textproduct: NWS Flagstaff

SYNOPSIS

Expect temperatures 5-10 degrees above average through the rest of the week. Starting today thunderstorm coverage begins to increase across the area as additional monsoon moisture is drawn across the state. A bit cooler temperatures arrive for the weekend.

DISCUSSION

High pressure centered over the state will begin to move off to the east starting today. Hot temperatures under this feature will peak today with some locations approaching record highs. An Extreme Heat Warning is in effect now for areas below 4,000ft in the Grand Canyon through Thursday night, so use caution if you hike below the Grand Canyon Rim. Some monsoon moisture will move in today increasing chances for afternoon thunderstorms mainly over the higher terrain, although it is possible for a couple of these storms to move into the lower elevations of Gila and Yavapai County by this evening.

As the second half of the week progresses the high pressure area shifts further to the east which will bring in more monsoon moisture across the state. Look for POPs to rise and coverage to increase Thursday into the weekend with most of the area seeing a chance for thunderstorms. Temperatures Thursday will be slightly cooler but close to Wednesday's highs, but as moisture and clouds increase, temperatures trend downward each day and get close to normal or just above normal by the weekend. 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...Wednesday 19/12Z through Thursday 20/12Z

Mainly VFR conditions, brief MVFR near heavier showers/storms. Expect scattered showers/storms over the Rim and White Mountains between 18Z-03Z, showers/storms may move off to the southwest into lower elevations between 21Z-03Z. Winds SW-NW 5-15kts daytime, light and variable or terrain driven overnight. Gusty and erratic winds near storms.

OUTLOOK...Thursday 20/12Z through Saturday 22/12Z...Mainly VFR conditions, brief MVFR possible near heavier showers/storms. Expect showers/storms to develop first over the Rim and White Mountains early afternoon, moving off into lower elevation deserts late afternoon/early evening. Winds SW-NW 5-15kts daytime, light and variable or terrain driven overnight. Gusty and erratic winds near storms.

FIRE WEATHER...Today and Thursday

Temperatures rise to 5-10 degrees above average with some areas approaching record heat. Isolated to scattered showers and thunderstorms each day with the best coverage over the Mogollon Rim and White Mountains. Winds W-NW at 5-15 mph each day. Gusty and erratic winds possible near storms. Minimum RH values 10-15% over the lower deserts to 25-30% on the Rim and in the White Mountains.

Friday through Sunday...Temperatures around 5 degrees above average each afternoon. Scattered showers and thunderstorms increasing in coverage each day with most of the area seeing a chance for shower/storms by the weekend. Winds S-SW at 5-15 mph. Gusty and erratic winds possible near storms.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 8 PM MST Thursday for AZZ006.