textproduct: NWS Phoenix

UPDATE

Updated 12Z Aviation Discussion.

KEY MESSAGES

- Temperatures will cool trend through the weekend reaching below normal levels for several days early next week.

- Unusually strong winds will impact the region through Sunday resulting in areas of blowing dust and critical fire weather conditions.

- More tranquil weather conditions and a slow warming trend will arrive during the middle of next week.

SHORT TERM /Today through Monday/

Current GOES Mid-level WV imagery shows broad troughing across the west coast with the core of the system over the coastline between Washington state and Canada. This system will continue pushing inland through the weekend, tightening the pressure gradient causing breezy to windy conditions over the weekend. Winds will be strongest today as there are also multiple shortwaves embedded in the upper level low and will work their way through the trough over the weekend. Peak gust speeds will be in the southwestern corner of Imperial Valley, however, widespread windy conditions will be present across the Lower Colorado River Valley area as well. Due to this wind advisories will remain in effect through today along the Lower Colorado River Valley areas, and through Sunday night in the far southwestern portion of Imperial County. Expect winds between 25- 35 mph and gusts up to 55 in these areas. These winds can make travel difficult for high profile vehicles and may produce localized dense blowing dust. Otherwise, in conjunction to the elevated winds, very dry conditions will promote elevated to critical fire weather conditions, especially in the eastern higher terrain/ Gila County. That being said a Red Flag Warning remains in effect through Sunday evening.

This large, and seasonably strong troughing feature will also bring temperatures trending to below normal starting Sunday and into early next week. H5 heights today will be between 588-591 dam dropping to between 582-587 dam by Sunday. Resulting in temperatures 5F-10F below normal, quite the treat for late June.

LONG TERM /Tuesday through Saturday/

Once the Pacific trough settles over the Western CONUS negative height anomalies will remain in place over the Desert SW through early to mid week at the latest. The negative height anomalies will keep temperatures between 98F-103F or around 4F-7F below normal for this time of year. Guidance shows temperature beginning to climb back towards normal by Thursday as the trough begins to be displaced by the subtropical high building to the region's SE, returning H5 heights to near seasonal normal. By the next weekend afternoon highs will yet again be in the 105F-110F range.

AVIATION

Updated at 1135Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: The main aviation concern will continue to be breezy afternoon and early evening conditions with gusts of 20-30 kt. Winds should follow familiar diurnal trends through the period, with a slow turn to SW'rly winds again this afternoon. So, a few hours of S'rly crosswinds are once again expected. Winds are then expected to go back SE'rly during the overnight hours into Sunday morning. Other than a FEW distant high clouds, skies should be mostly clear.

Southeast California/Southwest Arizona including KIPL and KBLH: Breezy to windy conditions will continue to be the main aviation concern through the next 24 hours. Outside of lighter winds early this morning, gusts 25-35 kt, with occasionally higher gusts near 40 kt, will be common this afternoon and evening. Slantwise and surface VIS impacts due to wind generated BLDU appear to be possible, though the exact timing is uncertain. A TEMPO group has been added at KBLH between 23-03Z to at least indicate the potential for impacts. Timing of this TEMPO may need to be adjusted, or even upgraded to a prevailing line if persistent sub- VFR conditions are observed. Due to the orientation of the wind, KIPL is not likely to see dust impacts, but a few obs of MVFR VIS cannot be ruled out. Other than some passing high clouds, skies will be mostly clear during the forecast period.

FIRE WEATHER

Elevated to critical fire danger will continue today due to low humidity, very warm temperatures, and afternoon upslope/upvalley breezy conditions. Red Flag Warnings have been issued today through Sunday for much of the area. Expect MinRHs to stay close to 5-15% for the next several days. Winds will again increase this evening with gusts in the 20-35 mph range and locally higher over higher terrain areas. Winds are likely to peak on this evening with gusts commonly reaching 25-40 mph. These windy and dry conditions will combine with the very dry fuels to create a risk of extreme fire behavior. Temperatures will cool this weekend reaching slightly below normal levels starting Sunday and lasting into early next week. Winds are expected to gradually diminish next Monday into Tuesday.

PSR WATCHES/WARNINGS/ADVISORIES

AZ...Red Flag Warning until 8 PM MST this evening for AZZ131.

Wind Advisory from 11 AM this morning to 11 PM MST this evening for AZZ530-533.

Red Flag Warning until 8 PM MST Sunday for AZZ133.

CA...Red Flag Warning until 8 PM PDT this evening for CAZ231.

Wind Advisory from 11 AM this morning to 11 PM PDT this evening for CAZ564>567-569-570.

Wind Advisory until 11 PM PDT Sunday for CAZ562.