textproduct: NWS Flagstaff

SYNOPSIS

Overall dry, breezy, and hot conditions are forecast through Tuesday, with critical fire weather today across portions of far eastern Arizona. A slight chance for showers and thunderstorms returns by the middle of next week.

DISCUSSION

A shortwave trough along the west coast will move eastward, passing north of the state today. This will cause the already breezy winds observed Friday to increase slightly. Today's winds are forecast to be southwesterly at 15-25 mph with gusts in the 30-35 mph range, strongest in northeast Arizona. Dewpoints are also forecast to crash during the afternoon, dropping relative humidities at or below 10% for all areas. A Red Flag Warning has been issued for parts of the Little Colorado River Valley and the Chuska Mtns/Defiance Plateau this afternoon where winds are expected to be strongest. For Sunday and Monday, high pressure builds northward into Arizona, allowing wind speeds to drop below critical fire weather criteria. Daytime temperatures will start to increase, reaching 5 to 10 degrees above normal for portions of the area by Monday. Highs at the lower elevations of Grand Canyon will reach toward the lower 110s for Monday into Tuesday, prompting an Extreme Heat Watch to be issued.

Tuesday through Friday - An area of high pressure is forecast to be centered near southeast Arizona, allowing for a return of moisture inflow around the west side of the high. Mean precipitable water forecasts from the grand ensemble peak around 0.70"-0.90" Wednesday into Thursday. This will bring slight chances for showers and thunderstorms, mainly during the afternoon and highest along/north of the Mogollon Rim. Otherwise, daytime temperatures will be 5-10 degrees above normal, with some localized Heat Risk values in the major category for the lower elevations of Yavapai County and around Page. Continued warning criteria for the lower elevations of Grand Canyon will in part depend on cloud cover, which returns to some extent by Wednesday. Breezy southwest to west winds are also expected mid to late week on the north side of the high.

AVIATION...Saturday 20/12Z through Sunday 21/12Z

Mainly VFR, periods of overnight MVFR possible near KSEZ in HZ/FU. Winds S/SW 5-15 kts through 16Z and after 03Z, otherwise increasing during the daytime to 10-20 kts with gusts 25-30 kts.

OUTLOOK...Sunday 21/12Z through Tuesday 23/12Z...Mainly VFR, periods of MVFR possible near KFLG/KSEZ in HZ/FU. Winds W/SW 10-15 kts up to 20 kts each day, becoming VRB 5-10 kts overnight.

FIRE WEATHER...Today and Sunday

Very dry and breezy conditions will bring areas of critical fire weather on Saturday. Winds are southwest 10-20 mph with gusts 25-35 mph, along with minimum RH 5- 10%. A Red Flag Warning will be in effect for portions of the Little Colorado River Valley and Chuska Mountains on Saturday, still expect near-critical fire weather elsewhere. Winds decrease on Sunday, becoming west 10-15 mph with gusts to 25 mph. Very dry conditions persist with minimum RH 4-8%.

Monday through Wednesday...Very dry on Monday with gradually increasing moisture thereafter. Winds are southwest through west 10- 20 mph each day, along with daytime temperatures 5-10 degrees above normal. Minimum RH is 5-10% on Monday, becoming 8-13% on Tuesday, then 10-20% on Wednesday.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Watch from Monday morning through Tuesday evening for AZZ006.

Red Flag Warning from 11 AM MST /noon MDT/ this morning to 6 PM MST /7 PM MDT/ this evening for AZZ111-113-114.