textproduct: NWS Phoenix

UPDATE

Updated 18Z Aviation Discussion.

KEY MESSAGES

- A large low pressure system will meander over California over the next couple of days leading to breezy to locally windy conditions and elevated fire weather conditions across the region.

- Below normal temperatures will be common across the region through at least the start of the weekend.

- Above normal temperatures are forecast to return by early next week with highs reaching around 100 for many locations by Sunday.

SHORT TERM /TODAY THROUGH SATURDAY/

An unseasonably strong area low pressure remains settled over Central California and Western Nevada and is expected to remain relatively stationary throughout today. By Friday the core of this system will begin to shift northeastwards over the Four Corners region and into the Central Rockies, however negative height anomalies are expected to remain over the region through Saturday. High temperatures today will be in the mid to upper 80s across much of the lower deserts while central Arizona, to include the Phoenix Metro, will be in the lower 90s. Friday's temperatures will remain fairly steady out west staying in the mid to upper 80s while central Arizona, and the Phoenix Metro, will cool into the upper 80s as the low pressure system moves eastwards just to the north of our region. These temperatures are around 10 degrees below normal for this time of year and won't last for long with Saturday expected to warm back into the low to mid 90s as H5 heights will begin to steadily increase, and will lead to tripple digits as early as Sunday across the entire lower desert region.

Breezy to windy conditions will subside around sunrise this morning and throughout the afternoon in southeastern California before picking back up in the evening through the over night hours tonight. A Wind Advisory remains in effect until 5 AM PST in the far Southwestern corner of Imperial County, then another will take effect starting tonight at 7 PM PST due to gusts expected to be as high as 55 mph. Other areas across Southeastern California will remain below advisory criteria but can still expect gusts between 20-30 mph this morning and then again late tonight.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

By this weekend temperatures will begin to warm towards normal with Sunday expected to be back in the tripple digits across the lower deserts as H5 heights begin to increase. Model guidance favors a ridge shifting westwards early next week with the axis centered through New Mexico by late Monday afternoon. While not centered over Arizona H5 heights will increase to 585-588 dam resulting in temperatures between 103F-108F starting as early as Monday and lasting through at least Wednesday before potentially cooling 1-2 degrees late next week. These temperatures will easily push our HeatRisk into the Moderate category, but relatively mild overnight lows in the upper 60s to mid 70s will help to limit the chance of reaching near the Major category. Otherwise, dry conditions with mostly clear skies through early next week.

AVIATION

Updated at 1830Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: Gusty S-SW winds this afternoon and evening, with a prolonged period with a southerly cross-runway component at KPHX, KSDL, and KDVT, will be the main weather impact through the TAF period under mostly clear skies. Expect southerly wind gusts upwards of 20 kts early afternoon before turning southwesterly later this afternoon with gusts persisting into the evening hours. Winds will go S-SE later than usual overnight tonight (08-10Z) with wind speeds aob 8 kt. Then an earlier than usual switch to SW'rly is expected tomorrow morning (15-16Z).

Southeast California/Southwest Arizona including KIPL and KBLH:

Strong wind gusts will continue to be the primary aviation weather impact through the TAF period. Winds will be westerly through the TAF period at KIPL. Gusts around 25kt is expected this evening into the overnight hours with a brief period of gusts of 30-35 kt possible between 03-07Z. Wind gusts will then die off after 08Z, but wind speeds will remain elevated (around 15 kt) through the remainder of the TAF period. S-SW winds are expected at KBLH through the overnight hours before switching to W'rly around sunrise. A period of wind gusts around 20 kt is expected this afternoon and evening. Clear skies will continue.

FIRE WEATHER

A large weather system situated over California and portions of the Desert Southwest will continue to bring breezy to locally windy conditions early this morning and again later this evening and into the overnight period. Elevated fire weather conditions will be a concern during the late evening hours with occasional wind gusts of over 25 mph and MinRHs between 12-20%. The strongest gusts of over 30-35 mph will affect portions of southeast California. Temperatures will cool off today across the western districts and eventually across the region of the area by Friday with readings stay at or below normal through Saturday. Winds are expected to diminish Thursday into Friday with overall light winds across the area by Saturday. High pressure is forecast to build across the region over the weekend into early next week leading to quick increase in temperatures and falling RHs, but winds will remain on the lighter side.

PSR WATCHES/WARNINGS/ADVISORIES

AZ...None. CA...Wind Advisory from 7 PM this evening to 5 AM PDT Friday for CAZ562.