913
FXUS65 KPSR 080531
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1031 PM MST Sat Mar 7 2026

.UPDATE...06Z Aviation Discussion.

&&

.KEY MESSAGES...

- Breezy conditions will linger as a weather system moves
  southwest of the area and settles off the Baja California Coast
  on Sunday.

- The weather system will then pass just south of the area early
  next week, increasing chances for showers and potentially some
  thunderstorms.

- High pressure returns midweek, allowing temperatures to warm
  back up into a well above normal category, with lower desert
  highs likely reaching the nineties by Thursday.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Midlevel water vapor imagery and 500 mb RAP analysis place the
center of an upper low just off the West Coast of the northern
Baja. Height falls to the southwest have lessened, and so surface
winds have already begun to relax across the area. Gusts this
morning to between 25-40 mph were common across Southeast
California, with lighter, yet still gusty winds across portions
of South-Central AZ in a 15-30 mph range observed at times.
Ensembles remain in good agreement that the upper low will stay
far enough to the southwest on Sunday that positive midlevel
height anomalies will fill back in over the region, allowing for a
quick warmup into the 80s across the lower deserts. GFS bufr
soundings also indicate at least a weak midtropospheric inversion,
perhaps indicative of subsidence on the backside of this upper
low and aiding in warming thermal profiles. Regardless, the spread
shown in the probabilistic NBM guidance is incredibly narrow for
KPHX, yielding excellent confidence in afternoon high temperatures
achieving near 10-13F above normal for South-Central AZ and 6-10F
above normal across the western deserts (closer to the low).

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
The cut-off low will be fairly stationary over the weekend but come
Monday afternoon will begin its journey eastwards over Northern
Mexico/Southern Arizona. Moisture advection into the region
associated with this system will begin early Monday morning and will
peak Monday evening into Tuesday morning, with PWATs around
180-220% of normal. PoPs and QPF have once again increased since
the previous forecast package, however, this high run-to-run
variation could be a result of the global model`s poor handling of
this cut-off low. Despite this uncertainty, this recent shift in
guidance has resulted in a more credible thunderstorm potential
across the area. Ahead of the low, upper level diffluence and
vorticity advection may be sufficient to realize upwards of
250-500 J/kg of MLCAPE (as indicated in KYUM GFS bufr soundings)
across Southwest AZ on Monday afternoon. The eastward progression
of the low will push the thunderstorm threat over South-Central AZ
later in the afternoon into Monday evening. With these
thunderstorms, small hail will possible, with 500 mb temperatures
in a -20C to -23C range and decent instability in the hail growth
zone. Bulk shear between 30-50 kts ahead of the upper will also
be sufficient to organize a few storms. Coverage of showers/storms
is still expected to be scattered at best, and not all will see
rainfall. Locally higher totals will be possible in t-storms, but
average totals across South-Central AZ will range from 0.05-0.25",
with higher totals focused east/southeast of the Phoenix area.

As the core of the cut-off low progresses eastwards over Northern
Mexico/ Southern Arizona, temperatures will cool into the upper 70s
for Monday afternoon. Afterwards, by Tuesday evening the cut-off low
will be ejecting into Western Texas and into the Plains. Once the
low is to the region`s east, upper level ridging will take place
over the Desert SW. With strong ridging moving in, temperatures by
mid to late next week will climb to 10-15 degrees above normal, with
H5 heights above the 90th percentile of climatological normal.

&&

.AVIATION...Updated at 0530Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
A brief period of gusty E-NE winds Sunday morning will be the
primary aviation weather concern throughout the period. W-NW flow
has been observed across the metro terminals and will remain for
the next couple hours. Winds will then revert back out of the east
late tonight with speeds generally aob 10 kts, although KSDL may
see periodic gusts near 20 kts through the overnight hours. All
terminals will likely see elevated easterly flow with gusts into
the teens by Sunday morning until the sfc gradient subsides and
winds relax by the early afternoon. Skies should remain mostly
clear through the first half of Sunday before SCT mid-high lvl
clouds arrive Sunday evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
Aviation weather concerns will remain minimal through the forecast
period. Winds at KIPL will shift out of west during the overnight
hours and return to the E-SE by tomorrow afternoon. Winds should
remain N-NE at KBLH through the entire period. Speeds at both
terminals will remain generally aob 11 kts. Skies should remain
generally clear through the first half of Sunday before high
clouds begin to arrive Sunday evening.

&&

.FIRE WEATHER...
Lingering breezy winds out of a northerly to easterly direction
will continue across portions of the area as a weather system
settles west of Baja California this weekend. Dry conditions will
persist across the region with minimum relative humidity values
staying entrenched between 10-15% through Sunday, while overnight
recoveries will only reach the 30-45% range. Lingering breezy
conditions across southeast California and over higher elevations
will continue, leading to locally elevated fire weather concerns
before slight increase in moisture arrives Monday. Monday`s
weather system will help increase MinRHs to between 30-40% with
good overnight recoveries before returning to drier conditions by
the middle of the week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

SHORT TERM...Whittock
LONG TERM...Whittock/Ryan
AVIATION...Salerno
FIRE WEATHER...Whittock/Ryan

NWS Phoenix (PSR) Office