textproduct: NWS Flagstaff

SYNOPSIS

Storm activity will be confined to far eastern Arizona today before gradually spreading back westward through the week. Temperatures will be close to normal through Labor Day, warming to above normal by mid week.

DISCUSSION...Today through Thursday

Heights begin to rise over Arizona as high pressure centered over the Mississippi River Valley begins to retrograde back over the southwest. Gradually warming temperatures are expected across northern Arizona as a result, with highs around 5-10F above normal by the middle of the week.

Moisture looks to remain trapped under the ridge, with PWATs remaining around 0.75 to 1.00 inches across northern Arizona. Therefore, at least isolated afternoon shower and thunderstorm activity looks to remain a possibility over the coming days. Any activity that does develop will be fairly minor, and isolated in nature, as warming aloft will inhibit any substantial convective development. The best chances for any activity look to mainly be across the eastern Mogollon Rim into the White Mountains, and potentially the Chuska Mountains. However, coverage should gradually extend westward some through the week as the subsidence aloft lessens.

Friday through Sunday...Later in the week, the details in the forecast get a little fuzzy. The high over the southwest remains fairly transient, once again moving back eastward and setting up over New Mexico. At the same time, a strong trough looks to move into the Pacific Northwest. Breezier, and cooler conditions look to set in across northern Arizona over the weekend as the ridge loosens it's grip.

The tricky part here results from uncertainty in how far south the trough may go. A further southward track into the Great Basin would result in a day of active monsoonal conditions, before eventually suppressing monsoonal moisture southward. If it were to track further north across northern Rockies, the high looks to remain in a favorable monsoonal pattern, thus keeping active conditions into the weekend. Much of the GEFS members seem to favor keeping a more active pattern in place, while the EPS and CMCE both seem to favor a stronger influence from the trough.

AVIATION...Tuesday 08/06Z through Wednesday 09/06Z

Primarily VFR conditions. Brief MVFR possible in ISOLD-SCT SHRA/TSRA from 19-03Z, mainly over the Mogollon Rim and White Mountains. Light and VRB or terrain driven winds tonight, becoming W-NW 5-15 kts from 18Z-03Z.

OUTLOOK...Wednesday 09/06Z through Friday 11/06Z...Mainly VFR conditions, brief MVFR possible near thunderstorms. SCT SHRA/TSRA over the Mogollon Rim and White Mountains on Wednesday, ISOLD elsewhere. Storm coverage increases and spreads westward on Thursday and Friday. Winds are variable 5-10 kts on Wednesday, turning W 5-15 kts on Thursday and Friday.

FIRE WEATHER...Tuesday and Wednesday

Warmer with temperatures 5-10 degrees above average. Expect low grade monsoon conditions with afternoon showers and thunderstorm chances along the Mogollon Rim and the mountains of eastern Arizona. Winds S-SW 5-15 mph with gusts to 25 mph each afternoon, light and variable or terrain driven overnight. Minimum RH's each afternoon ranging from 15% in the lower deserts to 30-40% in the mountains.

Thursday through Saturday...Low grade monsoon conditions continue with afternoon showers and thunderstorms remaining primarily over the higher terrain of the Rim and White Mountains. Daytime temperatures 5-10 degrees above normal. Winds S-SW 5-15 mph each day, light and variable or terrain driven overnight.

FGZ WATCHES/WARNINGS/ADVISORIES

None.