textproduct: NWS Phoenix

KEY MESSAGES

- A weak weather disturbance will move across the region today resulting in a few higher terrain showers and temperatures settling closer to the seasonal normal.

- Dry weather with locally breezy conditions will return during the first half of next week before rain chances return by around next Wednesday or Thursday.

SHORT TERM /Today through Sunday/

A weak trough is currently progressing eastward through the Desert Southwest with upper level moisture improving since yesterday afternoon. Low level moisture remains quite sufficient from south-central and eastern Arizona, but moisture in the mid-levels is lacking. The combination of the overall weak forcing associated with the disturbance and the lack of moisture in the mid-levels is resulting in only very light high terrain showers or just virga across the area. The best chance (40-60%) for any measurable rainfall for the rest of this morning and maybe into the early afternoon hours will be across the eastern Arizona high terrain. Lower desert PoPs this morning are generally 15% or less.

Temperatures will be noticeably cooler starting today with readings failing to reach 70 degrees across the lower deserts, despite skies clearing out from west to east during the afternoon hours. As the trough axis moves into southern and central Arizona tonight into Sunday, a surface high to our north will surge southward through our area resulting in strong drying throughout the entire column. Increasing northerly winds will also be seen on Sunday, first across the Lower CO River Valley during the morning and afternoon hours and then across the Arizona high terrain by late Sunday evening. Wind gusts of 25-35 mph will be common across the Lower CO River Valley Sunday afternoon with some more limited gustiness lasting throughout the overnight hours.

LONG TERM /Monday through Friday/

The pressure gradient will remain fairly strong across the Desert Southwest on Monday as a strong high pressure ridge centered off the coast of California nudges through the Great Basin into northern portions of our region. Breezy to locally windy conditions will prevail throughout much of Monday, particularly across the Lower CO River Valley and over the Arizona higher terrain. The ridge will continue to influence the Desert Southwest into Tuesday, but any warming will remain fairly limited with highs at most reaching the lower 70s.

Model uncertainty rises considerably during the latter half of next week as a broad cut-off low, forming well to our southwest earlier in the week, begins to nudge closer to our region. Models do agree the cut-off low will eventually affect the Desert Southwest, but to what degree and when is still uncertain. Moisture may begin to advect northward into our region on Tuesday into Wednesday, but there is still high spread with even the moisture increase. Assuming moisture does eventually improve enough for rain chances to move back into the region, we may run into a lack of good forcing for any organized rainfall later next week. NBM PoPs still look to be overdone with 30-60% chances covering much of the area later Wednesday through Friday. PoPs were again pared back with this forecast package due to the uncertainty, while QPF amounts for late next week remain on the light side. The unsettled weather pattern for the latter half of next week should keep temperatures at or just above normal readings.

AVIATION

Updated at 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation weather concerns expected through the TAF period. Winds throughout the period will be predominantly out of the west with speeds generally below 10 kts. BKN to occasionally OVC mid to high clouds with the lowest bases between 6-8 kft will prevail into Saturday morning before scattering out by the afternoon hours.

Southeast California/Southwest Arizona including KIPL and KBLH: No major aviation concerns are expected through the TAF period. Wind directions will generally be out of the W-NW throughout the period with speeds generally aob 10 kts. SCT-BKN mid to high clouds can be expected through Saturday morning before skies clear out during the afternoon hours. There will be a period of SCT lower-level clouds between 5-7 kft through early Saturday morning.

FIRE WEATHER

A weak weather system pushing through the region today will bring cooler temperatures and chances for light rain over high terrain areas of the eastern districts. Minimum humidity levels 40-70% today will quickly tumble into a 20-30% range Sunday. Light winds today will begin increasing Sunday, especially through the lower CO River valley where gusts in excess of 25-30 mph will be common Sunday afternoon. Breezy to locally windy conditions will prevail across the Lower CO River Valley and over the Arizona high terrain on Monday before diminishing into Tuesday. MinRHs will stay quite low early next week, bottoming out on Monday between 15-20% across the lower deserts. Moisture will begin to seep back into the region during the midweek raising humidities and bringing rain chances by around Thursday.

PSR WATCHES/WARNINGS/ADVISORIES

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