textproduct: NWS Phoenix

UPDATE...Updated 18z Aviation Discussion

KEY MESSAGES

- Temperatures near 10 degrees above normal will continue today through the start of next week with lower desert highs in the upper 70s to lower 80s.

- Minor HeatRisk starting today through at least Monday in the lower desert regions.

- Overall dry weather conditions should prevail through at least early next week before a pattern change later next week brings cooler temperatures and potential precipitation chances.

SHORT TERM /TODAY THROUGH SATURDAY/

Mid-level water vapor imagery shows the axis of the ridge stretching from the NW CONUS down through Western TX. Off the Pacific NW coastline a weak troughing feature has began to work its way down the coast line and looks to absorb the previous cut off low that has been affecting our region the past couple of days. This will result in another cut off low forming today off the southern coast of CA, and will progress down along the Baja peninsula over the few days. However, this will have litle effect on temperatures as afternoon highs across the lower deserts today and tomorrow will be generally in the lower 80s. Additionally overnight temperatures will remain above normal, with morning lows across the lower desert regions ranging between ~52-57 degrees. This morning Phoenix Sky Harbor has a 60-70% chance of tying the record warm low of 57 degrees, and a 50- 60% chance of setting a new record. If a record is broken, this will be the second day in a row of breaking a record warm low.

Due to the continuing of well-above normal afternoon highs, minor HeatRisk is noted for most of the lower elevation valley locations through at least Monday. This will put individuals that are extremely sensitive to heat at risk of health impacts. There have been many heat related calls for help over the previous couple of days, proving that heat can still be impactful in the desert in early February. Therefore, it is always a good idea to practice heat safety if planning to spend outdoors for a prolonged period of time.

LONG TERM /SUNDAY THROUGH NEXT FRIDAY/

The cut off low that has been to our SW will help lower heights aloft slightly, however, due to its warm nature we will continue to be under the influence of positive height anomalies through early next week. That being said, very little spread between the 25th and 75th percentile are seen for high temperatures for this weekend through Monday. Temperatures across the lower desert region are forecast to top out in the upper 70s to lower 80s with Minor HeatRisk. Model ensembles are still showing a deeper 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. Continued monitoring of model trends for this system will be needed over the next several days before there will be enough confidence to say how the region will be affected.

AVIATION

Updated at 1735Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns under rounds of mid to high clouds can be expected throughout the TAF period. SE winds turn variable after 23Z and back to SE around 08Z. Overall wind speeds will remain light aob 5 kts throughout the period.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns under rounds of mid to high clouds can be expected throughout the TAF period. Winds will generally be light and variable through most of the period, although a more definite northwesterly component is likely at KBLH by this evening.

FIRE WEATHER

Unseasonably warm temperatures and overall dry conditions will persist through Monday, with high temperatures in the upper 70s to lower 80s and afternoon MinRHs of 15-25%. A pattern shift is expected going into the middle to end of next week where temperatures will cool and humidities will improve slightly with MinRHs between 20-30%. Models are suggesting a slight chance for rain by the middle to late next week, mostly in the eastern districts, but current confidence is too low at this point in time for exact impacts.

PSR WATCHES/WARNINGS/ADVISORIES

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