Area Forecast Discussion
Issued by NWS Flagstaff, AZ
Issued by NWS Flagstaff, AZ
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339 FXUS65 KFGZ 050301 AFDFGZ Area Forecast Discussion National Weather Service Flagstaff AZ 801 PM MST Thu Jul 4 2024 .SYNOPSIS...Hot and dry conditions will continue for most of northern Arizona into early next week. The chance for showers and storms will be limited to the White Mountains through Monday, with a slow return of monsoon moisture possible later next week. && .UPDATE...It`s been a hot 4th of July across northern Arizona with high temperatures today reaching the 90s in the mountains and as high as 113 in the Verde Valley near Cottonwood. Heat will continue to be the main weather story over the coming weekend. The good news is that with such a dry air mass in place this evening, temperatures will cool off nicely overnight. Expect lows in the 40s to low 50s in the mountains and upper 50s to low 70s in the valleys. No forecast updates are needed this evening. && .PREV DISCUSSION /436 PM MST/...A strong ridge centered near the California coast will nudge slowly eastward over the next several days, resulting in a heat wave over the southwest US. An Excessive Heat Warning starts today below 4000 feet from Yavapai County to the Grand Canyon and Page/Lake Powell areas. With the persistence of this pattern in the latest model data, we have extended this warning all the way through Tuesday evening, and will need to monitor it each day for the need to extend even further unfortunately. The northerly flow around the ridge is a dry one for our area. Surface dewpoints have fallen off into the 20s for the majority of the area, except southern Yavapai where some 40s/50s linger and a few showers have developed this afternoon. This air mass is forecast to dry even further for Friday with dewpoints of 5-10F along/north of the Mogollon Rim which is just about unheard of for this time of year. This dry air will actually help things cool off overnight, and we have undercut the NBM guidance significantly in the high country - some upper 30s are likely at the usual cold spots (Bellemont, Tusayan) the next few nights. Winds will be breezy from the north and northeast at times later this evening through Friday, with some gusts to 25 mph mainly along/south of the Mogollon Rim. For Sunday and Sunday night, gradients tighten as a trough passes northeast of the region. Another round of breezy winds is forecast, from the W-NW at 10-15 mph and gusts to around 25 mph. By the middle and latter parts of next week, there is some indication that the center of the high pressure system will move north or even northeast of the state. This could allow for a modest moisture increase from the east, but confidence is low. For now, we have mainly used a blend of model data which brings a 20-40% chance of showers and thunderstorms to areas along and south of the Mogollon Rim with lower chances to the north. If this doesn`t happen, the heat wave will continue. && .AVIATION...Friday 05/00Z through Saturday 06/00Z...VFR conditions with N/NW winds around 10 kts, becoming mainly light and variable after 03Z. KSEZ will have gusty NE winds (to 25 kts) at night. Winds becoming N around 10 kts after 17Z Friday. OUTLOOK...Saturday 06/00Z through Monday 08/00Z...VFR conditions continue. Daytime winds N around 10 kts on Saturday, becoming light and variable overnight. NW winds around 15 kts with gusts to 25 kts on Sunday. && .FIRE WEATHER...This afternoon through Saturday...Hot conditions, with highs 5-10 degrees above normal. Isolated showers and thunderstorms over Yavapai County into this evening and then over southern Apache County Friday and Saturday. Winds north/northwest 5- 10 mph, becoming north to northeast on Friday, and then back to northwest on Saturday. Minimum afternoon RH 3-12%, recovering overnight to 15-30%. Sunday through Tuesday...Hot and dry conditions continue. Slight chances for showers and thunderstorms gradually increasing each day, mainly over the eastern Mogollon Rim and White Mountains. North to northwest winds on Sunday with gusts 20-25 mph. Minimum afternoon RH 5-15%, recovering overnight to 15-45%. && .FGZ WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST /9 PM MDT/ Tuesday for AZZ005-006-037. && $$ PUBLIC...MCT/JJ AVIATION...RR FIRE WEATHER...MAS For Northern Arizona weather information visit weather.gov/flagstaff