Fountain Hills, Arizona Weather Forecast Discussion

036
FXUS65 KPSR 091115
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
415 AM MST Tue Sep 9 2025
.UPDATE...Updated Aviation Discussion
&&
.KEY MESSAGES...
- Temperatures will stay within the normal range through mid
  week, resulting in locally Moderate Heat Risk for the lower
  deserts, before cooling slightly late week.
- Overall dry conditions are expected for the next 7 days with
  only slight chances for rain over the eastern Arizona high
  terrain Wednesday into Thursday.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
A deep Pacific trough remains nearly stationary over and offshore
of the Northwestern U.S. The deepening of this trough over the
past day or so has led to a slightly higher amplitude subtropical
ridge into the Desert Southwest prompting a warming trend and
lower desert highs now reaching between 100-105 degrees.
Eventually the trough will slowly drift southeastward toward our
region over the next couple of days, lowering heights aloft and
inducing some breeziness. Breezy conditions are likely across
southeast California by this evening before spreading areawide on
Wednesday. Temperatures will also begin to drop across the western
deserts starting Wednesday as highs stay under 100 degrees, but
the Phoenix metro is again expected to top out between 102-105
degrees.
The incoming trough will also shift our low and mid level winds
more out of the south starting Wednesday leading to some modest
moisture return out of northern Mexico. Although the moisture will
overall be fairly limited it should be enough with the help of the
weak upper level forcing to spark off some isolated showers and
maybe a weak thunderstorm or two across the far eastern Arizona
high terrain Wednesday afternoon/evening.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Guidance then shows the Pacific trough shifting more to the east
northeast Thursday in Friday with the low center eventually moving
into Idaho and a weak trough axis moving across our region on
Friday. Gradual height falls during this time should continue to
bring periods of breeziness along with some slight cooling across
the region. Similar to Wednesday, locations across far eastern
Arizona may see some low end rain chances on Thursday into
Thursday night. Most locations are not likely to see much if any
rainfall given the overall low moisture content air and weak
forcing associated with the passing weather system. Once the
trough axis passes through later on Friday, much drier air is
expected to spread across the area with surface dew points
dropping into the 30s by Saturday.
Temperatures later this week are expected to cool off slightly
with most lower desert locations topping out in the mid to upper
90s starting Thursday and likely staying there through at least
Saturday. Overnight temperatures will also cool off a good amount
with lows dipping into the 60s across the western lower deserts by
Friday morning and well into the 70s across the south-central
Arizona lower deserts.
The weather pattern is not likely to change much going into next
week as a second Pacific trough is likely to approach the West
Coast by Sunday before eventually moving inland early next week.
This should keep our temperatures at or just below normal and
maintain an overall dry westerly flow over our region.
&&
.AVIATION...Updated at 1115Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected during the TAF period. Winds
will follow familiar diurnal trends, with a slower than usual
shift to the W resulting in a window of S`rly crosswinds at KPHX.
Occasional afternoon breeziness with gusts 15-20 kts should also
be anticipated. Other than a FEW afternoon CU, skies will be
mostly clear during the majority of the forecast window.
Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation concerns are expected over the next 24 hours.
Winds will favor a W`rly component at KIPL, with gusts this
evening upwards of 25 kts. At KBLH, diurnal trends (S`rly shifting
SW`rly) will prevail, with some occasional gusts near 20 kts this
afternoon. Mostly clear skies will be observed through Wednesday
morning.
&&
.FIRE WEATHER...
The weather pattern over the next several days will continue to
bring overall dry conditions with near normal temperatures. A
weather system approaching the region from the northwest will
result in occasionally breezy conditions starting today with peak
winds likely on Wednesday as gusts reach to around 25 mph at
times in the afternoon. By Thursday, there may be some slight rain
chances across the eastern Arizona high terrain. MinRHs over the
next few days are likely to range from 10-15% across the western
districts to 15-25% across the eastern districts. By Friday and
into the weekend, even drier conditions are expected with winds
returning to a typical light and diurnal pattern.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 6 PM this evening to 6 AM PDT Wednesday for
     CAZ562.
&&
$$
SHORT TERM...Kuhlman
LONG TERM...Kuhlman
AVIATION...RW
FIRE WEATHER...Kuhlman

NWS PSR Office Area Forecast Discussion