On our first plant visit, we went to PAGASA. We were introduced to the equipment used to measure atmospheric pressure, wind and wind velocity, amount of rainfall and relative humidity. A reading is done in a 3 hour interval or 1 hour interval is there is a possible typhoon coming towards the country. The data is sent to the central office for analysis and used for forecasting the weather.
The person in-charge showed us the chart from the microbarograph that indicates that a typhoon is coming. We saw a V-shaped graph which means that there is a drop in atmospheric pressure when a typhoon is coming and goes back to its normal reading when it already far from the country.
With that highly sensitive device, we can directly observe that a possible typhoon is coming.