Skip to content

Storm Harvey Update

August 28, 2017

By Paul Homewood

 

 

Catastrophically for parts of Texas, Tropical Storm Harvey is not done yet:

 

 

image

“Catastrophic” flooding in the US state of Texas is only expected to worsen in coming days as waters rise following a storm of historic proportions.

A record 30in of rain (75cm) has already fallen on the city of Houston in the wake of Hurricane Harvey, turning roads into rivers.

But forecasters say that number could nearly double later this week.

image

http://www.bbc.co.uk/news/world-us-canada-41074919

 

Already some are attempting to link Harvey with global warming, for instance here. This is despite the US having gone a record amount of time without a major landfalling hurricane.

The real story is that Harvey has been stuck between two high pressure cells since making landfall, thus dragging in large amounts of moisture from the Gulf, and continuously dumping it on a comparatively small area around Houston.

 

Current forecasts suggest about another 15 in to fall over the next three days, before things settle down.

As of Sunday evening, rainfall totals have been up to 27 in.

 

image

https://web.archive.org/web/20170828050322/http://www.wpc.ncep.noaa.gov/discussions/nfdscc1.html

 

There is nothing at all unprecedented about amounts like this. The all time record for 24-hour rainfall in Texas was 42 in, set during Tropical Storm Claudette:

image

https://www.ncdc.noaa.gov/extremes/scec/records

 

 

In fact there was a succession of catastrophic storms during the 1960s and 70s, when the Texas climate became much cooler, as the Texas Almanac records:

image

image

image

image

image

image

image

http://texasalmanac.com/topics/environment/significant-weather-1960s

 

According to NOAA, the rainfall from Amelia  was actually much greater, amounting to 48 in at Medina, most over just four days, from Aug 2 to Aug 5.

 

Obviously most of the damage from Harvey has been due to the amount of rainfall, but it is worth taking a look at wind speeds as well, according to NCEP:

image

https://web.archive.org/web/20170828050322/http://www.wpc.ncep.noaa.gov/discussions/nfdscc1.html

 

As reported by satellites, Harvey peaked at a sustained speed of 115kt, or 132mph, just before landfall.

However, this appears to be at odds with the land based data, where the highest PEAK GUST was 132 mph. Wind gusts are typically about 1.3 times as high as 1-minute sustained speeds, according to NOAA, which suggests that Harvey’s sustained speeds at landfall were about 100 mph, making it a Cat-2 hurricane.

Note that hurricanes like Carla and Celia were much more powerful at landfall. Once more, this raises questions about the current practice of comparing satellite data with historical land data. This often results in claims that storms these days are more powerful than in the past.

 

 

In the meantime, let us pray that Texas stays safe.

24 Comments
  1. Athelstan permalink
    August 28, 2017 5:02 pm

    Warm sea, onshore spiralling winds constantly revitilizing the rotation producing near stationary cyclonic conditions, I pray for the people of Texas, we all should.

    The ghouls of globull warbling never let an opportunity pass, do they? Those unconscionable alarmists only deserve my contempt, spit – or worse.

  2. garyh845 permalink
    August 28, 2017 5:08 pm

    Another set of big numbers in Texas:

    San Antonio’s Great Flood – 1921

    September 7-11th, , 1921

    Later that year, a tropical storm rapidly spun up in the Bay of Campeche. It progressed northwest into Mexico and crossed the Rio Grande. After passing inland into Texas on the 8th, it could barely be identified as a cyclone, except for its associated deluge that drifted northward through Texas. At Taylor, 23.11″ of rain fell in 24 hours. A new 18 hour rainfall record for the United States was set in Williamson County when 36.40″ fell. Thrall reported nearly 40 inches of rain in total, 38.2″ in a 24 hour period. The map to the lower right shows the rainfall accumulations throughout southern and central Texas related to this cyclone (after Tannehill).

    Torrential rains accompanying the decaying system caused one of the most destructive floods in San Antonio’s history. The waters rose so rapidly (a flash flood) that automobiles were deserted and the occupants sought safety in high buildings. Nearly 7 feet of water stood in the large hotels, theaters, and stores. In San Antonio alone, 51 lives were lost in the flooding and damage was estimated at $5 million. The largest floods occurred on the Little and San Gabriel Rivers north of Austin and south of Temple. Along the Little River, at least 159 drowned. Total damages were estimated near $19 million. In all, 215 died due to the flood in the five county area around San Antonio.

  3. August 28, 2017 5:37 pm

    I’ve been looking out for solar panel & wind turbine damage; not seen any reported.
    But the MSM wouldn’t want to.
    Principle is that solar/wind would not be delivering much during/after storm whereas FF would deliver almost all the time.

  4. CheshireRed permalink
    August 28, 2017 5:47 pm

    With droll predictability the Guardian is now hysterically headlining Michael Mann’s claims that ‘It’s a fact, climate change made Harvey more deadly’ blah blah blah. Not opinion, fact. The BS is relentless with these guys.

