J07
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Posts posted by J07
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nope
But isn't that what's supposed to happen above a warm cored cyclone?
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the ironic thing about polar lows is that they have a slight warm core,
So we would see anticyclonic behaviour at higher levels above a polar low?
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Has there been any progress on stopping "Nice pics" comments?
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By far the most unspoilt, least touristy and most beautiful area of England IMO.
Can of worms!
I think "unspoiled" (or unspoilt?) is a very relative term in the UK. Much of the environment has been vandalised over many centuries. How much of our original forest remains?
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I'm coming into this very late but it has been perplexing me though I don't know if the OP is still around. Even if he is not, the continued discussion would be of interest.
When it comes to the water vapour partial pressure that is obviously not given in soundings so it has to be inferred. And it tells you in that paper how to do it. You need theta (sounding), RH (sounding) and e (2.718...blah). So no problems with that.
I am fairly tired so not much time to think about this but with all that data, just plot it on a t-phi gram for the first few significant and standard levels. Blank tephis are on the web. easy to find the LCL from this data, just look at the surface plots of temp and dewpoint. Follow a constant mixing ratio line up from the dewpoint, follow a dry abiabat up from the temp and where they intersect, that's at the pressure value of the LCL.
Only thing is, surely the precipitable water content is going to depend on the means of ascent. LCL => Forced ascent, i.e. over mountains. I would think that in Manaus, convective ascent is more important. For this you need to know the Level of Free Convection which gives the convective cloud base whereas LCL would give you the cloud base for forced ascent. Convective condensation level also can be inferred.
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Thanks guys
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Do you really get "Monsoonal Showers" in Ballina? AFAIK, the Monsoon trough sits firmly around the Australian tropics north of 20S, occassionally delving down to north of Brisbane in exceptional circumstances. Coastal NSW/temperate coastal QLD is more affected by SE trades than by monsoon troughs.
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Don't have the answer but I'm curious as to how they define "hit". There were a few decent sized quakes last year off the coast of NZ, magnitudes over 7.0 I think. They were "felt", but did not "hit"- then there was a 6.8 that "hit" in December, though it was centred offshore...is that a "hit" or one that was merely "felt"?
How can a prediction differentiate between whether the quake will hit a populated region, a dense city, open ground or ocean? It must surely be just a statistical fluke if they get it right?
If a 7.0 occurs 50km away from the Japanese shore, does that count as a success for the prediction?
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North Island high country. A major portion of I need to control my language, both the Desert Road
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I need the Netweather swear filter to grow a $%!^% brain!
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I wouldn't rule out Snow in March but when you consider in recent years Snow has been very rare in Dec Jan and Feb it's going to be even rarer in March. P
Can you really make this conclusion?
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Trying to find a better marker for "strength of sun", I have found that the total direct and scattered solar radiation in September at the locations mentioned is between 11 and 13 Megajoules per Square Metre.
Unfortunately, such information is not available for the UK (freely, anyway). By fudging my way through it using some theoretical model, and ignoring "inconvenient" terms, I came up with a value in the region of 1MJ m^-2 for a standard UK site. This doesn't sound right at all.
So I looked at fudging it in a way where I can actually keep track of my jam.
Just assuming radiation incident on a plane circle, which is parallel to the earth's surface at a given point.
The area of this circle comes out as being = pi * (r_a)^2 * sec ^2 ((latitude))
where r_a is the radius of the circle, were it directly incident to the solar radiation (ie at the equator). (for a quick case you would take this as 1, just left it in for book-keeping).
I think I got the trigonometry right.
Using latitudes of 52N and 42S, the area of the circle comes out as being larger in the UK by a factor of 1.45 over that in NZ. So the solar radiation is spread over a larger area, giving weaker sun. This is hardly groundbreaking stuff, it just suggests that I may have got my trig function correct in the equation.
In addition, compare the increased hours of sunshine in NZ, looking at 150-160 per month in September - call it 5 hours a day. In the Uk that would be more like 100-120, depending on location- call it 4 hours a day (though I suspect nearer to 3 for a snow-prone area).
Sticking it all together and you come out with:
Combining sunnier days with stronger sun between NZ and the UK and you find that in an average September day, total solar radiation would be 81% greater in the NZ locations.
