textproduct: NWS Flagstaff

SYNOPSIS

High pressure will build into the area this weekend. This will lead to some decrease in monsoonal moisture as well as hotter temperatures this weekend. A return to increased monsoon moisture is possible by the beginning of next week.

DISCUSSION

Upper level low that helped enhance the storm coverage and intensity yesterday has tracked into southeastern Utah. Some warmer and drier air aloft has moved in behind this low which has limited convection so far this afternoon and is expected to keep storm coverage more limited this afternoon. Still can't rule out the possibility of one of these storms producing enough rain for flash flooding, especially with numerous spots across the region having saturated soil.

Stronger high pressure will move west into the region Thursday and park over the Four Corners through the weekend. This will bring some drier air and warmer temperatures aloft which will start reducing the storm coverage with the high country having the best chances. Steering flow aloft starting Thursday will push any storms that form over the higher terrain northward which should limit some of the coverage over Yavapai and northern Gila Counties. By Friday and Saturday temperatures will warm above average and we may need some heat products for the lower parts of the Grand Canyon as temperatures at Phantom Ranch get close to 110 this weekend.

By Sunday some models are bringing another surge of monsoon moisture into the area. This combined with a east to west steering flow will likely lead to another active monsoon pattern for the first part of next week.

AVIATION...Thursday 23/06Z through Friday 24/06Z

Mainly VFR with ISO SHRA overnight, then mainly VFR with SCT SHRA/TSRA after 18Z. Brief MVFR/IFR conditions, gusty/erratic winds, and hail possible in stronger storms. Outside of storms, expect light and variable or terrain driven winds.

OUTLOOK...Friday 24/06Z through Sunday 26/06Z...Chances for SHRA/TSRA, mainly between 18Z-03Z each day. Coverage of SHRA/TSRA decreases each day, remaining focused over the higher terrain. Brief MVFR/IFR conditions, gusty/erratic winds, and hail possible in stronger storms. Outside of storms, expect light and variable or terrain driven winds.

FIRE WEATHER...Today through Friday

A medium grade monsoon environment continues today, then low to medium grade by Thursday and Friday. Scattered thunderstorms are still expected each afternoon/evening, with continued threat of localized flash flooding. Winds are generally light through the period outside of outflow and thunderstorm activity. Expect a strong warming trend through the period.

Saturday through Monday...Continued isolated to scattered thunderstorm activity, most numerous over the higher terrain. Generally light winds outside of outflow and thunderstorm activity. Expect warm temperatures with minimum RH 20-35%.

FGZ WATCHES/WARNINGS/ADVISORIES

None.