textproduct: NWS Phoenix

UPDATE

Updated Aviation

KEY MESSAGES

- Unseasonably strong high pressure will boost temperatures around 3 to 5 degrees above normal through the weekend, eventually reaching into a well above normal range by the middle of next week as lower desert highs reach 98-105 degrees.

- Periods of breezy to locally windy conditions can be expected across south-central and southwestern Arizona through Monday with gusts reaching 20-30 mph.

- Dry weather with zero rain chances will persist into much of next week.

SHORT TERM /TODAY THROUGH SUNDAY/

The upper atmosphere remains mostly unchanged with an area of strong high pressure remaining dominant over the Desert SW, centered over N AZ, while low pressure remains to the regions east. The strong high pressure is expected to peak this weekend with H5 heights reaching between 590-591 dam, which is near the 97th percent of climatology for this time of year. With this unseasonably strong high pressure, temperatures are expected to keep trending 3-5 degrees above normal throughout the weekend. Afternoon highs across the western lower deserts and along the Colorado River valley will be the upper 90s to low 100s. Meanwhile, south-central AZ will be slightly "cooler" with temperatures mostly staying below the century mark, however very localized areas may still see those dreaded triple digits. Overnight lows will also remain well above normal (8F- 12F), flirting with and likely breaking record warm lows throughout the weekend and into next week. Expect lows across the region to be in the upper 70s to low 80s, and with the combination of above normal highs and lows, moderate HeatRisk across the western deserts has started to develop.

With the aforementioned pattern remaining in place dry northeasterly winds aloft continue due to the increased pressure gradient. Winds associated with this pressure gradient will continue to produce gusts reaching 20-30 mph at times across southcentral and southwest AZ. Periods of gusts between 35-40 mph could develop Sunday morning in the higher terrain of E And SE AZ as well as in southwestern AZ as winds become channeled through terrain features, before quickly relaxing going into the afternoon hours. For the western portions, patches of blowing dust will be possible.

LONG TERM /SUNDAY THROUGH THURSDAY/

Heading into next week, deterministic and ensemble guidance show the unseasonably strong ridge weaken and retrograde wwd as an upper-lvl trough progresses through the Intermountain West. This will allow temperatures to dip a few degrees on Monday afternoon, although highs will still remain slightly above normal. The aforementioned trough will provide a temporary weakness in 500 mb hghts over southcentral AZ early next week, however positive hght anomalies will still exist over SE CA and SW AZ which will maintain highs in the low 100s. As ridging aloft begins to expand back over N AZ by mid-week, significant warming is progged to arrive with highs across the western deserts topping out around 100-105 degrees and approaching 100 degrees for the central AZ deserts on Wednesday and Thursday. These will likely be the hottest days of the forecast period before another trough potentially arrives onto the west coast by Friday into next weekend. Overall, subsidence aloft coupled with N-NE flow in the mid-lvls will maintain a dry forecast with near zero rain chances each day next week.

AVIATION

Updated at 2325Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: Gusty east winds will be the primary weather issue through Sunday evening under clear skies. Confidence is very good that winds will partially decouple overnight, losing gustiness but maintaining modest speeds. This should keep the majority of the region under LLWS criteria. Gusts will rapidly increase mid/late Sunday morning with a period of 25-35kt gusts possible before gradually weakening through the afternoon. Gusts may be maintained longer into Sunday evening than is typical before weakening. Depending on wind gust strength and recent land use, lofted dust affecting slantwise visibility is possible Sunday afternoon/evening.

Southeast California/Southwest Arizona including KIPL and KBLH: No major weather issues will exist through Sunday evening under clear skies. Confidence is excellent that a E/NE wind component will be favored with a light north drift or variable directions around sunrise. A few gusts near 20kt will be possible Sunday afternoon.

FIRE WEATHER

Dry conditions with slightly above normal temperatures are anticipated through this weekend before further warming occurs into the middle of next week. MinRHs will mostly range from 15-25% over the western districts to 25-35% for the eastern districts with fair to good overnight recovery area-wide. A persistent breezy easterly gradient wind will continue through at least Monday. Expect winds to remain elevated around 8-12 mph with early morning and afternoon gusts up to 20-30 mph.

PSR WATCHES/WARNINGS/ADVISORIES

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