834
FXUS65 KPSR 061136
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
436 AM MST Thu Aug 6 2026

.UPDATE...Updated 12z Aviation Discussion...

&&

.KEY MESSAGES...

- Extreme heat conditions will persist through the weekend with
  temperatures hovering near to several degrees above normal while
  humidity values remain higher than normal.

- Shower and thunderstorm chances will favor high terrain areas
  and Southeast Arizona the remainder of the week with gusty
  outflow winds and blowing dust the most likely impacts for
  south-central Arizona.

- Shower and thunderstorm chances start to increase across the
  lower deserts late this weekend and into next week.

&&

.SHORT TERM /Today through Friday/...
Current 500mb analysis reveals an elongated area of sub-tropical
high pressure, stretching from California to Atlantic Coast while
broad troughing advances through the Great Lakes Region. Closer to
home, another round of showers and severe storms were observed
across portions of Arizona yesterday into very early this morning,
especially across Southeastern and far Southern Arizona, aided by
enhanced moisture profiles provided by regional southeasterly flow.
As for our forecast area, the moisture is there, but the atmosphere
is heavily capped so we were unable to tap into the fair amount of
elevated instability. Unfortunately, this scenario looks likely to
play out again this afternoon and perhaps again on Friday as the
afternoon cap looks to remain in place, heavily limiting convective
activity. The one exception to this is, of course, where
orographically induced showers and storms are favored over eastern
portions of Gila County, where PoP chances currently stand around 20-
40% in the near-term. As for the lower deserts, any rainfall
potential will be heavily conditional on if a strong enough outflow,
or colliding outflows, can move through, but based on current hi-res
data, that outcome appears to be in the minority. This doesn`t mean
that outflows for areas such as the Phoenix metro and Pinal County
are being completely ruled out of the forecast, but any that were to
move through these areas are not expected, at least at this time, to
be strong enough to spark convection.

Much like the past few days, temperatures this afternoon will be
conditional on how much cloud cover sticks around from a fairly
expansive MCS down in the Tucson CWA. Current NBM forecast has
widespread highs for the lower deserts ranging between 105-111
degrees, but these may need to be adjusted during the next forecast
update if there is high enough confidence that lingering clouds will
limit surface heating. With how worked over the atmosphere is likely
to be down in Southeast Arizona, convective activity should be more
suppressed, so there is reason to believe that cloud cover will not
be as widespread Thursday night into Friday, therefore leading to
higher confidence that current projected afternoon highs should be
reached as we wrap up the workweek. With more limited cloud cover,
and the sub-tropical high expected to strengthen slightly,
widespread readings 110-115 degrees and above will make their
return. Regardless of all this, the enhanced moisture in the air
will make apparent temperatures feel even hotter, with "feels like"
temperatures ranging from 110 to even around 120 degrees for some
spots out in Southeast California.

The impact of the MCS down in Southern Arizona on our area may not
be limited to temperatures as there are signs that an associated
strong outflow may push through the Lower Colorado River Valley into
the morning hours. The HREF indicates the potential to see gusts
pushing toward 30-40 mph, which would likely be accompanied by
blowing dust that could result in hazardous travel conditions.
Depending how winds evolve, it is not out of the question that hazy
skies could linger through much of the day, but if winds remain
elevated through the morning, then that should be enough to clear
most of the dust out of the area. A similar scenario may play out
for areas of Pinal and Maricopa Counties as well, similar to what
occurred just a few days ago when dust hazy conditions lingered for
more than 12 hours. It is tough to say exactly how long any dust may
stick around, as many factors need to be taken into consideration,
but more than likely it would clear out by the afternoon hours at
the latest.

&&

.LONG TERM /Saturday through Wednesday/...
Heading into the weekend, the center of the anti-cyclone will shift
eastward towards the Four Corners region. As it does this, it will
actually pull in some slightly drier air off the Rockies, helping to
add to what is already a relatively unfavorable environment for
lower desert convection. It should not inhibit convection completely
in the typically active spots, but coverage may be a bit more
limited. This "drier` period should be short lived however as the
center of the high will settle off to our north and east, inducing
southeasterly flow once again and providing renewed moisture flux.
Rain chances for Sunday bump back up, and the lower elevations may
get in on some rain well as PoPs increase to around 20-30%, some of
the better chances seen in a while. There still might be some
recovery time from the drier air needed, so it would not be
surprising that activity Sunday evening is not very robust for areas
such as Maricopa and Pinal Counties, but it is a positive sign to
see an uptrend in rain potential nonetheless.

For next week, the forecast appears that it will not change much in
terms of convective activity as ensembles have the high parked over
the Four Corners. Less subsidence aloft, and continued moisture flux
bodes well for continued rainfall chances and that is reflected in
current PoPs sit between 20-40% basically from Monday through
Thursday. As typical with the monsoon, what days are active will
have heavy influence on what occurs the day after, so day-to-day
forecast changes should be expected once we get into this more active
period.

Temperatures over the next seven days will be at their hottest on
Saturday as current projections have widespread readings between 110-
116 degrees for the lower deserts. Add the humidity to that and it
will not feel particularly great outside. Some more good news is
that as that temperatures will begin to "cool" as the high shifts
east and weakens slightly, we may be able to finally escape extreme
heat criteria by the start of next week, at least for now.

&&

.AVIATION...Updated at 1135Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Slantwise visibility issues this morning due to lingering lofted
dust and gusty outflow winds this evening are the main aviation
weather challenges during the upcoming TAF period. Light easterly
winds to variable conditions will be common through early this
evening before a shift out of the west materializes mid to late
morning. Lofted dust is likely to linger throughout the area
through most of the morning, creating slantwise visibility issues
with conditions improving late morning into the afternoon.
Thunderstorm activity is likely across the high terrain areas to
the north and east of the terminals this afternoon into early this
evening with the potential for a northerly to northeasterly
outflow boundary to progress through the terminals with some
gusty winds this evening, mostly likely after 02-03z. However,
there is a chance that the outflow does not materialize if the
storm coverage across the higher terrain is more isolated and thus
wind directions will remain out of the west with an easterly
shift expected during the overnight period. SCT-BKN mid to high
clouds will be common through this morning, with coverage
decreasing to FEW-SCT this afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues under periods of mid/high cloud decks are
expected throughout the TAF period. Winds will generally be out
of the southeast at KIPL and out of the south at KBLH, with some
modest afternoon/early evening gusts. Some brief gusty winds
between 20-25 kts is likely early this morning due to an outflow
passage.

&&

.FIRE WEATHER...
Hot temperatures with relatively elevated humidity levels will
continue through the next several days. Though afternoon RHs do
trend downward for Friday, regional readings should remain at 15%
or above into next week. Overnight recovery will offer modest to
decent relief as MaxRHs range generally between 30-55%. Rain
chances through this weekend will be confined mostly confined to
high terrain areas and southeastern Arizona, with lower desert
chances remaining 10% or below through most of the weekend. By
Sunday, increasing moisture will result in an uptrend in lower
elevation shower and thunderstorm chances, which appears likely to
persist into the following week. Outside of thunderstorm outflows,
winds will follow familiar diurnal trends, with typical afternoon
upslope breeziness around 20 mph.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Extreme Heat Warning until 8 PM MST Sunday for AZZ530>544-546-
     548>551-553>555-559.

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

&&

$$

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

NWS Phoenix (PSR) Office