Must admit, that's a fair bit more than I expected. But remember, my working was not the most precise- though good enough for a quick flick through the problem. One issue is that really I should have considered an ellipse, not a circle, but that would lead to geometry that would be too awkward.
Anyway, if lying snow can happen in NZ in September, then this evidence above suggests that the "UK March Sun Strength" argument appears to be weakened. This wouldn't be a real conclusion if I didn't recommend further study. So someone else should look at it if they have the time and interest
Have attached scrawled diagram.
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Although most people's minds at present are on tomorrows storm and rightly so, I thought it would be good to start a new thread on what people think may happen weatherwise this easter, or what they hope will happen.
Easter 2008 is exceptionally early this year, this fact alone would favour colder conditions relative to many previous easters. However, the period from now until mid May is usually the most unpredicatable period of the year and literally can and does bring everything. With it being so early, its a strange one as normally I would wish for pleasant mild dry sunny conditions, useful weather for getting out and about in etc..., however, due to the abymsal lack of snow we have had all winter and how useless christmas was in this respect, and also in view of my expected trends in the weather towards easter, i'm hoping that we will see some snow this easter.
What do others think may happen, like to see happen?
You can use this thread to discuss easter weather of the past etc, memories of easter weather in the past aswell.
Was Christmas *that* bad for you? I just remember that wonderful 2 week period beforehand of nibbling easterlies and really cold temperatures, along with the odd hard grass and air frost. I know it shoved off in time for the festive season but was it really all that awful? I seem to remember showery rain preceding the big day, and then quite a cool crisp day itself. Not bad going by previous years!
Cold easters for me are a bit of a waste- in both Hemispheres! Down here it usually coincides with some of the most settled and pleasant weather of the year. With UV indices falling down to about 6 in many places, it's ideal for outdoor activities and the days are long enough for some decent walking.
Up North- Easter is really a celebration of Spring, is it not?
However, I somewhat see your point this year. As it has come so early, snow could make things pretty interesting and worthwhile! Likewise, a final flourish of hot weather wouldn't go amiss in the SH.
Not sure why I'm rambling on anyway...not as if "Mr Weather" will play along!
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Is Italian Spring generally unreliable or fairly settled?
I like those temperatures in the Foehn. When we get it over here it won't get that hot so early in the season- unlikely to get over 25C in the warmest places until October.
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Early season snow at Mt Hutt, Canterbury just a few days ago. (from Nzski.com)
This is usually the first ski resort to open in the Southern Hemisphere. Perhaps late May or early June.
Current predicted maxima for the next few days are 12C with overnight lows above freezing and NW conditions. Forecasts are for 1600m ASL.
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When looking at charts that show isotherms (or adiabats/quasi-adiabats) at 850hPa, 500hPa and so on, to what kind of temperature are they referring?
1) Temperature
2) Virtual Temperature
3) Potential Temperature
4) Potential Wet Bulb Temperature
5) Equivalent Potential Temperature
???
I always see it referred to as simply "temperature", but I don't know if this is abuse of definitions or not.
Thanks
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Haven't got time to read it in detail but what an excellent post
Snow lying in April is possible in the UK even in the english midlands though i have to admit the chance of lying snow lasting does rapidly diminish the further into spring you get, top class post.
I know new zealands climate is similar to the UK`s but have you had the same amount of warming as we have had since 1988?
I dont think you have i think your summers and winters have been cooler than ours since then.
Good point on the general warming. Pretty sure that NZ has not seen it to the degree of the UK. Having said that, the "catch-up" from the UK has not been great enough to overtake NZ. The rough guide is that NZ Winter = UK Spring (approximate national average temperature of 9C).
It has always been the case that there's a larger difference between the winters than between the summers. I'm not sure how that has changed since 1988. The average summer temperature for all of NZ is 16.6C. I have no idea what it is for UK summer.
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Greetings all,
Seems that March snow is divisive.
Which camp will it be?
1) The sun is too strong for lying snow- and it's spring!
2) It can still snow in June and it's not unusual to get good falls in March or April.
I fall more towards the latter.
