1040 hPa anticyclone ?

[NZ Thunderstorm Soc]

Bugger
I was hoping for a 1040hPa anticyclone, even though short lived, to develop over NZ this coming week but it looks as though the ECAL looks like to kick in again, with a shallow low, ruining our chances
Might get to 1039 hPa, somewhere, if we're lucky
There is nothing like an 1040hPa centred anticyclone

JohnGaul
NZ Anticyclone Appreciation Society

[NZ Thunderstorm Soc]

Might get to 1039 hPa, somewhere, if we're lucky


JohnGaul
NZ Anticyclone Appreciation Society

Looks like that centre may be around the Gisborne area according to MetServive's future map.

JohnGaul
NZ Anticyclone Appreciation Society

[Lawrence]

I see metservice has it going as high as 1041

[Michael]

Looks like it will be a cold one tonight down to 3 or 4° if it clearsup

[NZ Thunderstorm Soc]

I see metservice has it going as high as 1041

Yep. ...and it looks as though it will be off the coast of Canterbury

JohnGaul
NZAAS

[Lawrence]

Just reporting in,been quite busy today.So sorry to hear of your loss John,my condolences to you and your family.Fairly clear here just a small amount of cloud over the banks and as such temp is now at 1.0c and falling, very light wind from South West 5.0kph and baro reading 1023mb and rising.Looking fairly interesting towards the end of the week,just hope its not going to be murky gray drizzle days again though.

[Lawrence]

Met service is going 1042 now on latest future maps,smack bang over Canterbury. Bit of cloud coming up from south and off the coast.

[Andy]

1034mb this morning

[Gary McConnochie]

Has reached 1034.7 and still rising. This is an all time record for my station.

We had a frost here this morning but cloud and showers have come up from the south. We even had a couple of snow showers earlier.

[Lawrence]

Just making out some moderate to heavy showers making there way up the East coast on the M/S radar heading inland as they have been all morning,will be interesting to see if they make it or will the high pressure finally kill them off,seems like they are lessening.

[NZ Thunderstorm Soc]

Still going up, trying to hit the 1040hPa mark here but my barometer is not all that correct

JohnGaul
NZTS

[Lawrence]

1037mb here John at sea level reading,and 1032mb respectively and 0.6c.

[TonyT]

1037mb here John at sea level reading,and 1032mb respectively and 0.6c.

If you are 50m above sea level, then your correction to station level pressure is only about 1mb, not 5mb!

[Lawrence]

If you are 50m above sea level, then your correction to station level pressure is only about 1mb, not 5mb!

Sorry Tony, But thats not the information I have been using,Information could be wrong though,any one like to clear this up
Cheers

Hydrostatic Equation, that relates changes in pressure to changes in height. This equation is as follows

^p=-rho*g*^z

where ^p is the change in pressure and ^z is the corresponding change in height in m. Rho, as above, is air density and g is gravity held constant at 9.8 m/s2. If we want to make a quick calculation of what vertical distance in meters that corresponds to a change in pressure of 1 millibar (0.1 cb) near sea level where the density is 1.2*10-3 t/m3, we get the following result:

0.1 cb= - 1.2*10-3 t/m3 * 9.8 m/s2 * ^z

Solving for ^z, we get 8.5m. In other words, a change in height of 8.5 meters near sea level, as you go up in the atmosphere, results in a reduction (thus the minus sign in equation above) in pressure of 1 millibar. If your location is 34 meters (111 feet) above sea level you will have to add 4 millibars to your barometric pressure reading to get an estimate of the sea level value.

[Gary Roberts]

...Hydrostatic Equation, that relates changes in pressure to changes in height. This equation is as follows

^p=-rho*g*^z

where ^p is the change in pressure and ^z is the corresponding change in height in m. Rho, as above, is air density and g is gravity held constant at 9.8 m/s2. If we want to make a quick calculation of what vertical distance in meters that corresponds to a change in pressure of 1 millibar (0.1 cb) near sea level where the density is 1.2*10-3 t/m3, we get the following result:

0.1 cb= - 1.2*10-3 t/m3 * 9.8 m/s2 * ^z

Solving for ^z, we get 8.5m. In other words, a change in height of 8.5 meters near sea level, as you go up in the atmosphere, results in a reduction (thus the minus sign in equation above) in pressure of 1 millibar. If your location is 34 meters (111 feet) above sea level you will have to add 4 millibars to your barometric pressure reading to get an estimate of the sea level value.

Head asplodes...

[TokWW]

Reached 1036mb / hPa here now - slowly catching up to you guys down south - unusual event and shape of the Anticyclone...

[RWood]

I tried an online calculator which said that SLP of 1015mb gives a correction of about 6MB for 50m ASL.

Sounds rather high to me! Over to someone else!

[Manukau heads obs]

yes, approaching my previous record high baro of 10.37.4 on the 8th sep 2004
nice web site and banner Gary McConnochie, well done

[TonyT]

Sorry, you are correct. I misread 50 metres for 50 feet Is Rolleston really 50m above msl?

As a rule of thumb, allow 1mb for 10m of altitude.

[Manukau heads obs]

it gets complicated if you live in Colorado, being in the middle of the continent and at 6000 feet above sea level and with intense artic high pressure and very cold temperatures, they have to use field pressure (QFE), which is temperature compensated pressure...in those cicumstances a simple offset to sea level for the altitude does not work accurately

[TokWW]

I tried an online calculator which said that SLP of 1015mb gives a correction of about 6MB for 50m ASL.

Sounds rather high to me! Over to someone else!

Exactly Rupert - I have it done as a polynomial calculation and the answer is 6.06hPa or mb

HTH...

[Lawrence]

Is Rolleston really 50m above msl?

Hi Tony,
Yes,some parts of Rolleston are, it depends which part of the town you live in.For instance Amberley town center is 44m ASL,but just to the north it rises to 100m ASL.You can aquire this information fromhttp://www.nztopoonline.linz.govt.nz/we ... viewer.htmZoom in and look for the relative figure nearest your base.

[dija]

peaked here at 1036.7 (which is a station record for my 1.5 year duration)

[RWood]

[quote="Karshvardidgâh

Hi Tony,
Yes,some parts of Rolleston are, it depends which part of the town you live in.For instance Amberley town center is 44m ASL,but just to the north it rises to 100m ASL.You can aquire this information fromhttp://www.nztopoonline.linz.govt.nz/we ... viewer.htmZoom in and look for the relative figure nearest your base. [/quote]

Is that free or not? Miles of legalistic junk...

[Gary Roberts]

Is that free or not? Miles of legalistic junk...

It's free. And brilliant. It makes my job a little easier too.