280
FXUS65 KPSR 100510
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1010 PM MST Wed Jul 9 2025

.UPDATE...Updated Aviation Discussion

&&

.KEY MESSAGES...

- Extreme Heat Warnings are in effect today through tomorrow as
  lower desert highs reach 112 to 119 degrees and lead to
  widespread Major Heat Risk.

- Temperatures lower a few degrees Friday through this weekend,
  but will remain above normal, with lower desert high
  temperatures around 105 to 110 degrees.

- Thunderstorm activity will continue to be limited to the Arizona
  high terrain and southeast Arizona, likely through this weekend.


&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
You know it is going to be a very hot day when the temperature
reaches 110F before noon and 114F before 1 PM. This was the case
today in Phoenix and several other lower desert communities. High
temperatures this afternoon will be pushing 114-119F across most
of the lower deserts, as strong high pressure remains situated
overhead. Phoenix will likely tie or break the daily record high
temperature today of 116F, a few other locations may also break
records, like in El Centro, CA. This heat is resulting in
widespread Major HeatRisk (Level 3 of 4) today, meaning everyone
is susceptible to heat health impacts without adequate cooling.
An Extreme Heat Warning was expanded today to nearly all of
Southern AZ and SoCal. These are dangerous and deadly
temperatures. Please limit time outdoors, stay hydrated, and take
advantage of air conditioning. Phoenix has free cooling centers
across the metro area if needed.

The Extreme Heat Warning will continue through tomorrow for most
of the same areas. Temperatures are not forecast to be as hot as
today, as a shortwave trough passing through the Great Basin
flattens and weakens the ridge slightly. High temperatures
forecast around 110-116F will again lead to Major HeatRisk for
most communities. Plus, there will be limited relief overnight,
with lows only in the upper-80s to low-90s. In addition to it
already being hot, it will be mostly sunny today and tomorrow,
with very limited clouds. Maximizing solar radiation will
definitely be draining on the body.

With the high pressure overhead and sub-optimal moisture,
afternoon thunderstorms will again be limited to high terrain
areas northeast of Phoenix and in Southeast AZ. Mesoanalysis is
showing moisture levels have actually lowered from yesterday and
overall CAPE values are lower. Still, a gusty shower or brief
storm, with limited rainfall, may impact parts of southeaster Gila
County this afternoon. Moisture levels and instability lower even
more for tomorrow, with overall less convection across the state.
A tightening of the pressure gradient tomorrow, in response to the
passing shortwave trough to the north, will lead to widespread
breezier conditions. Afternoon and evening wind gusts are forecast
to reach up to 25-35 mph, rather than the 15-25 mph this
afternoon. These stronger winds combined with low humidity will
create some locally elevated fire weather conditions.


&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
The subtropical high is expected to continue to slowly migrate
westward towards the southern CA coastline heading towards the end
of the week through the upcoming weekend. This will result in 500 mb
height fields to decrease slightly closer to 591-594dm. This will
translate to slightly cooler temperatures, but still remain a few
degrees above normal as afternoon highs will average around 110
degrees across the lower deserts with widespread Moderate
HeatRisk.

The convective potential through the weekend will continue to be
very limited as the upper-level flow pattern will remain unfavorable
for any deep moisture influx. In fact, as the high settles over
the southern CA coastline, the flow will turn out of the north,
bringing drier air with PWATs dropping below one inch during the
weekend. However, enough low-level moisture may still be present
for some afternoon convection to materialize, mainly across the
vicinity of the White Mountains and the southeastern third of AZ.
Heading into next week, model guidance continues to show the high
repositioning towards the Four Corners Region, especially by the
middle of the week. This would result in a more favorable flow
pattern for deeper moisture advection, with convective coverage on
the increase across the higher terrain areas initially before
chances increase across the lower deserts, more likely by the
latter half of the week.

&&

.AVIATION...Updated at 0510Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No major aviation concerns are expected during the TAF period.
Winds will follow typical diurnal trends, with an earlier W`rly
establishment than usual, and familiar afternoon gusts around 20
kts. At KPHX, the usual E`rly shift appears uncertain, but if one
were to occur, it will be short lives, otherwise W`rly winds will
prevail through the forecast. Besides a FEW clouds over the
region, skies should be mostly clear.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected over the next 24 hours. Typical
diurnal wind trends will prevail with familiar afternoon and
evening breeziness later in the period, especially at BLH. Besides
a FEW high cirrus tonight, skies should be mostly clear.

&&

.FIRE WEATHER...
Regionally dry conditions and above normal temperatures will
persist through the next week as lower deserts highs reach 110-118
degrees today and tomorrow and then 105-110 through this weekend,
with temperatures peaking today. MinRH values will range from
15-20% nearly every day, while MaxRH values will be the lowest
tonight at 20-40% before increasing up to 30-50% the rest of the
forecast period. One exception will be across Imperial and
southern Yuma Counties where periodic gulf surges will result in
MaxRH values in excess of 50-60%. The overall wind pattern will
follow the familiar diurnal trends, with some afternoon/early
evening breeziness with 15-25 mph peak gusts. An uptick in the
winds is expected tomorrow and Friday afternoons with 25-35 mph
peak gusts. This may lead to locally elevated fire weather
conditions, primarily on Thursday due to drier conditions. Very
minimal rain chances will exist through this weekend, with
activity focused mainly across the eastern and southeastern third
of AZ, with CWR <10%.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Thursday for AZZ530>556-
     559>562.

CA...Extreme Heat Warning until 8 PM PDT Thursday for CAZ560>570.

&&

$$

SHORT TERM...Benedict
LONG TERM...Lojero
AVIATION...RW
FIRE WEATHER...Lojero/Benedict