textproduct: NWS Flagstaff

SYNOPSIS

Dry, cool, and windy weather will continue through Friday. Tropical moisture may return this weekend and into next week, bringing a chance of showers and thunderstorms.

DISCUSSION

Today through Friday - strong high pressure aloft will develop over the Great Basin while a low forms off the northern Baja coast. The result will be rapidly increasing easterly flow aloft over our region. There will also be tighter easterly surface pressure gradients as a surface high plunges down through the Rockies and plains. Expect northeast to east winds to increase through this period, especially along/west of terrain features. The period of strongest winds currently looks like later tonight through Friday morning, including areas around Flagstaff, Sedona, and the I-17 corridor from Flagstaff down to the Hwy 179 interchange. Gusts in these areas may reach 40-50 mph, with most other areas staying in the 30-40 mph range. Otherwise, expect dry and continued cooler than normal conditions through Friday.

Saturday and Sunday - Some moisture should move back into the region from the southeast by the weekend, and a low (10-25%) chance of showers and thunderstorms is included in our latest forecasts. Rain chances may increase as we get closer, depending on the track of the weak upper low as it ejects northeastward late in the weekend and possible interaction with deeper moisture associated with tropical systems far to the south off the coast of Mexico. While most of the ensemble guidance continues to keep the deeper moisture to our east through Sunday, a small percentage (including latest operational EC) bring it farther west, so this will be something to monitor. Daytime highs look to stay below normal through the weekend.

Monday through Wednesday - ensemble forecasts show deeper low pressure diving south along the West Coast, settling over or just west of central/southern California by Tuesday or Wednesday. This will bring the potential for deeper moisture from the south to interact with the low over our region, and our rain chances have increased to 30-50% Tue/Wed. Daytime temperatures will remain cooler than average for mid October.

AVIATION...Thursday 15/12Z through Friday 16/12Z

VFR conditions. Winds gradually increasing through 15Z-18Z and continuing this afternoon and overnight. Expect northeast to east winds 15-25 kts with gusts 30-40 kts in many areas from late this morning through tonight.

OUTLOOK...Friday 16/12Z through Sunday 18/12Z...VFR conditions forecast through the period. Isolated -SHRA/-TSRA possible along and south of the Mogollon Rim Saturday afternoon, then across all of northern Arizona Saturday night. Winds will easterly through the period, initially between 15-25 kts with localized gusts 30-40 kts on Friday, becoming lighter at 10-20 kts on Saturday.

FIRE WEATHER...Thursday and Friday

Cool and windy conditions throughout the period. Winds are northeast through east 15-25 mph with gusts 30-40 mph on Thursday through Friday, remaining elevated overnight. Strongest winds will be along/downwind of higher terrain features in Yavapai and Coconino Counties and north of the White Mountains. Min RH is 30-60% on Thursday then 20-40% on Friday. Daytime temperatures 5-10 degrees cooler than normal.

Saturday through Monday...Slight chance for showers and thunderstorms over the higher terrain for each day. Winds are 10-20 mph from the east on Saturday, light and variable on Sunday, then southwest 5-15 mph on Monday. Daytime temperatures remain 5-10 degrees cooler than normal.

FGZ WATCHES/WARNINGS/ADVISORIES

None.