textproduct: NWS Flagstaff

SYNOPSIS

Storm activity will be confined to far eastern Arizona today before spreading back westward through the week. Temperatures will be close to normal through Labor Day, warming to above normal by mid week.

DISCUSSION

High pressure aloft was centered over north Texas with a strong trough centered over the Pacific Northwest early Monday morning.

For today...A shortwave disturbance moving through the Pacific Northwest trough will brush Arizona then move to the northeast through the day. The net effect of this feature will be to deliver a drier air mass to most of northern Arizona. The only areas that will avoid this drying will be the eastern Mogollon Rim, White Mountains and to some degree the Chuska Mountains. Most areas will see partly to mostly cloud skies as mid to upper level moisture streams across the area but low chances for any precipitation. Substantial low-level moisture will be confined to the eastern portions of the forecast area.

From Tuesday into Thursday...High pressure will gradually build back over Arizona from the east. Monsoon moisture will continue to linger and even gradually increase through this period. As a result, the shower and thunderstorm threat will continue across the high terrain of eastern Arizona but gradually spread westward along the Mogollon Rim. Any heavy rain potential is expected to remain confined to the White Mountains region. Activity will continue to be focused in the afternoon and evening. Look for warmer temperatures as the high builds over northern Arizona with mountain temperatures climbing to the upper 70s to mid 80s and 95 to 105 at lower elevations.

Looking at Friday onward...Additional troughing enters the western states pushing the high center to the east. It isn't clear that this next trough will sweep monsoon moisture away. In fact, most models suggest monsoon moisture will interact with disturbances moving through the western trough modulated to some degree by daytime heating. We will have to wait and see on this one because if the trough comes in stronger than models currently show drying will likely follow. On the other hand, if trough energy remains on the northern periphery of the low-level monsoon moisture it could remain unsettled, most likely day and night.

AVIATION...Monday 07/12Z through Tuesday 08/12Z

Expect mainly VFR conditions. Scattered -SHRA/-TSRA with brief MVFR conditions/gusty winds 18Z through 02Z south of a KSOW-KSJN. Elsewhere, isolated activity. Winds generally northwest to southwest 10-20 kts between 18Z-02Z, light and variable the remainder of the time.

OUTLOOK...Tuesday 08/12Z through Thursday 10/12Z...Expect mainly VFR conditions. Isolated to scattered -SHRA/-TSRA each day, mainly in the afternoon hours along and south of a KFLG-KRQE line. Showers and thunderstorms may push as far west as the I-17 corridor by Wednesday. Winds generally light less than 15 kts.

FIRE WEATHER...Today and Tuesday

Today, isolated to scattered afternoon showers and thunderstorms will be confined to the higher terrain in the eastern third of Arizona. By Tuesday afternoon showers and thunderstorm chances begin to move westward along the Mogollon Rim with continued chances over the mountains of eastern Arizona. Winds southwest to west 5-15 mph with gusts to 25 mph each afternoon, light and variable or terrain driven overnight. Minimum RH's each afternoon ranging from 15% in the lower deserts to 30-40% in the mountains. Turning warmer.

Wednesday through Friday...Afternoon showers and thunderstorms remain primarily over the higher terrain of the Rim and White Mountains. Daytime temperatures 5-10 degrees above normal. Winds south to southwest 5-15 mph each day, light and variable or terrain driven overnight.

FGZ WATCHES/WARNINGS/ADVISORIES

None.