textproduct: NWS Flagstaff

SYNOPSIS

Mild temperatures are expected to continue through the next week. Chances for showers are forecast through early Friday, followed by drier conditions over the weekend. Unsettled weather returns next week as several disturbances cross the state.

DISCUSSION

A weakening shortwave trough was moving across the southwest states Thursday afternoon. The system has tapped into subtropical moisture but contains weak dynamics for large-scale lift and only modest terrain induced upslope flow. As a result, look for periods of drizzle or light rain with general rainfall amounts of a Trace to 0.20 inches through Friday morning over most of the area. In the upslope regions, especially along the southern edges of the Mogollon Rim and Kaibab plateau, additional rainfall amounts of 0.25-0.50 inches are forecast through early Friday. Also, the mild subtropical air mass will result in elevated snow levels, ranging from 9,000-10,000 feet through tonight, perhaps lowering to the 8,000-9000 foot level on Friday. As a result of the mild subtropical nature of the air mass the saturated layer will mainly be made up of super-cooled water drops not ice crystals. So, any snowfall at higher elevations will be fleeting and mostly due to very localized orographic effects. The trough will rapidly move eastward later on Friday with diminishing showers and, most likely, dry weather by Friday evening.

For Saturday and Sunday...High pressure and dry weather will dominate the weekend weather. Look for periods of high clouds as high level moisture spins off an upstream trough over the Pacific. Otherwise, light winds with temperatures 5 to 10 degrees above seasonal averages are forecast. A few showers could slide into northwest Arizona Sunday night with a very weak passing disturbance.

From Monday onward...Look for a week of unsettled weather. A series of shortwave troughs will brush northern Arizona resulting in periods of showers. Monday looks like another drizzly, light rain day. As the week progresses the shortwaves are expected to move from a progressively more northerly direction providing some hope for lower snow levels. At this time, a few solutions are developing a decent snow storm for the mountains of northern Arizona later next week but confidence is low. In any event, a bit more winter appropriate weather appears in store. Stay tuned.

AVIATION...Thursday 01/18Z through Friday 02/18Z

MVFR to IFR conditions along with mountain obscuration persist through much of the period due to isolated to scattered -SHRA and FG. Periods of LIFR VIS and CIGS are likely at KFLG-KGCN-KSEZ, especially between 02Z-07Z as another push of scattered -SHRA from the southwest is expected. Conditions begin to improve gradually after 12Z-15Z. Plan on southwest winds, 5-15 kts, throughout this time.

OUTLOOK...Friday 02/18Z through Sunday 04/18Z...Widespread VFR conditions return after 18Z Friday with clearing cloud cover as drier air moves in from the west. Cloud cover remains variable between SCT-BKN throughout the weekend, but above 10,000 ft AGL. Winds shift to the west-northwest, 5-15 kts, on Friday, followed by lighter southerly flow on Saturday and a return of southwest winds, 10-20 kts, on Sunday.

FIRE WEATHER...Tonight through Saturday

Isolated to scattered rain showers will persist mainly along upslope regions through late tonight. Precipitation will taper overnight as the airmass begins to dry out from west to east. Friday and Saturday remain dry with temperatures 5 to 15 degrees above average. Light southerly winds overnight will shift to the west-northwest on Friday, 5 to 15 mph. Light southerly flow, under 10 mph, returns on Saturday.

Sunday through Tuesday...The unsettled weather pattern persists next week. Temperatures remain 5 to 15 degrees above average on Sunday, cooling gradually Monday and Tuesday. Chances for precipitation return on Monday, mainly in the form of rain showers, persisting into Tuesday. Southwest winds return for Sunday and Monday, 10 to 20 mph, becoming lighter on Tuesday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.