textproduct: NWS Phoenix

KEY MESSAGES

- Near normal temperatures through mid week will turn hotter going into the weekend with lower desert highs into the nineties as early as Friday.

- A weather system for Thursday will bring an increase in rain chances with the best area of focus across southeast Arizona.

SHORT TERM /TODAY THROUGH THURSDAY/

Mid level water vapor imagery and RAP 40 analysis shows southwesterly flow aloft over the region, and a closed low well off the southern coast of California. Plenty of upper level moisture is being advected into the region from the SW ahead of the closed low. This upper level moisture will lead to an increase in cloud coverage throughout today and lingering into much of Thursday. Today's afternoon highs will be near normal across the lower deserts, in the upper 80s to lower 90s. Temperatures on Thursday will be a degree or two warmer, mostly in the lower 90s in the lower deserts.

By Thursday afternoon the aforementioned closed low is expected to be centered over northern Baja Peninsula just to the reion's southwest. Current model trends continue to track this system just south of our CWA, across northern Mexico. If these trends hold true, the system will bring less impacts to our area than previously expected, which is why current NBM PoPs have been curtailed once more from the previous forecast. Current PoPs for Thursday afternoon/evening now show a 5-10% chance in south-central Arizona, and in the eastern higher terrain PoPs are now a 15-25% chance.

LONG TERM /FRIDAY THROUGH TUESDAY/

By Friday, the close low will be exiting to the region's east, but negative height anomalies will remain over much of the Desert SW. Even with negative height anomalies temperatures will begin to warm as upper level ridging begins to build over the West Coast. Temperatures in response to the building ridge will warm into the lower to mid 90s in the western lower deserts and in the lower 90s across south-central Arizona.

Over the weekend another low pressure system will develop off the Californian coast, which will help amplify the ridge over the Desert SW driving temperatures into the mid to upper 90s. Models point towards this next system moving into our region by early next week which will most likely return breezy to windy conditions, cooler temperatures, and possibly some higher terrain rain chances.

AVIATION

Updated at 2320Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected during the TAF period. Winds will follow light and diurnal trends with some occasional gusts during the afternoon hours. SCT-BKN high clouds will be common across the region through Wednesday evening.

Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns are expected during the next 24 hours. Winds will at KIPL will switch from SE to more W'rly this evening, while KBLH sees mostly a W'rly component with windows of VRB conditions this evening and tonight. FEW-SCT high clouds will be present across the region through Wednesday evening.

FIRE WEATHER

Dry conditions along with warming temperatures will be observed through today. Winds will remain fairly light, following diurnal trends, with a few afternoon gusts to around 15-20 mph primarily across southern Gila County. A weather system will bring increasing rain chances Thursday with the best chances remaining south and east of Phoenix. However, chances for wetting rainfall will be low around 10% or less. MinRH values will be around 8-15% today before increasing to 15-20% on Thursday. Overnight MaxRH values will generally range between 25-40% through midweek. Gusty winds are expected to increase this weekend into early next week, which could lead to elevated fire weather conditions in some areas.

PSR WATCHES/WARNINGS/ADVISORIES

AZ...None. CA...None.