textproduct: NWS Phoenix

KEY MESSAGES

- Tranquil weather conditions will persist throughout this week with temperatures within a few degrees of the seasonal normal.

- A weather system passing north of Arizona during the middle of the week may bring a few light showers over the Arizona high terrain.

SHORT TERM /TODAY THROUGH TUESDAY/

Current satellite shows clear skies across the area with upper level ridging still stretched southeast to northwest across the Southwestern U.S. A stationary cut-off low remains situated roughly 600 miles southwest of San Diego with water vapor imagery showing very little moisture associated with the system. H5 heights increased over the weekend reaching to 588dm over much of southern California and the southern half of Arizona. For today, expect nearly identical temperatures as we saw yesterday with lower desert highs between 86-91 degrees. Guidance remains in good agreement the cut-off low will eventually begin to track toward southern California on Tuesday, but weather conditions over our region Tuesday will be similar to today's conditions. The only changes for Tuesday may be an added degree or two onto the daytime highs across the Phoenix area and the return of some thin higher level clouds.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

The cut-off low is still forecast to move through south-central California on Wednesday as it starts to weaken. The track of the low center may eventually move across northwest or most of northern Arizona Wednesday night into Thursday, but with little system moisture the vort center itself will have no impact on our area. However, guidance is still showing some modest higher level moisture advecting into Arizona Tuesday night into Wednesday with the highest PWATs of around 0.8" centered over south-central Arizona. This moisture may help to spark off some high-based light showers by Wednesday morning, but only light accumulations are expected and they will be confined to higher terrain areas north and northeast of Phoenix. The lower deserts may see some virga showers and some isolated sprinkles, but measurable rainfall is very unlikely. Once the low center moves into northern Arizona later on Wednesday, drier air will quickly spread west to east across southern and central Arizona. Upper level ridging will eventually move overhead by Friday and last through Saturday before more zonal flow is likely to affect our region Sunday into early next week. Dry conditions are expected to last through at least next weekend will only periods of higher level clouds from an AR affecting the northern half of California.

Temperatures for the latter half of the week into next week are not expected to vary all that much. Thursday is still likely to be the coolest day with highs in the lower 80s across south-central Arizona to the mid 80s over the western deserts. Once the ridge builds back in on Friday, highs should move more into the 85-90 degree range and stay there at least through Saturday before returning into a normal range by early next week.

AVIATION

Updated at 0505Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and Southeast California/Southwest Arizona including KIPL and KBLH:

No weather concerns will exist through Monday night under clear skies. Trends in wind shift timing will follow a persistence type forecast with speeds under 8kt and prolonged periods of nearly calm conditions.

FIRE WEATHER

High pressure will remain across the region through at least Tuesday with slightly above normal temperatures. Humidities will remain fairly stable with MinRHs mostly between 15-20% across the lower deserts to 20-25% for higher terrain areas. Light winds are also anticipated through at least Tuesday with directions mostly following common diurnal patterns. A mostly dry weather system is then expected to pass through the region on Wednesday bringing slight chances for higher terrain light showers. The system should also boost humidities slightly while also leading to a period of occasional breezy westerly conditions focused on Wednesday.

PSR WATCHES/WARNINGS/ADVISORIES

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