Have you tried looking at the "Forecast accuracy" on his site ?

www.***********.com

I've done a few assessments and find that whilst he may sometimes do reasonably well in terms of general trends (ie wet & windy second half of the month), he falls down a lot on specifics and of course he has had a few well documented 'disasters'.

For example, he wonders why the Govt still ignore him - after sending them a warning a catastrophic flooding in August 2007 ......

(and he did forecast that the weekend of the July 2007 floods hit here would be one of the few periods that month which were going to be warm, dry and sunny with no flooding)

When the Nov 2009 floods hit Cumbria he had, to be fair, warned of flooding and a storm surge .... In East Anglia ......

http://weatherearthnews.blogspot.com/2009/11/19th-november-flooding-in-britain.html

I've found his hindcasts pretty stunning though!

The wetest days were the 20th and 23rd July, either side of the weekend, and both within the forecast periods for heavy rain and floods. That weekend was actually the shortest dry period forecast on the whole month`s forecast.

If you want to inspect it, mail me and I will forward it.  [email protected]

He claims 85% success rate, not 100%. As the weather is mostly quiet or uneventful for much of the time, his successes may go un-noticed for much of the time. The examples n which you pick Andy would have a web presence because of the nature of the event. Maybe that constitutes the 15% errors .

Except the link I provided earlier credits him with much less than a 85% success rate.

It all depends on how he validates his forecasts. He may predict a storm in a 3-day window in October, but the chances of a depression crossing the UK in any 3-day period in October is fairly high. Does it count as a success if he predicts gales and flooding and it's just damp and a bit breezy?

Stu, there are independant verification pdf`s on the Weather Action site.

Well he did once claim success because he'd forecast a deep depression to the SW with gales and a storm surge affecting SW England ........ and there was a storm in the Baltic instead!

Thks, I already have his forecast, which reads:

"17-19th Rapidly becoming
wet or very wet with hail &
floods. Windy & cool.
Low pressures sweep in from West
as High pressure recedes. Deep
Low develops in Scandinavia later.
Enhanced tornado risk - Mod
Aurora likely
20-21st Dry fine & bec
warm or v warm & humid.
High pressure builds from North as
shallow lows wallow to
South/SouthWest."

The synoptic situation was completely different to what he forecast.  And the rain fell on the 20th/21st.

And if you keep forecasting floods in July every few days, then there's a very high chance that somewhere or other a thunderstorm will produce a flash flood within a day or so of one of the periods you said flooding would occur!   But he did not predict the nature, intensity, type or synoptic situation that actually did produce the floods.  An epic fail IMHO.

That would be tricky if there were no floods in a given July ! Persionally looking at the whole forecast, I would be more concerned about the lack of floods around the 9th to 12th. I am very conversant with solar forecasting, and would of myself picked the 20th as a very wet day. (only 28.6mm max on the 21st).

Is this you on WUWT Breezy?

Are you able to back this up? My master's thesis was about cooling after large volcanic eruptions.

You should have looked at cooling before them. How many can you name where you think there is cooling after the eruption?

The effects of an eruption that size might last five or six years. Your graph only shows three.

Show us a fifty year span with Krakatoa in the middle and then we'll talk.

What am I supposed to make of it? There was cooling after the eruption, which occurred in August.

So of the last 3 major eruptions, I say two caused cooling and one had its cooling masked by the biggest El Nino on record (at the time).

They show a large decrease in direct solar radiation following eruptions (because volcanic aerosols scatter sunlight) and a smaller rise in diffuse solar radiation, again due to scattering (figure 2 in particular). Let's take Pinatubo as an example, and see that the peak reduction in direct solar radiation, measured in Hawaii, is from ~530W/m2 to ~390W/m2, a drop of ~140W/m2. The concurrent rise is diffuse radiation is from ~40W/m2 to ~140Wm/2, a rise of ~100W/m2.

How do you propose this observed decrease of incoming radiation of ~40W/m2 does not have the effect of cooling the Earth's surface?

