El Mirage, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

961
FXUS65 KPSR 181138
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
438 AM MST Thu Sep 18 2025

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

&&

.KEY MESSAGES...

- A Flood Watch has been issued from early this morning through
  this evening for southeastern California and southwest Arizona,
  due to the potential for locally heavy rainfall leading to flash
  flooding.

- Lingering shower and thunderstorm chances will be possible
  Friday, primarily focused across the Arizona high terrain.

- Near normal temperatures over the next couple of days should
  warm to above normal this weekend into early next week with
  Moderate Heat Risk returning across the lower deserts.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...
Deep tropical moisture has advected northward into southeast
California and southwest Arizona over the past 12-18 hours with
PWATs at around 2" in Yuma and 1.6-1.9" for the rest of the
aforementioned areas. Good moisture also extends eastward through
much of south-central Arizona with PWATs between 1.3-1.6". The
remnants of TC Mario have also merged with a weak upper level low
off the coast of southern California providing ample dynamics for
showers and a few embedded thunderstorms across southern
California early this morning.

The forecast for the rest of today into tonight remains
challenging due to a number of factors. The moisture has basically
reached its peak across the region and drier air above 15-20K feet
is already starting to push north northeastward across northern
Baja. The drier air should reduce the cloud cover to a degree
later this morning allowing for better destabilization across
southeast California and southwest Arizona. Assuming this occurs,
it should give rise to scattered thunderstorm development as early
as mid to late morning, but more so during the afternoon with
PWATs still hovering somewhere between 1.7-1.9" across the
aforementioned areas. Hi-res guidance is still quite unsure on the
areal coverage for thunderstorms today, but it has at least been
consistent in showing the potential for heavy rainfall. It seems
quite likely a portion of this area will see anywhere from 1-2" of
rainfall today with some low-end potential for very localized
amounts exceeding 2". The best potential for heavy rainfall and
any flooding impacts are likely to occur across southeast
California into La Paz County. We have expanded the areal
coverage of the Flood Watch to include all of La Paz County and
much of Yuma County, although Hi-res CAMs have not specifically
shown much activity for Yuma County.

Looking farther to the east across south-central and eastern
Arizona, guidance continues to struggle with the rainfall
potential for today. Some model runs have indicated heavy rainfall
potential into western and southern Maricopa County, but they have
been quite inconsistent and have somewhat backed off on this
threat over the past 24 hours. Given moisture will still be quite
high into south-central Arizona, we can`t rule out some
thunderstorms producing heavy rainfall but the chances are much
lower compared to out west. It would not be surprising to see at
least one or two good thunderstorms later today that drop 1"
rainfall amounts outside of the Flood Watch area, but given the
low probability we do not see a need to expand the Watch into
Maricopa County. Rainfall amounts across south-central Arizona may
only average around 0.1" with a good portion of the area barely
seeing any rainfall.

The drier air aloft will spread across the rest of the region by
tonight with any shower and thunderstorm activity diminishing
considerably by around midnight. Forecast PWATs are expected to
drop to between 1.2-1.5" already by Friday afternoon with the best
rain chances shifting over the Arizona high terrain. Some
locations to the north and east of Phoenix may see an additional
0.25" of rain on Friday, but most locations will barely see any
measurable rainfall. The 06Z HRRR is quite optimistic for showers
and thunderstorms between Phoenix and Flagstaff Friday
afternoon/early evening, but that seems to be an outlier at this
point.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Model uncertainty will continue over the weekend into early next
week as models are having a difficult time resolving what will
happen with a cut-off low that is likely to form off the
California coast Friday into Saturday. Yesterday`s model runs had
mostly dismissed this cut-off low as it called for it stay well
to our west, but the latest trends indicate it may get quite close
to southern California Sunday into Monday. We are still expecting
our region to largely be under the influence of the subtropical
ridge this weekend with overall dry conditions, but if the low
does creep close enough to our area we may see some moisture
return Sunday into Monday. The NBM shows 10-20% rain chances for
later Sunday into Monday, but this seems overly optimistic given
the amount of moisture that is likely to be available. We tend to
believe the ridge will win out keeping the cut-off low far enough
to the west resulting in the bulk of our area staying dry through
at least early next week.

Temperatures will be trending upward this weekend into early next
week as the ridge builds in from the south, but with the model
trends of keeping the cut-off low closer forecast highs are
noticeably lower than what we saw 24 hours ago. Highs are
currently expected top out at around 100 degrees this weekend
before pushing closer to 105 degrees by around next Tuesday. The
upper end of guidance does still show the potential for record
highs for Phoenix next Tuesday and Wednesday, but that will only
happen if the cut-off low stays far enough to our west.

&&

.AVIATION...Updated at 1130Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The potential for thunderstorm activity and associated gusty winds
late this afternoon through this evening will be the main weather
issue through this evening. In the meantime, no major weather
issues are expected through at least mid-afternoon with winds
following the familiar diurnal tendencies and speeds remaining aob
10 kts. Forecast confidence deteriorates substantially late this
afternoon through this evening as there is potential for
thunderstorm activity to materialize across the Phoenix area,
however, latest hi-res model guidance are in big disagreement on
the overall coverage, thus lending to a low confidence forecast.
At this time, a PROB30 group for thunderstorms has been added to
this TAF package between the 00-06z timeframe when the chances are
the highest. If thunderstorms were to materialize, then gusty and
erratic winds and perhaps some blowing dust would be observed. If
no thunderstorm activity materializes, then the overall wind
pattern will continue to follow the typical diurnal trends with
westerly winds through early this evening switching out of the
east late this evening. SCT-BKN clouds aoa 10 kft will be common
throughout the TAF period.


Southeast California/Southwest Arizona including KIPL and KBLH:
The potential for thunderstorm activity and associated gusty winds
and heavy rainfall will be the main aviation weather issue through
this evening. In the meantime, some nuisance showers will continue
to affect the region through the morning hours with winds likely
to be light and variable although the eventual tendency will be
for the winds to obtain a southerly component at KBLH and an east
to southeast component at KIPL. Heading into the early to mid-
afternoon hours, confidence is high enough for thunderstorm
activity to erupt across the region, mostly during the 21-02z
timeframe, with gusty and erratic winds and perhaps some blowing
dust being observed. Weather conditions should improve after 02z
with winds becoming mostly light and variable. SCT-BKN clouds aoa
8-10 kft will be common through this evening before gradual
clearing takes place during the overnight period.

&&

.FIRE WEATHER...
Abundant moisture with a weather system residing across western
portions of the region today will help to bring fairly widespread
showers and thunderstorms. Best chances will be across southeast
California and southwest Arizona where a Flood Watch will be in
effect for much of today. Rain chances will continue into Friday,
but mainly across the Arizona higher terrain. Humidities will be
elevated over the next couple of days with MinRHs mostly between
30-40% before gradually lowering closer to 20% by Sunday. Outside
of any storms, winds will remain light over the next few days with
directions mostly following diurnal trends. High pressure should
settle back into the region over the weekend and into early next
week resulting in a warming trend and overall dry conditions.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch through late tonight for AZZ530>533-536.

CA...Flood Watch through late tonight for CAZ560>570.

&&

$$

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