textproduct: NWS Flagstaff

SYNOPSIS

Scattered showers and thunderstorms will continue through this evening, primarily along/north of I-40 in Navajo and Apache counties. Critical fire weather conditions today and continuing through the weekend, with strong winds and dry conditions area-wide. Wind speeds decline Monday, but near- critical fire weather conditions will persist into next week.

DISCUSSION

Showers and thunderstorms are firing across northern AZ this afternoon. A subtle wave is rippling through, bringing dynamical lift to far northeastern AZ. This is combined with morning destabilization and dewpoints in the 40s to bring scattered showers and thunderstorms to northern AZ. The majority of activity this afternoon will be confined north of I-40 in Navajo and Apache Counties. Further to the west, subsidence and a quickly drying airmass has shut things down. Showers will quickly diminish by the evening as the drier air overtakes the region.

Elsewhere, the concern turns to wind and fire weather. A Red Flag Warning is now in effect for all of northern AZ through Sunday evening. A Wind Advisory is also in effect for most of northern Arizona through the same period. Widespread windy conditions are being observed this afternoon, with gusts peaking in the 30-45 mph range. Away from shower activity, things will be just dry enough to support critical fire weather today, especially towards western AZ. Conditions turn even windier and drier this weekend. Peak wind speeds will be seen on Saturday, with southwest winds gusting to 40- 55 mph combined with minimum RH 10-20%. Into Sunday expect gusts to peak in the 40-50 mph range with continued low humidity. Also expect narrow bands of strong downslope winds during the overnight periods, including the Doney Park area. Do your part this weekend: no open flames or sparks, keep vehicles off of dry grass, properly dispose of cigarette butts, and avoid power equipment that creates sparks.

While critical fire weather conditions are expected to end by Monday, northern Arizona will be locked into a very dry and breezy pattern, resulting in near critical fire weather conditions through much of the work week due to a persistent West Coast trough. Otherwise, high temperatures gradually warm through the week with humidity in the teens and single digits each afternoon.

AVIATION...Saturday 27/00Z through Sunday 28/00Z

Mainly VFR conditions forecast through the period. HZ/FU possible over KFLG through the period from a local wildfire. Winds will remain elevated overnight out of the south at 10-20 kts. After 18Z, expect S-SW winds 20-30 kts gusting near 45 kts.

OUTLOOK...Sunday 28/00Z through Tuesday 30/00Z...Expect VFR conditions. Periods of HZ/FU possible near KFLG from a local wildfire. Gusty winds will persist through much of Sunday, where SW winds 15-25 kts, gusting near 40 kts are forecast. Lighter winds expected on Monday 10-20 kts out of the S-SW.

FIRE WEATHER...This evening through Sunday

Expect evening showers and thunderstorms, primarily over Apache County. All other areas will rapidly clear from the west, due to much drier air moving into the region. The remainder of the weekend will feature very dry and windy conditions. A Red Flag Warning is in place for the entire weekend. Expect daytime conditions with southwest winds from 15 to 25 mph and gusts from 30 to 50 mph. Only marginal improvement can be expected overnight.

Monday through Wednesday...Wind speeds will decrease compared to the weekend, but it will remain breezy. Expect daytime southwest winds from 15 to 30 mph each day. Very dry conditions will also continue with minimum relative humidity values ranging from the single digits to lower teens.

FGZ WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 8 PM MST /9 PM MDT/ Sunday for AZZ104>118- 137>140.

Wind Advisory until 8 PM MST /9 PM MDT/ Sunday for AZZ004>016- 039-040.

Wind Advisory from 7 AM Saturday to 8 PM MST Sunday for AZZ038.