textproduct: NWS Flagstaff

SYNOPSIS

Mostly dry and warm conditions will continue through Friday with some isolated showers or storms possible across the higher terrain each afternoon. Cold, windy, and wet conditions return over the weekend as tropical moisture moves back into the region, with the potential for a significant rainfall event.

DISCUSSION

A weak shortwave will push towards the east through tonight. This wave will help to trigger a few showers and thunderstorms, mainly towards the White Mountains and across far eastern Arizona through this afternoon. Outside of these isolated storms, we expect warm temperatures to continue with generally light winds across the region.

By Friday, the trough exits to the east as a ridge of high pressure tries to build into the area. The ridge is weak and doesn't really get established as a trough starts to develop over the Pacific Northwest and digs southward. A few lingering showers may develop on Friday across the higher terrain but expect most areas to remain dry with warm temperatures continuing.

As we head into the weekend, we start to see a shift in the weather across the Desert Southwest as the Pacific Northwest trough starts to dig to the south/southwest. As the trough digs south, it will interact with what will become the remnants of TS Rachel. Current model runs continue to drag that moisture up into the Desert Southwest over the weekend and into early next week. The trough looks to become cut off by late in the weekend and models are slow to push the low off to the north and east. Additional tropical moisture could be pulled northward into the region through at least midweek, so it looks like we could have a very active and wet period ahead of us. QPF ranges are fairly widespread at this time but the potential for 1-3" with locally higher amounts remain possible. Depending on where the trough ends up and how the moisture is advected into the region, will determine the areas with the biggest impact from the system. Current projections have western areas seeing the greatest potential for heavy rain but any slight shifts in the track could push things to the east. As Rachel weakens and the trough starts to dig south, we should start to see a better picture of just where the greatest impacts will be expected. On top of the potential for heavy rainfall, we will see increasing south to southwest winds with gusts 35-45 mph on Sunday. Keep any eye on the forecast as we get more refined over the next day or two.

AVIATION...Thursday 08/06Z through Friday 09/06Z

VFR conditions, a few isolated showers and thunderstorms along the Arizona/New Mexico border in the afternoon. Winds mainly E-SE or VRB at 5-10kts daytime, light and variable or terrain driven overnight.

OUTLOOK...Friday 09/06Z through Sunday 11/06Z...VFR conditions, a few isolated showers or thunderstorms in the White Mountains Friday afternoon. A chance of showers begins moving in over most of the area starting around 12Z Saturday as a weather system approaches, becoming numerous Saturday night. Winds S-SW 10-15kts Friday, increasing to 10-20 gust 30 kts Saturday.

FIRE WEATHER...Thursday and Friday

Expect mainly dry conditions and continued seasonably warm temperatures. A slight chance of high- based showers and thunderstorms remains possible for Thursday and Friday afternoons, primarily for the eastern zones. Chances for wetting rains are near zero. Winds light and variable 5-10 mph Thursday, becoming S-SW 10-15 mph on Friday.

Saturday through Monday...Unsettled conditions move in Saturday morning with scattered to numerous showers and thunderstorms possible all weekend and into Monday. Wetting rains are likely across the whole region. Winds S-SW 10-20 mph with gusts to 30 mph on Saturday, S-SW 15-30 mph with gusts 40-45 mph on Sunday, S-SW 15- 25 mph with gusts 35-40 mph on Monday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.