textproduct: NWS Flagstaff

SYNOPSIS

Temperatures warm up to 5 degrees above average throughout the week. Low grade monsoon conditions continue with only isolated storms for the first part of the week. By midweek, thunderstorm coverage begins to increase across the area as more moisture is drawn into the state.

DISCUSSION

High pressure across the region will result in warming temperatures early this week and minimal monsoon thunderstorm activity. Increasing moisture later this week will bring increasing chances for showers and thunderstorms.

High pressure centered across the southwestern U.S. will remain entrenched over the region through the week. Slight amplification and minimal monsoon moisture will allow for warming temperatures and potential heat related headlines yet again. Confidence is increasing that we will reach heat warning temperatures for the inner Grand Canyon (110F). The focus for thunderstorm activity early this week will be over the White Mountains, where the greater moisture resides. An isolated shower or storm is possible as far west as the Flagstaff and the Yavapai county mountains. By midweek, the high pressure ridge axis shifts toward the four corners, while a tropical disturbance is forecast to move northwestward across the southern Baja. Both of these will help to initiate the northward push of moisture across Arizona. Expect increasing moisture and thunderstorm chances from Wednesday onward. It looks like we will return to at least a moderate monsoonal pattern for the end of this week into next weekend.

Subsequently, the increase in moisture and rain chances will help decrease temperatures later this week making heat less of a concern. The potential for heavy rain and flash flooding will be on the rise late this week perhaps lasting into the weekend.

AVIATION...Monday 17/18Z through Tuesday 18/18Z

VFR conditions, brief MVFR near showers/storms. Scattered showers/storms through 03Z in the White Mountains, with isolated showers/storms possible over the Rim. Daytime winds SW-W 5-10kts, light and variable or terrain driven overnight. Gusty and erratic winds possible near storms.

OUTLOOK...Tuesday 18/18Z through Thursday 20/18Z...VFR conditions, brief MVFR near showers/storms. Chance of isolated to scattered storms Tuesday over Rim and White Mountains between 18Z-03Z. Better chance of storms over Rim and White Mountains Wednesday between 18Z-03Z. Winds SW-W 5-15kts daytime, light and variable or terrain driven overnight. Gusty and erratic winds possible near storms.

FIRE WEATHER...Tuesday and Wednesday

Temperatures 5 degrees above average with isolated to scattered showers and thunderstorms each day, best coverage over the eastern Mogollon Rim and White Mountains. Winds SW-W 5-10 mph each day, gusty and erratic winds possible near storms. Minimum RH values 15% lower deserts to 35% in the White Mountains.

Thursday through Saturday...Temperatures continue to be about 5 degrees above average. Scattered showers and thunderstorms over the Mogollon Rim and White Mountains with coverage increasing and spreading westward compared to Wednesday. Winds SW-W 5-10 mph each day, gusty and erratic winds possible near storms.

FGZ WATCHES/WARNINGS/ADVISORIES

None.