were better lapse rates aloft and shear. Overall you had higher MLCAPE and better shear aloft. I recall previous events having near 50kts or so around 850, but then dropped as you got near 500. The shear in this one was a bit higher and accompanied by a decent mid level s/w.  So this helps sustain mesos that do develop. Also winds screamed from the 200-230 direction just below 850mb. I think this event had winds more veered in that level compared to previous events.

IMO I think the difference between this event and last week's setup was the s/w support. We had s/w energy traverse right over the region...last week it was all in Canada. I overlooked the s/w support on Monday...I didn't think it was good enough, however, Tuesday night (or maybe it was Wednesday) Anthony Maisello (hope I spelled that right) made a great point in saying that in this situation the s/w forcing was just perfect...you didn't want it too strong b/c with uncapped warm sector crap would have blew up everywhere.

But watching just satellite alone was incredible...supercells right along the boundary. More like OV type stuff or midwest. 

This was quite impressive. One of the more impressive tornadic situations we've probably had. I don't recall if 11/16/89 had an EML or not off hand

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On 10/4/2018 at 5:21 PM, CoastalWx said:

That wasn’t a downer comment at all. I mean look at Pittsburgh NH. That would have went undocumented even 3 years ago, if it wasn’t for a met friend of mine and OceanStWx. Chris forced the issue. Lots of rinky dink funnels could have been easily missed. On the other hand, some tornado damage could have been straight line winds too. 

And you have this on 6/23/15



A viewer send Harvey Leonard this video, he sent it to me, and I forwarded it to NWS BOX.  They were not aware of this video.  They sent someone to check it out, and they indeed found tree damage from this not far from the video location.  It is unlikely this would have been documented without this single video and the forwarding along process.

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On 10/4/2018 at 3:05 PM, CT Rain said:

Yeah - and either way there's no real trend in tornado activity around here.

I could see in a warming world our severe weather season expanding some with more events happening in the spring and fall. Warmer waters off New England would certainly help that. 

There has been a distinct downward trend of U.S. tornado activity starting in 2012.  Some stats:

Going by inflation adjusted tornado counts, through 10/3/18, it is the lowest count on record (since 1950).
 
5 tornado fatalities so far this year.  This is the lowest on record for so late in the year.
 
No EF4 tornadoes in the U.S in 525 days.  This is the longest period on record by 40 days and counting.
 
10 EF3 tornadoes so far this year which is at record low levels for the second year in a row.  2017 had
15 which was the lowest in 30 years.
 
Through 10/6, it has been 1964 days since the last EF5 tornado.  This is the second longest period on
record.  The record is 2922 days set 1999 to 2007.
 
From 5/16/17 to 3/19/18 (306 days), no EF3 tornado occurred in the U.S.  This is by far the longest
EF3+ gap since reliable records began in early 1950s.

From 5/17/17 to 2/23/18 (283 days), there were no tornado fatalities in the 
U.S.  This is the longest
stretch on record.

In 2018, only 3 EF3+ tornadoes occurred through 5/31.  This is the least amount so late into a year in
modern records.
 
Longer term, the tornado drought since 2012 continues with 2018 possibly under 1000 tornado total,
which would make it the 5th time in 7 years.  From 1990 to 2011, every year except 2002 was above
1000.  Record low monthly tornado counts for February, March, May, July, and August have all
occurred since 2010 going back to 1985.
 
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6 hours ago, vortex95 said:

There has been a distinct downward trend of U.S. tornado activity starting in 2012.  Some stats:

Going by inflation adjusted tornado counts, through 10/3/18, it is the lowest count on record (since 1950).
 
5 tornado fatalities so far this year.  This is the lowest on record for so late in the year.
 
No EF4 tornadoes in the U.S in 525 days.  This is the longest period on record by 40 days and counting.
 
10 EF3 tornadoes so far this year which is at record low levels for the second year in a row.  2017 had
15 which was the lowest in 30 years.
 
Through 10/6, it has been 1964 days since the last EF5 tornado.  This is the second longest period on
record.  The record is 2922 days set 1999 to 2007.
 
From 5/16/17 to 3/19/18 (306 days), no EF3 tornado occurred in the U.S.  This is by far the longest
EF3+ gap since reliable records began in early 1950s.

From 5/17/17 to 2/23/18 (283 days), there were no tornado fatalities in the 
U.S.  This is the longest
stretch on record.

