textproduct: NWS Flagstaff

SYNOPSIS

Windy and dry weather will result in critical fire weather conditions across portions of northern Arizona this weekend. Then, chances for showers increase along and north of Interstate 40 from Sunday night into Monday. Cool, dry and breezy conditions are forecast on Monday and Tuesday, before quiet weather and near normal daytime temperatures overtake the area from Wednesday through the remainder of the work week.

DISCUSSION

For today, a passing shortwave trough will deliver a round of critical fire weather conditions to portions of northern Arizona. As a result, a Red Flag Warning is in effect for today from 11 AM MST / Noon MDT through 8 PM MST / 9 PM MDT for the higher elevations of Yavapai County, as well as most locations along and north of the Mogollon Rim. In these areas, the forecast calls for southwest winds of 15-25 mph with gusts of 30-40 mph and relative humidity between 8-17%.

On Sunday, a deeper low-pressure system is forecast to impact the area, bringing a continuation of critical fire weather conditions. Relative humidities are forecast to moisten into the 10-24% range, but stronger wind speeds of 20-30 mph with gusts of 40-50 mph will overtake the area. As a result Red Flag Warnings and Wind Advisories are in effect.

Sunday night through Monday morning, the low-pressure system crosses the area, bringing a 15-40% chance for showers generally from Interstate 40 northward. Cool, dry and breezy conditions return Monday afternoon and Tuesday.

From Wednesday through the remainder of the work week, a weak high pressure system will bring quiet weather and a return of near normal daytime temperatures.

AVIATION...Saturday 16/12Z through Sunday 17/12Z

VFR conditions. Winds S/SW 15-20 kts with gusts 25-35 kts after 16Z, decreasing after 03Z Sunday.

OUTLOOK...Sunday 17/12Z through Tuesday 19/12Z...Brief periods of MVFR in ISO -SHRA/-SHSN mainly north of a KGCN-KRQE line 00Z Sunday-18Z Monday. Slight chance for MVFR CIGS over the higher terrain Monday morning. Winds S/SW 15-25 kts with gusts 30-40 kts on Sunday, becoming SW-NW 10-20 kts with gusts 25-35 kts on Monday.

FIRE WEATHER...Today and Sunday

A Red Flag Warning is in effect for portions of northern Arizona both days. For today, expect SW winds 15-25 mph with gusts 30-40 mph and relative humidity 8-17%. On Sunday, relative humidity increases to 10-24% ahead of an approaching low-pressure system, but SW winds increase to 20-30 mph with gusts 40-50 mph. A 10-40% chance of showers is forecast Sunday night into early Monday morning along the Arizona/Utah border, but the probability of a wetting rainfall (> 0.1") is less than 30%.

Monday through Wednesday....Temperatures remain cool on Monday and Tuesday at 5-10 degrees below average before recovering closer to average on Wednesday. Winds will be W-NW 10-20 mph with gusts 25-35 mph on Monday, becoming SW-W 10-20 mph on Tuesday and Wednesday. Minimum RH values will be 10-20% Monday, 8-15% Tuesday and Wednesday.

FGZ WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from 11 AM MST /noon MDT/ to 8 PM MST /9 PM MDT/ Sunday for AZZ104>106-109>114-116-117-139-140.

Wind Advisory from 11 AM MST /noon MDT/ to 8 PM MST /9 PM MDT/ Sunday for AZZ004-006>009-011>017-038>040.

Red Flag Warning from 11 AM MST /noon MDT/ this morning to 8 PM MST /9 PM MDT/ this evening for AZZ107>109-112>116-139-140.