textproduct: NWS Flagstaff

SYNOPSIS

Monsoon moisture will return to the area through the coming week with daily storm chances, along with the risk for heavy rainfall and localized flooding. With the added moisture, temperatures will trend toward normal and even dropping below normal by late week.

DISCUSSION

Northern Arizona will remain in an active monsoon pattern as the general flow remains favorable for the continued movement of monsoon moisture to the area.

For Today...Monsoon moisture has made its way across all of northern Arizona. As a result, almost any location could see a shower or thunderstorms. The odds at any single location will 30-50% percent for this afternoon through this evening. As usual, the higher terrain locations will likely get hit first with storms then wandering into the lower elevations from the late afternoon into the evening. Isolated thunderstorms could even continue through the night as outflow boundaries running across the area encounter any remaining pockets of instability. The highest CAPE values will be south of the Mogollon Rim where pockets of 200-500 J/kg will exist. Isolated storm will be capable of producing localized flash flooding, wind gust 30-40 mph and hail up to around nickle size. From the Mogollon Rim northward CAPE values of 100-200 J/kg will be the norm with garden variety thunderstorms anticipated capable of producing locally heavy downpours and small hail but with a limited flash flood threat.

For the remainder of the week...The high aloft will remain over the north-central United States into Wednesday before an inverted trough moves across Arizona from the east. The arrival of the trough will place northern Arizona under a weak northeast to southwest steering flow aloft. However, moisture in the low levels will remain ample due to flow from over the Gulf of California/northwest Mexico and daily recycling of rainfall through evapostranspiration. The interesting aspect of this pattern is that there will be the typical afternoon development of showers and thunderstorms over the higher terrain followed by storm outflow in the evening from over New Mexico then later in the night from over Colorado. This will likely result in continued chances for showers and storms through the overnight periods. In other words, look for active monsoon weather through the weekend.

The weekend and beyond...High pressure becomes reestablished over a favorable position to the north and east of Arizona for active monsoon weather to continue.

AVIATION...Wednesday 15/00Z through Thursday 16/00Z

VFR mainly expected. Isolated to scattered -SHRA/-TSRA possible through 12Z, becoming more widespread after 18Z. Brief MVFR conditions possible throughout the afternoon/evening hours on Wednesday from heavier showers/storms. Gusty/erratic winds possible from outflows, with W-SW winds 10 kts or less otherwise forecast.

OUTLOOK...Thursday 16/00Z through Saturday 18/00Z...Continuous -SHRA/-TSRA expected, with greatest coverage generally between 18Z-04Z each day. Gusty/erratic winds possible near/around storms, with generally S-W winds 10 kts or less otherwise. VFR conditions expected outside of brief MVFR conditions in heavier storms.

FIRE WEATHER...Wednesday and Thursday

Daily chances for showers and thunderstorms, with the greatest chances over the higher terrain. Some activity may last into the overnight hours. Wetting rains and gusty outflow winds possible with any stronger storm. Outside of storm activity, winds south through west 5-15 mph.

Friday through Sunday...Daily chances for showers and thunderstorms continue, with the best chances over the higher terrain. Wetting rains and and gusty outflow winds possible with any stronger storm. Outside of storm activity, winds south through west 5-15 mph.

FGZ WATCHES/WARNINGS/ADVISORIES

None.