Imperial, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

606
FXUS65 KPSR 250535
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1035 PM MST Sun May 24 2026

.UPDATE...
Updated Aviation

&&

.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 0535Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will be the main weather issue though Monday evening under
periods of SCT-BKN midlevel decks. Multiple outflow boundaries have
generally resulted in S/SE winds with strong gusts across the PHX
airspace this evening. Confidence is low regarding the evolution of
wind directions into the overnight with the potential for
substantial variability (140v240) before likely settling on an east
direction well after midnight. There is a low chance (10%) for a few
showers around the airspace overnight/early morning which could
further complicate wind directions.

A period of light southerly cross runway winds are likely late
morning/early Monday afternoon before completing the switch to SW by
mid afternoon. Additional SHRA/TSRA will develop over the mountains
well north and east of the terminals, however could send a NE
outflow into parts of the Phoenix area Monday evening. Confidence
is low on how far into the metro any outflow could progress, and
whether gusts would survive this far removed from the storms.


Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues will exist through Monday night under clear
skies. Confidence is very good that wind directions at KIPL will
oscillate between a daytime SE direction and evening/overnight
westerly directions with some enhanced gustiness Monday evening.
KBLH will generally maintain a southerly component, though may have
periods of light and variable winds.


&&

.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...18
FIRE WEATHER...18