I am not old and yet I know that March snow is possible, and fairly common. The early 2000s we definitely got it- and April 1999 (or 2000, still can't remember which) was a classic. Big snow followed by sunny weather- and guess what? The legendary blistering heat of April sunshine failed to prevent the snow from prevailing throughout the day. Who'd have thunk it?!
I simply do not believe that the sun in March is strong. Strong *compared* with Feb and Jan, yes. But strong enough to preclude lying snow? I don't think so.
Looking at UV indices gives 1 across most of the country with some 2s floating around on clear, pollution free days. That's a cat's whisker, a tickle from a flower. I know that UV does not melt snow, but irradiance figures are harder to come by. It's natural to expect a correlation between UV and solar radiation though.
Furthermore:
SSTs are generally at their lowest,
We have not passed the equinox,
The UK is still in the coldest quarter of the year,
It's only spring according to our arbitrary calendar system.
Why the hurry for summer? Why can it not snow? I feel that it's all very reactionary, and highly dependent on people's feelings of the winter, the current weather and the long and short term prognoses. If there's no snow on the horizon, it's "roll on summer". If there's possible snow on the horizon, it's "yeah, I'm hoping for a bit, but after that I want Spring. And it doesn't matter anyway because it won't snow anyway. As usual. Since my location is the most snowless in the UK."
I'm sure it's fair to state that our seasons are becoming blended. My feelings are that it's hard to rule out anything at this time of the year.
Here is some interesting bits of information with regards to cold Spring snaps in NZ. Directly relevant to the UK? Not exactly. However, I have a point to make.
http://www.metservice.co.nz/default/index....tic=2004spring1
Spring 2004:
Started like this:
1 September. Heavy rain in northern and western parts, eg. 41.6mm at Westport in 24 hours to 10pm, including 20.6mm in 1 hour ending 9am. Foehn northwesterlies bring unusually mild temperatures to east of South Island, eg. 20°C in Kaikoura.
Severe cold snap in south18-19 September 2004
A very cold south to southwest airstream spread over New Zealand 18-19 September, bringing winter-like conditions to many places, especially the south and east. Worst affected was the Southland and Otago hill country where hundreds of thousands of newly born lambs died due to the hypothermic effects of low temperatures, wet grounds and strong winds. Hence, this storm was labelled by some the "lamb killer".
On 18 September, a southwest change swept over the South Island, bringing heavy showers with hail to Southland and Otago, and snow to near sea level. At midday, Invercargill reported hail, 3°C and a southwest wind gusting to 85 km/hr. Highs reached only 7°C at Manapouri and 8°C at Queenstown. As the change went through Canterbury temperatures fell quickly. One hour falls included Timaru: 17 to 8°C (3pm), Le Bons Bay (Banks Peninsula): 15 to 4°C (4pm), and Christchurch: 16 to 8°C (4pm).
On the 19th, the south to southwest airstream became general over the whole country. Snow fell to near sea level at first in Southland and Otago, also Banks Peninsula, but the freezing level rose slowly through the day. Around 50cm snow accumulated in the Otago hill country, stranding trucks, with graders required to clear the way. There were further hail showers, notably in Invercargill, and southwesterlies reached gale force in coastal Southland and Otago. Temperatures only reached 6°C in Dunedin, and 7°C in Invercargill and Queenstown. Places sheltered from the south to southwest flow recorded severe frosts, eg. Timaru -4°C.
The North Island also suffered, with snow falling on the North Island high country. A major portion of I need to control my language, both the Desert Road and the section between Waiouru and Taihape, was closed by snow overnight 19-20 September. On the 19th, Waiouru recorded a high of just 5°C and Taupo 9°C. Also, a tornado was reported in the Wairarapa on the 19th.
This snap is notable for massive accumulations inland. 50cm in September is pretty big. Otago hill country is not all that high- in the region of 200m-400m ASL.
The freezing level rose throughout the day, so maybe not the best example to illustrate my point.
Next up,
Spring 2005:
http://www.metservice.com/default/index.php?static=2005spring1
Started like this:
1-3 September. Morning fogs in central and northern North Island. Flights disrupted at Auckland Airport (1st/2nd). Persistent fog in Taupo suppresses daytime high to 12°C but nearby Kawerau reaches 24°C (1st). An early season fire ban is placed in Canterbury and north & central Otago due to dry conditions (1st). Wet in Fiordland and Westland due to a stalled front.