I thought you might try to give a long lists of events with cooling following, not that there really is enough to make such a list, as warming usually follows large events. The woodfortrees graphs you show are lower troposphere, that is not surface temp`s. The cooling of the lower trop` 92 would more likely be due to increasing low cloud cover.

So you want to claim 3 months cooling of 0.2C after Krakatoa then ? Mid 1885 goes a bit cold briefly, that`s too late by then though, the aerosols would have washed out by then.

Ok, 1783 Laki eruption, England under the ash cloud for 3 months continuosly, with the pavements so hot you could fry meat on them , according to Rev Gilbert White ???

I you had 3 or 4 ceturies worth, with many events that show cooling in European monthly temperature series, I might take you seriously.

What about the radiative physics? 40W/m2 is a lot.

5 or 6 years ? never.

50yrs ? no point talking with you, you make no sense.

40W of what visible wavel length, what about IR bands ?

Probably a super greenhouse effect occurring with the aerosols, especially if they are dark.

Anyway, if you check your large events data you will see the bigger temp` drops are before the eruptions and not after.

Yes by 3 years the vast majority of the aerosol would be gone. A longer time period would however help with seeing the effects in context and compare it to other natural variability.

BTW I realise I reglected to respond to your point about Laki. Two rebuttals:

First, you're not considering the global or even hemispherical effects. Yes it's clear NW Europe was incredibly hot that summer. But there was also extreme cold to follow shortly afterwards in the USA and Europe. But instrument records are not comprehensive enough to draw conclusions about what Laki did to the global climate.

Second, Laki was far from your typical explosive eruption. For 8 months it spewed lava and sulphur containing gases into the troposphere forming a vast cloud of volcanic fog. Usually these tropospheric aerosols are washed out in days to weeks, but these were constantly replenished. It is theorised, but of course far from proved, that the nature of this smog in the stagnant weather pattern Europe had that summer contributed to the intense heat by absorbing solar radiation.

Meanwhile Laki also had several exlosive episodes capable of injecting sulphur into the stratosphere, where aersols have a longer lifetime. After the dissipation of the tropospheric haze this would have an effect over the next 2-3 years.

The aerosols interact only weakly with IR because the size of sulphate aerosols, about 0.5 microns, is similar to the wavelength of visible light and considerably smaller than the wavelength of IR. Also, the power of the sun's visible output is much more than its IR output:

These effects combined mean that the effect on the visible is much greater. A warming of the stratosphere is observed due to aerosols absorbing a bit of visible and (mainly terrestrial) IR. This in turn can warm the poles a bit during the polar winter by re-radiating to the surface but the prevalence of water vapour's effect on the IR spectrum elsewhere make this effect negligible.

So overall the effect in the visible is significantly larger.

So you want it both ways. Sensibly you see the smog in 1783 trapping heat, as we saw with smoke in Moscow last summer, but you deny it will trap heat or IR further up. And BTW, according to popular notions, Europe would get warmer winters and cooler summers after an eruption, so that doesn`t fit with the 1783/4 winter, which was a natural event, being the almost exact astronomical analogue as 1962/3 winter. You see, you have absolutely no way of discerning as to whether any  temp` drop is from "natural variation" or not.

Almost half of surface heating from the Sun is from IR, and I doubt what you say about so2 not absorbing it.

So you`re saying the aerosols get heated by OLR but not incoming IR,  mmm !

The nature of the aerosols differs according to altitude. The sulphur dioxide and, to a lesser extent, hydrogen sulphide emitted by volcanoes forms sulphuric acid. This chemical attracts water like nobody's business, but there isn't much of that available in the stratosphere so the aerosols are very small and very thinly spread out (Pinatubo emitted just ~20 megatonnes of sulphur dioxide, mostly into the stratosphere, compare with Laki's ~120 megatonnes, with plenty into the troposphere). So with Laki producing more tropospheric aerosol, with more H20 available to react with, the aerosols would have been bigger. Tropospheric and stratospheric aerosols have such different properties it's not valid to compare them like-for-like.

Also, the aerosol cloud cannot efficiently trap heat higher up because it's too diffuse. 20MT spread globally in the stratosphere again cannot be compared to a thick volcanic fog sitting over Europe for weeks on end.

