026
FXUS65 KPSR 271806
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1106 AM MST Mon Jul 27 2026

.UPDATE...Updated 18Z Aviation Discussion.

&&

.KEY MESSAGES...

- Above normal temperatures will continue through the forecast
  period with Extreme heat Warnings in effect for portions of the
  area through mid week.

- Typical monsoon conditions are expected into next week with
  daily thunderstorm chances favoring Northern Arizona high
  terrain and Southeast Arizona and low chances in the South
  Central Arizona lower deserts.

- After a slight drop in temperatures during the first half of
  the coming work week, high pressure will strengthen over the
  region once again late in the week, resulting in another period
  of unseasonably hot temperatures and widespread Major Heat Risk.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
GOES mid-lvl WV imagery and RAP-40 500mb analysis shows
southeasterly flow aloft as the subtropical high is positioned near
the Four Corners region. The activity from the past couple of days
has helped cap the atmosphere, as the latest 12Z sounding showed
only around 200 MUCAPE but almost 600 CIN. Today will be another
quiet day with very little activity expected. Moving forward,
throughout the first half of the week south to southeasterly flow
aloft will remain in place, with PWATs staying above 1.6" keeping
chances for thunderstorms in the forecast, however storms will be
mostly confined in Northeastern AZ. Meanwhile the chances for
thunderstorm and showers to develop in south-central AZ and the
lower deserts are very limited, with current guidance pointing
towards Tuesday morning as the best chances for any development in
south-central AZ, to include the Phoenix metro.

Outside of any storm chances, dangerously hot temperatures with
little overnight relief will be the main impact as we head into the
first half of the work week. With that said, the widespread Extreme
Heat Warning will remain in effect through this evening as morning
low temperatures today will be in the upper 80s to lower 90s, and
afternoon highs will be between 108F-115F. By Tuesday, temperatures
in south-central AZ fall by a 1-2 degrees, however highs will remain
4F-6F above normal as H5 heights will only dampen to near 594-596
dam. While most of the region will fall out of the Extreme Heat
Warning Monday evening, the Phoenix metro, Imperial Valley and the
Lower Colorado River Valley will remain under the effect of the
Warning through at least Wednesday evening. This is driven largely
due to overnight lows remaining well above normal leading to very
little relief in these areas. More expansive headlines will likely
be needed again by late week as the subtropical high moves closer
and restrengthens. This is expected to drive temperatures back in
the upper teens, with the lower deserts between 112F-118F, flirting
with record highs yet again. H5 heights near the end of the work
week will climb to between 595-597 dam, or in the 99th percentile to
near max for climatology for this time of year.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
By the end of the of the week and heading into the weekend, most
global ensembles continue to support the strengthening of the
high pressure, with H5 heights up to 600dam and the center of the
anticyclone shifting to over northern AZ/southern UT. These
heights are near or at the max of NAEFS percentile for climatology
for this time of year, which are quite frankly impressive. The
peak of the extreme heat is expected to be Friday and Saturday,
where the chances of Phoenix Sky Harbor at least tying the record
high (116F) will be 65% on Friday and 50% Saturday. As mentioned
previously, an additional widespread Extreme Heat Warning will be
likely near the end of the workweek. Additionally, this setup will
likely add more subsidence over the area and subdue afternoon
convection. Global ensembles also show a slow downtrend in PWATs,
falling under 1.5" by Thursday- Friday. So, this is not great for
the prospects of seeing storms push into the lower deserts.
However, the NBM keeps slight PoPs focused in the AZ high terrain.

&&

.AVIATION...Updated at 1805Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:

Aviation concerns will remain low through the forecast period.
Somewhat elevated westerly winds are expected through the
majority, if not all of the upcoming TAF period. Gusts in the
upper teens to around 20 kt are expected this afternoon/early
evening and again tomorrow afternoon. There is low confidence in
an easterly shift tomorrow morning. Currently, only KIWA is
anticipated to go SE`rly during the overnight and early morning
hours tomorrow. FEW-SCT mid and high level clouds are expected
throughout the period.

Southeast California/Southwest Arizona including KIPL and KBLH:

Aviation concerns will remain low through the forecast period.
Current SE winds at KIPL will go SW`rly this evening, then back
SE`rly early tomorrow morning. Wind speeds are anticipated to
mainly be aob 10 kt. At KBLH, winds will stay southerly the whole
period with some gusts up around 20 kt expected this afternoon and
early evening. FEW-SCT mid and high clouds will persist.

&&

.FIRE WEATHER...
Typical monsoon conditions are expected through much of the
forecast, with thunderstorm activity mainly favoring the high
terrain of northern AZ and southeastern AZ and low chances (<10%)
in the lower deserts of south-central AZ. Above normal,
temperatures will contribute to seasonally dry afternoon
conditions each day through the first half of the week, before
temperatures once again heat up during the second half of the
week. Minimum RH values of 15-30% will be common through the
first half of the week before dropping into the 10-20% range late
in the week as temperatures heat up again. Overnight recoveries
will be fair most nights with RH values mostly in the 35-50%
across lower deserts to 45-65% across southern Gila County.
Wind speeds 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 Wednesday for AZZ530-532-537-
     540-542>544-546-548-550-551.

     Extreme Heat Warning until 8 PM MST this evening for AZZ531-
     533>536-538-539-541-545-547-549-552>555-559.

CA...Extreme Heat Warning until 8 PM PDT Wednesday for CAZ567-569-570.

     Extreme Heat Warning until 8 PM PDT this evening for CAZ560>566-
     568.

&&

$$

SHORT TERM...Ryan
LONG TERM...Ryan
AVIATION...Berislavich
FIRE WEATHER...Ryan/Benedict