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Extraordinary High Pressure

Posted: Mon Jan 20, 2020 8:51 am
by tenchboy
Hap't to notice my barometer this morning on which I have marked various high and low pressures in the past; the high pressures all clustering around the quarter past three mark; this morning the needle is way beyond any previous recording: right round to the four o'clock mark. Unfortunately tis vey old and the numbers have long since faded but I can just make that out to be 30.8 inches of mercury which converts to 1043 millibar.
Seems others have also noticed.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 9:22 am
by bjn
tenchboy wrote: Mon Jan 20, 2020 8:51 am Hap't to notice my barometer this morning on which I have marked various high and low pressures in the past; the high pressures all clustering around the quarter past three mark; this morning the needle is way beyond any previous recording: right round to the four o'clock mark. Unfortunately tis vey old and the numbers have long since faded but I can just make that out to be 30.8 inches of mercury which converts to 1043 millibar.
Seems others have also noticed.
I certainly have. I was tracking the high in the hope of it bringing more stable weather so I could get my wing out and go paragliding today. Sadly the weather is too stable with no surface wind to speak of and not much chance of thermals. The centre of the high is 1050!

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 11:31 am
by Pucksoppet
Cue David Bowie & Queen...

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 2:00 pm
by rockdoctor
My pal sent me this pic from his old barometer yesterday evening. It correlates to 1050mB, when the Met Office were stating 1049mB and rising. He was amazed by both the reading and by the accuracy of his old barometer
31inches.jpg
31inches.jpg (198.08 KiB) Viewed 4766 times

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 2:08 pm
by science_fox
Although I don't have a barometer, I do have some high vacuum instruments which are sometimes required to be vented to atmospheric pressure. It remains one of the small joys that the pressure at which the door opens varies according to the weather. Not the best or most efficient use of £500k worth of kit, but they do make good barometers. They'd take extra long today to vent today, but sadly none are scheduled.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 2:37 pm
by lpm
Interesting. But the BBC didn't explain why it's so high, just the jet stream mechanism.

Is this why dawn was so spectacular this morning? Very clear skies, but with high altitude light clouds.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 2:52 pm
by tenchboy
lpm wrote: Mon Jan 20, 2020 2:37 pm Interesting. But the BBC didn't explain why it's so high, just the jet stream mechanism.

Is this why dawn was so spectacular this morning? Very clear skies, but with high altitude light clouds.
Spec so: more pics here

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 3:14 pm
by shpalman
My phone says it's 1015 hPa, which wouldn't be so remarkable except that I'm at about 210 m above sea level (the sea-level references at the nearby airports are 1040 hPa or so). I seem to remember recently noticing the barometer in my apartment, which is nearer 270 m ASL, going over 1000 mbar.

(The fact that there's only 16% relative humidity in the lab would make this a good day to open vacuum equipment.)

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 3:37 pm
by tenchboy
Holding 30.8 inches at 140 metres a.s.l.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 3:45 pm
by insignificant
The old barometer in this house hasn't shown higher than 30.6 inches of mercury / 1036 millibars, but the METAR for the airport (less than 2 miles away) reported 1046 millibars at 1400 UTC. The airport is at an elevation of 84 metres and this house is somewhere between that and sea level, so hmmm.

There are some fantastic low tide walks (and kayaking) here during the equinoctial tides and it would be nice to get some more high pressure then. Tide tables are based on 1013 millibars and every millibar above that lowers low tide by 1 centimetre.

During the second week of March, 1043 millibars would turn a 0.2 metre low tide in to a minus 0.1 metre one. That will uncover a large area on some of the beaches here.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 3:52 pm
by shpalman
insignificant wrote: Mon Jan 20, 2020 3:45 pm The old barometer in this house hasn't shown higher than 30.6 inches of mercury / 1036 millibars, but the METAR for the airport reported 1046 millibars at 1400 UTC. The airport is at an elevation of 84 metres and this house is somewhere between that and sea level, so hmmm.
The pressure the airport reports would be corrected for altitude. Around here, Lugano (279 m ASL) Malpensa (305 m ASL) and Linate (108 m ASL) are all reporting 1040 or 1041 hPa. (These are the nearby references which my Accurate Altimeter app is using.)

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 3:57 pm
by Gfamily
My personal weather station is currently showing 1043.5mb, having peaked at 1047 mb earlier today.
(NW England)

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 4:01 pm
by Gfamily
tenchboy wrote: Mon Jan 20, 2020 8:51 am Seems others have also noticed.
Why is that dated for Saturday?

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 4:01 pm
by insignificant
Just looked at local met office Twitter, highest recorded figures since 1905 - link

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 4:52 pm
by tenchboy
Gfamily wrote: Mon Jan 20, 2020 4:01 pm
tenchboy wrote: Mon Jan 20, 2020 8:51 am Seems others have also noticed.
Why is that dated for Saturday?
It was originally written as a forecast "blah blah is expected monday morning" sims they've updated it but not changed the date stamp.

ETA: It still reads "is expected" lower down!

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 5:48 pm
by Boustrophedon
So that's why my clocks are slow.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 10:36 pm
by shpalman
The airports around here are now reporting 1045 mbar which means there's 1012 mbar up here at 280 m asl.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 10:53 pm
by tenchboy
Hold tight.

Re: Extraordinary High Pressure

Posted: Mon Jan 20, 2020 11:04 pm
by tenchboy
Just bin an given er a tap. The needle dropped just a fraction, no more than its own width so still best part of 30.8" (1043mb) at 140m a.s.l. 2°C with light, high cloud outside, 14°C with Middlemarch and a cup of hot chocolate in here.
Happy Days!