textproduct: NWS Flagstaff

SYNOPSIS

Widespread rainfall will continue through late Sunday evening. Heavy accumulations are expected, especially along/south of the Mogollon Rim. Flooding/flash flooding will be possible across the entire region. This is a serious situation. Stay tuned to your favorite weather source and find a way to receive warnings. Stay away from waterways. Turn around, don't drown.

DISCUSSION

A concerning hydrological threat will evolve across Northern Arizona over the next 24 hours with the arrival of an atmospheric river. Widespread areas will see 1-3 inches, with some localized areas along/south of the Mogollon Rim up to 4-6 inches. Hydrological issues will be enhanced due to the already very saturated soil conditions, and it will take less rainfall than usual to cause problems. Both flash flooding and river flooding will be a problem, with some area waterways remaining elevated for days beyond the main event. Be prepared in case you need to take action or need to head to higher ground. Have a way to receive warnings and always remember, TURN AROUND, DON'T DROWN!

The deep surge of subtropical moisture has already arrived early this morning. Current mesoanalysis shows a strengthening mid-level jet and a plume of PWAT values >1 inch moving in from the southwest. Also, current surface observations show south-southwest winds gusting as high as 30-40 mph as of 1 AM MST. Widespread light to moderate showers are currently ongoing as a result of these factors. The heaviest rainfall is currently along/south of the Mogollon Rim with help from orographic influences, though periods of moderate rain can be expected virtually area wide this morning and into the daytime today. By the late afternoon through evening, a cold front associated with a strong northern stream low will cross the region bringing continued threats of heavy rain and even a marginal severe threat across southern and eastern AZ. Much drier air will follow in the wake of the frontal passage. A Flood Watch will remain in effect for all of northern and central Arizona through Sunday night, though river flooding will likely linger for several days after.

There will also be a strong wind threat. Very gusty surface winds have already been noted early this morning, and are forecast to strengthen into the daytime today. A Wind Advisory will go into effect today for the Little Colorado River Valley, Eastern Mogollon Rim, and White Mountains where gusts as high as 40-50 mph are possible. Breezy winds up to 30-40 mph are still possible outside these regions.

There is also potential for snow mostly above 7500-8000 ft elevation before things fully dry out on Sunday night. The main area of concern is the Kaibab Plateau where 1-2 inches of snow are possible. A dusting of snow will also be possible for the higher elevation locations around the Flagstaff area. Fully dry conditions are expected by Monday afternoon and through the week as ridging dominates. Another trough will brush past Arizona on Wednesday, but this looks to remain mostly dry at this time.

FIRE WEATHER...Sunday and Monday

Widespread rainfall will continue today, eventually decreasing in coverage by the late evening. A few embedded thunderstorms are possible. Heavy accumulations are expected especially along/south of the Rim. Threats of flooding and flash flooding will be exacerbated by the already very saturated ground conditions. Strong winds are also expected. Winds are southwest 15-25 mph gusting up to 30-40 mph this morning, then gusts as high as 50 mph possible across eastern AZ this afternoon. Winds turn more westerly and gradually diminish through Sunday night, becoming northwest 10-20 mph on Monday afternoon.

Tuesday through Thursday...A drier weather pattern is expected through this period, with lingering flooding impacts possible. Winds are easterly 5-15 mph on Tuesday, turning westerly 10-20 mph on Wednesday, then light and variable on Thursday. Minimum RH above 30- 50% through the period.

FGZ WATCHES/WARNINGS/ADVISORIES

Flood Watch through late tonight for AZZ004>018-037>040.

Wind Advisory until 11 PM MST this evening for AZZ012>014-016- 017.