501
FXUS65 KPSR 141012
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
312 AM MST Tue Jul 14 2026

.KEY MESSAGES...

- Hot and muggy conditions will continue through mid week,
  particularly across southeast California and southwest Arizona
  where Extreme Heat Warnings have been issued through Thursday.

- Shower and thunderstorms chances will be fairly limited today,
  but increase again starting Wednesday.

- A disturbance will help to bring more widespread shower and
  thunderstorm activity on Thursday and Friday with the potential
  for heavy rainfall and localized flooding over eastern and
  central Arizona.

- Temperatures will cool later this week with below normal
  temperatures across much of Arizona to near normal for southeast
  California by Friday.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
The Desert Southwest monsoon is well underway and looks to remain
active at least for the next couple of weeks. The subtropical
ridge has moved far enough to the north to allow for very good
moisture transport into the region over the past few days. Deep
moisture and conditions conducive for monsoon storms are likely to
be present for most days through the weekend and probably longer.
There are two main forecast concerns over the next several days:
First is the Extreme Heat impacting portions of the western
deserts today through Thursday, and then the heavy rain potential
for the eastern 2/3rds of Arizona starting Thursday.

Currently, a near record strength upper level ridge remains
centered over the North-central U.S., extending through the
entire central U.S. and much of the Rockies. Moist southeasterly
flow continues across Arizona and even extending as far north as
Montana. This fetch of moisture is likely to remain in place for a
good amount of time with an active eastern Pacific tropical scene
also helping to direct moisture northward through Mexico.

The convective activity on Monday was expansive enough to overturn
the atmosphere throughout much of southern and central Arizona, so
today`s convective potential will be much more limited. Forecast
temperatures today across south-central Arizona have been lowered
slightly due yesterday`s rainfall activity with some lower desert
areas not even reaching normal readings. However, the western
deserts will heat up even further today under mostly sunny skies
as highs likely reach 110 degrees. Boundary layer moisture has
also increased enough to push surface dew points into the mid 60s
to the lower 70s. This amount of moisture will somewhat curtail
temperatures, but it will make it feel much more uncomfortable as
heat indices top 110 degrees across the western lower deserts to
as high as 115 degrees in the El Centro area. Guidance indicates a
worsening of the heat across the western deserts Wednesday into
Thursday with highs peaking at 110-113 degrees, but with heat
indices as high as 113-119 degrees. An Extreme Heat Warning has
been issued for the lower deserts of southeast California and
throughout the Lower CO River Valley starting late this morning
through Thursday evening. Overnight forecast lows right around
record high minimums were also a factor in the Extreme Heat
Warning issuance.

Atmospheric instability is expected to recover starting Wednesday
with hi-res CAMs showing good coverage of afternoon convection
forming over higher terrain areas with a decent likelihood of it
moving into the lower deserts during the evening hours. As of now,
the coverage may end up being on par or even slightly better than
what occurred last evening. The upper level flow pattern later on
Wednesday should begin to become more favorable for storm
development over eastern Arizona as a large upper level low moves
eastward into Texas. The threat for any strong to severe storms
on Wednesday looks to be very marginal as forecast instability is
only around 500-750 J/kg and the winds aloft are overall weak.
However, we are more likely to see at least a minor threat of
heavy rainfall and localized flooding starting Wednesday as low
level mixing ratios remain around 11-12 g/kg and the steering flow
weakens.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Active monsoon weather is expected to continue through the period
with Thursday and Friday showing the highest potential for
impactful weather. An important ingredient for more organized
showers and thunderstorms is expected to be introduced by
Thursday. A large easterly disturbance will continue to track
across Texas into New Mexico Wednesday into Thursday before
stalling out over New Mexico on Friday. This is expected to place
at least the eastern half of Arizona in a favorable ascent region
for Thursday and Friday, and potentially into Saturday.

Thursday has the better odds of being the best convective day as
we are anticipating the highest instability to go along with the
upper level support. The amount of cloud cover on Thursday is
still a question and it very well may influence the amount of
potential instability, but forecast soundings still show upwards
of 1000 J/kg of CAPE for Phoenix. Additional moisture transport
into the region should also push PWATs to between 1.8-2.1",
suggesting heavy rainfall will an increasing threat. NBM PoPs
increase to 70-80% for eastern and south-central Arizona Thursday,
while WPC has introduced a large Slight Risk for excessive
rainfall. We will continue to monitor the latest guidance as Flood
Watches are likely to be needed for some areas later this week.
Shower and thunderstorm chances should also expand westward toward
the Lower CO River Valley Thursday night with chances continuing
areawide through at least Friday. As of now, a Slight Risk for
excessive rainfall is also present for Friday, but the uncertainty
is higher as instability is likely to be lower and the easterly
wave should begin weakening on Friday.

Abundant monsoon moisture will persist over the weekend into early
next week with day-to-day storm chances continuing, but forecast
uncertainty is quite high. Another easterly wave looks to be
possible at some point during the first half of next week which
may bring another round of higher storm/rainfall coverage.

Forecast temperatures for later this week into next week are also
of low confidence due to the expected convective potential over
much of the area. The latest NBM forecast highs show readings
dipping below normal over the south-central Arizona lower deserts
as early as Thursday, but remaining right around normal for the
western deserts. Although model forecast spread for temperatures
is quite high beginning Thursday, it seems likely the Phoenix area
will see at least a day or two in the 90s on Friday and/or Saturday.
Depending on the amount of cloud coverage and even morning/afternoon
rainfall on Friday, highs may struggle to reach the low to mid
90s.

&&

.AVIATION...Updated at 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
After widespread strong gusty winds and thunderstorm activity
earlier this evening, conditions are improving across the area.
Conditions through Tuesday afternoon should remain tranquil with
the overall wind pattern following the typical diurnal tendencies
with easterly winds overnight through early Tuesday morning
shifting out of the west late Tuesday morning/early afternoon with
some occasional afternoon gusts in the mid to upper teens. At this
time, there is a much lower chance of thunderstorm activity
Tuesday evening with a better potential of an easterly outflow
from distant activity. Outflow magnitude will be all dependent on
the overall coverage and intensity of distant storm activity. SCT
to occasional BKN mid to high clouds will prevail through the
overnight hours before coverage decreases to FEW by Tuesday
morning.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns are expected throughout the TAF period
under FEW to SCT mid to high clouds. At KIPL, light and variable
winds currently will shift out of the southeast by early Tuesday
morning and remain out of the southeast through the afternoon
hours with another temporary shift out of the west during the
early evening hours. At KBLH, winds will generally fluctuate
between the south-southeast to southwest with a period of light
variability Tuesday morning. Overall wind speeds are expected to
remain aob 10 kts.

&&

.FIRE WEATHER...
Elevated moisture levels will result in daily chances for showers
and thunderstorms over the eastern districts through Wednesday
before increasing in coverage and spreading westward late week.
Humidities will continue to improve through the rest of the week,
while temperatures eventually cool to around or even below normal
by Thursday. MinRHs are expected to hover between 20-30% over the
lower deserts to 30-40% over the AZ high terrain through Wednesday
before improving further late week. Outside of potential
thunderstorm outflows, winds will tend to be light and somewhat
favor diurnal trends.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning from 10 AM this morning to 8 PM MST
     Thursday for AZZ530-532.

CA...Extreme Heat Warning from 10 AM this morning to 8 PM PDT
     Thursday for CAZ562-563-565>567-569-570.

&&

$$

SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...Lojero
FIRE WEATHER...Kuhlman