An Aviation Selected Special Weather Report (SPECI) is an unscheduled report taken when there is a significant change in the weather during the period between the hourly reports. SPECIs contain all data elements found in a METAR, plus additional plain language information which elaborates on data in the body of the report.
You're about to depart an airport under IFR with low ceilings. There's no SID and no ODP. When can you start your on-course turn, and why? It's called a "diverse departure assessment", and here's how it works.