textproduct: NWS Flagstaff

SYNOPSIS

Moderate monsoon conditions will continue through Monday, mainly along the higher terrain during the afternoon and evening hours. Then, as a high pressure system builds over Arizona, warmer and drier conditions are expected to develop by midweek as the flow of moisture northward into the region decreases.

DISCUSSION

A 500 mb high pressure system located above west- central New Mexico is expected to slowly build westward by the middle of the upcoming week. In its current position, the high is supporting moderate monsoonal conditions as some moisture continues to be transported northward into northern Arizona, supporting shower and thunderstorms across and near the higher terrain during the afternoon and evening hours. Southerly steering flow will also push the developing showers and thunderstorms northward. This pattern is expected continue Monday, then as the high builds westward and over Arizona midweek this will slow the transport of monsoonal moisture and allow for drier and more stable air to develop over northern Arizona. This will lead to a decrease in the potential for showers and thunderstorms, along with allowing max daytime temperatures to climb a few decreases, especially in areas that have been experiencing increased cloud cover due to the current monsoonal pattern.

AVIATION...Sunday 23/06Z through Monday 24/06Z

VFR conditions mostly expected, but brief MVFR conditions possible in heavier SHRA/TSRA. Isolated -SHRA overnight, mainly east of a KPGA-KPAN line. Another round of scattered SHRA/TSRA developing Sunday after 18Z and continuing through at least 03Z. Outside of gusty/erratic outflow driven winds, look for variable daytime winds 5-15 kts.

OUTLOOK...Monday 24/06Z through Wednesday 26/06Z...VFR conditions mostly expected. Scattered afternoon/evening mainly high terrain SHRA/TSRA Monday, then coverage decreasing to isolated by Tuesday. Outside of gusty/erratic outflow driven winds, look for daytime winds mainly SW-W 5-15 kts.

FIRE WEATHER...Sunday and Monday

Expect daily chances for showers/thunderstorms, with greatest coverage across the higher terrain. Activity will ramp up around 11 AM MST each day, and continue through the evening hours. Storms will be capable of producing gusty winds, heavy rain, small hail, and frequent lightning. Outside of storm driven winds, look for variable winds generally 10 mph or less.

Tuesday through Thursday...Drier conditions will gradually return, with activity becoming limited to the White Mountains Wednesday and Thursday. Daytime highs forecast to increase, reaching 8-15 degrees above normal. Look for southwest winds 5-15 mph each afternoon.

FGZ WATCHES/WARNINGS/ADVISORIES

None.