114 FXUS65 KFGZ 210348 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 848 PM MST Sun Feb 20 2022 .SYNOPSIS...Windier and colder weather arrives for Monday and Tuesday, with scattered rain and snow showers expected over the high terrain. Widespread rain and accumulating snow down to 4000 feet set in late Tuesday into Wednesday, leading to potentially hazardous travel conditions across the region. && .UPDATE...The southwest winds have decreased in intensity this evening across north-central Arizona. Winds will remain breezy for higher terrain locations tonight with increasing mid to high cloud cover. This will result in low temperatures being a few degrees warmer compared to last night's. The forecast is on track with a return to a more active winter weather pattern for the first half of this week. First, the winds and colder temperatures for Monday into Tuesday and then the rain and accumulating snow for late Tuesday through Wednesday. Southwest winds increase in intensity by Monday morning, peaking for the afternoon hours. Though Tuesday's winds are not expected to be quite as strong as Monday's, nevertheless they remain gusty. Please refer to the Wind Advisory for more details regarding wind speeds and impacts. Scattered showers looks to develop later on Monday, mainly for areas near the AZ/UT border and around the Flagstaff region, but impacts (if any) will be minimal. The bulk of the precipitation for this week is expected for late Tuesday through Wednesday with accumulating snowfall down to 4000 feet. && .PREV DISCUSSION /225 PM MST/...Monday and Tuesday...A longwave trough developing over the Pacific Northwest digs southward into the Great Basin on Monday. As an initial shortwave moves into Arizona, the pressure gradient increases resulting in a strong upper-level jet developing. Consequently, winds increase over much of the area during the late morning and into Monday night. Model soundings show vertical mixing through around 700-650 mb where winds initially in the 30-40 kt range. However, as the trough axis draws the boundary layer depth decreases but at the same time low-level winds at the top of the boundary layer increase to around 50-60 kts, so the potential to mix down strong gusts looks to remain. Winds begins to die down over western Arizona by Monday evening, however, winds remain locally gusty overnight, before increasing yet again Tuesday afternoon along and downwind of the Mogollon Rim. As a result, wind advisories have been issued for much of the area for wind gusts in the 40 to 50 mph range. The strongest winds are expected to be downwind of the Mogollon Rim during the afternoon Monday, where gusts up to 55 mph are possible. Consequently with the strong southwesterly flow, moisture is advected into the region with scattered rain/snow showers developing over the higher terrain by Monday afternoon. Shower coverage is expected to continue into Tuesday with a slight uptick in coverage with increasing moisture. However, moisture initially remains fairly limited, with little in terms of coverage and amounts expected. Snowfall amounts through Tuesday afternoon will generally be 1 to 2 inches for areas above 6000 feet. Late Tuesday and Wednesday...Upper-level dynamic support increases over the region as the mean trough axis approaches. As it does, the base of the trough extends out off the California coast over the Pacific allowing for increase moisture advection. This increase in upper-level support combined with the increased moisture will result in more widespread shower activity. Much colder air also moves into the region, allowing for snow levels to drop to around 4000 feet by Wednesday afternoon. At this time, the time frame for the most significant impacts looks to be late Tuesday night into Wednesday afternoon. Snowfall amounts look to be generally 1 to 3 inches for areas between 4000 to 5500 feet and 4 to 8 inches above 5500 feet. Locally higher amounts of 8 to 12 inches will be possible along the high terrain of the Mogollon Rim and White Mountains. Hazardous travel will be possible Tuesday night and Wednesday, so be prepared for slippery and snow covered roadways. Areas of gusty winds are expected to remain on Wednesday, resulting in blowing and drifting snow which could significantly reduce visibility at times. Wednesday Night onward...As the trough begins to lift eastward, precipitation begins to diminish from west to east late Wednesday night into Thursday. Drier conditions with cooler temperatures and light winds are expected to prevail from Thursday onward, with heights beginning to rise with the ridge building back once again off the Pacific. && .AVIATION...For the 06Z package...VFR conditions prevail through Monday afternoon with variable mid to high cloud cover. Periods of MVFR VIS/CIGS are possible after 00Z Tue for KFLG-KGCN-KPGA due to isolated/scattered rain and snow showers. South-southwest winds remain overnight around 10 kts, increasing to around 20-30 kts by 18Z. Gusts of 35-45 kts are anticipated in the afternoon, especially along and near a KGCN-KINW-KSJN line. Minor to moderate turbulence is likely during this time. Winds remain breezy to gusty Monday night. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered rain/snow showers develop over the high terrain late Monday and again on Tuesday. Colder temperatures along with gusty to strong southwest winds are also forecast. Expect widespread peak gusts of 30-50 mph for Monday afternoon, remaining gusty on Tuesday. Wednesday through Friday...Widespread rain/snow showers continue through much of Wednesday, tapering off from west to east overnight. Drier conditions with continued cooler temperatures continue through Friday. Breezy conditions remain on Wednesday, with lighter winds thereafter. && .FGZ WATCHES/WARNINGS/ADVISORIES...Wind Advisory from 11 AM Monday to 5 PM MST Tuesday FOR AZZ012>017. Wind Advisory from 11 AM to 9 PM MST Monday FOR AZZ004>011-039- 040. && $$ PUBLIC...LaGuardia/Humphreys AVIATION...LaGuardia FIRE WEATHER...LaGuardia For Northern Arizona weather information visit weather.gov/flagstaff