Summer in the Southwest

Each year, Southern Arizonans experience a variety of weather related dangers, especially from late spring into early autumn. Through a collaborative effort between National Weather Service offices serving the states of Arizona and New Mexico, which includes offices located in Tucson, Phoenix, Flagstaff, Las Vegas, Albuquerque, El Paso/Santa Teresa and Midland/Odessa, the time period from June 15th through September 30th has been defined as "The Monsoon." A period of extreme heat is typically ongoing at its onset, which in the coming days or weeks is followed by an influx of moisture leading to daily rounds of thunderstorms. The heat is deadly in its own right, causing dozens of deaths in Arizona each year. In addition, thunderstorms present an array of hazards which often strike suddenly and with violent force.

In Arizona, lightning strikes, high winds, tornadoes, and flash flooding have caused an average of five deaths, 27 injuries, and $66 million in property damage every year since 1995. Road closures, power and communication outages and wildfires are additional consequences of monsoon weather hazards experienced by Southern Arizonans each year. Arizonans experience a variety of dangers caused by thunderstorms including:

• Flash Floods
• Power and Communication Outages
• Lightning
• Damaging Winds

The goal of Monsoon Safety Awareness Week is to reduce the number of injuries, deaths and property damage caused by thunderstorms by educating Arizonans about weather related dangers that occur during the monsoon and the precautions they can take to protect themselves and minimize property damage.

Warning Information for Monsoon Season

Armed with Doppler radars, powerful supercomputers, advanced weather satellites, automated weather and stream gages, and an advanced lightning detection network, forecasters at the National Weather Service are able to provide highly accurate severe weather warnings.

Advanced National Weather Service computer systems now allow warnings to be generated in seconds for highly detailed areas. Those warnings are then transmitted to the public, the media and emergency management officials via NOAA Weather Radio, the Emergency Alert System, and the Internet.

Television meteorologists play critical roles in the warning process. They relay National Weather Service warnings to the public and provide additional detail about the storms, what they are doing and where they are going. 

Weather Terminology — Understanding Watches, Warnings, and Advisories

• Watches mean that widespread severe weather is possible.
• A watch means that severe weather has not occurred yet, but weather conditions are becoming highly volatile. Pay close attention to the weather, and tune into TV, radio, or NOAA Weather Radio broadcasts frequently.
• Warnings (Severe Thunderstorm, Flash Flood, Dust Storm, or in rare cases, Tornado) mean that life-threatening weather is about to occur, or has been reported. Take action immediately.
  
• Flood Advisories mean heavy rains will cause minor flooding of washes, streams, and typical flood-prone areas. Flooding in this situation is usually not serious. If the flooding does become life threatening, then the flood advisory is upgraded to a Flash Flood Warning.

Warnings are not issued for lightning, mainly because most thunderstorms, no matter how weak, produce deadly cloud-to-ground lightning.

Weather Statistics

• Tucson's average rainfall during the summer thunderstorm season is 6.06 inches. The wettest was an incredible 13.84 inches in 1964. The driest was only 1.59 inches in 1924.
• Arizona ranks Number 23 in lightning frequency among the lower 48 states and Washington DC.
• Even though Arizona rarely experiences a tornado, they do occur (an average of four every year). However, thunderstorm-generated winds can exceed 100 mph over a fairly large area, with the damage looking very much like tornado damage.

Thunderstorms can develop quickly.

Be prepared!