Casa Grande, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

136
FXUS65 KPSR 142015
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
115 PM MST Thu Aug 14 2025

.KEY MESSAGES...

- Increased shower and thunderstorm chances will exist through
Friday with gusty winds, blowing dust, and lightning the greatest
threats.

- Rainfall chances decrease substantially over the weekend with
storms primarily relegated to higher terrain areas of central and
eastern Arizona.

- Temperatures will drop into a seasonal normal range through the
weekend before readings rebound back above normal by the middle of
next week.

&&

.SHORT TERM /Today through Friday/...
WV imagery and objective analysis shows the H5 subtropical anti-
cyclone having shifted into southern Colorado in response to
anomalous troughing approaching the California coast. In between
these features, two discernible MCV`s are spinning across the region
1) over NE Arizona and 2) more notably for the local CWA over
Pinal/Pima counties indicative of enhanced midlevel ascent and
moisture. While this moisture intrusion and associated lapse rates
have been insufficient in yielding little more than isolated light
showers, the resulting cloud cover has locally limited insolation
and instability early this afternoon. The overall synoptic pattern
remains favorable for sustained convection though not quite to the
same extent as yesterday; and with uncertainty tied to which areas
can clear and destabilize later today, this results in another
complex and challenging forecast.

Recent trends in satellite and high resolution models suggest
convective initiation most likely across central Pima through SW
Maricopa County this afternoon, and over recently clearing areas of
the Rim and White Mountains. Sufficient instability (greater than
1000 J/kg) should eventually be realized given a larger pool of 9-10
g/kg boundary layer mixing ratios while also incorporating DCape
values greater than 1500 J/kg. As a result, probabilities of
multiple colliding outflow boundaries are enhanced this evening
though the preponderance of HREF modeling suggest this outcome would
be later in the evening tapping elevated instability. Larger
uncertainty is tied with a more precise location where these
intersections may occur, but the scenario certainly justifies 30-40%
POPS across much of south-central Arizona through the overnight and
into Friday morning.

The overnight convective activity and outflow mixing should infuse
even better moisture profiles into the south-central Arizona
environment Friday with forecast soundings showing sfc-H7 mixing
ratios 10-11 g/kg. However, the approaching Pacific trough will
impart strengthening SW flow over this moist layer with partial top
down erosion and drying through the afternoon, despite
simultaneously steeping midlevel lapse rates and cooling of the top
of the boundary layer (a common conundrum experienced much of this
monsoon). Thermodynamic profiles actually appear quite favorable
during a small temporal window Friday afternoon with MLCape 1000-
1500 J/kg coincident with little to no CinH. Interestingly, models
initially struggle to reflect any deep convection over the CWA which
may be due to a forecast of vorticity forced ascent and robust
thunderstorm development over SE Arizona and north-central Arizona,
leaving much of the CWA temporarily under weak subsidence. Any
storms that can form Friday afternoon/evening may become quite
strong given the MLCape/DCape balance along with modest effective
deep layer shear. Shear profiles may also promote back-
building/training echoes yielding locally heavy rainfall, though
drier air and more dominant outflows would tend to preclude a more
pronounced threat.

&&

.LONG TERM /Saturday through Wednesday/...
By Saturday, the Pacific trough, which is expected to remain fairly
stationary just to our northwest will usher in drier air into our
area from west to east. This dry air will first move in aloft early
Saturday and then mix down into the boundary layer Saturday
afternoon. The lingering boundary layer moisture should be enough to
spark off some afternoon convection over higher terrain areas (20-
40% PoPs), but for the south-central Arizona lower deserts chances
will be at most 10-15%. The dry air advection will persist through
the rest of the weekend with PWATs dropping to below 1.0" again on
Sunday. This will end any rain chances across the lower deserts
leaving only very minimal chances of 10-20% over the far eastern
high terrain through Monday.

The influence of the Pacific trough will help to keep temperatures
near normal through the weekend with highs mostly between 102-105
degrees across the lower deserts. We will also see noticeably cooler
overnight temperatures as lows fall back into the 70s across the
western deserts to around 80 or the lower 80s in the Phoenix area
for Sunday and Monday mornings.

The weather pattern will begin to shift again beginning early next
week as the subtropical highs shifts westward into our region by
next Tuesday. Ensemble guidance shows the ridge center strengthening
during this time before reaching its peak at some point mid to late
next week. This will likely bring H5 heights of 595-597dm back into
our area by the middle of next week resulting in highs warming back
to around 110 degrees by next Tuesday or Wednesday. Overnight lows
will also begin to warm, but with low level moisture remaining on
the lower side readings should stay near or just above normal into
mid week. Depending on the eventual strength of the ridge, we may
end up seeing some localized Major HeatRisk again later next week.
Although still fairly uncertain, models do show some moisture
beginning to return back into the region late next week into the
following weekend.

&&

.AVIATION...Updated at 1758Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The greatest weather concern will be the chance of returning
thunderstorms late this evening from outflows. The outflows may
also interfere with routine wind shifts late tonight. There is a
low probability (~30%) of thunderstorms redeveloping across the
terminals that could see gusts near 15-25 kts starting late this
evening. Confidence is low, but expect initial VCSH around 01Z
with winds 10-15kts (with higher gusts) out of the west-
southwest. Around the 06Z timeframe winds are expected to shift
out of the east-southeast with BKN ceilings at around 12kft with
periods of VCTS (06-09Z).


Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues will exist through the forecast period
with mostly clear skies expected. Winds will follow a near
persistence forecast with directions varying between SE and SW and
gusts around 25kt common at KBLH.

&&

.FIRE WEATHER...
Thunderstorm chances will remain elevated over the eastern districts
through Friday with moderate chances of wetting rainfall,
particularly over higher terrain of Gila County. Abrupt wind shifts
with gusty outflows will be common with any storms. Temperatures
will slowly cool closer to the seasonal normal through Friday, and
in combination with better moisture profiles, afternoon humidity
levels should improve closer to a 20-30% range in eastern districts,
but remain 10-20% in western areas. Overnight recovery will vary
widely across the area from 30% to 80%. Drier air will usher back
into the area over the weekend mostly ending rain chances except for
far eastern Arizona. MinRHs will eventually lower to closer to 10-
15% by next Monday.

&&

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

&&

$$

SHORT TERM...18
LONG TERM...Kuhlman
AVIATION...Ryan/95
FIRE WEATHER...Kuhlman