textproduct: NWS Flagstaff

SYNOPSIS

For today, dry and windy weather will bring critical fire weather conditions to northern Arizona, although scattered showers and thunderstorms are expected across portions of the Navajo Nation and along the Arizona/New Mexico border this afternoon. Critical fire weather conditions continue over 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

Critical fire weather conditions are the main concern beginning today and lasting through the weekend. This is due to the passage of a deep low pressure system forecast to bring unusually strong wind speeds, even during what is typically the windy season across northern Arizona. As a result, a Red Flag Warning is in effect from 11 AM MST / Noon MDT today through 8 PM MST / 9 PM MDT Sunday. In addition, Wind Advisories are in effect for most of the area during this timeframe as well.

Today, wind speeds begin to increase, with gusts between 35-45 mph during the afternoon. These winds will combine with minimum humidity ranging from 5-25%, with the lowest values across Yavapai and western Coconino Counties. However, there is enough lingering moisture for a 10-40% chance of showers and thunderstorms over the Navajo Nation and along the Arizona/New Mexico border. In these areas, a mix of wet and dry thunderstorms is expected, so new fire starts are a concern there.

Even windier and drier conditions are forecast for the weekend. Wind speeds will peak Saturday, with southwest wind gusts between 40-55 mph combining with minimum humidity in the teens and single digits area-wide. Wind speeds decline at most locations Saturday night, but narrow bands of strong downslope winds will occur to the east of high terrain features, including the Doney Park area downwind for the San Fransisco Peaks. Southwest wind gusts in the 40-50 mph range continue Sunday.

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...Friday 26/18Z through Saturday 27/18Z

Mainly VFR conditions are forecast for today. ISOLD-SCT -SHRA/-TSRA for the remainder of today, especially NE of the Mogollon Rim. Stronger cells may produce brief MVFR conditions. Sfc winds S-SW15-25g30- 45kts, strongest in the daytime/afternoon hours.

OUTLOOK...Saturday 27/18Z through Monday 29/18Z...Expect VFR conditions. Sfc winds S-SW15-25g30-45kts, strongest in the daytime/afternoon hours.

FIRE WEATHER...Today and Saturday

For today, a Red Flag Warning is in effect for all of northern Arizona beginning at 11 AM MST/12 PM MDT. Widespread SW winds of 15-25 mph, gusting to 35-45 mph, are forecast. These winds will combine with minimum humidity ranging from 5-25%, with the lowest values across Yavapai and western Coconino Counties. That said, a 10-40% chance of showers and thunderstorms is forecast over the Navajo Nation and along the Arizona/New Mexico border. In this area, a mix of wet and dry thunderstorms is expected, so new fire starts are a concern. A Red Flag Warning remains in effect for all of northern Arizona on Saturday, due to even drier and windier conditions. SW winds of 20- 30 mph, gusting to 40-55 mph, are forecast to combine with minimum humidity in the teens and single digits area-wide.

Sunday through Tuesday...The Red Flag Warning continues Sunday for strong winds and low humidity. SW winds Sunday will be 20-30 mph with gusts 40-50 mph. Wind speeds decline on Monday and Tuesday, with southwest gusts from 20-30 mph. Minimum afternoon RH values will remain in the teens and single digits each day.

FGZ WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from 11 AM MST /noon MDT/ this morning to 8 PM MST /9 PM MDT/ Sunday for AZZ104>118-137>140.

Wind Advisory from 11 AM MST /noon MDT/ this morning to 8 PM MST /9 PM MDT/ this evening for AZZ004>016-039-040.

Wind Advisory from 7 AM MST /8 AM MDT/ Saturday to 9 PM MST /10 PM MDT/ Sunday for AZZ004>016-038>040.