Area Forecast Discussion
Issued by NWS Flagstaff, AZ
Issued by NWS Flagstaff, AZ
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300 FXUS65 KFGZ 211729 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 1029 AM MST Sat Sep 21 2024 .SYNOPSIS...A low pressure system crossing through Arizona will bring cooler temperatures, breezy winds, and chances for showers and thunderstorms through this afternoon. Warmer and drier weather is expected to return for much of the upcoming week. && .UPDATE...Upper level low pressure moved into Arizona overnight bringing showers and thunderstorms across the area. The upper low is centered over north central Arizona this morning with a more organized band of rain and thunderstorms stretching from near Holbrook north to the Utah border and west towards Page. This band will continue to gradually move north and east through the morning hours. With the low overhead early in the day, we expect additional convective showers to develop with daytime instability, and this is in line with this morning`s hi-res guidance. Precipitation chances were nudged upward for early this afternoon, particularly from Flagstaff northwest toward the Grand Canyon. Precipitation amounts should mostly remain less than 0.25 inches. We should start to see a drying trend with decreasing convection by late afternoon with showers coming to an end by early evening. Today will be the coolest day yet this season with temperatures nearly 10 degrees below average. && .PREV DISCUSSION /454 AM MST/...An upper level low is located along the Arizona-California border early this morning. The low will push towards the east-northeast through the day today, exiting off towards Four Corners by late tonight. Scattered showers and thunderstorms have developed mainly along the rim. As we go through the day, the precipitation will start to push off to the east and northeast. Temperatures remain warm near the surface with colder air aloft. This cold pool combined with the instability available this morning has allowed for some of the stronger storms to contain a decent amount of small hail (around 1/2" or so). Storm motion is fairly quick so do not expect there to be any flooding concerns through the event. Some of the stronger storms may be able to drop a quick 0.25- 0.50" of rain but most areas will see less than 0.25". Snow levels remain high, above 10,000 ft, so expect that only the highest elevation will see snow with this event. While amounts will be fairly light, we could see a few tenths of an inch of snow up on the San Francisco Peaks. As the low tracks towards Four Corners, dry air will start to be wrapped into the west/northwest side of the low. As this occurs we should start to see the precipitation come to an end and drier conditions will arrive across the area this evening. Temperatures will warm and conditions dry out for Sunday and through much of the coming week. The trough moving through the Four Corners area around Tuesday looks weaker than it did even a day ago so that has brought the chances for more preciptation down. Maybe a few isolated showers find their way in but it is looking to be drier than previously thought. Should the trough become stronger, chances may return but more than likely confined to extreme eastern Arizona. The ridge building down from the northwest becomes more dominant through midweek and expect us to remain warm and dry as we head towards the end of the week. && .AVIATION...Saturday 21/18Z through Sunday 22/18Z...Scattered -SHRA/-TSRA with localized/brief MVFR conditions spreading eastward through the day. Precipitation chances will come to an end area wide by around 00Z. West to northwest winds 10-20 kts this afternoon turning light overnight. OUTLOOK...Sunday 22/18Z through Tuesday 24/18Z...Dry weather and VFR conditions are forecast. Variable winds mostly 10 kts or less for Sunday through Tuesday morning. && .FIRE WEATHER...Today and Sunday...An area of low pressure will bring chances for showers and thunderstorms through this afternoon. Dry and warmer weather arrive Sunday. West to northwest winds 10 to 20 mph are expected today and northerly winds at 5 to 10 mph on Sunday. Monday through Wednesday...Warm days and dry conditions will continue through Wednesday. Light and variable winds under 10 mph are forecast for Monday with northerly winds at 10-20 mph expected to develop on Tuesday and Wednesday. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...MCT/Meola AVIATION...McCollum FIRE WEATHER...McCollum For Northern Arizona weather information visit weather.gov/flagstaff