textproduct: NWS Phoenix

UPDATE

Updated 12Z Aviation Discussion.

KEY MESSAGES

- Much quieter weather is expected today into Saturday with only a slight chance of a few showers over the central Arizona high terrain.

- Below normal temperatures through early next week will warm closer to the seasonal average by the middle of next week as dry conditions prevail across the region.

SHORT TERM /Today through Saturday/

The strong weather system that brought severe weather to portions of the Desert Southwest over the past couple of days is now progressing far enough to the northeast to allow for strong drying through Arizona. This has led to an end to the shower activity and clearing skies for much of the area. A cooler air mass has also settled into the region and with the mostly clear skies tonight, overnight lows should dip into the 50s for all of the lower deserts except for the urban core of Phoenix.

Even though the main cold front has pushed through the area, the upper level trough will remain entrenched across the Southwestern U.S. through Saturday. The low center is currently situated over Nevada with some residual moisture still spinning around the low. Guidance shows the main energy within the low still ejecting to the northeast away from our region today, but another shortwave or two is expected to swing back into our region tonight into Saturday from the northwest. This should form another low center somewhere over southern California tonight before turning east through Arizona on Saturday, but not much is expected to come from its passage. The latest CAMs are hinting as some isolated showers developing Saturday afternoon over the high terrain north of Phoenix, but given the expected overall low moisture environment (low level mixing ratios of 5-6 g/kg) rain chances will essentially be zero over the lower deserts. Saturday should bring some afternoon mid-level CU for south-central Arizona, but overall our weather conditions will remain quiet with afternoon highs in the mid to upper 70s in Phoenix to as warm as the lower 80s in southeast California.

LONG TERM /Sunday through Thursday/

The benign weather conditions will continue to prevail well into next week with the lingering trough finally moving out of the region on Sunday and being replaced by weak ridging to zonal westerly flow. This pattern shift will lead to continued mostly clear skies and dry conditions, while allowing temperatures to gradually warm back into the normal range by the middle of next week. Expect the bulk of the lower deserts to have daily highs in the low to possibly mid 80s and lows from the mid 50s to mid 60s during the first half of next week. Model uncertainty comes into play later next week as there are hints at some moisture return into the region out of the southeast and then a potential atmospheric river approaching by next weekend. Either or both of these moisture sources may eventually help to bring a return to rain chances at some point before the end of the month, but it is too early to have a good idea on timing and/or placement for any weather systems over a week out.

AVIATION

Updated at 1116Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No aviation weather concerns are expected through the forecast period under mostly clear skies and with light winds, mostly staying below 7 kts. Typical diurnal wind patterns are favored, however, the wind direction is expected to remain W'rly at KPHX this morning and not shift E. E winds will develop at all terminals later tonight.

Southeast California/Southwest Arizona including KIPL and KBLH: No aviation weather concerns are anticipated through the forecast period under mostly clear skies. Winds will favor a westerly component at KIPL through the TAF period and west this morning at KBLH before veering NW-N this afternoon. Speeds should remain light around 5-7 kts or lower.

FIRE WEATHER

Drier air has spread through the area since yesterday morning resulting in clearing skies and an end to the rain chances. The weather system will still linger across the region over the next couple of days bringing light shower chances to mountain areas Saturday, but no wetting rainfall is expected. Minimum humidity levels will fall into a 25-50% range following good to excellent overnight recovery. Light winds are forecast for today and for much of the area on Saturday with only some breeziness possible early Saturday across the western districts. Overall quiet weather conditions are forecast Sunday into next week with fairly stable humidities and temperatures rebounding back into the normal range by around Tuesday.

PSR WATCHES/WARNINGS/ADVISORIES

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