697
FXUS65 KPSR 230810
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
110 AM MST Thu Jul 23 2026

.KEY MESSAGES...

- Temperatures much above normal will persist through the weekend
with readings approaching near record levels resulting in Extreme
Heat Warnings.

- The high pressure system responsible for the extreme heat will
also restrict thunderstorm development with chances retreating into
the mountains through the end of the week.

- Above normal temperatures should cool slightly early next week as
increased thunderstorm coverage returns to the region.

&&

.SHORT TERM /Today through Saturday/...
Early morning WV imagery and objective analysis depicts a
retrogressive anti-cyclone over west Texas while the easterly
cyclonic wave that passed through the region earlier in the week has
lifted into northern Colorado. This places the region under a more
subsident regime with some modest drying aloft as total column PWATs
slowly deteriorate. While current boundary layer mixing ratios sit
around 10-12 g/kg, even these levels will be pushed closer to 8-10
g/kg the next few days. As warmer temperatures aloft advect into the
area with subtropical ridging building into Arizona, instability
will be reduced while adding substantial convective inhibition. HREF
members suggest a few pop-up pulse showers/storms over the most
favored locations today and Friday, though chances are essentially
under 10%. As the center of the anti-cyclone migrates north into the
four corners over the weekend, this will allow easterly waves and
better convective potential to return to east/southeast Arizona.
While distinct differences in thunderstorm coverage among models
exists, there is sufficient evidence that more aggressive outflows
and isolated storms descend into lower elevations.

Models remain in good agreement showing a 598dm H5 anti-cyclone
center becoming situated over western New Mexico on Friday with 596-
598dm readings across the forecast area. This will easily result in
widespread major HeatRisk with afternoon highs 5F-10F above the
daily normals Friday and Saturday. Numerical guidance spread still
exhibits a wider than expected range likely due to uncertainty in
surface dewpoints. With the expectation of boundary layer moisture
lingering through the weekend, official NBM 50th percentile
forecasts are likely sufficient, though some areas that may scour
away moisture could achieve levels closer to the 75th percentile of
the full ensemble envelop (i.e. some lower deserts locations 115F to
120F). Regardless, the hottest temperatures will settle over the
region Friday and Saturday with excellent forecast confidence of
most lower desert communities reaching or exceeding 115F. Even some
higher elevation valley population centers in Gila County will
attain major HeatRisk Saturday, and the Extreme Heat Warning has
been expanded in these locations prior to better thunderstorm
potential Saturday evening.

&&

.LONG TERM /Sunday through Wednesday/...
During the first half of next week, the anti-cyclone center will
propagate across the four corners into central Colorado allowing
enhanced easterly flow and better chances of inverted shortwaves
entering the SW Conus. However, there is considerable uncertainty
regarding the timing and location of any particular feature which
would enhance thunderstorm chances, not to mention mesoscale details
from decayed convective complexes which further complicates the
forecast. However, as early as Saturday night, long tracking, strong
outflows may be sufficient to incur isolated storm development over
lower elevations, while deepening moisture profiles, increasing
total column PWATs, and setting the stage for enhanced convective
coverage on following days. Various modeling suites highlight
different days with a more preferred chance of storms sweeping into
lower elevations early next week, but all models indicate at least
one easterly wave influencing enhanced activity.

This easterly flow will also help erode higher midlevel heights and
temperatures; and combined with the convective influences, may
significantly reduce and complicate heat related impacts. A growing
trend in models shows outflows and convection rapidly cooling
temperatures across Arizona early in the week such that by Monday,
readings return to normal levels. GFS BUFR soundings are even more
aggressive towards outflows affecting temperatures suggesting
extensive cloud cover much of the day Sunday, and readings falling
well short of 110F. Not putting too much stock in these types of
details 3-4 days in advance, but certainly the pattern supports this
evolution where somewhat lower temperatures and a return to only
moderate HeatRisk arrives quicker than previously forecast.

&&

.AVIATION...Updated at 0500Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation weather concerns are expected throughout the TAF
period. The overall wind pattern will continue to favor light and
diurnal tendencies along with extended periods of variable
conditions. FEW to occasionally SCT mid to high level cloud decks
with bases as low as 10 kft will be common throughout the period.


Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns under a FEW mid to high level
cloud decks are expected throughout the TAF period. The overall wind
pattern will favor light and diurnal tendencies along with extended
periods of variable conditions.

&&

.FIRE WEATHER...
Thunderstorm chances will remain quite low the rest of the week with
only slight chances remaining over high terrain areas of far eastern
districts. Better chances for more expansive storm coverage and
wetting rainfall will arrive next week. Temperatures will warm
significantly with much above normal readings resulting in Extreme
Heat Warnings for lower elevations and foothill locations. Despite
the warmer and drier conditions, humidity levels will not fall
substantially with minimum afternoon readings in a 10-25% range
improving closer to 15-30% next week. Correspondingly, overnight
recovery will mostly be in a fair to good range of 30-60% with
somewhat higher values next week. Winds should be fairly light
through the period with only local afternoon gusts 20-25 mph.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Monday for AZZ530-532.

     Extreme Heat Warning from 10 AM this morning to 8 PM MST Monday
     for AZZ531-533>555-559.

     Extreme Heat Warning from 10 AM Friday to 8 PM MST Saturday for
     AZZ556-560>562.

CA...Extreme Heat Warning until 8 PM PDT Monday for CAZ562>570.

     Extreme Heat Warning from 10 AM this morning to 8 PM PDT Monday
     for CAZ560-561.

&&

$$

SHORT TERM...18
LONG TERM...18
AVIATION...Lojero
FIRE WEATHER...18