textproduct: NWS Phoenix

UPDATE

00Z Aviation Discussion.

KEY MESSAGES

- Dry conditions, well above normal temperatures, and occasional passing high clouds are expected through the next 7 days.

- Periods of breezy winds will develop across the area with the most widespread breeziness later next week.

SHORT TERM /TODAY THROUGH SUNDAY/

Current midlevel water vapor imagery and objective analysis show a continuation of the large scale pattern, characterized by East Pacific troughing, downstream ridging over the western US, and longwave troughing further downstream over much of the Eastern CONUS. Overall, this hemispheric pattern looks to persist through the next week. However, ensembles show changes in the North Pacific Jet that will begin to perturb the downstream split jet regime this upcoming work week, sending a few shortwave disturbances over/near the region that will bring periods of mostly high clouds. Specifically, the North Pacific Jet has begun to show signs of retreating into the Western Pacific, eventually entering a more retracted phase during the upcoming work week.

Most relevant to the local weather for the remainder of this weekend is the midlevel anticyclone centered over SoCal early this afternoon and the associated positive height anomalies, allowing for well above normal temperatures. Ensembles are in excellent agreement that the anticyclone will slide eastward across the area Sunday, though mean H5 heights are shown peaking today, with values around 584 dam. Widespread highs in the upper 70s to near 80F will be common this afternoon across the lower deserts. Afternoon highs are likely to warm by another few degrees Sunday, potentially challenging the record high in Phoenix for the date (see Climate section.) Meanwhile, surface high pressure over the Southern Plains will allow for continued easterly breeziness over portions of Southern AZ into Sunday, particularly over the higher terrain and ridgetops.

LONG TERM /MONDAY THROUGH NEXT SATURDAY/

Model guidance continues to trend warmer with less chances for any weather systems impacting the Desert Southwest next week. The upper level ridge this weekend will weaken and push to the east by Monday with very broad upper level troughing briefly moving in from the southwest. This will help to lower heights slightly and in turn bring daytime highs back down into the upper 70s for the lower deserts on Monday. Guidance also shows a slug of upper level moisture moving across the region Sunday night through Monday night bringing a decent amount of mostly thin high clouds.

By Tuesday, an even stronger upper level ridge is expected to nudge northeastward into the Western U.S., while a piece of lingering upper level energy to our south and southwest forms a cut-off low by Wednesday morning. As a result, another Rex block will take shape Wednesday into Thursday with the center of the ridge strengthening further and slowly drifting from northern California through Nevada. The position and the strength of the ridge will result in another round of downslope warming and drying for much of our region. The latest NBM forecast highs for Tuesday-Thursday are once again warmer than yesterday's runs with readings between 78-82 degrees Tuesday, 80-84 degrees Wednesday, before dropping back to 77-81 degrees starting Thursday.

Ensembles show good consensus with the ridge now dominating through at least midweek before allowing the blocking pattern to somewhat break down Friday into next Saturday. The cut-off low that forms early in the week should eventually come back into or near our region by Friday, but it is heavily favored to be an open wave by that point with not enough energy or moisture to bring any rain chances. After the midweek blocking pattern breaks down, ensembles do start to show potential for another (weaker) Rex block and cut-off low for next weekend. Initial forecast thinking and trends over the past few model runs show this next disturbance is also likely to bypass our region to the south.

AVIATION

Updated at 2345Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns under clear skies can be expected throughout the TAF period. Winds will follow similar trends from 24 hours ago with a brief W-NW shift anticipated this evening, followed by a return of easterly flow late tonight. Easterly winds will become elevated again late Sunday morning with a few gusts into the teens possible at KIWA and KPHX. Winds should remain easterly through Sunday evening.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns under generally clear skies can be expected throughout the TAF period. Winds will fluctuate between westerly and northerly at both SE California terminals tonight and again Sunday afternoon. Speeds should remain aob 7 kts.

FIRE WEATHER

Dry weather conditions will prevail through next week, with MinRH values in the 10-20% range most afternoons. There will be a subtle moisture increase late this weekend into Monday, but MinRH values only increase to 20-25% at best. Overnight recoveries will remain poor to fair with humidities mostly between 30-55%. Gusty easterly winds will mainly affect ridgetop areas over the eastern districts this weekend with light winds on Monday. The weather pattern will again support breezy daytime conditions mid to late next week. Temperatures will warm further this weekend with lower desert highs likely topping 80 degrees in many locations.

CLIMATE

Phoenix, AZ Daily Record High Temperatures.

2/1 83 (2003) 2/2 82 (2025) 2/3 86 (2025) 2/4 86 (2025) 2/5 87 (1963)

PSR WATCHES/WARNINGS/ADVISORIES

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