In 2018, only 3 EF3+ tornadoes occurred through 5/31.  This is the least amount so late into a year in
modern records.
 
Longer term, the tornado drought since 2012 continues with 2018 possibly under 1000 tornado total,
which would make it the 5th time in 7 years.  From 1990 to 2011, every year except 2002 was above
1000.  Record low monthly tornado counts for February, March, May, July, and August have all
occurred since 2010 going back to 1985.
 

My senior research project is on quantifying tornado data (I switched from my previous topic). But what I've been doing is taking spring tornado data (for the purpose of the project I'm only focusing on spring...mainly due to time available but I do plan on growing this) and creating averages and standardizing the data. I've done the following breakdowns;

1950-Base Periods:

1950-1965; 1950-1975, 1950-1985, 1950-1995, 1950-2005, 1950-2015

1960-Base Periods:

1960-1975, 1960-1985, 1960-1995, 1960-2005, 1960-2015

1970-Base Periods:

1970-1985, 1970-1995, 1970-2005, 1970-2015

1980-Base Periods:

1980-1995, 1980-2005, 1980-2015

1990-Base Periods:

1990-2005, 1990-2015

I just hope my method for computing standard deviations has been correct. I've tried doing so using quartiles to find outliers so they don't alter the average

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On 10/4/2018 at 3:28 AM, ct_yankee said:

Yes, the razor's edge difference. Why does one day fizzle, and another go crazy? That is the key question. It often seems to me that shear doesn't behave as a linear continuum, but rather as a threshold, beyond which you get supercells and rotation, with nothing much happening until that threshold is reached. I've seen countless days out on the Plains where storms will go up and strengthen for hours without showing any signs of rotation, and then bam, suddenly every storm along the dryline will begin to spin and form a strong low-level meso, as if a switch was flipped... But it's almost as if we're not quite measuring the right things, because helicity values and the other parameters we look at don't seem to me to be able to predict exactly when and where that changeover to a supercellular regime occurs. Perhaps it's just that the numbers we look at via mesoanalysis and modeling aren't really reflecting the true state of the atmosphere, I don't know... But we're missing something, or we wouldn't keep getting surprised by these events. Not that Tuesday was a surprise, the SPC and others pretty much nailed it, but you know what I mean... Why was this event nailed, when so many others that looked pretty similar did not perform as expected?

There is a lot of evidence that points to thresholds being necessary for severe weather. But it is a sliding scale, because you are trying to balance shear with instability. Too much shear and too little instability isn't good, but neither is too much instability and too little shear. 

Then you also have issues like our tornado parameter space looks an awful lot like our flash flood parameter space. How do we establish which threat will dominate?

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On 10/4/2018 at 5:21 PM, CoastalWx said:

That wasn’t a downer comment at all. I mean look at Pittsburgh NH. That would have went undocumented even 3 years ago, if it wasn’t for a met friend of mine and OceanStWx. Chris forced the issue. Lots of rinky dink funnels could have been easily missed. On the other hand, some tornado damage could have been straight line winds too. 

Reporting is worlds better now than it used to be. It's not just our wooded tornadoes that produced undocumented blow downs in the past, but even in the Midwest you have every chaser able to film a dust swirl on their phones that otherwise produced no damage.

I mean most of our severe weather doesn't have that "classic" look on radar, and so it's easy to attribute storm damage to straight line winds. Dual-pol certainly helps, because I'm not sure anyone would've thought tornado in Mansfield, CT if it wasn't for the weak TDS.

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On 10/4/2018 at 8:03 PM, weatherwiz said:

IMO I think the difference between this event and last week's setup was the s/w support. We had s/w energy traverse right over the region...last week it was all in Canada. I overlooked the s/w support on Monday...I didn't think it was good enough, however, Tuesday night (or maybe it was Wednesday) Anthony Maisello (hope I spelled that right) made a great point in saying that in this situation the s/w forcing was just perfect...you didn't want it too strong b/c with uncapped warm sector crap would have blew up everywhere.

But watching just satellite alone was incredible...supercells right along the boundary. More like OV type stuff or midwest. 

This was quite impressive. One of the more impressive tornadic situations we've probably had. I don't recall if 11/16/89 had an EML or not off hand

The timing and location of forcing is certainly important. I think also having the warm front draped across the region was helpful too, whereas the busted event before that it blew through to Canada.

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