Then, almost a year to the day!
http://' target="_blank">Over 19-20 September, a very cold south to southwest flow swept over New Zealand following the passage of the low. On the 19th, snow fell to sea level in Southland, Otago and Canterbury causing much disruption, including killing thousands of lambs by hypothermia. A small low formed just east of the South Island (see maps for the 19th) which intensified conditions over eastern Canterbury. In Christchurch, the snow there was the heaviest since 1992, with many roads and schools closed (about 7cm fell in the central city, 10cm at the Airport). Dunedin and Christchurch only managed highs of 5°C and Queenstown 4°C. Also on the 19th, southwest winds reached gale force in many coastal places, and heavy showers with thunder and hail peppered northern and central districts, notably Hastings and Blenheim.
Overnight 19-20 September, the North Island bore the brunt of the cold snap, with snow falling as low as 300-400m in central and southern parts of the island. Four State Highways (including the Desert Road) were closed by snow in central regions, and the Rimutaka Road was also closed briefly. Dustings of snow were visible on some northern mountains on the 20th, eg. Mt Tarawera, Mt Pirongia and Mt Te Aroha.
Conditions slowly eased on the 20th, although it remained very cold, with Waiouru's high only 3°C.
It wasn't all bad news however, with ski-fields doing well out of the late-season snowstorm. Fresh snow on Coronet Peak allowed it to reopen for a time.
I realise there are many factors that influence snow fall (John Holmes pointed out a site the other day, it seems there's a lot to take into account).
However, two crucial ones that keep popping up in "March Snow" posts are:
1) Increasing air temperatures rule out snow
2) Strength of sun rules out lying snow
In the above cases:
1) Both Alexandra (Otago Hill Country) and Christchurch (Canterbury coast) average highs of 15C in September, significantly higher than most of the UK in March. Yet, cold snaps knocked down temperatures enough for snow, and decent accumulations to be fair!
2) Although I can't argue the point of solar irradiance, I can try a UV-analogue. UV in mid September in NZ ranges from 6/7 in the far North (never gets snow anyway) to 3-4 in the deep South. In other words, a fair old bit higher than the UK in March. Also, it's 10 degrees nearer the equator, which will naturally make the radiation from the sun greater. Yet, lying snow still came about!
Both NZ and the UK can and do get good cold snaps. Yet, if anything, the conditions at ground level in NZ are more marginal in Spring than they are in the UK (especially in Christchurch). It's my feeling that the two common arguments for improbability of snow in the UK in March are not really valid. I won't argue the point of what set-up is required and whether it is on the horizon, what I am saying is that the climate at this time of the year in the country still make it quite vulnerable to snow. All of this has happened before and all of this will happen again.
All comments welcome, even if it's to inform me of how awfully wrong I am.
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Does anyone know where I can find statistics for February 2008 for cities? The Met Office gives them for regions (as in Wales, England, Scotland, N Ireland) but I can't find any greater detail on there..
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Gimme some of that "cold" anytime mate .
weatherzone.com.au described Sydney's February as "icy".
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Well, "relatively" cold anyway!
All data and claims from:
From www.weatherzone.com.au
Coldest Canberra February for 12 years. Average maxima "only" 25C. One day max of 17C was coldest day for 3 years.
Coldest Sydney February for 23 years. Wettest in 6 years. Average maxima on occassions have been "only" 21C.
Mildest (as in cool) Brisbane February since 2003. Double the normal rainfall. Average maxima "only" 29C.
Coldest Hobart February in 12 years. Average maxima were only 21C. One day only reached 14C, being the coldest February day in 5 years.
Wettest Perth February in 15 years. However, they also recorded their warmest February since 1996. Maximum was 41C.
Wettest Darwin February in 5 years. Temperatures close to normal. However, there was some variability. The average maximum should be 31C, on one occasion they hit 34C and on another only 26C (!), the coolest February day for 52 years! I've never been to Darwin but that sort of climate sounds like something out of a nightmare- having to wait half a century to get a wet-season temperature in the mid 20s! (Though in that humidity I would most likely still fall apart).
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Meteorologists seem to be saying all this is typical of a La Nina year.
