According to the (Indonesian Meteorology Agency), at the time of the aircraft's disappearance the weather along the planned route was very good with mostly clear skies, light winds and visibility > 10km.
However, today bad weather in the area is preventing SAR teams from reaching a probable crash site, according to local media.
Apparently the location of the probable crash site was determined in part from detection of a mobile phone signal. Aviastar confirmed that the mobile phone belongs to one of the crew members.
This accident hits close to home for investigators. All of the passengers are reportedly employees of the Indonesia's Department of Transportation (Kemenhub) and their families. Six are employees & family members from the departure airport (Masamba) and one is the Chief of the nearby Seko airport.
All of Aviastar's Twin Otters are now grounded pending further investigation.