A cirrus cloud
species characterized by long, fine, fibrous (hairlike) striations with distinct, separated filaments whose ends are thin without tufts or hooks.
If they are spreading across the sky in irregular, isolated patterns without much moving or if they are slowly drifting from easterly directions, the dry and fine weather will persist for a while.
However, if they are raising from west or southwest, they are an early indicator for the approaching jet stream and hence, the warm front. The weather will deteriorate within 18 to 36 hours.