textproduct: NWS Flagstaff

SYNOPSIS

Cooler temperatures with rain and high elevation snow are expected into this evening. Dry and warmer conditions return for the weekend. A strong storm system is expected to move into the region late Monday through much of next week, bringing gusty winds and chances for rain and snow.

DISCUSSION

The upper low is shifting eastward across southern Arizona this afternoon, with widespread rain and higher elevation snow continuing across northern and central Arizona. Snow levels have been much lower than forecast by the blended model guidance (NBM), and these have been adjusted down accordingly in the latest forecast package. Observed snow levels have been between 6500-6800 ft in the Flagstaff region all day (NBM forecast was near 8200 ft), and these are expected to remain fairly steady into the evening. With a bit of instability developing as the low crosses the area, there should be a period of localized heavier showers and even a rumble of thunder, gradually ending from west to east by mid to late evening. Snowfall rates around 1"/hour or higher may accompany these heavier showers, creating some hazardous travel conditions so please use caution into this evening. For Saturday and Sunday - dry and much warmer weather is forecast as brief ridging develops over the state. Daytime highs will be 5-10 degrees above normal.

Monday through Thursday - a pattern change is still expected, with a strong trough over the west coast, sending shortwave disturbances eastward into Arizona at times. The first shortwave and shot of precipitation is currently forecast for Monday evening/night into Tuesday. There are still some discrepancies in snow levels/temperatures, but models are in fairly good agreement on timing of precipitation. Higher snow levels may limit accumulation Monday evening, but this is still not certain. Accumulations of several inches are forecast in the blended model guidance above 6000 feet for this period, with the NBM in the 2-5" range though these could go up if the system comes in colder. It is also going to be windy Monday into Tuesday with gusts 30-45 mph creating a threat for some blowing snow. The timing of the second shortwave currently looks like Wednesday into Thursday morning. This one looks colder, with snow levels potentially down to 5000 feet or so. Latest NBM probabilities of 24 hr snowfall 4" or greater are 40-60% along the Mogollon Rim/Kaibab Plateau from Wed AM to Thu AM. We'll get a better handle on this one over the next few days, but definitely stay tuned for updates if you have travel plans.

AVIATION...Saturday 14/06Z through Sunday 15/06Z

MVFR/IFR conditions continue in -SHRA/-SHSN in vicinity of KSOW/KJTC through 10Z. MVFR CIGS and BR/FG possible along the higher terrain through 12Z. VFR conditions expected thereafter, with VRB winds 5-10 kts.

OUTLOOK...Sunday 15/06Z through Tuesday 17/06Z...VFR conditions. Winds S/SW 10-15 kts on Sunday, increasing to 15-25 kts with gusts 30-40 kts on Monday.

FIRE WEATHER...This afternoon through Sunday

Widespread rain and snow showers through tonight, clearing from west to east. Lingering showers across eastern Arizona into Saturday morning. Dry conditions with warming temperatures for Saturday and Sunday. Light and variable winds through tonight, becoming west to northwest 5-15 mph on Saturday, then S-SW 5-15 mph with gusts 20-25 mph on Sunday.

Monday through Wednesday...Dry conditions expected through Monday, then cooler temperatures and increasing chances for rain and snow showers Monday night through Wednesday. Southwest winds 20-30 mph with gusts 35-45 mph each day.

FGZ WATCHES/WARNINGS/ADVISORIES

None.