textproduct: NWS Flagstaff

SYNOPSIS

Temperatures warm up to 5-10 degrees above average throughout the week. Low grade monsoon conditions continue today with only isolated storms over the White Mountains. By midweek, thunderstorm coverage begins to increase across the area as more moisture is drawn into the state.

DISCUSSION

High pressure over the state will keep the region in low grade monsoon conditions today. Only the White Mountains and parts of the Rim are expected to see any activity. High temperatures under this feature will warm to 5-10 degrees above average and stay there most of the week. An Extreme Heat Warning has been issued for areas below 4,000ft in the Grand Canyon from Tuesday morning and lasting through Thursday night, so use caution if you hike below the Grand Canyon Rim.

By midweek the high pressure area shifts to the east and centers over the Four Corners which is more conducive for monsoon moisture to overspread the state. Look for POPs to rise across the higher terrain starting Wednesday and by Thursday or Friday most of the area should see a chance of showers/storms. Increased moisture and cloud cover by this weekend should get temperatures back down to seasonal averages. As storm coverage increases and soils once again become wet, flash flood concerns will be on the rise late this week and into the weekend.

AVIATION...Tuesday 18/12Z through Wednesday 19/12Z

VFR conditions, brief MVFR near showers/storms. Scattered showers/storms in the White Mountains, with isolated showers/storms possible over the Rim between 18Z-03Z. Daytime winds SW-W 5-10kts, light and variable or terrain driven overnight. Gusty and erratic winds possible near storms.

OUTLOOK...Wednesday 19/12Z through Friday 21/12Z...VFR conditions, brief MVFR near showers/storms. Isolated to scattered showers/storms over Rim and White Mountains Wednesday between 18Z-03Z. Scattered showers/storms Thursday starting on the high terrain and spreading into lower elevations by late afternoon/early evening. Winds SW-W 5-15kts daytime Wednesday, W-NW 5-15kts daytime Thursday, light and variable or terrain driven overnight. Gusty and erratic winds possible near storms.

FIRE WEATHER...Today and Wednesday

Temperatures rise to 5-10 degrees above average. Expect isolated to scattered showers and thunderstorms each day with the 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 10-15% over the lower deserts to 30-35% in the White Mountains.

Thursday through Saturday...Temperatures 5-10 degrees above average Thursday, 5 degrees above average Friday, cooling to near normal over the weekend. Scattered showers and thunderstorms increasing in coverage each day with most of the area seeing a chance for shower/storms by the weekend. Winds W-NW 5-15 mph Thursday, S-SW 5- 15 mph Friday and Saturday. Gusty and erratic winds possible near storms.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning from 10 AM this morning to 8 PM MST Thursday for AZZ006.