From what I've seen, the mid-latitude anticyclone belt has usually centred around the latitudes of about 42S (ish). Often, they have stalled in the South Australia Bight and moved quite slowly into the Tasman Sea. All of this has meant persistent cool southerlies and south easterlies for much of TAS, SA, Vic, ACT and NSW. On the otherhand, it has also given rise to hot easterlies/ north easterlies affecting WA. I don't know what La Nina means for tropical meteorology but I believe it pushes SSTs up in Carpentaria and the rest of Northern Aussie, probably increasing monsoonal rainfall.
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It woke me and the missus up.
I said to her what the hell was that. Was going to say I bet it was a earthquake but thought that would have been a waste of time. I first thought it was a very strong gust of wind, but with the number of alarms that got set off outside made me think otherwise.
Checked the time on the clock (12.57am) so I could have a look this morning on the news or internet to see if it was a earthquake and there it was, all over the news.
I've always found that earthquakes *sound* (and often feel) like a long, sustained and strong gust of wind. If it comes at night, and you wake up, then your brain is not exactly at 100%- so it takes a few seconds to think "hang on....that was no gust of wind!" There be earthquakes!
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Can't believe a 5.3 is causing such excitement
Still, that is good one for the UK and it seems to have originated near to populated areas, and was felt over a wide area.
What is the situation with UK buildings- how earthquake proof are they? Over here there is a Kiwi invention (of which they are rather proud) called the Base Isolators, which are installed under several important buildings in the capital. I don't know how the older houses would fare (like the one in which I reside
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Hi,
Over here we don't have many high public roads, despite the country being much more mountainous than the British Isles. I assume this is because of historical purposes. Why build a road over a 3000m high pass when you can build one over a 1000m pass?
Due to this, our highest public road perhaps only gets to about 1400m ASL. This is actually the main road in NZ- State Highway 1, when it passes over a region of the central plateau known as the Desert Road (Rangipo Desert). Frequent snow in winter, and also during summer cold snaps.
The highest actual mountain pass road is probably Arthur's Pass (about 1000m ASL). Another high public road is driving over the Crown Range. Other notable passes with sealed roads passing over them are the Lindis Pass, Haast Pass, Takaka Hill and Lewis Pass.
All these high roads can technically get snow year round. However, permanent lying snow will not occur until May or June, and will persist until October or November. But usually, permanent snow lines in NZ are over 2000m, and I would say more like 2500m. There are two well known permanent snowfields called the Garden of Eden and the Garden of Allah, and of course several hundred glaciers in the country; some very small and some a bit bigger (not big on a world scale, but impressive for how close they approach the sea at this latitude).
Due to this, you rarely have to drive through old, accumulated snow, though if you go to ski fields obviously you will be driving on bad gravel roads at high altitude and requiring chains and/or 4WD. This is a bit different to what the average city or country driver will experience. Having said that, in a cold winter, highland areas (basins above 700m ASL, or very sheltered inland basins above 200m) can accumulate snow which does not thaw. No cities or major commercial towns exist in these regions though.
I've attached some reasonably relevant photos. One shows a non-permanent snowfall at approx 1500m ASL last March (cold snap). It definitely did not persist.
Another shows a glacier transitioning into permanent snow.
Another shows a permanent snow level, extending from maybe 2500m ASL up to 3800m ASL.
Finally, from the other end of the season, a Spring photo (October) showing non-permanent but persistent (through winter) snow levels perhaps down to 1500m ASL.
This is obviously a bad time for snow. It's unlikely that anything serious will land before early/mid June.
But, we had a brief cold snap about two weeks ago, roughly. Here is a photo of Benmore Peak in Central Otago, roughly 1900m ASL. Please note that I did not take this photo.
I can be fairly certain this snow was gone in a few days.
Over 19-20 September, a very cold south to southwest flow swept over New Zealand following the passage of the low. On the 19th, snow fell to sea level in Southland, Otago and Canterbury causing much disruption, including killing thousands of lambs by hypothermia. A small low formed just east of the South Island (see maps for the 19th) which intensified conditions over eastern Canterbury. In Christchurch, 
distant mountain images
in Archived weather photography area
Posted
Beauty
I like number 5 the best.
What mountains are we looking at there? Names? Elevations?