textproduct: NWS Flagstaff

SYNOPSIS

Monsoon moisture will return to the area through the coming week bringing better storm chances, especially for areas along and south of the Mogollon Rim. With the added moisture, hot temperatures begin to trend downward Monday ending up towards seasonal averages later in the week.

DISCUSSION

A strong high pressure system aloft continued to build toward the north-central United States. The position of the high will place Arizona in a favorable position for increasing monsoon moisture over the coming week.

For today...The bulk of deeper moisture remains from the Mogollon Rim southward with a drier air mass further north. It isn't quite as unstable as on Sunday (CAPE in the mountains 150 J/kg, 250 to 400 J/kg south of the Rim) but we still expect scattered showers and storms to build over the White Mountains, Mogollon Rim and toward the Grand Canyon starting around Noon. After that the combination of flow aloft and the movement of thunderstorm outflow toward the lower terrain will result storms generally heading to the west to southwest. The strongest storms will be across Yavapai County and western Gila county, which will last into the evening hours. A few of these storms will be capable of producing wind gusts of 45 to 55 mph with hail up to nickle size. North of the Mogollon Rim, activity will be isolated with a drier air mass in place. Could see some evening activity across northeast Arizona as thunderstorm outflows move in from New Mexico and initiate localized convection. The main threat will be locally gusty winds to 40 mph but otherwise, thunderstorms generally weak.

For the remainder of the week...The high aloft will remain over the north-central United States into Wednesday before an inverted trough moving from east to west (south of the high center) dominates the weather across the southwest United States through the weekend. The net result is the door will remain open to the continued intrusion of moisture from over the Gulf of California and northwest Mexico, gradually working it's way further north. Look for active monsoon weather to continue with the chances for daily showers and thunderstorms continuing through the weekend.

AVIATION...Monday 13/18Z through Tuesday 14/18Z

Mainly VFR conditions. SCT SHRA/TSRA from 19Z to 04Z over the higher terrain, with the greatest chances mainly south and west of a KGCN-KFLG-KJTC line. Brief MVFR and gusty outflow winds possible in and around TS. Winds SW-SE 5-15 kts through 03Z, then becoming light and VRB.

OUTLOOK...Tuesday 14/18Z through Thursday 16/18Z...Mainly VFR conditions. Daily chances for SHRA/TSRA mainly over the higher terrain each afternoon and evening. Brief MVFR and gusty outflow winds possible in and around TS. Winds S/SW 5-15 kts each day, becoming light and VRB overnight.

FIRE WEATHER...Tuesday and Wednesday

Daily chances for showers and thunderstorms, primarily over the higher terrain. Wetting rains and gusty outflow winds possible with any stronger storm. Outside of storm activity, winds south/southwest 5-15 mph.

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

FGZ WATCHES/WARNINGS/ADVISORIES

None.