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presure trend ?

Discussion and questions about Cumulus weather station software version 1. This section is the main place to get help with Cumulus 1 software developed by Steve Loft that ceased development in November 2014.
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n9mfk
Posts: 845
Joined: Sun 10 May 2009 8:52 pm
Weather Station: davis vp2 Serial datalogger
Operating System: Windows 7 64-bit
Location: Springfield, IL

presure trend ?

Post by n9mfk »

Hi Steve cod you tell me at what level in hpa
wood each of these happen
Rising very rapidly
Rising quickly
Rising
Rising slowly
Steady
Falling slowly
Falling
Falling quickly
Falling very rapidly
Thanks
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steve
Cumulus Author
Posts: 26672
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
Contact:

Re: presure trend ?

Post by steve »

Here's the code; hopefully self-explanatory:

Code: Select all

  if HourlyPressureChangeMB > 6 then
    presstrendstr := Risingveryrapidly
  else if HourlyPressureChangeMB > 3.5 then
    presstrendstr := Risingquickly
  else if HourlyPressureChangeMB > 1.5 then
    presstrendstr := Rising
  else if HourlyPressureChangeMB > 0.1 then
    presstrendstr := Risingslowly
  else if HourlyPressureChangeMB > -0.1 then
    presstrendstr := Steady
  else if HourlyPressureChangeMB > -1.5 then
    presstrendstr := Fallingslowly
  else if HourlyPressureChangeMB > -3.5 then
    presstrendstr := Falling
  else if HourlyPressureChangeMB > -6 then
    presstrendstr := Fallingquickly
  else
    presstrendstr := Fallingveryrapidly;
Steve
gemini06720
Posts: 1700
Joined: Mon 10 Aug 2009 10:16 pm
Weather Station: No weather station
Operating System: No operating system
Location: World...

Re: presure trend ?

Post by gemini06720 »

According to Davis Instruments (manual), for their Vantage Pro2 and Vantage Pro2 Plus consoles:

Barometric Trend (3 hour):

5 Arrow Positions:
- Rising Rapidly
- Rising Slowly
- Steady
- Falling Slowly
- Falling Rapidly

Change Rates:
- Rapidly: ≥.06” H; 1.5 mm Hg; 2 hPa; 2mb
- Slowly: ≥.02” H; 0.5 mm Hg; 0.7hPa; 0.7mb
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steve
Cumulus Author
Posts: 26672
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
Contact:

Re: presure trend ?

Post by steve »

steve wrote:Here's the code; hopefully self-explanatory:
That'll teach me to refactor code on the fly. Those figures apply to the three-hourly change in pressure (not the hourly change), and the cut-offs are those used by the UK Met Office. So the code actually looks like this (only the variable name has changed):

Code: Select all

  if ThreeHourlyPressureChangeMB > 6 then
    presstrendstr := Risingveryrapidly
  else if ThreeHourlyPressureChangeMB > 3.5 then
    presstrendstr := Risingquickly
  else if ThreeHourlyPressureChangeMB > 1.5 then
    presstrendstr := Rising
  else if ThreeHourlyPressureChangeMB > 0.1 then
    presstrendstr := Risingslowly
  else if ThreeHourlyPressureChangeMB > -0.1 then
    presstrendstr := Steady
  else if ThreeHourlyPressureChangeMB > -1.5 then
    presstrendstr := Fallingslowly
  else if ThreeHourlyPressureChangeMB > -3.5 then
    presstrendstr := Falling
  else if ThreeHourlyPressureChangeMB > -6 then
    presstrendstr := Fallingquickly
  else
    presstrendstr := Fallingveryrapidly;
Apologies for the confusion.
Steve
n9mfk
Posts: 845
Joined: Sun 10 May 2009 8:52 pm
Weather Station: davis vp2 Serial datalogger
Operating System: Windows 7 64-bit
Location: Springfield, IL

Re: presure trend ?

Post by n9mfk »

Hi Steve
if use cumulus pressure names is unchecked
so davis name are used what that code look like
beau
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steve
Cumulus Author
Posts: 26672
Joined: Mon 02 Jun 2008 6:49 pm
Weather Station: None
Operating System: None
Location: Vienne, France
Contact:

Re: presure trend ?

Post by steve »

n9mfk wrote:Hi Steve
if use cumulus pressure names is unchecked
so davis name are used what that code look like
I don't know for certain; Cumulus just reads the string from the Davis code. But I assume it's the same as Ray has posted above.
Steve
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