Washington's historical 1900 weather signal tower is again displaying flags notifying passers-by of what to expect for the day's weather. Before the existence of daily weather radio broadcasts, the public would check the local weather flags to know what kind of weather to expect for the day. This system of signal flags was established in 1887 by the U. S. Army Signal Corp and was continued by the U. S. Weather Bureau into the 1920's.
The Washington tower is displaying the old signal flags, which are fairly easy to understand. A white flag means fair weather, a blue flag means rain or snow, and a white over blue flag means "local rain," what we know today as scattered showers. A fourth flag, a black pennant, flown with one of the previous three flags indicates a temperature change from the previous day. Black pennant above any flag indicates that the temperature will be noticeably "above" what it was the previous day. Flown below, the temperature will be below yesterday. No black pennant, the temperature will be close to the previous day's temperature.
In addition, the Washington tower will be displaying coastal warning flags. Many people are familiar with the hurricane warning flags, two square red flags each with a middle black square. Additional warning signals are small craft advisory (single red pennant), gale warning (two red pennants), and storm warning (one square red flag with a middle black square). Flags will be displayed according to the marine zone forecast issued by the National Weather Service for the Pamlico River, the river being in the same zone as Pamlico Sound.
The displays of weather signal flags on the Washington tower are a representation of a historical method of communicating weather related information and should not be used for planning purposes. The public is urged to tune to National Weather Service radio broadcasts or check on-line for the latest weather forecast.