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Barometric Pressure


#1

Anyone follow barometric pressure? Suggest a decent site and when we can expect a jump?

TIA

73
Mike 2E0YYY


#2

Hi Mike,
I usually watch the weather station on Hilbre Island as it is fairly close to me. The link is to a 7 day trend.

http://cobs.pol.ac.uk/cobs/met/hilbre/getimage.php?code=4&span=2

I think the next peak will be in two or three days with good weather predicted for the Royal wedding.

I usually find the best conditions for sporadic E are just as the pressure starts to drop after a peak.

Steve GW7AAV


#3

In reply to 2E0YYY:

I recommend the met office synoptic and forecast charts coupled with the weather radar and the weather gadget. The charts are available on www.metoffice.gov.uk/weather/uk/surface_pressure.html and the weather radar on www.metoffice.gov.uk/weather/uk/radar/index.html and if you go to the home page you can download the weather gadget which puts an icon on your screen that will take you to the weather details from your selected weather station (pick the closest, in my case Coleshill) along with the most recent radar image and IR satellite picture.

73

Brian G8ADD


#4

In reply to 2E0YYY:
If you want tropo predictions then this sight is handy!

http://www.dxinfocentre.com/tropo_nwe.html

Hope that is of some benefit!

Matt 2E0XTL


#5

In reply to 2E0XTL:

Ah, the Hepburn charts - I gave up using them, they sometimes seemed to be more fantasy than fact: the tipping point was when I found him predicting good tropo in the middle of a big depression! The best advice is to tap your barometer (every V/UHF man should have a barometer!) and in high pressure if the pressure starts to fall, check the beacons. Oh yes, get all the beacons in the memories of your rig and check them religiously every evening (and morning if possible) anyway!

Bear in mind that we are now in the sporadic E season, openings are now appearing on six metres and a good sporadic E opening can spread to 2 metres and give you S9 continentals even in the pouring rain! Es appears on 2m roughly (VERY roughly!) a dozen times a year, it can be almost daily on six.

73

Brian G8ADD


#6

In reply to GW7AAV:

I usually find the best conditions for sporadic E are just as the
pressure starts to drop after a peak.

I think you must mean tropospheric ducting not SpE. I have never read a paper that suggests SpE is related to pressure in the troposphere. And even if it was, it would surely not be related to the pressure near you but the pressure at the reflection/refraction point?

73

Richard
G3CWI


#7

In reply to G3CWI:

Yes Richard you are right I meant tropo - Brain malfunction due to a combination of a long night shift (posted 06:27) and creeping daftness.

73 Steve GW7AAV

As the reflection/refraction point is unknown until it happens the local pressure is all I have to go with.


#8

In reply to GW7AAV:

Your comments suggest that you are still a bit confused. An atmospheric thermocline needs to be near to you to be useful because your signal needs to be refracted locally to enter the duct - there is no single identifiable refraction point unlike SpE.

Local atmospheric pressure is a rather poor indicator of the presence of thermoclines. A vertical temperature profile is more useful.


#9

In reply to G8ADD:

In reply to 2E0YYY:

I recommend the met office synoptic and forecast charts coupled with
the weather radar and the weather gadget. The charts are available on
www.metoffice.gov.uk/weather/uk/surface_pressure.html and the weather
radar on www.metoffice.gov.uk/weather/uk/radar/index.html

Excellent Brian, many thanks. The Thorncliffe station is about 10 miles from me, as the crow flies.

73
Mike 2E0YYY


#10

In reply to G3CWI:

Now you are talking of thermoclines I am confused, that went right over my head so to speak.


#11

In reply to GW7AAV:

Now you are talking of thermoclines I am confused, that went right
over my head so to speak.

LOL! Most people call it a temperature inversion.

73,
Walt (G3NYY)


#12

In reply to G3NYY:

No need to use two long words where one does the job!

73

Richard
G3CWI


#13

In reply to G3CWI:

The second question that was asked at the start of this topic,

"when can we expect a jump "

I would say late on in the evening of the 29th April 2011

I think a warm front will be moving in

73
Graham Gw0hus


#14

In reply to G3CWI:

This is interesting because I learned about thermoclines in an oceanography course and have never heard it applied to the atmosphere before. Whilst there is nothing wrong in applying it to the atmosphere, in this particular application I think it is a little ambiguous because it will apply equally well to a boundary where the lapse rate goes the other way, if you see what I mean. In other words, whilst a temperature inversion is undoubtably a thermocline, not all thermoclines are temperature inversions: I think that any sudden change in the lapse rate in any direction would bound a thermocline unless a more particular definition has been applied to it in meteorology than in oceanography.

73

Brian G8ADD


#15

In reply to G8ADD:

unless a more particular definition has been applied to it in
meteorology than in oceanography.

It has and is used to refer to inversions.

The term thermocline applies to fluids - liquids and gases. It is relatively common in professional publications on radiowave propagation.

73

Richard
G3CWI