8/2/14  @ 8:45

News from the National Weather Service, Flagstaff: Flash Flood Watch

PRIMARY IMPACTS and TIMING:

A low pressure system will move into northern Arizona later this afternoon enhancing shower and thunderstorm activity through the afternoon and overnight hours. Wind flow will be light and heavy rain from storms that develop will tend to move slowly across the landscape. The combination of these weather factors will increase the risk for flash flooding across the state and a flash flood watch has been issued as a result. We have a high degree of confidence in the timing of the excessive rainfall threat which may lead to flash flooding. Flash flood location impacts may vary due to typical uncertainties in the smaller scale thunderstorm development.

Saturday and Sunday:

Deep tropical moisture and instability are spread across Arizona today, while a seasonably strong low pressure system over Baja and large trough extending east to El Paso Texas moves slowly northward into Arizona. This low pressure system will be the spark to the fuel of the atmospheric instability, and enhance shower and thunderstorm development through the afternoon and overnight hours.