209 FXUS65 KFGZ 302141 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 241 PM MST Tue Jan 30 2024 .SYNOPSIS...High pressure will bring warming temperatures and dry conditions through Wednesday. A storm system arrives Thursday lasting through Saturday with much colder temperatures and periods of rain and mountain snow. There will be a lull late Saturday and Saturday night before the next system arrives on Monday lasting into the middle of next week. && .DISCUSSION...An extremely weak low pressure system will continue to meander over Arizona through Wednesday before pushing to the northeast in advance of much stronger low and the start of a dramatic pattern change. For the remainder of today through Wednesday...Look for mild daytime temperatures and chilly overnight lows under the influence of the weak meandering low. Skies will remain clear through much of Wednesday before some increase in high clouds is anticipated later Wednesday afternoon in advance of the strong Pacific low. Winds will generally remain light from the east to northeast the remainder of today but will become southerly on Wednesday and a bit more gusty as the Pacific low approaches. For locations along and west of a Prescott/Flagstaff/Grand Canyon line those gusts could be as high as 30 mph Wednesday afternoon. For Thursday through Saturday...The Pacific low will move across the western states delivering mountain snow and lower elevation rain to northern Arizona. The most notable weather during the day Thursday will be the arrival of gusty southwest winds at 15 to 25 mph gusting to near 40 mph in spots as surface pressure gradients strengthen. Dynamics for widespread upward motion begin to sneak in Thursday morning with a few mountain snow flurries or lower elevation sprinkles possible. The body of the system along with rain/snow showers moves in Thursday afternoon, lasting through much of Friday. Snow levels will start out around 7500 feet midday Thursday but then steadily fall through Friday to about 5000 feet Friday evening, dipping as low as 4500 feet Saturday morning. Decent large-scale lift will be accompanied by strong upslope flow and deep Saturation for widespread liquid equivalent precipitation amounts (rain and melted snow) from 0.50 to 1.00 inches. As a result, we're looking at 5 to 10 inches of snow accumulation across the mountain areas by early Saturday. Gusty southwest winds will continue on Friday with the strongest winds slowly shifting eastward through the day. Slick roadways in addition to blowing snow and areas of reduced visibility are likely Thursday afternoon through Friday. The low gradually exits our area on Saturday but unsettled conditions will persist with lingering moisture resulting in scattered instability showers, primarily in the form of snow over portions of the Mogollon Rim, White Mountains, Kaibab Plateau and Chuska Mountains. Obviously, much colder with high temperatures dipping by 15 to 20 degrees compared to highs observed on Tuesday. Sunday into early next week...High pressure will move over Arizona Sunday. However, moisture will continue to linger across northern Arizona on Sunday and with such a dynamic jet stream aloft a few light rain/snow showers can't be ruled out. In any case many locations will see partly to mostly cloudy skies on Sunday. By Monday the next storm system begins to approach with gusty winds, increasing clouds and chances for rain/snow showers developing west of a Payson/Flagstaff/Page line. && .AVIATION...Tuesday 30/18Z through Wednesday 31/18Z...VFR conditions persist through Wednesday with mostly clear skies. Light east to southerly winds, under 10 kts, are expected through 01Z, becoming variable overnight. OUTLOOK...Wednesday 31/18Z through Friday 02/18Z...Cloud cover and south-southwest winds increase on Wednesday, 15-20 kts, ahead of an incoming storm system. Conditions worsen Thursday through Friday with widespread rain and high elevation snow expected. MVFR/IFR with localized periods of LIFR conditions and mountain obscuration are anticipated during this time. Accumulating snow of greater than an inch is forecast at KGCN-KCMR-KFLG-KSOW by Friday morning. Southwest winds peak on Thursday, 25-35 kts, remaining gusty, 20-30 kts, from the west-southwest on Friday. Minor turbulence is likely. && .FIRE WEATHER...Wednesday and Thursday...Above average temperatures will continue on Wednesday with the start of an increasing moisture trend. Southwest winds return for Wednesday afternoon, 10 to 20 mph. A storm system impacts the region on Thursday resulting in gusty southwest winds, 25 to 35 mph, and widespread rain and high elevation accumulating snowfall above 6000 feet. Friday through Sunday...Widespread rain and snow persists through Friday with scattered snow showers for Saturday and Sunday. Temperatures, 5 to 10 degrees below average, are expected each day. The gusty west-southwest winds, 25 to 35 mph, continue on Friday becoming breezy, 15 to 25 mph, from the west on Saturday. Lighter westerly winds are forecast on Sunday. This active winter weather pattern looks to continue into next week with additional chances for widespread rain and snow. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...McCollum AVIATION...LaGuardia FIRE WEATHER...LaGuardia For Northern Arizona weather information visit weather.gov/flagstaff