557
FXUS65 KPSR 162235
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
335 PM MST Wed Jul 16 2025

.KEY MESSAGES...

- Chances for scattered showers and isolated thunderstorms will
  continue through Thursday with the best chances likely focused
  over higher terrain areas.

- Drier conditions by the weekend should limit any rain chances to
  the eastern Arizona high terrain.

- Below normal temperatures continue tomorrow before gradually
  warming back into the normal range starting Friday.

&&

.SHORT TERM /Today through Thursday/...
Early this afternoon objective analysis shows there is a ruminant
MCV in southern AZ, leftover from yesterday`s activity down in
Tucson. This MCV has caused an abundance of cloud cover over
south-central AZ, including the Phoenix Metro. Despite a decent
amount of moisture, PWATS of 1.7-1.8", this cloud clover has
severely limited shower and storm chances for the Phoenix Metro
this afternoon and evening. The MCV will meander
north/northwestward tonight and eventually get wrapped up into the
closed low, that is off the coast of the Baja California Peninsula,
early tomorrow morning. Showers and a few storms, associated with
the MCV, are expected to develop as the MCV moves northwestward
tonight. Showers and storms are expected to linger through
tomorrow morning, with most activity in La Paz and western
Maricopa Counties. PoPs are generally around 35% or less for the
Phoenix Metro through tomorrow morning, with western portions of
the Metro having the best chances of seeing some activity. As for
thunderstorm chances tonight there is minimal instability, the
SPC Mesoscale Analysis page shows MUCAPE values around 250-500
J/kg with some pockets of 1000 J/kg out there, but the Phoenix
Metro area is currently capped.

Drier air will start to move into the region tomorrow evening.
While there is a slight chance (<30%) for some showers and storms
in the lower deserts of south-central AZ, but most of the activity
will be confined to the higher terrain areas. The lower desert
chances will depend on how quickly the drier air moves in and if
there is any forcing to help get storms going. NBM PoPs came in
high again, so we did lower them again.

Temperature wise the abundance of clouds will keep temperatures on
the cooler side, especially for this time of year. As of 2pm, the
current temperature at Phoenix Sky Harbor was 92 degrees. And with
cloud cover increasing this afternoon, it is likely that we will
not reach 100 degrees this afternoon. Other lower desert locations
in SE CA and SW AZ, where there is no/minimal cloud cover, have
already reached into the low 100s and should top out near or
slightly below normal. An abundance of cloud cover again tomorrow
should also keep temperatures well below normal (upper 90s to low
100s across the lower deserts).

&&

.LONG TERM /Friday through Tuesday/...
The upper level low is forecast to move northward Thursday into
Friday likely reaching southern California during the daytime
hours Friday. Dry air is currently wrapping around this low and as
it moves into our area, this dry air will add to the already
drying conditions. As PWATs drop to around 1.1-1.3" on Friday, the
chances for rain will continue to diminish. We may be able to
squeak out some isolated showers or a weak storm or two across
southwest Arizona and south-central Arizona, but PoPs are mostly
below 20%. Lingering moisture over the Arizona higher terrain
should allow for some afternoon scattered showers and isolated
thunderstorms, but we are not expecting much from this activity.

Temperatures will also begin to warm up starting Friday as we will
lose most of our cloud cover. Forecast highs Friday fall just
short of normals by a degree or two. Models are a bit uncertain
with how fast to kick out the upper level low, or even it does at
all, but they do agree it will weaken quickly Friday into
Saturday. By Saturday, the subtropical ridge centered over the
Southern Plains will begin to influence our region a bit more
helping to push temperatures back into the normal range.
Fortunately, the high is likely to stay displaced well to our
east through at least the first part of next week, so temperatures
are not likely to warm past normal levels. Moisture levels over
eastern Arizona may also stay high enough for some isolated
afternoon convection each day starting this weekend, but chances
over the lower deserts should mostly remain below 10%.

&&

.AVIATION...Updated at 1815Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
Mostly showers to the south of all terminals continue to creep
northward but weakening, thus VCSH chances remain too low (10-20%
scattered showers) to mention in this current forecast package.
Mainly southerly winds with periodic gustiness up to 20 kts
fluctuating 140v190 over the last few hours will eventually turn
primarily out of the westerly direction this afternoon.

Tonight, higher potential for VCSH conditions are advertised due
to overnight scattered showers anticipated to develop, with
chances for SHRA across the Greater Phoenix Area around 30-40%.
The latest HREF guidance is a bit more robust with convection in
the higher terrain areas, thus confidence in this scenario is a
bit higher than previous forecasts. Though winds will likely
maintain a W/NW configuration during the overnight hours, nearby
SHRA activity could produce brief erratic behavior, especially if
the uptick in afternoon convection in the higher terrain comes to
fruition and sends outflows from the north. SCT to BKN cloud
decks AOA 8 kft will be common through tonight, but hints of some
FEW-SCT down to around 6 kt may linger through the morning hours
tomorrow.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns are expected throughout the TAF
period under mostly clear skies and gradually increasing coverage
of mid level clouds overnight into early Thursday morning. Winds
will generally be out of the east to southeast at KIPL and out of
the south at KBLH. Wind gusts upwards of 20-25 kts can be expected
at times once again Wednesday afternoon/evening, with the
strongest gusts mainly at KBLH.

&&

.FIRE WEATHER...
Increased moisture and cooler temperatures are continue through
tomorrow with scattered showers and isolated thunderstorms
primarily focused over higher terrain areas. Drying conditions
begin tomorrow evening and continue into the weekend. These drying
conditions will end almost any rain or storm chances across the
lower deserts. Afternoon MinRHs will be between 25-30% tomorrow
before dropping closer to 20% by Friday. Expect south southeasterly
gusts of 20-30 mph this afternoon and evening over the CO River
Valley before dropping off tomorrow with more diurnal lighter
winds over the eastern districts. High pressure will return to
the region this weekend with RHs dropping back into the teens,
temperatures returning to near normal, and rain chances ending for
all but the higher terrain.

&&

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

$$

SHORT TERM...Berislavich
LONG TERM...Kuhlman
AVIATION...Young/Whittock
FIRE WEATHER...Berislavich/Kuhlman