I do not deny that the aerosol cloud warms, in fact I already noted that it does. Trouble is it warms the stratosphere, not the troposphere or surface (apart from the limited case of the polar night when it can conceivably have a measurable effect). See the paper I linked to on the previous page, it very clearly show stratospheric warming following the eruptions.

Generally the thinking is volcanoes cause warming winters in Europe. I agree!

But: Warmer winters applies to tropical eruptions and usually not high latitude ones. The reason is fairly simple to explain, in that following a tropical eruption the stratospheric aerosol cloud tends to be thickest in the tropics (sorry for stating the obvious). As I mentioned above, the aerosol cloud warms the stratosphere. Also, due to the tropics having a greater availability of energy coming in and going out, this is where the stratosphere warms most.

This increases the equator to pole temperature gradient, and via thermal wind and all that the jet streams tend to strengthen in the 1 or 2 winters following a tropical eruption. Hence zonal flow and warmer than normal continental winters. This is also in the paper I linked to earlier. High latitude eruptions are not able to do this as effectively as the aerosol can't reach the equator in any great quantity (stratospheric meridional flow is slightly poleward).

But as I said more than once, Laki was not tropical and was not a typical explosive eruption. One thing you're right about is that you can't tell whether the winter would have been cold anyway.

(Quibble: the aerosols are little droplets of h2so4, sulphuric acid, not so2 which is a precursor chemical).

I realise I have been a bit sloppy, sorry. You are right about near IR, I had it stuck in my head that IR = longwave but this is not necessarily the case. I should have partitioned the spectrum into 'shortwave' and' longwave', the dividing line being 4 micons wavelength, because there is very little solar radiation longer and very little terrestrial radiation shorter. So here goes a hopefully clearer explanation:

Most solar IR is in the near IR, close to the visible spectrum. As you move away from the characteristic size of the aerosols, they interact less with the incoming radiation, but it does help warm it up and reduce the radiation received at the surface. This all counts as 'shortwave forcing' and affects incoming solar radiation. Consider this a correction to my previous post, replacing 'visible' with 'shortwave'.

You raised the possibility of a greenhouse like effect; because the aerosols are only in the stratosphere, the stratosphere warms up. But they don't interact that strongly with longwave so the longwave effect is much smaller than the shortwave effect (see, well, any of the literature to back this up).

Well, this has been a bit rambling. Dr. Alan Robock is his 2000 paper 'Volcanic Eruptions and Climate' explains it better than I (emphasis mine):

"Since the sulfate aerosol
particles are about the same size as visible light, with a
typical effective radius of 0.5 micrometres, but have a singlescatter
albedo of 1, they strongly interact with solar
radiation by scattering. Some of the light is backscattered,
reflecting sunlight back to space, increasing the
net planetary albedo and reducing the amount of solar
energy that reaches the Earth’s surface. This backscattering
is the dominant radiative effect at the surface and
results in a net cooling there. Much of the solar radiation
is forward scattered, resulting in enhanced downward
diffuse radiation that somewhat compensates for a large
reduction in the direct solar beam."

What makes you think you know better than him? You are yet to actually present evidence of a lack of cooling after volcanic eruptions (the graph for Krakatoa did show cooling) and indeed are yet to provide a solid reason why there shouldn't be cooling. Is this left as an exercise for the reader?

While I wont discount longer term trends in volcanic activity being related to extraterrestrial effects, any link has to be tentatively made and well substantiated.

As for climate considerations: rare, massive eruptions (like the yellowstone caldera theory the discovery channel seemed so fond of a few years ago) definitely have the potential to alter global climate for a long time. So do massive asteroid strikes. Both pepper the earth on geological timescales, but for us right now? Interesting to investigate but useless to factor in. If they happen we're screwed anyway. That's not to say you shouldn't look at volcanoes at all. They're vital for climate change attribution studies and give their own clues as to climate sensitivity.

I'm just astonished that Breezy is arguing that eruptions don't cause cooling at the surface (globally averaged of course). Is he being contrary to the accepted science just for the sake of it?