textproduct: NWS Phoenix

SYNOPSIS

The weather pattern through the upcoming weekend will keep any weak weather disturbances just to the north of the region, but we will see periods of higher level clouds. Temperatures will initially be on the cooler side through Friday, but overall still a few degrees above normal. High pressure will then become more dominant over our region by Sunday into early next week leading to slightly warmer temperatures and lower desert highs reaching to near 75 degrees. Dry conditions will also continue to prevail with no chances for precipitation through next week.

DISCUSSION

The dry weather system that moved across northern portions of the region yesterday is now moving across the panhandle of Texas with weak ridging currently moving quickly through the Desert Southwest. A larger weather system is also coming ashore across the Pacific Northwest with yet another atmospheric river impacting northern California and the Pacific Northwest. This moist Pacific trough is being supported by a strong west to east oriented polar jet. This jet is forecast to continue to pump moisture into the aforementioned areas through the upcoming weekend with a good deal of upper level moisture and clouds spreading into our region. Despite the upper level moisture affecting our region, our weather will remain quiet as the bulk of the shortwave energy will bypass our region to the north. However, guidance does show the trailing end of the shortwaves for this afternoon and again Friday afternoon bringing a narrow band of mid-level moisture through the northeastern half of Arizona. The moisture will mainly be above 15k feet, but it may be enough to bring a band of virga showers or some sprinkles to the Arizona high country. The clouds and the northwesterly flow aloft will help to keep temperatures from warming up much through Friday with highs mainly in the upper 60s.

By the weekend, a fairly strong high pressure ridge centered to our southwest will edge eastward into our region raising H5 heights from the current 572-576dm range to 580-584dm. Even with the ridge moving in on Saturday, we will continue to see higher level moisture and clouds spilling into the ridge from the northwest keeping temperatures from rising much on Saturday. Starting Sunday, we should lose this upper level moisture feed resulting in sunny skies and better warming conditions. This should help to push daytime highs into the mid 70s on Sunday and likely into Monday before a slight cooling trend commences as the ridge gets pushed back to the south of our region. Ensemble guidance then supports more of a zonal westerly flow impacting the Western U.S. going into the middle of next week with a couple weak shortwaves passing through the Great Basin and/or the Northern Rockies. Losing the support of the high pressure ridge will knock temperatures down a few degrees starting Tuesday, but lower desert highs are still forecast to top 70 degrees through the middle of next week. Looking out even further, there is good model support for another ridge to build over the Southwestern U.S. late next week, likely pushing daytime highs back into the mid 70s. The extended outlook also shows no support for any precipitation chances across our region through at least next week.

AVIATION

Updated at 0520Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation concerns are anticipated through the forecast period. Winds have shifted out of the E and will remain light with speeds aob 7 kts overnight. Winds will return out of the WSW at all terminals between 19Z-21Z tomorrow afternoon. SCT high clouds will continue to overspread the region tonight before increasing in coverage to BKN tomorrow morning with bases aoa 15 kft.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns are expected through the forecast period. Winds will remain out of the W-NW at both terminals tonight with speeds aob 8 kts. Winds will likely become NW at KIPL and N at KBLH early tomorrow. SCT high clouds will gradually become BKN over SE California by sunrise tomorrow.

FIRE WEATHER

The weather pattern for the rest of the week will continue to promote dry conditions with slightly above temperatures and periods of higher level clouds. Humidities will remain stable with MinRHs between 20-30% over the majority of the area. Overall light winds generally following diurnal patterns are also expected. Stronger high pressure is then anticipated to move into the region this weekend into early next week bringing even warmer temperatures with humidities gradually decreasing closer to 15% across the lower deserts.

PSR WATCHES/WARNINGS/ADVISORIES

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