Apache Junction, Arizona Weather Forecast Discussion

808
FXUS65 KPSR 052318
AFDPSR
Area Forecast Discussion
National Weather Service Phoenix AZ
418 PM MST Fri Sep 5 2025
.UPDATE...Updated Aviation Discussion.
&&
.KEY MESSAGES...
- Chances for showers and isolated thunderstorms will remain
  through Saturday before rain chances end completely starting
  Sunday.
- Temperatures will be below normal through Sunday before warming
  back into the normal range for at least south-central and
  eastern Arizona through the middle of next week.
&&
.SHORT TERM /Today through Saturday/...
Chances for monsoonal activity will linger into the weekend, but
will see a downtrend as drier conditions prevail. Earlier this
morning, a complex of thunderstorms made its way south across
western/northwestern Arizona and eventually helped initiate new
convection across portions of La Paz and Maricopa Counties. This
thunderstorm activity has since dissipated with only an isolated
shower and thunderstorm or two on the radar this afternoon, while
better thunderstorm coverage remains across portions of northern
Arizona.
For the rest of this afternoon and evening, HREF guidance keeps the
best coverage of showers and thunderstorms across the Arizona higher
terrain with isolated activity across the lower deserts. Forecast
soundings remain favorable for additional thunderstorms today and
look to favor terrain/orographic features. Mesoanalysis and
observed sounding data showed PWAT values ranging upwards of
1.6-1.9". Given the moisture content in place combined with weak
steering flow, any additional thunderstorms that were to develop
through the afternoon and evening will be capable of producing
locally heavy rainfall that could lead to isolated flash flooding.
Several HREF members also support the idea of additional shower
and thunderstorm activity developing overnight tonight, which
could lead to additional locally heavy rainfall/flooding impacts
if it were to materialize.
Drier westerly flow aloft along with upper level ridging building
over the Desert Southwest will lead to decreasing rain chances
across the area for tomorrow. By tomorrow afternoon and evening,
paintball plots place the best coverage of convection across the
Rim and down across southeast Arizona. Nevertheless, we may still
see isolated thunderstorms develop across our area, particularly
along terrain features.
Heights will continue to build this weekend as ridging builds over
the region, promoting warmer temperatures for tomorrow. NBM highs
remain largely in the mid to upper 90s across the lower deserts
tomorrow and upper 80s to lower 90s for higher terrain areas
including Globe and San Carlos. As temperatures trend warmer
tomorrow, they will still remain around 5-6 degrees below normal.
&&
.LONG TERM /Sunday through Thursday/...
Overall quiet and drying conditions are forecast for Sunday
through at least the middle of next week. The Pacific trough is
expected to deepen and fully close off west of Northwest U.S.
coast this weekend before moving onshore on Monday. As it deepens
starting Sunday, it should promote amplified upper level ridging
centered along the Arizona/New Mexico border northward into
Wyoming. This is expected to briefly boost H5 heights over much
of our region into a 590-593dm range leading to warmer
temperatures for at least Sunday and Monday. NBM forecast highs
show readings right around 100 degrees for Sunday across the lower
deserts to between 101-104 degrees on Monday and Tuesday. Further
drying through early next week should completely end rain chances
even across the higher terrain by Monday and eventually lower
surface dew points into the 40s by next Tuesday or Wednesday.
Model uncertainty increases somewhat during the middle to latter
part of next week as there are differences within the models with
the eventual evolution of the Pacific trough. There is at least
good agreement with H5 heights lowering over our region by next
Wednesday as the trough moves fully over the Western U.S., but
there are bigger differences late next week with how far south
and east the base of the trough will track. For now, we can safely
say this pattern should keep considerable dry air over most if
not all of our region through late next week. Forecast
temperatures show higher spread later next week, but the overall
consensus shows a slight cooling trend and readings staying at or
just below normals during the latter half of next week.
&&
.AVIATION...Updated at 2317Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major aviation concerns are expected through this TAF period,
as any activity looks to remain away from the terminals. Westerly
winds will continue through the afternoon until they become light
and variable through the overnight period, as no defined easterly
shift is expected. FEW low cloud decks will persist through the
TAF period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns are expected throughout the TAF
period. KIPL will remain out of the SE and KBLH will remain out of
the south. Both terminals can expect wind speeds to generally be
aob 10kts, but could see speeds slightly higher at times. FEW mid
to high clouds will persist throughout the period.
&&
.FIRE WEATHER...
Moisture levels will remain elevated through the weekend with rain
chances diminishing and ending by Sunday. Periods of isolated
showers and thunderstorms are expected through Saturday, while
wetting rain chances will mostly range between 10-30%,
particularly across the higher terrain north and east of Phoenix.
MinRHs are only expected to drop into a 30-45% range through the
weekend as temperatures stay below normal. Winds will tend to
favor diurnal patterns across the eastern districts, while
favoring the south across the western districts. The gradual
drying conditions will continue during the first half of next week
keeping rain chances near zero and eventually lowering MinRHs
back into the teens by next Tuesday.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
SHORT TERM...Smith
LONG TERM...Kuhlman
AVIATION...Ryan
FIRE WEATHER...Smith/Kuhlman

NWS PSR Office Area Forecast Discussion