Area Forecast Discussion
Issued by NWS Flagstaff, AZ
Issued by NWS Flagstaff, AZ
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987 FXUS65 KFGZ 140333 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 833 PM MST Sat Jul 13 2024 .SYNOPSIS...Scattered showers and thunderstorms are expected each day through next week as we enter into an active monsoon pattern. Temperatures will remain near average during this time with typical afternoon winds. && .UPDATE...Made some adjustments for POPs for this evening as most activity is already over for the night. Likewise, looking at latest CAMs and WRF guidance for tomorrow, much of the activity from Flagstaff west looks to be more isolated/subdued compared to today. Meanwhile, from Flagstaff down south along the Rim, activity will increase for tomorrow afternoon and evening, which is a flip from today where most activity was to the west and the eastern half of the area was far more tame. It does still looks like showers and storms will push of the Rim, traveling southwest into part so of Gila and Yavapai Counties. Timing could be pretty late in the afternoon/evening for Yavapai county when instability would be decreasing. && .PREV DISCUSSION /427 PM MST/...High pressure in the mid-levels of the atmosphere was centered over southwest Colorado and the Four Corners midday Saturday, forecast to remain in place through Monday. By Tuesday a trough diving over the eastern states in combination with a separate trough moving across the Pacific Northwest will cause the high center to move westward and amplify. It`s looking like the high will become centered over northern Arizona on Tuesday and Wednesday then gradually shift further north later in the week. In any case, monsoon moisture will remain over the state with chances for showers and storms continuing. For the remainder of Today...Looks like the target zone for showers and thunderstorms remains from about Prescott northward toward the Grand Canyon and northwest portion of Coconino County. The flow has shifted to more southeasterly helping to deliver additional moisture to central and western portions of Arizona. In addition, the southeast flow will tend to push storms toward the northwest. Elsewhere, if anything, the southeast flow has moved drier air from over New Mexico across eastern and northeast portions of Arizona with isolated thunderstorms anticipated across those areas. Sunday and Monday...High pressure will remain in place with monsoon moisture gradually increasing across northern Arizona leading to somewhat better chances for showers and thunderstorms. The steering flow during this period will tend to push any storms southwestward. Most will form over the high terrain first then move into the lower elevations. The deepest moisture will remain from the Mogollon Rim southward where storms will be most numerous. However, the circulation around the high will allow for additional moisture to move over the northeast portion of the state with a slight uptick in storm coverage there. From Tuesday onward...The high moves over Arizona on Tuesday and Wednesday. Moisture will remain, although in reduced amounts, as a slightly drier north to northeast flow develops. We could see a bit of a downturn in activity over these two days but not a complete shutdown like we experienced earlier this month. Look for low grade monsoon activity with the best chances over the higher terrain. Starting Thursday the high begins to shift northward toward Utah and Nevada. If this shift occurs the door will open to a period of very active weather from the Mogollon Rim southward as thunderstorm outflows from over Mexico and southern Arizona bank up against the Mogollon Rim. Isolated activity will continue further to the north where drier air will likely filter in from the northeast. && .AVIATION...Sunday 14/00Z through Monday 15/00Z...Bulk of -SHRA/TS remains west of I17/a line from KPRC-KSEZ-KFLG-KPGA. Much more isolated activity remains to the east of aforementioned locations. Hires guidance shows activity diminishing early this evening instead of persisting overnight. Tomorrow looks like more convective activity will be south from KFLG to KSOW. Elsewhere SHRA/TS will be more isolated. Winds in the afternoons and evenings will be highly influenced by outflows. OUTLOOK...Monday 15/00Z through Wednesday 17/00Z...Daily SHRA/TS opportunities will persist, but VFR conditions are expected outside of those. Winds will remain variable, especially in the afternoons and evening when outflows will be spread out across the region. && .FIRE WEATHER...Sunday and Monday...Monsoon moisture will continue to increase. Expect widespread afternoon and evening showers and thunderstorms, most numerous near the Grand Canyon and along and south of the Mogollon Rim and White Mountains. Isolated activity further north. Outside of gusty/erratic outflow winds at 35-45 mph, winds will be southerly around 5 to 15 mph each afternoon. Slightly cooler daytime temperatures. Tuesday through Thursday...Shower and thunderstorm coverage will be on the decrease coinciding with a bit drier air mass. West to northwest winds around 5 to 15 mph each day with gradually warming temperatures. && .FGZ WATCHES/WARNINGS/ADVISORIES...None. && $$ PUBLIC...RKR/McCollum AVIATION...RKR FIRE WEATHER...MAS For Northern Arizona weather information visit weather.gov/flagstaff