textproduct: NWS Flagstaff

SYNOPSIS

High pressure will dominate the Southwest through the forecast period. Expect hot daytime highs through the week, and diurnally driven showers/storms each day across the higher terrain. Activity looks to slightly expand in coverage by the middle of the week from a shift in the upper-level ridge, which could also drop daytime highs by a few degrees.

DISCUSSION

Heat will continue to be the main story this week as a strong area of high pressure remains over the Southwest. This synoptic pattern has brought hot daytime temperatures (roughly 5-15 degrees above normal), and limited chances for showers/storms. Although the available moisture is not abundant throughout our CWA, there's still enough to see some diurnally driven activity each afternoon across the higher terrain. Activity is forecast to be mostly focused across the eastern Rim and White Mountains today and Tuesday, before coverage expands westward by mid-week. The westward expansion of showers/storms will be due to the strong ridge wobbling northward, but there is still some uncertainty with where the high will eventually settle. Regardless, we can anticipate more showers/storms to break out across the higher terrain by Wednesday.

With slightly cooler temperatures coming in later this week with the movement of the high/increased moisture, we do not expect to have any heat headlines Wednesday onward at this time. The one location that could still be up for question is the lower elevations of the Grand Canyon. For now, an Extreme Heat Warning remains in place for the lower elevations of Yavapai County, the lower elevations of the Grand Canyon, and Marble and Glen Canyons today, with Heat Advisories in place for many locations across NE Arizona. The Heat Warning for the Grand Canyon and Marble and Glen Canyons extends through Tuesday evening as well.

In short, expect hot daytime temperatures to persist and daily chances for showers/storms primarily across the higher terrain.

AVIATION...Monday 03/12Z through Tuesday 04/12Z

VFR conditions forecast through the period. -SHRA/-TSRA possible across the higher terrain, with greatest chances along and south of a KPAN- KSJN line. Look for westerly winds 5-15 kts after 18Z, with light and variable returning overnight. Gusty/erratic winds possible near showers/storms.

OUTLOOK...Tuesday 04/12Z through Thursday 06/12Z...VFR conditions forecast through the period. Look for daily -SHRA/-TSRA chances across the higher terrain each afternoon. Expect westerly winds 10-20 kts each afternoon, becoming light and variable overnight. Gusty/erratic winds possible near showers/storms.

FIRE WEATHER...Monday and Tuesday

Expect above normal temperatures and isolated showers/storms primarily across the higher terrain, with dry conditions elsewhere each day. Look for westerly winds 5-15 mph each afternoon, becoming light and variable overnight. Minimum RH values between 10-30%, with the lowest values along and north of the Little Colorado River Valley.

Wednesday through Friday...Above normal temperatures forecast to persist through the end of the week, along with daily chances for showers/storms. Greatest coverage for activity will be across the higher terrain. Minimum RH values mostly 12% or less along and NE of the Mogollon Rim, and values between 20-35% southward.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 8 PM MST /9 PM MDT/ Tuesday for Azz006-006.

Heat Advisory until 8 PM MST /9 PM MDT/ this evening for Azz006- 010-012>014-040.

Extreme Heat Warning until 8 PM MST this evening for Azz017-037- 038.