WiFi connection lost. Reboot required
You can try to connect without UI

Manually connect to WiFi

Turn On

networksetup -setairportpower en0 on


Find

/System/Library/PrivateFrameworks/Apple80211.framework/Versions/A/Resources/airport scan


Connect

networksetup -setairportnetwork en0 WIFI_SSID_I_WANT_TO_JOIN WIFI_PASSWORD


If it works it is not the hardware. In that case the Console report would be helpful to find out who is turning your airport off. That is indicated by the fact that rebooting fixes it, so you have a app messing up your Airport.