textproduct: NWS Flagstaff

SYNOPSIS

High pressure will continue to dominate the Southwest through the forecast period. This pattern will allow for above normal temperatures and daily chances for showers and storms. Greatest coverage will be across the higher terrain each afternoon and evening.

DISCUSSION

There will be little change over the coming week with hot temperatures and low to medium level monsoon activity continuing. A strong high pressure system aloft will remain centered over New Mexico and Colorado through Wednesday and then slowly shift westward over Arizona and Utah by next Saturday.

Widespread cloud cover and light showers have lingered overnight across much of northern Arizona. While modest moisture and instability remains in place today, overall activity does not look any more involved than yesterday. The HREF favors the most thunderstorm coverage to be over the White Mountains into New Mexico this afternoon. More isolated activity with gusty outflows will then spread into the lower elevations. An Extreme Heat Warning remains in effect through 8PM MST for the elevations below 4000 feet from the Grand Canyon northeastward to Page.

Monsoon moisture will remain in place this week, though slightly fade later in the week as the strong, hot high pressure peaks. Look for isolated to scattered showers and thunderstorms each day. The mountains will tend to see the first activity by late in the morning where storms will be scattered. Later in the afternoon thunderstorms will move into the valleys and generally be more isolated. Additional Extreme Heat Warnings are likely to come.

AVIATION...Sunday 26/12Z through Monday 27/12Z

Mainly VFR conditions. ISO -SHRA early, then SCT SHRA/TSRA returns after 18Z. Brief MVFR/IFR conditions and gusty, erratic winds in stronger storms. Outside of storms, expect variable winds around 10 kts or less, becoming light and variable overnight.

OUTLOOK...Monday 27/12Z through Wednesday 29/12Z...Mainly VFR conditions. SCT-NMRS SHRA/TSRA between 18Z-03Z each day, with greatest coverage across the higher terrain. Brief MVFR/IFR conditions and gusty, erratic winds in stronger storms. Outside of storms, expect westerly winds 5-15 kts, becoming light and variable overnight.

FIRE WEATHER...Today through Monday

Isolated to scattered showers/storms each day, primarily across the higher terrain. Localized heavy rain causing flash flooding will remain one of the main concerns. Outside of precipitation, very hot temperatures forecast for lower elevations with lowest RH at 15-20%. Storm driven winds could be gusty/erratic, but variable winds generally 10 mph or less expected otherwise.

Tuesday through Thursday...Warmer than normal afternoon highs will continue through the week, along with daily chances for showers/storms. Main coverage will be across the higher terrain. Gusty/erratic winds possible from storm driven outflows, with light westerly winds forecast otherwise.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 8 PM MST /9 PM MDT/ this evening for AZZ005-006.