474
FXUS65 KPSR 111019
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
319 AM MST Fri Jul 11 2025

.KEY MESSAGES...

- Dry conditions will prevail across the forecast area through
  the next several days with only isolated thunderstorm activity
  over the Eastern Arizona high terrain this weekend.

- Temperatures will be fairly stable through early this upcoming
  workweek, generally a few degrees above daily normals, with
  lower desert highs around 105 to 110 degrees.

- A better monsoon pattern for South Central Arizona sets up
  during the upcoming workweek, allowing thunderstorm activity to
  increase over the Eastern Arizona high terrain initially and
  introducing slight chances for lower desert storms by the latter
  half of the week.


&&

.SHORT TERM /TODAY THROUGH SATURDAY/...
The zonally elongated subtropical high that sat almost directly
overhead yesterday continues to retrograde westward early this
morning, with current 500 mb RAP analysis placing its center just
off the Northern Baja/SoCal Coast. With the influence of the high
diminishing as it slides off to the west, a fairly strong gulf
surge was able to occur, spreading over South-Central AZ and
helping to increase dewpoint temperatures upwards of 60-65F so far
early this morning. Further west across the Yuma area and
Imperial Valley, dewpoint temperatures in excess of 70F have been
observed. Though this is quite a shallow layer of moisture,
radiative cooling at the surface will not be as efficient, making
for another unusually warm morning. Forecast morning lows across
the lower deserts are in the 80s and even lower 90s in central
Phoenix this morning. Though different models show some
discrepancies in the exact placement and strength of the
aforementioned subtropical high as we head into this weekend, H5
heights are likely to fall in a 592-595 dam range through the next
few days, maintaining slightly above average values for the time
of year. This will translate to afternoon highs generally a few
degrees above daily normals today and Saturday, around 105-110 for
the lower deserts.

Thunderstorm activity will remain minimal across the state
through Saturday, with the latest HREF membership showing
essentially no convection this afternoon except near the
international border in Cochise County. This is in large part due
to dry, west northwest flow aloft today that will turn more
northerly by Saturday, effectively scouring out moisture in the
midlevels. In fact, PWATs are expected to drop below one inch
across the entire forecast area by late Saturday. Despite this
fact, some lingering low level moisture looks like it will be
sufficient to spark high terrain convection Saturday along the
Rim, White Mountains, and far Southeast AZ, but quite isolated in
coverage.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
By Sunday, ensembles hint at another high beginning to develop
north of the area, turning the midlevel flow from north to
northeasterly. This second high will likely develop into a Four
Corners high later in the week. Latest guidance suggests a slight
uptick in afternoon thunderstorm activity over the Eastern AZ high
terrain Sunday, with a similar level of activity being maintained
each day through Tuesday. Meanwhile, ensembles show PWATs
gradually increasing over Southern AZ, with mean values upwards of
1.25-1.50" by the middle of the upcoming workweek. This would
lead to gradually increasing convective coverage over the
Southeastern third of the state. By Wednesday-Thursday, the high
pressure aloft is also anticipated to slide over the Four Corners,
which would help turn the flow east and then southeast over the
forecast area. This could prove a much more favorable setup for
monsoon thunderstorm activity for South-Central AZ in this
situation, as we start the week rather moisture-starved, and
better quality moisture will be situated to the south. With this
evolution in mind, convective coverage will be on the increase
across the higher terrain and foothills initially before chances
increase across the lower deserts, more likely by the latter half
of the week. A lot of details are still uncertain this far out,
but the preponderance of ensemble guidance would suggest that some
monsoon thunderstorm impacts (likely strong, gusty outflow winds
and dust at first) will be possible across South-Central AZ late
next week.

Temperatures will moderate closer to mid-July normals by the
middle of the upcoming workweek as moisture gradually increases
and H5 heights aloft fluctuate around 591 dam, near the
climatological average for this time of year. As such, the latest
NBM shows a continuation of lower desert highs in a 105-110 degree
range through Monday, dropping into a 102-108 degree range by
midweek.

&&

.AVIATION...Updated at 0505Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No major aviation concerns are expected during the TAF period
under mostly clear skies. Winds will follow familiar diurnal
patterns, with some occasional breeziness tonight and once again
tomorrow afternoon. The usual E`rly shift at KPHX still appears
uncertain, but if one were to occur, it will be relatively brief.
Otherwise, W`rly winds will prevail through Friday evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns are expected over the next 24 hours
under mostly clear skies. Sustained winds at KBLH should remain
relatively elevated through tomorrow afternoon evening, with a
couple period of gusts, some occasionally occurring during the
morning hours, and once again Friday afternoon. Weaker winds are
anticipated at KIPL. Familiar diurnal patterns direction wise
will prevail.

&&

.FIRE WEATHER...
Above normal temperatures and dry conditions will persist through
the weekend. This afternoon, gusts upwards of 25-30 mph will be
mostly confined to the high terrain of the eastern districts.
Elsewhere, anticipate typical afternoon upslope breeziness for the
time of year. Afternoon minRHs will generally bottom out between
15-20% areawide today and Saturday, and overnight recoveries will
generally range between 40-60% tonight and drop to 30-50% Saturday
night. Very minimal rain chances will exist through this weekend,
with activity focused mainly across the Eastern AZ high terrain
and southeastern third of AZ, with CWR <10%.

&&

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

$$

SHORT TERM...Whittock
LONG TERM...Whittock
AVIATION...RW
FIRE WEATHER...Whittock