textproduct: NWS Flagstaff

SYNOPSIS

Chances for showers return later this afternoon, and increase in coverage through the overnight. Rain and high-elevation snow continue into Saturday, tapering off in the afternoon. Drier and warmer conditions set in for Sunday and Monday, before unsettled weather returns by the middle of the week.

DISCUSSION...Today

Clouds will be on the increase through the day as moisture begins to stream into the region from a weakening low over southern California. A bit cooler temperatures and breezier conditions are expected as a result this afternoon. Dry conditions should prevail for much of the day, however a few isolated showers and possibly a thunderstorm will be possible as the day progresses.

Tonight into Saturday...A secondary through sags southward through the Great Basin into Arizona. As the assocaited upper-level jet moves overhead, the potential for for showers and thunderstorms begins to increase. The greatest confidence in precipitation looks to mainly be along and north of the I-40 corridor as the better forcing looks to be further north. Coverage looks to peak overnight into Saturday morning, before diminishing from west to east through the afternoon hours.

QPF looks to be on the lighter side given a lack of any robust forcing. Though a brief period of steadier precipitation looks possible Saturday morning with a transient band of frontogenetic forcing. All and all, amounts look to generally be around 0.25-0.50 inches across the higher terrain, with some locally higher amounts in the more favored upslope areas. Across the lower elevations, a few hundredths to a tenth a best seem likely.

Snowfall amounts look to generally be confined to areas above 7500- 8000 feet, as 700 mb temperatures remain around 0C to start before falling to -2C Saturday morning. Snow accumulations look to be around 1 to 3 inches for most areas above that elevation, however the most likely spot will be the Kaibab Plateau where 2 to 4 inches seem probable. Model soundings do show the potential for a rain/snow mix down to around 7000 feet or so, but no accumulations are expected at this elevation given that surface temperatures look to remain above freezing. Some elevated surfaces (bridges, overpasses) may be slick early Saturday.

Winds are also expected to increase downwind of the higher terrain overnight as the upper-level jet increases. Coverage of the winds looks to be limited given that much of the area will decouple, aside from the downslope areas, where gusts upwards of 30-40 mph will be possible. During the day Saturday, some gusty winds will be possible over a more broad area, but will likely not be as strong given the subsiding jet overhead.

Sunday through Thursday...Dry conditions set in for Sunday and Monday as high pressure briefly builds back into the region. This is short-lived however as unsettled conditions are expected to return late Monday into Tuesday as a trough lifts through Arizona. Uncertainty remains in the exact track of this system with guidance split between a further north or southward track of the vort max. If the more southerly track wins out, we can expect a colder and wetter outcome vs the northward track where we remain in the warm sector and with less forcing. Drier conditions set in for Wednesday and Thursday, however unsettled conditions look to potentially return once again late next week.

AVIATION...Friday 13/18Z through Saturday 14/18Z

Widespread VFR conditions expected through 00Z, then MVFR will become common with localized IFR conditions due to -SHRA/-SHSN. Winds S-SW at 10-15 kts with gusts to 25 kts, increasing gusts up to 35 kts after 10Z.

OUTLOOK...Saturday 14/18Z through Monday 16/18Z...VFR/MVFR conditions forecast through around 00Z Sunday due to -SHRA/-SHSN. Drier conditions return afterward, along with improving ceilings/visibilities. Breezy SW winds 15-25 kts anticipated throughout Saturday, shifting more out of the west throughout the day. Light and variable winds return for Sunday.

FIRE WEATHER...Tonight through Sunday

Daytime highs will be 5-10 degrees below normal and precipitation chances last through Saturday afternoon, primarily along and south of the Mogollon Rim. Total liquid amounts look to be mostly 1/4" or less, with higher amounts around 1/2-3/4" for the Kaibab Plateau. Light snow accumulation is likely above 8000' Saturday morning. Look for southwest winds 10-25 mph through Saturday, becoming light Saturday night. Minimum RH ranges from 35-55 percent Sunday with dry conditions.

Monday through Wednesday...Dry and cool conditions forecast for Monday, with additional precipitation expected on Tuesday. Snow levels look to drop by Tuesday evening, so a dusting to 0.5" of snow could be seen down to 6500-7000'. As for rain, areas long and south of the Mogollon Rim have moderate confidence to see 0.5-1.0", with 0.25" or less across the northeast portion of the state. Winds become southerly at 5-15 mph on Monday and Wednesday, strengthening out of the southwest at 10-25 mph on Tuesday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.