textproduct: NWS Flagstaff

SYNOPSIS

Look for dry weather, gusty southwest winds and cooler daytime temperatures through Friday. The strongest winds will be on Wednesday when a Wind Advisory and Red Flag Warning will be in effect for portions of northern Arizona. Unsettled weather returns for the weekend.

DISCUSSION

A weakening Pacific trough was approaching Arizona on Tuesday. In advance of the trough a west to southwest flow was pushing a drier air mass across northern Arizona. In addition, strengthening surface pressure gradients in response to the approaching trough were bringing south to southwest winds at 10-20 mph gusting to 25-30 mph during Tuesday afternoon. Overnight, winds will diminish to 5-10 mph in valley locations but for elevations above 6000 feet winds will generally remain at 10-20 mph with a few gusts to 30 mph possible. On Wednesday, as the trough axis moves Arizona, southwest winds will strengthen. Look for southwest winds at 15-25 mph gusting to 30-45 mph (the higher values especially from the Mogollon Rim northward). Pressure gradients will remain strong enough for winds to remain gusty through Wednesday night. A Wind Advisory is in effect for much of northern Arizona on Wednesday due to the stronger winds. In addition, due to dry conditions and the gusty winds a Red Flag Warning is also in effect for Wednesday. Otherwise, a bit cooler during the daytime under just a few clouds.

For Thursday and Friday...The trough will head eastward. Consequently, winds will shift to more southwest to west direction. It will remain gusty with southwest to west winds at 10-20 mph gusting to around 25 mph most areas. Look for mainly sunny skies on Thursday with some additional cloudiness on Friday with a weak passing disturbance. Little change in high and low temperatures.

From Saturday onward...Unsettled weather returns with a series of weak shortwave troughs continuing to brush Arizona. Look for near to below average temperatures and daytime breezes with chances for showers at times.

AVIATION...Tuesday 21/18Z through Wednesday 22/18Z

VFR conditions. Winds S/SW 10-20 kts with gusts up to 30 kts through 03Z, then subsiding to 5-15 kts overnight. Winds remain elevated downwind of the higher terrain.

OUTLOOK...Wednesday 22/18Z through Friday 24/18Z...VFR conditions. Winds SW 15-25 kts with gusts 30-40 kts on Wednesday, becoming W/SW 10-20 kts with gusts up to 30 kts on Thursday.

FIRE WEATHER...Wednesday and Thursday

Critical fire weather conditions expected across northeastern Arizona on Wednesday. Dry and cooler conditions. Winds southwest 15-25 mph with gusts 35-45 mph on Wednesday, becoming west/southwest 10-20 mph with gusts 30-35 mph on Thursday. Minimum afternoon RH 10-20% each day.

Friday through Sunday...Dry conditions, outside of a slight chance for high-based showers on Sunday. Winds southwest/west 10-20 mph with gusts 25-30 mph each day. Minimum afternoon RH 10-20% on Friday, rising to 15-30% over the weekend.

FGZ WATCHES/WARNINGS/ADVISORIES

Wind Advisory from 8 AM MST /9 AM MDT/ to 8 PM MST /9 PM MDT/ Wednesday for AZZ004>007-009>017-039-040.

Red Flag Warning from 10 AM MST /11 AM MDT/ to 8 PM MST /9 PM MDT/ Wednesday for AZZ109>114-139-140.