San Luis, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

694
FXUS65 KPSR 021104
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
404 AM MST Mon Feb 2 2026

.UPDATE...Updated 12z Aviation Discussion...

&&

.KEY MESSAGES...

- Dry conditions and well above normal temperatures will continue
  to prevail this week.

- A period of breezy northeasterly to easterly winds will return
  for Wednesday and Thursday.

- A pattern change looks likely starting early next week which
  could bring much cooler temperatures and precipitation chances.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
The strong upper level ridge that brought a record daily high for
Phoenix on Sunday has moved to the east with very broad upper
level cyclonic flow attempting to move into our region from the
southwest. The slight dip in upper level heights as well as some
periodic high clouds today will help to bring daytime highs back
to around or just below 80 degrees. Even with this noticeable
cooling, highs will still top out at around 10 degrees above
normal.

The brief dip in temperatures will however not last long as the
next strong ridge is already taking shape off the California
coast. Guidance continues to show this feature sliding eastward
and becoming the dominant feature for the bulk of the Western U.S.
starting Tuesday. The ridge is also forecast to strengthen enough
to put the entire Western CONUS above the 90th percentile of
climatology for H5 heights on Wednesday. The core of the ridge
will be well to our north (northern CA, northern NV), but it will
still allow for another good rise in temperatures Tuesday into
Wednesday for our area. NBM forecast highs show lower desert
readings topping out in the lower 80s on Tuesday before peaking
between 82-85 degrees Wednesday. A return of easterly downslope
winds across south-central Arizona on Wednesday very well could
push a few Phoenix locations above 85 degrees. The latest NBM
probabilities show nearly a 50% chance Phoenix will tie the daily
record of 86 degrees on Wednesday.

&&

.LONG TERM /THURSDAY THROUGH NEXT MONDAY/...
The brief Rex block set up for Tuesday and Wednesday is expected
to break down somewhat by Thursday as an upstream kicker trough
moves toward the Pacific Northwest and northern California coast.
A weak cut-off low west of Baja midweek is also shown to open up
and move north northeastward Thursday into Friday, moving across
at least western portions of our region. This disturbance will
help to bring an good amount of higher level moisture and clouds
into our region on Thursday, but nearly all indications keep very
dry air in place below 10K feet. The most optimistic ensemble
members do show a chance of some light high-based showers over
higher terrain areas Thursday night into Friday, but PoPs remain
below 5%. Lowering heights along with the clouds late week are
likely to drop daytime highs back down to around or just below 80
degrees starting Thursday.

Model guidance is starting to come to a better consensus for the
upcoming weekend with the kicker trough and the weakening cut-off
low feature merging by Saturday, likely along the California coast
or just to the west. Much like the past several weak systems,
this next one for the upcoming weekend is likely to be mostly cut
off from the main flow. At the moment ensembles generally agree
this system will form and become a closed low somewhere to our
southwest by the weekend and mostly pass to our south. Even with a
track to our south, it should at least result in an increase in
moisture across our region. However, so far models show the
moisture advection will not be enough to bring much in the way of
any precipitation chances over the weekend.

Long range model output is starting to show some positive signs of
a pattern adjustment for next week with at least a 50% probability
of a deeper and colder trough developing across the Southwestern
U.S. at some point during the first half of next week. If this
holds true, we should see some PoPs appearing in the forecast soon
along with a more meaningful cooling trend next week.

&&

.AVIATION...Updated at 1100Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No aviation weather concerns expected throughout the TAF period.
The overall wind pattern will follow light and diurnal tendencies
with speeds aob 7 kts along with extended periods of variable to
calm conditions. SCT to occasionally BKN high cirrus will stream
across the region throughout the period.

&&

.FIRE WEATHER...
Well above normal temperatures and dry conditions will persist
this week. Humidities will remain quite low with with afternoon
minRHs commonly between 12-20% range areawide. Overnight
recoveries will remain fair to poor with humidities generally
topping out in a 35-55% range. Light and mostly terrain driven
winds will prevail into Tuesday before the weather pattern again
supports breezy northeasterly to easterly winds mid to late week.

&&

.CLIMATE...Phoenix, AZ Daily Record High Temperatures.

2/2  82 (2025)
2/3  86 (2025)
2/4  86 (2025)
2/5  87 (1963)

&&

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

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Lojero
FIRE WEATHER...Whittock/Kuhlman
CLIMATE...Benedict