textproduct: NWS Flagstaff

SYNOPSIS

Hot temperatures continue through much of the week, along with increasing chances for showers and thunderstorms over the higher terrain. Drier and windier conditions return by the weekend, with critical fire weather conditions expected.

DISCUSSION...Today

A strong ridge of high pressure centered of New Mexico will continue to drive hot temperatures across much of northern Arizona today. Flow around the high will also drive sub- tropical moisture from the Gulf of California northward into Arizona. As a result, a few isolated showers and thunderstorms are expected to develop later this afternoon, mainly from the Mogollon Rim and northward. Model soundings do depict a fairly dry sub-cloud layer, given the still very dry surface. As a result, any storms that do develop look to primarily be high-based, with the main threats being dry lightning and gusty outflow winds.

UofA WRF guidance does support outflows moving out of the Lower Deserts later this evening, potentially leading to a few isolated overnight/early morning convection into early Wednesday.

Wednesday and Thursday...Another round of showers and thunderstorms is expected on Wednesday, however any early morning convective and debris clouds could potentially limit coverage. As of now through, guidance points towards better moisture in place on Wednesday, which would lean towards the best coverage being on this day. Storms do look to remain on Thursday again as well, but coverage does begin to wain as mid-level flow shifts more westerly. Storms will again be mainly high-based, with dry lightning and gusty outflow winds. A few brief heavy downpours could be possible in any stronger/persistent storm.

Friday through Monday...A strong trough looks to approach Arizona by the weekend. Slighty cooler, but winder conditions look to ensue over much of the region as a result. Moisture is quickly suppressed back to the south as soon as Friday, with only a few isolated storms possible near the White Mountains on Friday before turning dry through the weekend.

Gusty winds look to set in by Friday and continue through the weekend. As of now Saturday looks to be the windiest day, with gusts upwards of 40 to 50 mph possible. Given that afternoon relative humidity for much of the region is expected to be in the 10-15% range, critical fire weather conditions look to return. Combined with the potential for a few new lightning-caused fire starts from the preceding few days, this fire weather pattern is concerning. Red flag headlines will likely be needed going into this weekend.

AVIATION...Tuesday 23/12Z through Wednesday 24/12Z

Mainly VFR conditions. ISO -SHRA/TSRA mostly along and north of KCMR-KSOW from 20Z to 03Z. Gusty, erratic outflow winds possible in and around TS. Winds VRB 5-10 kts, becoming SW 10-15 kts from 18Z to 03Z.

OUTLOOK...Wednesday 24/12Z through Friday 26/12Z...Mainly VFR conditions. SCT -SHRA/TSRA each afternoon and evening, mainly along and north of a KCMR-KJTC line. Gusty, erratic outflow winds possible in and around TS. Daytime winds SW 10-15 kts on Wednesday, increasing to 10-20 kts on Thursday. Winds VRB 5-10 kts overnight.

FIRE WEATHER...Today and Wednesday

High-based thunderstorms are expected each day, primarily along and north of the Mogollon Rim. Otherwise, hot temperatures with west/southwest winds 10-20 mph each day. Minimum afternoon RH 10-15% today, rising to 15-25% on Wednesday.

Thursday through Saturday...Showers and thunderstorms remain possible on Thursday from the Mogollon Rim and northward. Critical fire weather conditions are then expected on Friday and Saturday as drier conditions set in. Winds southwest 15-20 mph on Thursday, increasing to 20-25 mph on Friday, and 20-30 mph on Saturday. Minimum afternoon RH 15-25% on Thursday, falling to 10-20% Friday, and 5-15% by Saturday.

FGZ WATCHES/WARNINGS/ADVISORIES

Extreme Heat Warning until 7 PM MST this evening for AZZ006.