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2019 Rain Thread


Biff Tannen

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Well, no one got time fo' dat shit (i.e. too deep to tackle with my time right now), but while my first thought would be "nah, you just think that" and I still sorta go with that, there is evidence that "tornado alley" has shifted more towards the SE than say 50 years ago.  While the Central Plains (north of Dallas up through BlowU and into Kansas) is still "tornado alley" it's turning out that Arkansas, Missouri, and especially the southern tier of Mississippi, Alabama and Georgia (and southeastern Tennessee) have seen upticks in large, devastating tornadoes in the last 40 years.  One possible reason is that evidence exists that our climate zones might have shifted a bit.

What that means, maybe, is that storm fronts could possibly be more from the NW than "straight down" but hell if I know, and if there are studies out there, they are buried way too deep in some weathergeek journals than even I regularly check.  But there might be...

Austin sits in an interesting spot... about 150 miles east of a definite more arid zone and about 100 miles south of a more "continental" zone (about Waco up is actually a slightly different climate).  Being on these borders, my impression over 30 years has been that weather in Austin is more likely to come from different directions, as, say, the Northeast U.S. or the Great Lakes area (which sit more in the center of large climate areas).  But there is no question that our prevailing summer pattern is SE→NW (with some hotter days SW→NE).  Since fronts in the summer months per se don't happen - most of 'em wash out in DFW or just north), we get very little weather from the north, so this is more the cooler months.  And it's well-known and established that most of our rain in the summer comes from the Gulf (E→W).  Any storms coming from the west simply ride the Dry Line but the hugeass high pressure systems which are normal here late June through early Sept. usually simply block those out - they die maybe as far east as San Angelo (again, a different climate zone).  My guess is that prevailing pattern hasn't changed much in 100 years.

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5 hours ago, phdhorn said:

There have been pretty accurate rain gauges for thousands of years.  What we didn't have as many of 100 years ago are reporting stations.  But believe it or not, the Smithsonian began to supply a lot of people with basic stuff (barometers, wind meters, rain gauges, etc.) to help facilitate the new and growing railway system as far back as the 1840s.  Probably the first large-scale national reporting to one source.  Like everything else almost, war greatly speeds up technology, and the Civil War greatly expanded the accuracy and number of these reporting stations and their data (have to know what the weather's like to blow stuff/people up!).  From there the first real systematic forecasting was done (the invention of the telegraph made this grow quickly).  Pre-Civil War there were about 100 national stations; after the Civil War, there were over 500.  There were thousands of other reporting to local governments/churches/schools. 

The accuracy of a rain gauge hasn't had to improve much in thousands of years, so chances are the reporting is pretty accurate from at least colonial times onward.

The use of local radar as reliable dates from the mid-1960s, and even back then the radars weren't so good.  Probably the biggest leap occurred in the early 1990s.  Actually, if you see what the Doppler really reports to an observer, you would say, "WTF?".  The radar you see has been filtered greatly with "smoothers", it's kind of a user interface on top of raw Doppler data.  It comes out looking something like this: 
c_scale,fl_progressive,q_80,w_800.png


There are actually meteo-snobs who think anyone who looks at the "smoothed" image is a hack, that you need to know how to interpret pixilated imagery exactly.  Yeah, whateverz...

In any event, new-fangled Doppler (say from the last 10 years) is pretty nice. 

But regarding rainfall, people have been reporting amounts to the government since the Egyptians at least.

Useless Fact but kinda cool incoming

 

Weather nerds throughout Europe and the US using barographs learned the awesome power of the Krakatoa explosion in 1883.  Their machines which measure atmospheric pressure usually don't move very much as it notes the pressure on a roll of paper.  When the paper was changed (weekly I think) they saw 7 upticks on the line. After discussing what that could mean they determined that the shock wave of the Krakatoa traveled around the world 7 times.

950.jpg?v=1527194533

Edited by Post Oak
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Update:

While I'm here on a break from my normally busy say mastu... er, doing business, the day went about as planned, no rain.

