textproduct: NWS Flagstaff

SYNOPSIS

Drier and slightly breezy conditions through Thursday, with only isolated showers and thunderstorms each afternoon/evening. Precipitation chances increase again beginning Friday and into the weekend.

DISCUSSION...This morning

The shortwave trough spurring activity in northwest Arizona has propagated well to our northeast, and the last bit of convective activity is quickly losing intensity early this morning under subsidence. Expect clearing skies with slightly chillier morning lows than previous days.

Today through Thursday...The large west coast trough continues to deepen and bring stronger southwest flow across northern AZ. This will introduce drier air with PW falling to the 40th-60th percentile for early September. There is still enough moisture for some convective activity, but just isolated showers and thunderstorms are expected each afternoon/evening. The troughing will also bring noticeably breezier daytime winds, with gusts up to 30 mph strongest in northwest AZ. Also expect daytime temperatures a few degrees below normal each day. Overall expect a reprieve from the recently active late monsoon conditions.

Friday through Monday...The forecast uncertainty ramps up considerably this weekend. The trough looks to gradually back off through this period. This would open the door for the flow turn more southerly and moisture to stream back in, first to White Mountains and then to most of northern AZ. The most uncertain factor during this period is a potential tropical system moving off the coast of the Baja Peninsula, which could impact the magnitude of moisture. The ensemble consensus is for the moisture to return, with the LREF mean PW climbing back above the 90th percentile by Saturday. The forecast maintains a 30-60% chance of precipitation each day, higher in the White Mountains.

AVIATION...Tuesday 01/12Z through Wednesday 02/12Z

VFR conditions expected. ISOLD-SCT SHRA/TSRA returns from 19-03Z. Gusty/erratic winds possible near storms. Winds are light and VRB or terrain driven through 18Z, becoming SW 10-15 kts gusting to 25 kts. Winds return to light and VRB or terrain driven after 03Z.

OUTLOOK...Wednesday 02/12Z through Friday 04/12Z...VFR conditions expected. Winds are SW 10-20 kts each afternoon, light and VRB or terrain driven each night. ISOLD-SCT SHRA/TSRA each afternoon, with main impacts being gusty/erratic winds.

FIRE WEATHER...Tuesday and Wednesday

Drier and breezy. Isolated shower and thunderstorm chances continue each afternoon/evening. Winds are southwest 10-20 mph with gusts up to 30 mph each day, strongest in northwest AZ. Daytime highs slightly below normal. Minimum RH is 30-50% each day.

Thursday through Saturday...Increasing moisture. Continued isolated showers and thunderstorms on Thursday, with coverage increasing on Friday and Saturday. Best chances will be seen near the White Mountains each day. Winds are southwest 10-20 mph with gusts to 30 mph on Thursday and Friday, then south through southwest 5-15 mph on Saturday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.