textproduct: NWS Flagstaff

SYNOPSIS

Mild, dry, and breezy conditions are on tap through Tuesday across Arizona. The pattern looks to become active from Wednesday through the Christmas holiday weekend with cooler temperatures, stronger winds, and chances for widespread precipitation. Most of the precipitation is forecast to be in the form of rain, with some high elevation snow possible toward next Friday or Saturday.

DISCUSSION

A continuation of the unusually mild and dry weather pattern is expected through Tuesday, with daytime temperatures 15-25 degrees above late December averages. Daytime south to southwest breezes in the 10-20 mph range are expected. The ridge responsible for this mild weather will gradually shift from off the Baja eastward toward Texas over the next several days as low pressure develops off the west coast. Much of the model ensemble data is in decent agreement for our area through around Thursday, then solutions diverge more by Friday with a wide range of possible solutions. As the west coast trough slowly approaches, a rapid moistening of the atmosphere is expected by Tuesday evening and Wednesday with rain chances reaching 30-50% by Tuesday night and then showers becoming likely Wednesday into Christmas. The highest chances will be from the central Mogollon Rim toward the south and west through this period. The Pacific and even subtropical origins of this moisture are forecast to keep snow levels fairly high through Thursday, likely 8500+ feet. With the moisture tap combined with orographic lift, early projections for rainfall Wed/Thu are in the 0.75"-1.25" range from the central Mogollon Rim westward through Yavapai/Gila counties and much less (<0.30") northeast of the Mogollon Rim. By Friday into next weekend, again model solutions diverge quite a bit, with some bringing the trough through our area and others holding it to our west longer. The faster/colder solutions would bring falling snow levels with some chance of minor impacts down to at least 7000 feet Friday or Friday night, but it's just too early for many details. Overall, there has been a trend in the latest guidance toward the slower solutions (holding the trough to our west). This would suggest a decrease in precip chances by next weekend. However, our current forecast is based on a model blend (NBM) that doesn't contain these later model runs so they could be a bit high. You will want to stay updated with the latest forecasts if you have travel plans from the middle of next week into next weekend.

AVIATION...Sunday 21/00Z through Monday 22/00Z

VFR conditions persist through the period with SCT-BKN cirrus clouds. Expect southwest winds, 10-15 kts, to weaken by 01Z, becoming light and variable overnight. Breezy southwest winds, 15-20 kts, return by 18Z/19Z Sunday.

OUTLOOK...Monday 22/00Z through Wednesday 24/00Z...VFR conditions with variable cloud cover continues for Monday. Mid to high-level cloud cover increases Monday night and into Tuesday with chances for isolated to scattered rain showers by Tuesday night, mainly along and south of the Mogollon Rim and White Mountains. Lighter south-southwest winds, 10-15 kts, are anticipated on Monday followed by stronger southerly winds, 15-25 kts, for Tuesday and Wednesday.

FIRE WEATHER...Sunday and Monday

Dry conditions continue with daytime temperatures 15-25 degrees above average. Winds southwest 10- 20 mph, gusts 20-25 mph each day. Winds remaining southwest 10 mph tonight along and just north of higher terrain, with otherwise light and variable overnight winds. Minimum afternoon RH values 15-35%.

Tuesday through Thursday...Dry through Tuesday afternoon with temperatures remaining 10-20 degrees above average. By Tuesday evening a chance of showers arrives, increasing Wednesday through the end of the week along with a gradual cooling trend. Winds southwest 10-20 mph Tuesday, and 15-25 mph Wednesday and Thursday. Minimum RH 15-25% Tuesday, 30-60% Wednesday, 40-80% Thursday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.