But here comes the next disturbance from the Southwest.  Squall line right now is running slightly NE coming up from Boerne/Bulverde/Wimberley running NE smack towards us.

This little disturbance is weaker than the bigger one yesterday, but of course the air is so ripe and ground so wet that flooding will probably happen in the usual suspects' places (like yesterday).  Take note!

There will probably be 2-3 lines sweeping in between now and lunch tomorrow... each line could put down up to 2 inches (or more), so we're back in the water again.  I'll keep you posted, but yeah looks like we're about to get hit.  So far nothing severe, but lots of rain.  First line should be in by 5, out by 6.

We'll get a break Thursday daytime, then back into it overnight into Friday.  But the next more concerning stuff is late late Friday, more towards Saturday sunup/a.m.  More on that over the next 24.

Keep alert... these are wet times, when even shrubbers have to fear for their lives.

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Kinda dyin' out, forcefield got to it (I guess it wanted some dignity after the last two weeks).  Looks like the air is still fairly stable above us.

Still, this disturbance is moving over us so these lines can happen between now and tomorow a.m.

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may 25, 2015: rockets play the warriors in the western conference semis, memorial day floods occur in houston.

april 16, 2016: rockets play the warriors in the first round, tax day flood occur in houston.

may 10, 2019: rockets play the warriors in the western conference semis,

 

 

Edited by elfenix
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6 hours ago, phdhorn said:

There have been pretty accurate rain gauges for thousands of years.  What we didn't have as many of 100 years ago is reporting stations.  But believe it or not, the Smithsonian began to supply a lot of people with basic stuff (barometers, wind meters, rain gauges, etc.) to help facilitate the new and growing railway system as far back as the 1840's.  Probably the first large-scale national reporting to one source.  Like everything else almost, war greatly speeds up technology, and the Civil War greatly expanded the accuracy and number of these reporting stations and their data (haveta know what the weather's like to blow stuff/peoplez up!).  From there the first real systematic forecasting was done (invention of the telegraph made this grow quickly).  Pre-Civil War there were about 100 national stations; after the Civil War there were over 500.  There were thousands of other reportings to local governments/churches/schools. 

The accuracy of a rain gauge hasn't had to improve much in thousands of years, so chances are the reporting is pretty accurate from at least colonial times onward.

The use of local radar as reliable dates from the mid-1960's, and even back then the radars weren't so good.  Probably the biggest leap occurred in the early 1990's.  Actually, if you see what the Doppler really reports to an observer, you would say, "WTF?".  The radar you see has been filtered greatly with "smoothers", it's kind of a user interface on top of raw Doppler data.  It comes out looking something like this: 
c_scale,fl_progressive,q_80,w_800.png


There are actually meteo-snobs who think anyone who looks at the "smoothed" image is a hack, that you need to know how to interpret pixilated imagery exactly.  Yeah, whateverz...

In any event, new-fangled Doppler (say from the last 10 years) is pretty nice. 

But regarding rainfall, people have been reporting amounts to government since the Egyptians at least.

Interesting info. Thanks for posting. I know rain measurements have been taken for a very longtime. I was mainly thinking about Tuesdays rain event in a Houston. Two localized areas (Kingwood and Sugarland) received a ton of rain, everywhere else was a normal event. Unless there was one of those buckets located in the right spot I’m not sure you get the true grasp of the total storm. How many of these type of events are missing from the record.

Maybe I’m missing something but how our rain gauges correlated across distances? Similar to wells? 

Im sure some fancy statistics can be used to infill but with our fancy new radars we get a much better picture. Then again equations are used to totalize those values so yea.  

It sure does seem over the last two decades it rains a lot more though. 

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I am supposed to be in the Woodlands all weekend, would cancelling be a good idea?  All I keep seeing is that Houston is going to go all Harvey this weekend.


The Woodlands drains pretty well. Unless your plans are outside, I wouldn’t sweat it too much.
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1 hour ago, Telegraph_it said:

Interesting info. Thanks for posting. I know rain measurements have been taken for a very longtime. I was mainly thinking about Tuesdays rain event in a Houston. Two localized areas (Kingwood and Sugarland) received a ton of rain, everywhere else was a normal event. Unless there was one of those buckets located in the right spot I’m not sure you get the true grasp of the total storm. How many of these type of events are missing from the record.

