SA

• duststorm, sandstorm, rising dust or sand

  METAR

• record observation (weather reports only)

  Weather

• sand, sandstorm, or dusting

  ICAO

• surveillance approach

  General

SA has 4 meanings; the right one depends on context. A weather report, a NOTAM or an ATC clearance. Got a NOTAM full of contractions? Paste it into the decoder.

Source: FAA Order JO 7340.2 Contractions. Not for operational use.