    No doubt their BTL hemp-knickered hysteria mob are doing his exaggeration proud, but I can’t be arsed to look as I’ve just had my tea.

    https://www.theguardian.com/commentisfree/2017/aug/28/climate-change-hurricane-harvey-more-deadly

  5. August 28, 2017 5:55 pm

    Nice work Paul. I’ve lived in Texas all my life and just turned 65, so I remember all these events and witnessed the passage of the eye of Hurricane Beulah 1967 in South Texas first hand. I agree that the US National Weather Service often seems to rate hurricanes a bit stronger than actual measurements confirm, especially over land. Unfortunately, most land weather stations do not have backup power and therefore miss the highest winds because of power failures well before the peak of the storm, as happened with the airport weather stations KRKP at Rockport and KRAS at Port Aransas and several others that are still offline today. There are a few widely scattered hardened weather stations and buoys in the CMAN network and other similar networks that survived the storm and provided the high measurements you noted. The highest measurement was from a CMAN station on a small platform over water by a jetty with the wind instrument about 14 meters above the normal ocean level, ANPT2 at Port Aransas. You can see a photo of the station and access measurements here:
    http://www.ndbc.noaa.gov/station_page.php?station=ANPT2

    The southwestern portion of Harvey’s eyewall passed over ANPT2, but it’s not clear if the highest winds were in the southwest quadrant. Radar showed the strongest echoes on the northwest through west through southwest side of the eyewall as it made landfall, so it is possible that this measurement does a fairly good job of representing the surface wind speed maximum. There were a couple more hardened weather stations that sample winds in the eyewall near Rockport but measured lower peak speeds (see the NOAA buoy site referenced above).

    Sustained wind speed estimates from the US National Hurricane Center for hurricanes are for 10 meters above the surface and for a 1-minute average (many other countries, as well as NOAA weather buoys, use a 10-minute average so measurements must be converted to match). Over the ocean, or near the coast, this can be very problematic because of high waves and storm surge. I have not seen a definition of “surface” when there are 10 or even 20 meter waves all around, as many buoy stations witness in strong storms. Likewise, land stations at the shoreline can have instruments at 10 meters above the surface of the nearby water in normal conditions, but are not as high above the mean water level with a high storm surge that can sometimes reach 3 to 5 meters or more with waves on top (as happened along the coast with Hurricane Ike 2008).

    Over land, there are often buildings and trees that can partially block and channel winds at 10 meters. Most home weather stations suffer from this problem. Even some airport weather stations can have this problem if the instruments are poorly sited near buildings or trees. Buildings and trees increase the surface roughness, which in turn greatly decreases wind speeds and increases the gust to sustained speed ratio. High surface roughness also decreases the peak wind gusts. Ocean waves also increase surface roughness and buoys may have trouble keeping masts from tilting on steep wave slopes and may get hit by crashing waves. However, regardless of the difficulty of getting accurate wind measurements in severe storms, I agree that the NHC may be pushing their wind estimates a bit too high, especially for typical land locations like homes and business. Tall buildings or towers will be exposed to higher winds than what is experienced at 10 meters above ground, but are not typical.

    • It doesn't add up... permalink
      August 28, 2017 9:23 pm

      You make a number of excellent points about the potential shortcomings of instrumentation, but we have relied on instruments to give us some calibration over time and between events. It’s not clear which measurements NHC are relying on for their categorisation, but as I understand it the Doppler radar measurements are well above surface levels. The other rough and ready guide we have is an assessment of damage caused – the Saffir-Simpson scale extends the Beaufort in just such a way. Wind damage does seem to have been surprisingly limited against the wind speed claims.

    • nigel permalink
      August 30, 2017 6:57 am

      The loop in the link is pretty clear:

      100 knots when it came ashore (=115 mph) and it immediately died. It came ashore on a narrow front (as regards max. wind), and in an unimportant place. Then it got stalled, and it has rained ever since.

  6. manicbeancounter permalink
    August 28, 2017 6:14 pm

    It should come as no surprise that the attribution of Hurricane Harvey to global warming is from Prof Kevin Trenberth of Boulder Colorado. The same wrote in an email to Michael Mann on Mon, 12 Oct 2009 (and copied to the leaders of the surface temperature data sets, such as Gavin Schmidt and Thomas Karl)

    The fact is that we can’t account for the lack of warming at the moment and it is a travesty that we can’t. The CERES data published in the August BAMS 09 supplement on 2008 shows there should be even more warming: but the data are surely wrong. Our observing system is inadequate.

    The result, as is well known to regulars here, has been to bring the temperature data into more line with the theory, rather admit the theory is wrong.

  7. Broadlands permalink
    August 28, 2017 6:24 pm

    Professor Kerry Emmanuel of MIT weighed (waded?) in on hurricanes…12 years ago.

    http://www.nature.com/nature/journal/v436/n7051/abs/nature03906.html?foxtrotcallback=true

    “I find that the record of net hurricane power dissipation is highly correlated with tropical sea surface temperature, reflecting well-documented climate signals, including multi-decadal oscillations in the North Atlantic and North Pacific, and global warming.”

    …And global warming?? Our added CO2 has overwhelmed all the natural variations? Or is there the possibility that they pay no attention to our CO2?

