textproduct: NWS Flagstaff

SYNOPSIS

Monsoon moisture will remain over the area through the coming week with daily storm chances, along with the risk for heavy rainfall and localized flooding. With the added moisture, temperatures will trend toward normal and even dropping below normal by late week.

DISCUSSION

An active period of monsoon thunderstorms is expected over the next 7 days or longer. High pressure will remain centered north and northeast of our region through the coming weekend, with continued favorable conditions for monsoon moisture to flow into Arizona. Moisture levels as measured by precipitable water are above normal and are forecast to remain there for the foreseeable future. This means that storms that develop will have a potential for producing heavy rainfall and localized flash flooding. The steering flow becomes more northeasterly today through Friday as an inverted trough approaches from the east and the ridge axis shifts to our northwest. This flow is still looking fairly weak (5-15 kts), and this will enhance the potential for storms with heavy rainfall and flash flooding. WPC continues to target areas from the Mogollon Rim through Yavapai/Gila counties in a slight risk for excessive rainfall today, spreading north to include all of our area by Thursday and all but northeast AZ Friday. The potential will certainly be there for flash flooding, especially for more flood prone areas such as fire scars. A Flash Flood Watch has been issued for Yavapai County, Oak Creek/Sycamore Canyons, and northern Gila County from 11 AM to 11 PM MST today. Storms are expected to fire along the Mogollon Rim by mid day and move southwestward into these areas. There is some concern that morning showers/clouds may weaken afternoon instability and heavy rain potential so this will need to be monitored. Outside of storm potential, the added moisture and cloud cover will allow for our recent hot weather to ease. Daytime temperatures for most areas will be near normal today, falling to several degrees below normal by the end of the week/weekend.

AVIATION...Wednesday 15/12Z through Thursday 16/12Z

Mainly VFR conditions. -SHRA/-TSRA developing after 18Z over higher terrain, moving southwestward through the afternoon and evening. Brief MVFR conditions possible from heavier showers/storms. Gusty/erratic winds possible from outflows, with W-SW winds 10 kts or less otherwise.

OUTLOOK...Thursday 16/12Z through Saturday 18/12Z...Periods of -SHRA/-TSRA expected, with greatest coverage generally between 18Z-02Z each day. Gusty/erratic winds possible near/around storms, with generally S-W winds 10 kts or less otherwise. VFR conditions expected outside of brief MVFR conditions in heavier storms.

FIRE WEATHER...Today and Thursday

Daily chances for showers and thunderstorms, with the greatest chances over the higher terrain. Some activity may last into the overnight hours. Wetting rains and gusty outflow winds possible with any stronger storm. Outside of storm activity, winds south through west 5-15 mph.

Friday through Sunday...Daily chances for showers and thunderstorms continue, with the best chances over the higher terrain. Wetting rains and and gusty outflow winds possible with any stronger storm. Outside of storm activity, winds south through west 5-15 mph.

FGZ WATCHES/WARNINGS/ADVISORIES

Flood Watch from 11 AM MST this morning through this evening for AZZ008-018-037-038.