1. A square white flag indicates fair weather. (See Fig. [13].)
2. A square blue flag indicates rain or snow. (See Fig. [14].)
3. A white and blue flag, half white and half blue, indicates local rain or snow. (See Fig. [15].)
4. Black triangular flag indicates a change in temperature. (See Fig. [16].)
5. White flag with a square black center indicates cold wave. (See Fig. [17].)
When No. 4 is placed above No. 1, 2, or 3, it indicates warmer weather; when below, colder; when not displayed the temperature is expected to remain stationary.
The following flag warnings are used along the Atlantic and Gulf coasts to notify inhabitants of this section of the country of impending danger.
Fig. [18]. The Small Craft Warning. A red pennant indicates that moderately strong winds that will interfere with the safe operation of small craft are expected. No night display of small craft warnings is made.
Fig. [19]. The Northeast Storm Warning. A red pennant above a square red flag with black center displayed by day, or two red lanterns, one above the other, displayed by night (Fig. [19A]), indicates the approach of a storm of marked violence, with winds beginning from the northeast.
Fig. [20]. The Southeast Storm Warning. A red pennant below a square red flag with black center displayed by day, or one red lantern displayed by night (Fig. [20A]), indicates the approach of a storm of marked violence with winds beginning from the southeast.