San Luis, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

894
FXUS65 KPSR 242350
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
450 PM MST Sun May 24 2026

.UPDATE...Updated 00Z Aviation Discussion.

&&

.KEY MESSAGES...

- A chance of showers and a few thunderstorms will exist over
  areas south and east of Phoenix tonight and Monday, albeit with
  limited rainfall potential.

- Showers and storms that form late this afternoon into the
  evening will be capable of producing locally strong, gusty winds
  and blowing dust, with the greatest risk over Pinal County.

- Increasing wind speeds with occasionally stronger gusts will
  develop across parts of the area through the middle of the week.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...
Early afternoon water vapor and visible satellite imagery
indicate an increase in midlevel moisture across eastern/northern
portions of AZ aided by southerly flow aloft, as cumulus decks
continue to expand and begin to vertically develop over and
downstream of ridgetops and other prominent terrain features. This
southerly flow has developed ahead of a subtropical jet streak,
intensifying as it punches onshore along the Baja Peninsula, with
an attendant upper low approaching SoCal/Northern Baja at this
hour. As the system draws near, the forecast area will fall under
the left front quadrant of the jet streak with excellent upper
level divergence noted, providing for strong ascent (likely
maximized sometime tonight into early Monday morning). However,
moisture will be a huge limiting factor for accumulating
precipitation through the next 24- 36 hours. In GFS bufr soundings
for KTUS, KPHX, and even the Globe, AZ area, only a relatively
shallow saturated layer above 650-700 mb can be seen at times,
with a deep, dry sub-cloud layer. Latest HREF membership continues
to show showers and storms forming across Santa Cruz and Eastern
Pima Counties over the next few hours, with activity pushing
northward with time and sending a quasi-organized outflow into
northern Pinal County late afternoon/early evening which could
conceivably import some lofted dust towards the Phoenix metro.
HREF neighborhood (within 25 miles) probabilities also indicate a
50% chance for wind gusts in excess of 30 kts near storms,
focused over Pinal County between 4-8 PM MST today. A few residual
isolated showers would not be out of the question across the
Greater Phoenix Area this evening, but these would tend to become
focused over higher terrain areas to the east of Phoenix later on.

As the core of the upper low draws overhead Monday, lapse rates
will steepen more noticeably resulting in better instability.
Latest HREF membership and GFS bufr soundings for Globe, AZ
indicate MUCAPEs peaking over the eastern CWA mid-late Monday
morning upwards of 200- 500 J/kg. With a lesser sub-cloud dry
layer over high terrain locations and the best ascent occurring
overnight, the opportunity for rainfall will increase through
Monday morning in Gila County. However for the most part, HREF
mean QPF barely eclipses 0.01" though persistent robust moist
ascent in the midlevels will ensure several opportunities for
minor accumulations. Additional deep convection may erupt later
Monday afternoon with peak heating and lingering midlevel moisture
with dry lightning and gusty outflow winds the greatest threat.
However, any activity should be short- lived as dry air and
subsidence arriving behind a passing trough axis shuts down the
threat by Monday evening.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
There is now resounding agreement among the full suite of
ensembles that deep negative height anomalies entering the Pacific
NW will descend into central/southern Nevada midweek as the North
American flow pattern evolves into a high amplitude block. This
evolution will favor the development of a large cutoff temporarily
stalling just NW of the forecast area before filling and lifting
into the northern Rockies late in the week. Temperatures may cool
as much as 5F-10F below normal during the middle of the week, and
narrowing numerical guidance spread yields improved forecast
confidence. Prevailing deep westerly flow will ensure dry weather
through this period despite the cold core aloft skirting the
northwest parts of the CWA.

The most impactful aspect of this system should be increased wind
speeds as a strong jet core and seasonally impressive height falls
surge into the region. The initial round of height falls and leading
edge of stronger jet winds will punch into southern California late
Tuesday, then sweep across the entire CWA on Wednesday. This setup
along with the deepening windward marine layer and potential passage
of a midtropospheric front will favor strong sundowner winds and
possible mountain rotors and hydraulic jumps across western Imperial
County Tuesday and Wednesday where advisories may be necessary.
Otherwise, deep mechanical mixing should tap higher momentum 20-30kt
winds through the boundary layer across the entire CWA Wednesday
afternoon resulting in an enhanced fire danger given fairly low
humidity levels and very receptive dry fuels. As midlevel heights
start filling and the cold core slowly lifts north Thursday and
Friday, wind speeds will gradually relax while temperatures edge
higher.

&&

.AVIATION...Updated at 2350Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Main aviation weather impact and forecast uncertainty is the
potential for brief elevated wind gusts and a sudden wind shift
from an outflow boundary this evening. Guidance continues to
support an outflow boundary arriving from the south around 03-04Z
this evening, however guidance has backed off on the intensity and
thus the boundary may only lead to a brief S-SE wind shift. Wind
directions may go from W-SE-W within an hour window. Odds of
visibility restrictions from blowing dust is low, but hazy skies
cannot be ruled out. Winds should otherwise follow typical diurnal
trends, similar to the previous few days.There is a low chance
(10%) for a few weak vicinity showers early Monday morning, mainly
between 09-12Z. Additional showers and storms Monday, through the
afternoon, will stay east and northeast of terminals. FEW to SCT
clouds around 10-12K ft AGL will be common through Monday morning.

Southeast California/Southwest Arizona including KIPL and KBLH:

No major aviation weather concerns under mostly clear skies can
be expected throughout the TAF period. At KIPL, winds will
continue out of an easterly direction ahead of a westerly shift
this evening. Westerly will prevail through the night and then may
trend toward a S-SE component during the day Monday. At KBLH,
winds will generally fluctuate between the south and southwest,
with periods of light variability. Overall wind speeds will range
between 6-12 kts, with some occasional afternoon and evening
gusts upwards of 20 kts.


&&

.FIRE WEATHER...
Slightly above normal temperatures will briefly cool into a below
normal category during the middle of the week. Minimum afternoon
humidity levels will fall into a 10-20% range with mostly fair to
good overnight recovery of 30-50%, though some areas will
occasionally only reach poor recovery near 20% at times. An increase
in midlevel moisture late this afternoon will result in a slight
chance for showers/thunderstorms in southern Arizona leading to
locally gusty outflow winds and the potential for a few lightning
strikes moving towards southern Gila County. A 20% thunderstorm
threat will continue in far eastern districts Monday though limited
accumulating rainfall should be anticipated, and the threat for new
wildfire starts due to lightning strikes will be heightened. Typical
afternoon upslope gustiness of 15-25 mph will be common early this
week with speeds increasing markedly during the middle of the week.
Stronger gusts over eastern district high terrain and through the
lower Colorado River valley Wednesday combined with low RH and dry
fuels will result in an elevated fire danger, though cooler
temperatures and higher humidity level may preclude critical
conditions.

&&

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

$$

SHORT TERM...Whittock/18
LONG TERM...18
AVIATION...Lojero
FIRE WEATHER...18