textproduct: NWS Flagstaff

SYNOPSIS

Rain chances will be limited mainly to the White Mountains region this weekend, with otherwise dry and seasonable weather expected across northern Arizona. Rain and thunderstorm chances will gradually increase next week with an expected return of monsoon moisture, especially by the second half of the week.

DISCUSSION

High pressure is centered over the southwestern U.S. this morning, stretching northward into the Northern Rocky Mountains. This overall synoptic pattern makes very little movement in the coming days, which will lead to the continuation of seasonal late summer weather and light winds.

Most areas will remain dry today, with the exception of the White Mountains in eastern Arizona, which will see scattered showers and thunderstorms develop this afternoon and evening. As the aforementioned high pressure center slowly shifts northward early in the week, minor shifts to a low level south/southeasterly flow will begin to draw moisture northward. Expect increasing chances for showers/storms Monday through the week, especially for areas along and south of the Mogollon Rim. The positioning of the high near the AZ/UT border on Tuesday/Wednesday should keep a northeasterly mid-level steering flow. This pattern favors afternoon storm development along the Rim, moving southward into Yavapai/Gila counties with some stronger storms possible in the late afternoon and evening. An overall more active pattern looks to be shaping up late in the week as monsoon moisture increases across the state and has the potential to interact with a trough moving in from the west. There is model consensus in the returning moisture, but still some differences in the eventual interaction of any trough features. We can expect a more active monsoon pattern across the area late this week into next weekend with correspondingly cooler temperatures.

AVIATION...Sunday 31/12Z through Monday 01/12Z

VFR conditions are expected to continue. Isolated to scattered -TSRA south of a KPAN - KSJN line from 19-03Z. Brief MVFR and wind gusts up to 35 kts possible in/near storms. Otherwise, light winds 10 kts or less.

OUTLOOK...Monday 01/12Z through Wednesday 03/12Z...Isolated to scattered -SHRA/-TSRA each afternoon/evening, mainly along and south of a KCMR - KSJN line. Storm coverage increases on Tuesday. Stronger storms may produce MVFR conditions and wind gusts up to 40 kts. Outside of any storms, expect light winds mainly less than 10 kts.

FIRE WEATHER...Sunday and Monday

Isolated to scattered thunderstorms will be possible in the White Mountains today, spreading to areas along and south of the Mogollon Rim on Monday. Temperatures will be near to a few degrees above average with daytime humidity ranging from 10-30%. Light winds less than 10-15 mph can be expected both day.

Tuesday through Thursday...Gradually increasing monsoon moisture will lead to increasing rain and thunderstorm chances, especially along and south of the Mogollon Rim. Expect seasonal temperatures with a gradual increasing trend in humidity. Generally light winds less than 10-15 mph are expected.

FGZ WATCHES/WARNINGS/ADVISORIES

None.