textproduct: NWS Flagstaff

SYNOPSIS

Warm temperatures and mostly dry weather are expected for today with isolated to scattered showers and thunderstorms arriving for Memorial Day. Expect typical southwest breezes each afternoon, with increasing winds and cooler temperatures arriving for the second half of the week.

DISCUSSION

West Coast trough starts to push in later this evening. Some mid level moisture is already being drawn in ahead of this system producing some high based convection and maybe even a few virga showers or sprinkles this afternoon. Lower level moisture gets drawn in later tonight with scattered showers developing and moving up from southern Arizona into eastern Arizona early Monday morning. Scattered showers and thunderstorms will fill in westward over the Kaibab Plateau and Mogollon Rims by mid morning to early afternoon as CAPE values rise to between 500-1000 j/kg. Storms will move off towards the northeast deserts by mid to later afternoon. Rainfall amounts from these showers/storms will range from a trace to a few hundredths over the northeast high deserts to around a tenth to quarter inch along the Rim and White Mountains with locally heavier amounts possible under the heaviest downpours. Lightning and locally gusty winds will also be hazards to consider. Most of the shower/storm activity will wind down by Monday night as the low ejects across the state but wrap around moisture in the form of a few showers/storms will still impact the northeastern corner of the state on Tuesday.

Temperatures will remain on the cool side for most of this week as a unseasonable cold upper level low forms over the Great Basin and lingers there keeping our area under consistent troughing. The position of the low at this time is expected to stay far enough north to not draw in any substantial moisture for our area, however it will draw in some wind Wednesday into Thursday out of the southwest at 20-25 mph, gusting 30-40 mph. The trough does draw in just enough moisture to keep the area out of critical fire weather conditions for now. Will continue to evaluate day by day to make sure this stays the case.

By the weekend the Great Basin Low opens up and moves northeast and southwesterly flow aloft takes over for the Southwest. This will allow temperatures to climb back up to end of May averages.

AVIATION...Sunday 24/18Z through Monday 25/18Z

Mainly VFR conditions expected. Winds S to SW at 5-15 kts today, light and variable overnight, then SE to S at 5-15 kts after 15Z. Isolated -SHRA/-TSRA developing after 06Z.

OUTLOOK...Monday 25/18Z through Wednesday 27/18Z...Isolated to scattered -SHRA/-TSRA through 06Z Tuesday with brief MVFR conditions and erratic winds in -SHRA/-TSRA. After 06Z Tuesday, activity becoming isolated and shifting toward the Four Corners and Arizona/New Mexico border. Dry conditions move in after 00Z Wednesday. Outside of storms, daytime SE to SW winds 5-15 kts gusting to 20 kts Monday then SW at 10-20 kts gusting to 30 kts on Tuesday. Overnight winds generally light and variable.

FIRE WEATHER...Tonight through Tuesday

Isolated to scattered showers and thunderstorms developing tonight and Monday. Areas of wetting rain will be possible along with cloud-to-ground lightning and gusty/erratic winds. Drier air will move in on Tuesday but with isolated showers and thunderstorms lingering toward the Four Corners and along the Arizona/New Mexico border. Expect southeast to southwest winds at 5-15 mph gusting to 20 mph on Monday, shifting to south to southwest at 10-20 mph gusting to 25 mph on Tuesday. Minimum afternoon RH decreasing to 10-20% on Tuesday.

Wednesday through Friday....Dry with little change in temperatures. Expect south to southwest winds at 15-25 mph with gusts to 35 mph on Wednesday and Thursday, diminish to 5-15 mph gusting to 25 mph on Friday. Afternoon minimum RH between 10-20% each day.

FGZ WATCHES/WARNINGS/ADVISORIES

None.