textproduct: NWS Phoenix

UPDATE

Updated Aviation Discussion.

KEY MESSAGES

- Unseasonably warm temperatures will be seen today with highs in the upper 70s to lower 80s, or around 10 degrees above normal.

- Breezy northeasterly to easterly winds will continue this morning with wind gusts between 20 and 30 mph across the lower deserts and upwards of 30 to 40 mph across the higher terrain.

- Above normal temperatures and overall dry weather should prevail through at least the weekend before a pattern change later next week brings cooler temperatures and potential precipitation chances.

SHORT TERM /TODAY THROUGH FRIDAY/

The Rex block will start to breakdown today with the low beginning to move northeastwards into the SW portions of our CWA due to the center of the high steadily progressing eastward. With the center of the low beginning to move into our region H5 heights will see a slight decrease in comparison to yesterday with heights between 576- 582 dm for today and between 573-579 dm Friday. Despite the slight decrease, these heights remain near the 90th percentile for this time of year. That being said temperatures will yet again will be 8-12 degrees above normal. The lower desert region today and Friday will see afternoon highs in the upper 70s to lower 80s, while the higher terrain areas will see afternoon highs in the mid to upper 60s.

Easterly winds from a low level jet will affect much of the region today, mostly throughout the morning into the early afternoon hours before subsiding by evening. The most affected areas will be South Central Arizona into the higher terrain areas. Unsheltered higher terrain areas and ridgetops may see wind gusts at times of 35-40 mph, while regions in the lower deserts may see gusts peak between 25-35 mph through this morning. Otherwise, the aforementioned cut off low will bring a quick moving swath of mid to high level clouds passing over the region starting late this morning. Model guidance show moisture increasing further this afternoon into this evening with only a chance of virga to sprinkles across the western deserts because the lower atmosphere will remain considerably dry below 700 mb.

LONG TERM /SATURDAY THROUGH NEXT THURSDAY/

The cut off low will help lower heights aloft but due to its warm nature we will continue to be under the influence of positive height anomalies through early next week. Very little spread between the 25th and 75th percentile are seen for high temperatures for this weekend through Monday. That being said temperatures across the lower desert region are expected to remain in the upper 70s to lower 80s. Model ensembles are still hinting at a troughing feature digging down the West Coast by the later half of the week but there is still uncertainty with the strength and positioning of this system. Given this is still a week away, we should not put much stock in the guidance for another few days.

AVIATION

Updated at 1755Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: The primary aviation weather concern will be occasionally gusty E/SE winds under increasing mid and high cloud decks (bases remaining generally AOA 10 kft AGL). Winds remain elevated out of the E/SE and will gust to 15-20 kts at times through approximately 22Z, after which gusts should mostly subside and sustained speeds should remain AOB 10 kts. A period of virga showers will be possible late this afternoon through this evening, with low confidence in brief VCSH/-SHRA conditions.

Southeast California/Southwest Arizona including KIPL and KBLH: The only weather issues will be low confidence on wind directions this evening through Friday morning and the potential for virga or brief VCSH/-SHRA conditions. Winds will favor NE through this afternoon, with low confidence on a NW/W component developing this evening. Instead, winds may begin to exhibit extended periods of variability this evening through Friday morning, with speeds AOB 6 kts. Periods of SCT-BKN mid and high cloud decks with bases remaining above 10 kft AGL are anticipated through Friday morning.

FIRE WEATHER

Unseasonably warm temperatures and overall dry conditions will persist through the end of the workweek. Today will see highs in the upper 70s to lower 80s with MinRHs of 15-20%. Winds will continue through this morning with wind gusts as high as 30-40 mph across portions of the eastern districts. Gusts upwards of 45 mph, mainly along the ridgetops across the eastern districts. Humidities will improve further going into Friday with MinRHs between 20-25%. Lighter winds with fairly stable humidities are expected for the weekend.

PSR WATCHES/WARNINGS/ADVISORIES

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