C06 · When made, when meant · educator whole source and model
Complete source: Imaginary Birch Desk has a forecast issued at yesterday's story breakfast, about today's story afternoon in Birch Square: rain is possible. Its issue time and forecast period are different labels. No newer forecast or today's afternoon observation is provided. A separate old statistics note says it summarises many past months; it does not supply today's weather.
Worked meaning: The issue tag dates the message; the period tag identifies when its prediction applies. Ask whether a newer suitable message is available, but do not invent it or assume the old prediction is certainly wrong. Past statistics do not become today's result.