An ambient pressure change on approach is a somewhat “expected” possibility. The airport surface wind, temperature and pressure will come from the current METAR for the airport, and if the values being provided by Live Weather’s model differ from the METAR, you will see a transition. As near as I can tell, METAR winds and temperature become active below about 1500 feet AGL on descent to landing - it appears that METAR pressure extends farther vertically and horizontally from the airport than wind and temperature.