EDWARDS AIR FORCE BASE, Calif. -- With the start of summer at Edwards, it also means the start of thunderstorm season for the 412th Operation Support Squadron's Weather Flight.

During summer, the wind flow in Southern California can shift to a southeast to southerly directional flow. This flow brings tropical moisture from the Gulf of Mexico or the Pacific Ocean into Southern California.

This moisture - combined with intense desert heat and mountainous terrain - aid in producing afternoon and evening scattered thunderstorm activity throughout the Antelope Valley.

With thunderstorm activity in the forecast, the weather flight and the Operational Weather Squadron will issue weather watches and warnings for Edwards when appropriate.

A weather watch is a special notice provided to supported agencies that alerts them of a potential for hazardous weather conditions of such intensity as to pose a hazard to life or property.

There are three weather watches that can be issued for Edwards concerning thunderstorms and lightning. The three are: potential for thunderstorms and lightning within 25 nautical miles of Air Force Research Laboratory; within 20 NM of the Edwards air traffic control tower, and; within 5 NM of AFRL and the tower.

A weather warning, on the other hand, is issued when a hazardous weather event is occurring, is imminent, or has a very high probability of occurring. A warning is used for conditions posing a threat to life or property. There are four weather warnings that can be issued for Edwards concerning thunderstorms and lightning. The four warnings are: thunderstorms and lightning within 25 NM of AFRL; 20 NM of Edwards; 10 NM of AFRL, and; 5 NM of AFRL and Edwards.

If there is thunderstorm activity occurring near Edwards and AFRL, you better "watch" out for the potential of hail, lightning and strong surface winds. If there is thunderstorm activity occurring at Edwards and AFRL, you should have already been forewarned of imminent danger with these storms.

Speaking of lightning, it is the number two cause of weather-related deaths in the United States. Floods and flash floods are number one. On average, 57 people are killed by lightning every year with considerably more than 100 seriously injured.

Regarding thunderstorms and lightning, keep the following six ideas in mind and it will help to keep you safe this summer:

Plan: Plan outdoor activities to avoid thunderstorms. Know the latest weather forecast.

30-30 Rule - If the time between seeing lightning and hearing thunder is 30 seconds or less, go inside! Stay inside 30 minutes or more after the last thunder is heard.

Safe Places - Large, fully enclosed buildings with wiring and plumbing provide good lightning protection. Vehicles with solid metal roofs and solid metal sides give some protection.

Indoor Safety - Don't use corded telephones. Keep away from electrical appliances and wiring. Stay away from plumbing - don't take a bath or shower.

Outdoor Safety - Avoid elevated places and open areas such as golf courses, sports fields and beaches. Avoid water - swimming, boating and fishing. Avoid tall objects - do not go under trees! Allow time to get to safety. Do not use open structures like picnic pavilions and rain shelters. In low-lying natural drainage areas, be on the lookout for flash floods.

First Aid - If someone is struck by lightning, start CPR or rescue breathing immediately. Have someone call 911.

A final factor to consider during the summer, especially on days with the potential for thunderstorms, is heat stress. High temperatures alone can cause heat stress, but the addition of moisture when thunderstorms are expected further increases the likelihood for this to occur.

Heat stress is monitored and advisories are issued by the Bioenvironmental Engineering Flight in accordance with Air Force Flight Test Center Instruction 48-7. Updates are posted on the Air Force Portal Web site under Edwards (My Base) and Heat Stress Updates.

The thunderstorm season for Edwards can start as early as May, peaks in August and usually ends in early to late October.

More information on lightning safety is available on the Web at www.lightningsafety.noaa.gov/.