Maybe I’m missing something but how our rain gauges correlated across distances? Similar to wells? 

Im sure some fancy statistics can be used to infill but with our fancy new radars we get a much better picture. Then again equations are used to totalize those values so yea.  

It sure does seem over the last two decades it rains a lot more though. 

According to FEMA, it doesn't look like the frequency of flood events increased in a straight trend line from 1996 to 2016. There are peaks and valleys, though, that seem to correspond to periods of wet and drought.

Pull the dropbox down for Texas:

https://www.fema.gov/data-visualization-floods-data-visualization

That said, the NOAA recently updated its 100-year and 500-year flood maps which show that it requires more rain to constitute an historic flood in substantial portions of the state (Austin, the Hill Country, Southeast Texas), because of either a) we have better data or b) the events aren't as rare as they used to be. Another way to put it is that we flood more often now than we used to think that we would on a normal basis, at least, as far as I understand it.

https://www.noaa.gov/media-release/noaa-updates-texas-rainfall-frequency-values

Edited by bolverk
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2 hours ago, phdhorn said:

Well, no one got time fo' dat shit (i.e. too deep to tackle with my time right now), but while my first thought would be "nah, you just think that" and I still sorta go with that, there is evidence that "tornado alley" has shifted more towards the SE than say 50 years ago.  While the Central Plains (north of Dallas up through BlowU and into Kansas) is still "tornado alley" it's turning out that Arkansas, Missouri, and especially the southern tier of Mississippi, Alabama and Georgia (and southeastern Tennessee) have seen upticks in large, devastating tornadoes in the last 40 years.  One possible reason is that evidence exists that our climate zones might have shifted a bit.

Tornadoes just trying to prove they SEC good 

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1 hour ago, bolverk said:

According to FEMA, it doesn't look like the frequency of flood events increased in a straight trend line from 1996 to 2016. There are peaks and valleys, though, that seem to correspond to periods of wet and drought.

Pull the dropbox down for Texas:

https://www.fema.gov/data-visualization-floods-data-visualization

That said, the NOAA recently updated its 100-year and 500-year flood maps which show that it requires more rain to constitute an historic flood in substantial portions of the state (Austin, the Hill Country, Southeast Texas), because of either a) we have better data or b) the events aren't as rare as they used to be. Another way to put it is that we flood more often now than we used to think that we would on a normal basis, at least, as far as I understand it.

https://www.noaa.gov/media-release/noaa-updates-texas-rainfall-frequency-values

Again, historic floods increase due to increased housing.  Less dirt to absorb water = more runoff. Regular wet year rains turn into flooding rains due to concrete.   

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That’s me. A vicious hail storm with golf ball sized hail just ended. Blew out four windows on my north side. I’m now sitting in the dark.
Damn, that's crazy. Golf ball sized supposedly just missed us. Looks like more coming from the SW so I'm sure we'll get hit before the night is through.
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3 hours ago, Telegraph_it said:

Interesting info. Thanks for posting. I know rain measurements have been taken for a very longtime. I was mainly thinking about Tuesdays rain event in a Houston. Two localized areas (Kingwood and Sugarland) received a ton of rain, everywhere else was a normal event. Unless there was one of those buckets located in the right spot I’m not sure you get the true grasp of the total storm. How many of these type of events are missing from the record.

We had a much worse event around Marble Falls within the last 10-15 years - something like 20 inches of rain in 24 hours.  Rain bombs or whatever probably happen more than we think,  but if you’re not in that area, you wouldn’t know it.  

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1 hour ago, BLKNSTY said:

r/houston.

A dozen pictures of golf to tennis sized hail from Sugarland to Humble.


Sent from my iPhone using Tapatalk

I'm glad I missed out on that earlier shit. Southern Sugar Land was bone dry until about an hour ago. Still plenty of time to get rekt.

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