677
FXUS65 KPSR 220914
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
214 AM MST Mon Jun 22 2026

.KEY MESSAGES...

- Hotter temperatures this week will lead to widespread Moderate
  Heat Risk much of the week and localized Major Heat Risk on
  Wednesday and Thursday.

- An Extreme Heat Watch has been issued for portions of the area
  on Wednesday and Thursday with forecast highs between 110 to 115
  degrees across the lower deserts.

- Overall dry conditions will prevail all week with only very
  limited chances for isolated showers and a few weak storms mid
  week across the western deserts.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...
The subtropical high is gradually taking over across the region
with the high center now positioned just south of southwest New
Mexico. H5 heights have increased to 589-591dm across our area
with heights forecast to continue to rise into mid-week.
Temperatures will also heat up further over the next few days with
the rising heights and continued dry conditions. The latest
guidance has shifted back to the higher end of potential H5
heights (595-598dm) centered on Wednesday before lowering late
week. Forecast highs have ticked upward 1-2 degrees from
yesterday`s guidance with the bulk of the lower deserts reaching
110 degrees starting Tuesday.

Despite the continued overall dry conditions, the repositioning of
the high just to our southeast will shift our flow out of the
south allowing for some modest moisture return beginning later
today and continuing through Wednesday. Even with the southerly
flow, there is not a plethora of moisture available to our south.
Guidance shows surface dew points increasing to into the 40s to
the lower 50s starting Tuesday, but the average moisture in the
low to mid levels is not expected to increase enough to bring much
in the way of convective potential. Any shower and isolated
thunderstorm chances should be quite limited with a 10-20% chance
focused across central Riverside County late Tuesday and then
maybe extending into southwest Arizona for Wednesday.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The increasing influence from the subtropical high pushing
temperatures even hotter Wednesday into Thursday will be the main
forecast concern later this week. The peak strength of the ridge
is expected to occur on Wednesday with H5 heights ranging from
593-595dm across southeast California to as high as 596-598dm
across southeast Arizona. This will put all of southern and
central Arizona above the 97th percentile of climatology for H5
heights and near record strength across southeast Arizona. The
latest NBM forecast temperatures have bounced back from the slight
dip with yesterday`s guidance with the bulk of the lower desert
showing highs between 111-114 degrees for both Wednesday and
Thursday. The increase in low level moisture will also lead to
much warmer overnight lows with readings only dipping into the low
to mid 80s for much of the area to as warm as the upper 80s to
around 90 degrees for much of the Phoenix metro. Due to the
building heat, we have issued an Extreme Heat Watch for portions
of the area, including Phoenix, Yuma, and El Centro for Wednesday
and Thursday.

An upper level trough will slide southeastward into the
Northwestern U.S. starting Wednesday and eventually closer to our
region by Friday. This feature will help to lower heights across
our region starting Thursday, but there will be a noticeable lag
to any decent cooling. Forecast highs Friday are still between
110-113 degrees, but overnight temperatures should cool off more
quickly due to the expected drier air that will work into the
area from the west starting on Friday. The trough to our north
should really start to influence our region by the coming weekend,
knocking down H5 heights more into a 585-588dm range Saturday to
as low as 582-585dm on Sunday into next Monday. NBM forecast highs
are shown to dip into or even a few degrees below normal by
Sunday. The main forecast concern will turn away from Extreme Heat
Friday into the coming weekend and more toward breezy to locally
windy conditions causing critical fire weather concerns.

&&

.AVIATION...Updated at 0450Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation weather concerns under some passing high cirrus cloud
decks can be expected throughout the TAF period. The overall wind
pattern will favor the typical diurnal tendencies with overall
speeds aob 10 kts. Some occasional afternoon/early evening gusts
in the mid to upper teens will be possible Monday.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns under some passing high cirrus
cloud decks can be expected throughout the TAF period. At KIPL,
winds out of the west will prevail into the overnight period
before shifting out of the southeast Monday morning. At KBLH,
winds will generally fluctuate out of the south-southeast to
southwest. Overall wind speeds will remain aob 12 kts with some
minor afternoon gustiness at KBLH.

&&

.FIRE WEATHER...
Locally elevated fire weather conditions due to very low humidity
and afternoon upslope/upvalley breeziness will continue early
this week. Afternoon minimum humidities in the single digits today
will improve into a 10-15% starting Tuesday, following generally
poor overnight recoveries between 15-35%. Winds will generally
remain terrain-driven, with upslope/upvalley gusts during the
latter half of the afternoon into the early evening peaking around
15-20 mph today and increasing slightly up to as much as 20-25
mph Tuesday. Temperatures will warm to above normal for much of
the week with lower desert highs topping 110 degrees at least on
Wednesday and Thursday. Elevated fire weather conditions are
expected to continue through the rest of the week with afternoon
minimum humidities staying between 10-15% while winds increase
further by Thursday. Areas of critical fire weather conditions
look likely by Friday or Saturday.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Watch from Wednesday morning through Thursday
     evening for AZZ530-532-533-537-540-542>544-546-548-550-551.

     Extreme Heat Watch from Tuesday morning through Wednesday
     evening for AZZ560.

CA...Extreme Heat Watch from Wednesday morning through Thursday
     evening for CAZ562-566-567-569.

&&

$$

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