Basics to predict what the weather will do 

1st Step

Build yourself a simple weatherstation , examples are here

 

          

 

Once you got this to work and understand it, you are ready for the next steps

 

For the next steps you require Internet access.  

What you probably got, since you are reading this web page.

Step 2 - Get a Forecast for next few days ahead

For South Africa, to get some idea what will happen the next few days one can use WindGuru

 http://www.windguru.cz/int/index.php?lang=eng 

 

WindGuru tends to be too optimistic on the wind speed. Double what they forecast to cater for the worst case  gusts.

Or one can use   http://www.myweather.co.za/forecasts.html  to get an idea what might happen in future.

Example of the rain forecast by myWeather

 

Step 3 - Predict today's weather 

So you want to know if this will be a flyable day>

 Start with using the Spot Graph. 

 http://old.weathersa.co.za/Aerosport/graphsNEWMODEL.jsp

Select a Spot closest to you 

Check if wind speed and direction is suitable

The first image in the Spot graph gives Wind direction and speed, plus some idea how much cloud or rain we might get.

Lots of green is bad = lots of rain.

Wind Direction - If you plan to fly from a hill then you need the wind to come up the front face of you take off.

So check if the wind direction is suitale.  You have to know what direction you takeoff is facing.

Like Rustenburg would be W/NW. Or Bambi is S,E,NE. Or Barberton is NW,N,NE.

In the spotgraph the line is showing from where they reckon the wild will come.

(Opposite of what the windsock would do ).

Wind Speed - the small or bgger ticks are wind speed. small is 5kt, big is 10kt. For a nice day you need a small or a big one. But not more.

If there is a small tick on the ground, and the next higher up level lines got lots of ticks , then we got stronger wind higher up

And the higher wind tends to come down.... making it a blown out day => no fly.

Compare the forecasts from the Spot Graph and/or WindGuru  windspeeds with the actuals either by finding a weather station closest tovyour flyingsite.

http://iweathar.co.za//stations.php    

or use a METAR report from an airfield

http://aviation.weathersa.co.za/aviation/metars.php?type=metar&view=nw

 

Gauteng
   FAJS 021130Z 31017KT 9999 FEW025 23/15 Q1018 NOSIG=
   FAWK 021100Z 32010KT 9999 SCT025 23/// Q1020=
   FAJB 021100Z AUTO 31004KT //// // ////// 24/16 Q1018=
   FALA 021100Z 33013KT 9999 SCT060 25/18 Q1017=
   FAWB 021100Z 33009G14KT 9999 SCT030 27/17 Q1015=
   FAPR 021100Z 02007KT 9999 BKN040 21/12 Q1016=
   FAIR 021100Z 31010KT 9999 BKN025 23/16 Q1018=
   FASI 021100Z AUTO 29010KT //// // ////// 25/18 Q1017=
   FAGC 021100Z AUTO 32009KT //// // ////// 22/15 Q1019=
   FAGM 021100Z 35016KT 9999 FEW020 23/15 1018=
   FAVV 021100Z AUTO 31012KT //// // ////// 26/15 Q1015=

In this case FAJS ( JHB OR Tambo) got a 17kt wind.  

kt = knots = is roughly 2x km/h .  In this case 17kt  is about 30km/h+  = too strong for a comfortable flight.

In most cases WindGuru is too optimistic and tends to give us less wind speed , compared to what really happens.

Thermal strength from Spot Graph

The next image in the spot graph gives an expected thermal strenght and some cloud amount and height info.

 

 

 

 

Check for Over Development (OD) = Thunderstorms?

Check the weather radar for any cloud moving in, what will kill the thermals.

Or any thunderstorms building up , what will make it dangerous to fly.

  http://metsys.weathersa.co.za/RadSat.html

And check for thunderstorm potential on AeroSport

 http://old.weathersa.co.za/Aerosport/ThunderstormsNEWMODEL.jsp

 

Cell Phone links

http://wap2.windguru.cz/view.php?username=deviljf&password=jfdevil1&sc=60626&m=3&n=&start=-4&full=1

and replace the number 60626 with the site number below

Harties - 60626

Eagles - 158856

Langberg - 104102

Leopards Rock - 153059

Wigwam - 153062

Porterville - 164315

Bronkies - 78631

Bambi - 60872

Barberton - 60875

Bulwer - 61520

De Aar - 73873

Dumbe - 127040

Dunnothar - 74260

Ngwodwana -160072

Vaalkop - 60879

Thabazimbi - 60724

Monks Cowl - 191886

Amatava - 197554

Maanhaarrand 194713

Koppies Dam - 160591

 

 

More links  and references

  http://stpxml.sourceforge.net/skygod/Weather/Weather.html

 http://stpxml.sourceforge.net/skygod/Weather/Sounding.html

 http://stpxml.sourceforge.net/skygod/Weather/NOAA/NOAA_SOUNDING.html

 http://www.xcskies.com/   for soaring forecasts = fee based

 http://old.weathersa.co.za/Aerosport/Aerosport.jsp  Aero Sport weather website

 http://aviation.weathersa.co.za  one has to register