If the wind shifts from east to northeast to north to northwest, you know the eye is passing north of Guam. If the wind shifts from Northeast to East to Southeast, you know the storm is passing south of Guam. If the winds remain steady from the same direction with no shift, the storm is still heading straight for Guam. A compass is a handy tool to tell you which way you are facing. Guam's roads curve and sometimes it's hard to tell which direction you are facing so a compass will help when figuring the wind direction.
Some wrist watches come with a built-in barometer.
Some dive watches have barometers built in. It will also tell you whether the storm is coming or going. If the pressure is falling, the storm is still getting closer to you. If the pressure starts to rise, the storm is moving away. When the pressure remains steady and the wind remains out of the same direction, the storm has probably stalled.