textproduct: NWS Tucson Arizona

SYNOPSIS

Drier air across southeast Arizona will continue into Monday. Moisture then spreads back across portions of southeast Arizona next week for a chance of showers and thunderstorms. High temperatures will be near to slightly above normal into the middle of next week.

DISCUSSION

On the large scale, an upper low was centered over south central Idaho, with a trough axis extending southward through the Great Basin into northern Arizona. Broad high pressure aloft was centered from northeastern Mexico into far eastern Texas. The upper low will continue to move east into the high plains early next week, while the area of high pressure flattens out across northeast Mexico and the southern tier of states. A secondary low then moves into the central California coast late Sunday and shears out as it lifts to the northeast across the Intermountain West early to mid next week. The area of high pressure amplifies to our east mid to late next week.

Satellite layer blended total precipitable water imagery indicates PWATs were currently in the 0.60 to 0.80 inch range across southeast Arizona. Drier air will continue to move into the region today as the upper low and trough axis shift eastward. PWATs will fall into the 0.40 to 0.65 inch range across the entire CWA today and Sunday. This will shut down convection over the weekend.

By Monday, as the secondary low begins to move northeast through California into Nevada and the high begins to nudge west and amplify, flow around these two features begins to pull moisture northward along the Arizona/New Mexico state line and areas eastward. Although the official forecast still remains dry for southeast Arizona on Monday, we will have to monitor any convective outflow boundaries over Sonora which may push convection northward along the International Border in Cochise County. PWATs increase back into the 0.70 to 0.90 inch range Monday.

By mid/late next week the upper high amplifies to our east and flow turns back to southerly across southeast Arizona, with increasing amounts of moisture moving back into southeast Arizona. PWAT values are back up into the 1.0 to 1.25 inch range across southeast Arizona. The latest POP grids show a chance of showers/thunderstorms east of Tucson Tuesday, from Tucson eastward Wednesday and across much of southeast Arizona Thursday and Friday. In addition, there will be the possibility for some tropical influences late next week. It will come down the position/strength of the upper high on how these features track. Still a lot of uncertainty this far out.

Otherwise, high temperatures through Tuesday are near to slightly above normal, with highs in the mid to upper 90s in the Tucson metro, near 100 degrees across the western deserts and in the mid 80s to lower 90s across the valley locations of Santa Cruz, Cochise, Graham and southern Greenlee counties. Highs then lower 2-4 degrees mid to late next week as increasing moisture moves back into the region.

AVIATION

Valid thru 20/12Z. Mainly clear skies/SKC conditions from KTUS west thru the forecast period. East of KTUS, FEW-SCT clouds at 8k-11k ft AGL. SFC wind less than 12 kts thru the forecast period, favoring a WLY direction during the afternoon/early evening hours and variable in direction at other times. Aviation discussion not updated for TAF amendments.

FIRE WEATHER

Dry conditions across southeast Arizona into Monday. Moisture then spreads back across portions of southeast Arizona next week for a chance of showers and thunderstorms. High temperatures will be within a couple of degrees of normal through next week. Min RH values will be in the 13-20 percent range west of Tucson through the weekend and 20-27 percent in valley locations east of Tucson (25- 40 percent in the mountains). RH values then increase 10-20+ percent east of Tucson next week as deeper moisture moves back into the area. 20-foot winds will be less than 15 mph into at least the middle of next week. Gusty and erratic winds will accompany any thunderstorms.

TWC WATCHES/WARNINGS/ADVISORIES

None.