CNN doesn't have much yet but there will be more to come.
Haaretz now has some additional info, quoting from al-Arabiya:
Eye witnesses told the Britain-based Syrian Observatory for Human Rights said Tuhrsday that the explosion, heard on Wednesday, took place near Snobar Jableh, south of Latakia.
Citing anonymous sources, Al-Arabiya reported that Israel Air Force carried out two attacks on Latakia and Damascus on Wednesday.
It said that the strikes targeted an SA-8 surface-to-air missile shipment for Hezbollah and that the two targets were destroyed.
The article notes that there were allegations that Israel was responsible in July for a similar explosion at a warehouse in Syria suspected of holding Russian-made surface-to-air missiles suspected of being stored for transport to Lebanon. (There were also several other such suspect incidents this year.)
Here is the Haaretz article that covered that incident, with select quotes
If the report is proven to be true, this would be the fourth Israeli strike in Syria in six months. In January, Israel struck a convoy carrying weapons evidently meant for Hezbollah while it had stopped at a Syrian research center on the outskirts of Damascus. Israel attacked twice more, over the course of one weekend in May, targeting a shipment of advanced surface-to-surface missiles at the Damascus international airport.