textproduct: NWS Phoenix

UPDATE

00Z Aviation Discussion.

KEY MESSAGES

- Dry conditions and well above normal temperatures will continue to prevail this week.

- A period of breezy northeasterly to easterly winds will return for Wednesday and Thursday.

- A pattern change looks likely starting early next week which could bring much cooler temperatures and precipitation chances.

SHORT TERM /TODAY THROUGH WEDNESDAY/

Mid-level water vapor satellite imagery and objective analysis reveal that a weak shortwave trough has made its way into southern California early this afternoon. This weak shortwave trough will quickly move through AZ through the rest of this afternoon and evening. With this trough moving through our are, it has brought slightly lower heights aloft and some high clouds to our area allowing for a brief and slight cooling trend. Afternoon temperatures should be noticeably cooler today compared to yesterday as temperatures are forecasted to only be in the upper 70s to around 80 degrees today, which is still around 10 degrees above normal. As of 130pm, temperatures are around 1-6 degrees cooler today than they were at this time yesterday.

Despite the brief cool down today, another strong ridge of high pressure is setting up over the eastern Pacific. This ridge will then move eastward over western CONUS on Tuesday and Wednesday. The ridge will max out late Tuesday into Wednesday with H5 heights above the 90th percentile of climatology. Models continue to show that the center of the ridge will be over northern California/northern Nevada. Despite this, the NBM forecast continues to show the lower deserts seeing highs in the 82-85 degree range for both Tuesday and Wednesday, peaking on Wednesday. The higher terrain areas are forecasted to see afternoon high temperatures ranging from the upper 60s to upper 70s on both Tuesday and Wednesday. Easterly downslope winds will pick up on Wednesday with gusts of 15-25 mph possible, with some higher gusts upwards of 30-35 mph possible in the higher terrain. These easterly downslope winds on Wednesday could easily push some Phoenix locations above 85 degrees. The latest NBM probabilities show a 50% chance of Phoenix tying the daily record of 86 degrees on Wednesday. Afternoon high temperatures for Tuesday and Wednesday are around 12-16 degrees above normal for this time of year. Due to this most lower desert locations will see Minor HeatRisk for both Tuesday and Wednesday. So make sure to take proper precautions to protect yourself from the heat (like drinking plenty of water, using sunscreen, and taking breaks in the shade), especially if you're outside for prolonged periods of time and/or are extremely sensitive to the heat.

LONG TERM /THURSDAY THROUGH NEXT MONDAY/

The brief Rex block set up for Tuesday and Wednesday is expected to break down somewhat by Thursday as an upstream kicker trough moves toward the Pacific Northwest and northern California coast. A weak cut-off low west of Baja midweek is also shown to open up and move north northeastward Thursday into Friday, moving across at least western portions of our region. This disturbance will help to bring an good amount of higher level moisture and clouds into our region on Thursday, but nearly all indications keep very dry air in place below 10K feet. The most optimistic ensemble members do show a chance of some light high-based showers over higher terrain areas Thursday night into Friday, but PoPs remain below 5%. Lowering heights along with the clouds late week are likely to drop daytime highs back down to around or just below 80 degrees starting Thursday.

Model guidance is starting to come to a better consensus for the upcoming weekend with the kicker trough and the weakening cut-off low feature merging by Saturday, likely along the California coast or just to the west. Much like the past several weak systems, this next one for the upcoming weekend is likely to be mostly cut off from the main flow. At the moment ensembles generally agree this system will form and become a closed low somewhere to our southwest by the weekend and mostly pass to our south. Even with a track to our south, it should at least result in an increase in moisture across our region. However, so far models show the moisture advection will not be enough to bring much in the way of any precipitation chances over the weekend.

Long range model output is starting to show some positive signs of a pattern adjustment for next week with at least a 50% probability of a deeper and colder trough developing across the Southwestern U.S. at some point during the first half of next week. If this holds true, we should see some PoPs appearing in the forecast soon along with a more meaningful cooling trend next week.

AVIATION

Updated at 2350Z.

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

No aviation weather concerns are expected throughout the TAF period. The overall wind pattern will follow light and diurnal tendencies with speeds aob 7 kts along with periods of variable to calm conditions at times. SCT to occasionally BKN high cirrus will continue to stream across the region tonight, becoming less extensive by tomorrow afternoon.

FIRE WEATHER

Well above normal temperatures and dry conditions will persist this week. Humidities will remain quite low with with afternoon minRHs commonly between 10-20% range areawide through Thursday. Overnight recoveries will also remain fair to poor with humidities generally topping out in a 35-55% range through Thursday. A slight increase in humidity is expected Friday and this weekend with minRHs going into the 20-30% range and overnight recoveries going into the 50-70% range area wide. Light and mostly terrain driven winds will prevail into Tuesday before the weather pattern again supports breezy northeasterly to easterly winds mid to late week.

CLIMATE

Phoenix, AZ Daily Record High Temperatures.

2/2 82 (2025) 2/3 86 (2025) 2/4 86 (2025) 2/5 87 (1963)

PSR WATCHES/WARNINGS/ADVISORIES

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