textproduct: NWS Flagstaff

SYNOPSIS

Showers and a few thunderstorms will continue through this evening across the region, becoming confined to northeast Arizona late tonight into Wednesday. Expect dry but cool and breezy weather Thursday and Friday. A chance of showers may return to the region Friday night into the weekend.

DISCUSSION

Upper level Low is moving into the state this afternoon. This will continue the shower chances this afternoon, but the 18Z sounding is already showing some significant drying in the mid and upper levels of the atmosphere so additional rainfall amounts will be lower than the last few days. By this evening and overnight hours showers will end over the western half of the area, but will linger along the Utah/Arizona border and the far eastern part of the state through Wednesday afternoon. Not only will this Low bring some drier air but tonight could see some of the coldest if not the coldest readings so far this Fall. Could even see some snow mix in briefly at elevations above 7000 ft before these showers move east.

By Wednesday evening this Low will have pushed east and things finally dry out for Thursday and Friday. As the trough pushes east it takes a positive tilt and will spin up a cutoff Low to the southwest of the state by the weekend. At the same time a ridge moves in over the West forming a Rex block pattern. Winds from the east and northeast will be funneled between this ridge and the cutoff Low making for a breezy Thursday and Friday with winds remaining elevated Thursday night. Didn't issue an Advisories during this shift but future shifts will have to monitor closely to see if a Wind Advisory is warranted Thursday into Friday.

As the Low settles to our southwest, it may be able to tap some subtropical moisture, possibly from Tropical Cyclone Simon. If this happens the higher elevations could see some showers move in Friday night, Saturday and into midday Sunday. The rainfall potential from this scenario does not look to be the magnitude of the last event at this time. However cutoff Lows are famously tough to forecast for and the subtropical moisture tap may not be realized so this remains a very fluid forecast. Will just have to keep monitoring and see how things start coming together in the upcoming model runs.

AVIATION...Tuesday 13/18Z through Wednesday 14/18Z

Areas of MVFR conditions expected through 02Z from SCT -SHRA/-TSRA. After 02Z, SCT -SHRA mainly north of I-40. Winds are SW 15-25 kts with gusts near 30-35 kts through 02Z. Elevated SW-W winds 10-20 kts may continue overnight north of the Mogollon Rim and White Mountains.

OUTLOOK...Wednesday 14/18Z through Friday 16/18Z...Primarily VFR conditions expected. Lingering -SHRA/-TSRA in far northeast AZ on Wednesday afternoon, then fully dry thereafter. Winds are W-NW 5-15 kts on Wednesday, then NE-E 10-20 kts with gusts up to 25-35 kts after 15Z Thursday and continuing thereafter.

FIRE WEATHER...Today through Thursday

Scattered showers will continue today, mostly along the higher terrain. Showers diminish and push eastward tonight through Wednesday, fully dry by Thursday. Winds are west/southwest 15-25 mph with gusts 30-40 mph today, becoming north/northwest 5-15 mph on Wednesday, then northeast 15-25 mph with gusts 30-40 mph on Thursday and continuing overnight. Daytime temperatures 10-15 degrees cooler than normal.

Friday through Sunday...Slight chance for showers and thunderstorms over the higher terrain each day, best chance on Saturday. Winds are east 15-25 mph with gusts 30-40 mph on Friday, subsiding to 5-15 mph from the east/southeast on Saturday, then light and variable by Sunday. Daytime temperatures 5-10 degrees cooler than normal.

FGZ WATCHES/WARNINGS/ADVISORIES

None.