Author Topic: Vantage Pro2 Forecast Algorithm  (Read 3965 times)

0 Members and 1 Guest are viewing this topic.

Offline SOCALWX

  • Member
  • *
  • Posts: 23
    • DW3849 NOAA
Vantage Pro2 Forecast Algorithm
« on: November 13, 2009, 08:02:21 PM »
I am new to the forum-- and plan to get a Vantage Pro2 for the holidays.  There is excellent info here.   I searched the forum for information regarding the Vantage Pro2 forecast algorithm, but couldn't find any info.  Davis says it takes into account thing such as barometric pressure, lat/long, etc.   Is the algorithm very accurate?  Any pros or cons to it?   I appreciate it.

Offline Downlinerz2

  • Forecaster
  • *****
  • Posts: 2936
Re: Vantage Pro2 Forecast Algorithm
« Reply #1 on: November 13, 2009, 08:17:06 PM »
hi,
    Welcome to the forum!!  I have had my VP2 for 2 months and the forecasts are
not something you would use to make, or cancel, any plans.  I would not say they are accurate but sometimes they have been right and other times wrong.  They can be vague and they can change rapidly.  The one I have seen most lately is "increasing clouds with little change in temperature".  But I need to follow them for a longer time.  Good luck with your new station!!

Offline d_l

  • Forecaster
  • *****
  • Posts: 1683
  • Slide Mtn - Mt Rose
    • Thomas Creek Estates neighborhood weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #2 on: November 13, 2009, 09:08:54 PM »
I'd say they are probably more accurate here than the NWS forecasts for the equivalent predictive timeframe.  I've thought they might use a simplified Sager algorithm.  Davis forecasts are often very similar to or nearly identical to Sager forecasts .
--Dave--

Wireless VP2 w/ solar, 24hr FARS, Heater, (Envoy-WLIP)*3-Meteohub, plus custom VP2 @ 26', WL 6.0.3, WU & W4U=KNVRENO37 NetcamXL

People always talk about the weather, but they never do anything about it.  Not me.  I'm gonna measure it.  https://www.tceweather.com

Offline SOCALWX

  • Member
  • *
  • Posts: 23
    • DW3849 NOAA
Re: Vantage Pro2 Forecast Algorithm
« Reply #3 on: November 13, 2009, 09:33:40 PM »
Thanks for the info. Never heard of the Sager forecast--learn something new every day.  Davis claims the forecast uses lat/long.   I wonder how that works--that can be really complex?

Offline Bushman

  • Forecaster
  • *****
  • Posts: 6690
    • Eagle Bay Weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #4 on: November 13, 2009, 10:57:36 PM »
AFAIK, Sager does not use lat/long.  http://www.weather-above.com/Sager%20Algorithm.html

Offline Cienega32

  • Forecaster
  • *****
  • Posts: 2571
    • East Mesa Weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #5 on: November 14, 2009, 12:21:52 AM »
All mine ever says is "Precipitation possible in the next 12 hours - possibly heavy at times" or something to that effect. Rain or shine and most of the time it'll say that. I found it to be fairly useless at my location.

Pat ~ Davis VP2 6153-Weatherlink-Weather Display-StartWatch-VirtualVP-Win7 Pro-64bit
www.LasCruces-Weather.com   www.EastMesaWeather.com

Offline Arthurhh

  • Senior Contributor
  • ****
  • Posts: 266
  • IT Fixer
    • Tokoroa Weather Live
Re: Vantage Pro2 Forecast Algorithm
« Reply #6 on: November 14, 2009, 05:32:43 AM »
Thanks for the info. Never heard of the Sager forecast--learn something new every day.  Davis claims the forecast uses lat/long.   I wonder how that works--that can be really complex?

in general terms they look at northerly/southerly lats easterly/westerly lats and make a generilized call on that. If you exist in a micro clime you are screwed unless it conforms to the generilized formula thatthey use.

Offline George Richardson

  • WxElement panel
  • Forecaster
  • *****
  • Posts: 1391
    • Smith Mountain Lake Weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #7 on: November 14, 2009, 09:40:29 AM »
Socalwx,
The Davis Vantage Pro2 is excellent for giving you what the weather is. There are several software packages that will record and store what the weather has been. If you are interested in what the weather will be, I suggest you look at WXSIM. I don't own it but I think it is a pretty good package.
FWIW
George

Offline Bushman

  • Forecaster
  • *****
  • Posts: 6690
    • Eagle Bay Weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #8 on: November 14, 2009, 09:42:39 AM »
For my locale, I find the Davis forecast to be pessimistic.  And the microclimate here means one side of the lake it could be sunny while the other side has rain.  But overall I  think it is adept at forecasting GENERAL conditions for the next day or so.  It is as accurate as the  weather service.  ;)

Offline SOCALWX

  • Member
  • *
  • Posts: 23
    • DW3849 NOAA
Re: Vantage Pro2 Forecast Algorithm
« Reply #9 on: November 14, 2009, 01:43:36 PM »
The WXSIM looks impressive--good suggestion George.   That is probably more than I can imagine trying to use and assimilate.  :-P

By the way, does the Vantage Pro2 forecast fog, or does it only say cloudy?   

Offline d_l

  • Forecaster
  • *****
  • Posts: 1683
  • Slide Mtn - Mt Rose
    • Thomas Creek Estates neighborhood weather
Re: Vantage Pro2 Forecast Algorithm
« Reply #10 on: November 14, 2009, 02:51:39 PM »
No fog forecasts that I've seen.  That would involve forecasting dewpoints and more exact temperature ranges, not just warmer or colder or no change in temperature.  Way more than a simple algorithm can handle.  For example, the basic Sager forecasts only use wind direction modified by recent change of direction, barometric presssure, change of barometric pressure, and cloud conditions.  Dewpoint conditions are not used in those forecasts.
--Dave--

Wireless VP2 w/ solar, 24hr FARS, Heater, (Envoy-WLIP)*3-Meteohub, plus custom VP2 @ 26', WL 6.0.3, WU & W4U=KNVRENO37 NetcamXL

People always talk about the weather, but they never do anything about it.  Not me.  I'm gonna measure it.  https://www.tceweather.com

 

anything