textproduct: NWS Phoenix

KEY MESSAGES

- Well above normal temperatures will continue into early next week, with lower desert highs reaching the lower to middle eighties, resulting in areas of Minor Heat Risk.

- A pattern change next week will cool temperatures somewhat and may eventually bring rain chances to eastern portions of the forecast area by late next week.

SHORT TERM /TODAY THROUGH TUESDAY/

Over the past 24 hours the cut-off low to our southwest has progressed well down the Baja Coast with the center of the low currently positioned approximately halfway down the peninsula. Today through Tuesday the low will traverse over Northern Mexico and into Western TX. With the center of the low being so far to our south, the Desert SW will remain under the influence of positive height anomalies, with H5 heights ranging between 575-580 dam, in addition, negative PWATs anomalies (~60-90% of normal) will also be in place through Monday keeping skies mostly clear. Expect afternoon highs today and Monday in the low to mid 80s across the lower deserts. Starting Tuesday, cooler afternoon highs of near 80 degrees are expected across the lower deserts due to another low pressure system beginning to dive down the West Coast, lowering heights aloft. These well-above normal afternoon highs will keep the lower desert areas with Minor HeatRisk through Tuesday. Minor HeatRisk will mean those extremely sensitive to heat may experience heat- related health impacts. Staying hydrated and taking breaks in shaded areas is encouraged, especially during outdoor events being held over this weekend. Morning low temperatures will continue to be well-above normal as well, continuing the trend of Phoenix Sky Harbor flirting with record warm lows.

LONG TERM /WEDNESDAY THROUGH SATURDAY/

Ensembles continue to be in good agreement in the next troughing feature diving down the West Coast starting Tuesday and will remain off in the Eastern Pacific throughout most of the work week. However, this feature will bring an increase of high clouds starting Tuesday with the addition of cooler temperatures as heights aloft will begin to lower in response by Wednesday. This will lead to afternoon high temperatures in the lower to mid 70s mid to late next week in the lower desert areas (still above normal for this time of year). Though models are not in great agreement with the PVA and moisture associated with this trough, some of the deterministic guidance suggest very limited short- lived rain chances mainly in the eastern portion of the region Friday afternoon, while other suggest more widespread light showers later Friday evening into early Saturday morning. Continued monitoring of how this system will progress later in the week will be needed. If you were excited about seeing precipitation, this system will not be the last hope for precipitation chances as another stronger and better positioned trough looks to be trailing behind. This could lead to more widespread precipitation chances across the Desert SW for the following week, but with this potential system being over a week out, it is difficult to put too much weight into it at this time.

AVIATION

Updated at 0455Z.

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

No major weather issues will exist through Sunday afternoon under occasional high cirrus. Winds will follow familiar diurnal trends with speeds generally aob 8kts. Prolonged periods of VRB to calm conditions will be common across the region.

FIRE WEATHER

Well above normal temperatures and dry conditions will continue into early next week. Afternoon MinRHs will range from 15-25% areawide through Monday, with overnight recoveries generally in a 35-65% range. Winds will remain light, generally below 15 mph through Monday, with a northerly fetch. By the middle of the upcoming work week, a pattern change is expected which will help cool temperatures several degrees (though they will remain above normal), increase MinRHs slightly to 20-30%, and bring occasionally breezy conditions. Late in the week, a weather system will pass through the region, providing 15-30% chances for wetting rain over higher terrain areas of the eastern districts.

PSR WATCHES/WARNINGS/ADVISORIES

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