  8. August 28, 2017 7:01 pm

    ‘It should come as no surprise that the attribution of Hurricane Harvey to global warming is from Prof Kevin Trenberth of Boulder Colorado.’

    Is this the climate alarmist equivalent of ambulance chasing?
    http://en.wikipedia.org/wiki/Ambulance_chasing

  9. Douglas Brodie permalink
    August 28, 2017 8:07 pm

    Don’t forget the Galveston hurricane of 1900 which killed at least 6,000 people.

  10. HotScot permalink
    August 28, 2017 8:11 pm

    As sorry as I feel for the Texas residents, I feel I must point out that they seem to go from boom to bust. Beautiful sunny weather they all enjoy for years on end where stories of drought are frequent (as it seems to me), and an occasional violent hurricane dumps lots of water on the place in one go.

    But try living in Ireland, or the West coast of Scotland where the situation is one of almost constant, miserable, annual rain, with the very occasional appearance of the sun. A friend of mine had winter skied all over the world in temperatures down to less than – 20 degrees C, then eventually tried Aviemore. He told me it was the most miserable experience of his life as he had never felt colder, despite it being only -5 degrees C.

    I wonder what the cumulative precipitation levels are like in my home town of Glasgow over the years, between the periods Texas has been being struck by hurricanes? And I wonder what the cumulative sunshine measurements are like in both areas.

    I’m sorry, but you takes your pick, and you takes your chances.

    I don’t pray for Texas as I’m not religious. I do hope the residents are spared tragedies (although I believe there have been some deaths) and I’m sure their local and national government will be working hard to alleviate suffering.

    Now, I would like someone from the climate alarmist fraternity to attempt to persuade me that Glaswegians wouldn’t like the persistent 3 – 5 degrees centigrade difference in temperature between London and Glasgow (a mere 400 miles) to swing their way.

    I live in the South East of England and can assure any alarmist observer that the difference is massive, entirely acceptable, and pleasant.

    • dave permalink
      August 28, 2017 8:50 pm

      • HotScot permalink
        August 28, 2017 9:00 pm

        dave?

        Speak to me. 🙂

      • dave permalink
        August 28, 2017 9:01 pm

        I put up the above link without comment as I was not sure what it would do.
        It actually shows nicely, on a loop, the archived intensity of ‘Harvey’ from satellite measurements.

        It will be seen that the hurricane peaked at slightly above 100 KNOTS (=115 MPH) Which means it snuck into CAT III.

        Those single wind gusts – at Port Aransas of 132 mph and at Copano village of 125 mph – are kind of interesting; as Aransas is a location on an island off-shore and Copano is on the end of a peninsular.

      • dave permalink
        August 28, 2017 9:05 pm

        Just click on the little logo…

  11. August 28, 2017 8:52 pm

    Harvey has certainly been the source of an unprecedented, catastrophic, disastrous deluge of … Hurricane Porn on the BBC, its been like a Christmas pantomime in which the villain (AGW) is made visible to the audience indirectly. All known statistical-artifice weapons have been deployed, with ever increasing hysteria. Clearly a major operation, probably years in the planning, dusted-off in response to The Donald.

    • dave permalink
      August 28, 2017 9:10 pm

      The reams of copy are always ready. We know that. I predicted this a few days ago; perhaps you recall?

      That the howl of joy will go up:

      “THIS PROVES GLOBAL WARMING!!!!!!!!!

      • dave permalink
        August 28, 2017 9:13 pm

        Of course, it will prove a seven day wonder. Unless there is permanent destruction all weather is forgotten.

  12. RogerJC permalink
    August 29, 2017 6:50 am

    Huston is growing at 1,000,000 people per decade, building over Parie and Wet Lands that in the past have absorbed rainfall. But, as usual, this is ignored in favour global warming as the reason for flooding.

    • nigel permalink
      August 29, 2017 11:05 am

      I find it truly odd that most people cannot distinguish the phenomena of Nature from the accidents of their effects on us.

      ‘Harvey’ was a tiddler – it added just 10 to ACE. Less than a year ago, ‘Mathew’ added nearly 50 to ACE – but it happened to wander off into the North Atlantic, in preference to soaking Americans.

      Hurricane (or Tropical Cyclone) activity is still well below last year’s, in both the Northern and Southern Hemispheres:

      http://models.weatherbell.com/tropical.php

      But, mere scientific facts count for nothing in a world of infantile fools.

  13. Farmer Sooticle permalink
    August 29, 2017 7:18 pm

    An article on the BBC website tries to blame climate change, although to its credit there are some opposing arguments:
    “The hurricane is just a storm, it is not the disaster,” said Dr Ilan Kelman, at the Institute for Risk and Disaster Reduction and Institute for Global Health at University College London.
    “The disaster is the fact that Houston population has increased by 40% since 1990. The disaster is the fact that many people were too poor to afford insurance or evacuate.
    “Climate change did not make people build along a vulnerable coastline so the disaster itself is our choice and is not linked to climate change.”

  14. nigel permalink
    August 29, 2017 8:31 pm

    “…the disaster itself is our choice…”

    Correction.

    It is THEIR choice.

Comments are closed.

%d bloggers like this: