textproduct: NWS Flagstaff

SYNOPSIS

Expect warm weather to finish off this week and into the weekend. Winds will be much more manageable, compared to the last several days. Some moisture will arrive over the weekend, with chances for showers and thunderstorms developing. Hot and dry weather then sets up again for most of next week.

DISCUSSION

High pressure building over the southwest United States and northwest Mexico will open the door to a moisture incursion into Arizona. Southerly surface flow over the Gulf of California, likely helped along the by outflow from thunderstorms over the Sierra Madre Occidental, will push low-level moisture into Arizona. Moisture will remain somewhat limited today but a stray shower or thunderstorm is not out of the question.

For Saturday through Monday...Moisture will continue to push across Arizona on Saturday and Sunday and interact with a weak trough brushing Arizona from the north. Increased moisture and slightly cooler mid-level temperatures associated with the trough will combine with daytime heating to produce widespread instability. On Saturday, the main focus of scattered showers and thunderstorms will be from the Kaibab Plateau and Mogollon Rim southward based on the expected northward progress of deeper moisture. By Sunday, isolated to scattered showers and thunderstorms are anticipated across all of northern Arizona. The very best chances will be over the higher terrain. The trough axis will head eastward on Monday with a drier west to northwest flow developing. However, the dry-out will be slow enough for the threat of showers and thunderstorms to continue from about the Mogollon Rim southward.

From Tuesday onward...A drier air mass will take over with high pressure becoming reestablished over the southwest United States. Look for daytime temperatures to climb into the hot category for all locations with mainly dry conditions and the usual afternoon breezes. As long as high pressure remains over the southwest there is always the possibility of some monsoon moisture slipping into Arizona for a slight chance of showers. At this time any moisture push that may occur looks to be trivial.

AVIATION...Friday 12/18Z through Saturday 13/18Z

VFR conditions, isolated showers or thunderstorms south KPRC-KPAN line. Winds SW 5-10kts, gusts to 20kts daytime, light and variable or terrain driven overnight.

OUTLOOK...Saturday 13/18Z through Monday 15/18Z...Mainly VFR conditions, but brief MVFR possible near heavier showers/tstorms. Scattered showers/tstorms possible after 18Z each day with the highest chance over the higher terrain. Winds S-SW 5-10kts, gusts to 20kts daytime (higher downburst gusts possible near storms). Light and variable or terrain driven overnight.

FIRE WEATHER...Today and Saturday

Warm weather with increasing moisture. Today will remain mostly dry, then isolated to scattered showers and thunderstorms (20-50% chance) on Saturday afternoon. Expect southwest to west winds 5-15 mph each day. Minimum RH 8-15% on Friday, increasing to 10-25% on Saturday.

Sunday through Tuesday...Warm with chances (20-50%) for showers and thunderstorms on Sunday and Monday afternoon. Mostly dry conditions return by Tuesday. Winds southwest to west at 10-20 mph on Sunday, turning west to northwest on Monday and Tuesday. Look for minimum RH of 15-25% on Sunday, decreasing to 10-20% on Monday, then 8-15% on Tuesday.

FGZ WATCHES/WARNINGS/ADVISORIES

None.