Catalina, AZ 85738 Weather

Synopsis

There will be a slight chance of showers and thunderstorms along the New Mexico state line through Saturday. Dry conditions are then expected areawide Sunday through Wednesday of next week. High temperatures will be below normal into early next week, warming to near normal during the middle of next week.

Discussion

The upper low that brought severe weather to Arizona the last two days has moved into the western Great Basin. Dewpoints remain elevated across the eastern half of the forecast area in the mid to upper 50s, with dewpoints in the mid to upper 40s across the western half of the state. Cloud cover continues to hang in from Tucson eastward with clear skies across the western half of the state. KEMX radar shows a few light returns/showers over eastern portions of the forecast area. Satellite layer blended PW values are currently around one-half inch west of Tucson and between 0.75-1.00 inches to the east of the Tucson.

Through Saturday the main upper low will shift northeast into the northern tier of states, while a secondary lobe of energy will drop down the back side of the trough into the desert southwest. This developing upper low will move into far southeast California tonight and into western Arizona early Saturday. This system will then track northeast across Arizona into southern Utah late Saturday night. This system will not be like its predecessor, in that it will have neither strong jet dynamic support or a subtropical moisture plume to work with. However, there will still be enough moisture in place to work with the trough/upper low to bring a slight chance of showers and thunderstorms over far eastern portions of the forecast area through Saturday.

Shortwave ridging and southwest flow aloft will then prevail Monday through Wednesday of next week, as a series of upper lows move into the Pacific Northwest. This will result in dry and warmer conditions areawide across southeast Arizona.

During the latter half of next week the deterministic GFS/ECMWF solutions diverge significantly. The Ensembles favor west coast troughing, which is reflected in our grids/forecast, with high temperatures lowering below normal and a slight chance of showers and thunderstorms Thursday and a chance of showers/thunderstorms on Friday.

Overall, high temperatures will be 1-5 degrees below normal through Monday, near normal next Tuesday and Wednesday, lowering to 4-8 degrees below normal by the end of next week. Near freezing to sub- freezing morning lows look likely in the White Mountains and Hannagan Meadow Sunday morning through next Tuesday morning.

Aviation

Valid through 24/12Z. SCT-BKN clouds at 5k-9k ft AGL east of KAVQ to KOLS line, with clear skies west of this line thru the forecast period. Slight chance of -SHRA/-TSRA primarily east of a KDUG to KSAD line thru the forecast cycle. SFC wind 12 kts or less, except in the vicinity of KALK and KDUG between 23/18Z and 24/02Z when SFC wind will be 12-16 kts with gusts to near 25 kts. SFC wind direction SWLY thru NWLY between 23/17Z and 24/03Z and variable in direction at other times. Aviation discussion not updated for TAF amendments.

Fire Weather

High temperatures will be below normal through Monday, warming to near normal Tuesday and Wednesday of next week, then lowering back below normal by the end of next week. There will be a slight chance of showers and thunderstorms through Saturday along the New Mexico state line and in the White Mountains. 20-foot winds will generally be 15 mph of less through at least the middle of next week. Minimum RH values will be in the 25-40 percent range in the valleys through Sunday (higher in the mountains), lowering into the 20-30 percent range next Monday through Wednesday.