451
FXUS65 KPSR 190557
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1057 PM MST Tue Nov 18 2025

.UPDATE...Updated Aviation Discussion.

&&

.KEY MESSAGES...

- A slow moving weather disturbance will continue to bring
  periodic rain showers with a few isolated thunderstorms mainly
  cross southern and central Arizona through Wednesday night.

- Another weather system should bring rain chances Friday into
  the weekend with the main area of focus across southeast
  California.

- Temperatures this week will hover below the seasonal normal
  with readings around 10 degrees below normal Wednesday through
  Friday.

&&

.SHORT TERM /Today through Wednesday/...
Water Vapor imagery shows the low pressure system finally making
it onto the shore of the Southern California Coast and slowly
drifting to the southeast. This has already brought measurable
rainfall across the forecast region, most notably in Western
Maricopa County, and will continue throughout today and tomorrow.
During this time PWAT values look to maintain 0.8-1", or 175-225%
of normal for this time of year. Along with increased moisture,
this system has increased CAPE values to near 200-500 J/kg, this
will result in the continuation of shower activity developing
across much of Arizona, with the potential for some embedded
thunderstorms.

The main focus for rainfall will be across central Arizona as the
system slowly migrates eastwards over the next couple of days.
However this is not to say other portions of the forecast region
wont see any rainfall. The western lower deserts of southeast
California will largely miss out on the rain with amounts
generally less than 0.10". The Arizona lower deserts should
average between 0.50-1.00" with even the higher amounts already
reached in localized areas across northern La Paz and Maricopa
Counties today. Going forward expect precipitation totals as high
as 1.50-2.00" along the Maricopa/Yavapai border as storms today
have been training along the county borders. Normally dry washes
have already began to flow, impacting some low water crossings, in
response flood advisories, watches and warnings have been
appropriately issued for these areas. As rainfall continues ensure
to stay up to date with the current advisories, watches and
warnings for your area and stay weather aware.

Otherwise, as this system continues its slow journey over the
region temperatures will continue to trend downwards, with
tomorrow forecasted highs in the low to mid 60s across the lower
deserts. Overnight lows will follow suit dropping into mid to
upper 50s, and Wednesday night lows in the lower 50s, to upper 40s
in the western portion of the forecast region.

&&

.LONG TERM /Thursday through Sunday/...
The slow moving trough is expected to be finally pick up speed on
Thursday as it finally exits to the east by later in the afternoon.
Guidance is still showing some lingering showers focused across the
eastern Arizona high terrain for Thursday morning and potentially
into the afternoon, but additional rainfall amounts should fall
short of 0.25". The Phoenix area may also see some lingering light
shower activity through the first part of the morning hours on
Thursday. The exiting system should allow for a decent amount of
sunshine across the area by the afternoon, but the cold air mass
will keep daytime highs in the lower 60s across the Phoenix area to
the mid to upper 60s across far southwest Arizona into southeast
California.

Ensemble guidance is finally starting to have better agreement with
the third weather system which is slated to quickly dive southward
into the back side of the larger scale trough later Thursday into
Friday. Models are now favoring a track which would largely bypass
Arizona on Friday, but it should place southern California into a
prime area of forced ascent and precip development. This should
result in a fairly rainy day on Friday across southeast Califonria
into portions of far southwest Arizona. The latest QPF amounts show
rain totals as high as 0.75" across the western half of Imperial
County and central Riverside County to 0.25-0.5" into the Yuma area.

The low center is likely to keep moving south southeastward to over
the northern Baja area Friday night and Saturday with the most
likely path taking it more toward the east across northern Mexico on
Sunday. If this forecast track holds, it is likely to be far enough
to the south to not bring much rainfall to south-central or eastern
Arizona. That`s not to say those locations won`t see additional rain
over the weekend, but it is likely to be on the lighter side and
more sparse compared to what the western deserts should see on
Friday.

&&

.AVIATION...Updated at 0556Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Periods of SHRA, lower cigs and visibilities, variable wind
directions, and a lower chance for TS will all be weather issues
through Wednesday night. There will be chances for isolated to
scattered SHRA throughout the TAF period. Exact timing of rounds
of SHRA is low confidence, but there are a couple time periods
when SHRA impacts are more favored, after midnight tonight through
Wednesday morning and Wednesday night. In general, the greatest
impacts with lower cigs, reduced vsby, and wind shifts will occur
with individual rounds of showers. VFR conditions with cigs
040-060 will be the most likely outcome through the day Wednesday,
then higher probabilities of MVFR cigs arrive Wednesday evening,
with low chances (20-30%) for IFR cigs. Winds will favor a W
component while showers persist to the west. Then a S/SE direction
will follow during the morning, however directions become far
more uncertain Wednesday afternoon as a west or north component
starts to become more likely.

Southeast California/Southwest Arizona including KIPL and KBLH:
Weather issues through Wednesday morning will be slight chances
(20%) for SHRA, with occasional lower cigs down to around 050 and
variable winds. Overall, VFR conditions are expected to prevail.
Winds will favor a westerly direction at KIPL and southwest
veering to northerly at KBLH. Variability in direction and speed
will be common near any robust SHRA.

&&

.FIRE WEATHER...
Periodic showers along with a few isolated thunderstorms will affect
much of Arizona through Wednesday providing very good chances for
wetting rains. Below normal temperatures and elevated moisture will
remain in place keeping MinRHs in a 40-70% range following excellent
overnight recovery greater than 80%. Locally gusty winds upwards of
20 mph will be possible at times, though weaker wind speeds will be
more common through the period.  Another weather system is expected
to move across the western districts on Friday leading to additional
wetting rain chances with chances eventually moving over the eastern
districts over the weekend. Temperatures will mostly remain below
normal through the weekend with humidities staying elevated.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Flood Watch through late Wednesday night for AZZ541-542-545-547-
     557.

     Flood Watch through Wednesday afternoon for AZZ534-537-538.

CA...None.
&&

$$

SHORT TERM...Ryan/Kuhlman
LONG TERM...Kuhlman
AVIATION...18/Benedict
FIRE WEATHER...Ryan/Kuhlman