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 weather Thursday, but a chance of showers may return to the region Friday into the weekend. Gusty east to northeast winds will develop Thursday and Friday.

DISCUSSION

An upper low across central Nevada will approach Arizona today, then move across far northern parts of the state this evening into Wednesday morning. Winds aloft ahead of the low continue to be elevated, resulting in southwesterly surface winds of 15-25 mph gusting 30-45 mph through the day. While the heaviest rainfall with this pattern is over, there is still enough moisture for plenty of showers and an isolated thunderstorm through the day, most widespread over the higher terrain upslope regions. Heavy rainfall over the past several days continues to cause elevated flows on area creeks and rivers, especially the Verde River system, including West Clear Creek and the East Verde River. A Flood Warning is in effect until 8 AM in this area, primarily south of Camp Verde. As the low moves into Arizona later this evening and overnight, snow levels will to 7000 ft or slightly lower, with some light accumulation possible over the highest portions of the San Francisco Peaks, Kaibab Plateau, and Chuska Mtns. Showers may linger into Wednesday afternoon in far northeast Arizona, but most of the the region will dry out on Wednesday. With the much colder air mass moving in tonight, some higher elevation areas (Flagstaff/Williams/Tusayan) could see their first hard freeze of the season though this will depend on how quickly skies clear and winds drop off. Some frost will also be possible as low as 5000 feet including the Prescott region.

Thursday and Friday - a weak upper low is forecast to cut off from SW Arizona to northern Baja, with strong surface high pressure diving southward to our east. This will produce tight east/northeast pressure gradients in our region, leading to gusty winds. Sustained speeds of 20-30 mph with gusts 35-45 mph are currently forecast for much of the region. The strongest winds in this pattern are typically along and just south of the Mogollon Rim and Yavapai County mountains. Some moisture could also move back into the region from the southeast by Friday into the weekend, and a low (10-20%) chance of showers and thunderstorms is included in our latest forecasts. Rain chances may increase as we get closer, depending on the track of the weak upper low as it ejects northeastward over the weekend. Daytime highs look to stay below normal into the weekend.

AVIATION...Tuesday 13/12Z through Wednesday 14/12Z

Areas of MVFR conditions expected through 02Z due to scattered -SHRA/-TSRA. IFR conditions due to fog/low clouds likely through 15Z-18Z for higher elevation TAF sites. Outside of gusty/erratic winds from showers/storms, look for S-SW winds 10-20 kts through 16Z, increasing to 15-25 kts with gusts near 30-35 kts through around 02Z. After 02Z, scattered -SHRA mainly north of I-40.

OUTLOOK...Wednesday 14/12Z through Friday 16/12Z...-SHRA/-TSRA will mainly be confined to far northeast Arizona through Wednesday afternoon, with improving conditions elsewhere. Expect light and variable winds through 18Z Wednesday, becoming W-NW 5-10 kts afterwards. Winds look to remain elevated along and south of the Mogollon Rim Wednesday night/Thursday morning, where localized gusts could reach near 20-25 kts. Winds will increase out of E-NE after 18Z Thursday with gusts 25-35 kts.

FIRE WEATHER...Today and Wednesday

Scattered showers and occasional thunderstorms are expected today, mainly over the higher terrain. Drier conditions are expected by Wednesday, with scattered showers confined to the northeast corner of the state. Daytime temperatures 10-15 degrees cooler than normal. Winds west/southwest 15-25 mph with gusts 30-40 mph today, becoming north/northwest 5-15 mph on Wednesday.

Thursday through Saturday...Slightly warmer temperatures. Mainly dry conditions, outside of a slight chance for showers and thunderstorms over the higher terrain Friday and Saturday. Winds north/northeast 15-25 mph on Thursday, becoming east on Friday. Wind gusts Thursday and Friday 35-45 mph. Winds subsiding to 5-15 mph on Saturday from the east/southeast.

FGZ WATCHES/WARNINGS/ADVISORIES

None.