787
FXUS65 KPSR 141106
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
405 AM MST Tue Oct 14 2025

.UPDATE...
Updated Aviation

&&

.KEY MESSAGES...

- A slight chance for a few light showers exists today across higher
terrain areas of south-central Arizona, as well as southeast
California.

- Dry weather will return to the region the remainder of the week
with temperatures primarily remain below normal.

&&

.SHORT TERM /Today through Wednesday/...
The final shortwave in a parade of tropically originating features
was lifting into NE Arizona early this morning with substantially
drier air punching into SW Arizona. In fact, objective analysis
depicts a dryline across western Maricopa County with sfc dewpoints
in the upper 50s/lower 60s and mixing ratios above 10 g/kg still
present in advance of this boundary. Sufficient ascent on the
southern periphery of the shortwave along with deep southerly flow
pulling moisture over terrain features continues to support isolated
showers north and east of Phoenix. This scenario may persist for a
few more hours this morning, however loss of ascent mechanisms and
increasing advection of dry air aloft should force any remaining
shower to mountain peaks heading through the afternoon.

The most obvious feature on early morning WV imagery is an intense
cold core circulation diving south along the central California
coast. The southerly propagation of this vorticity center has just
about ceased with excellent confidence this feature pivots inland
towards southern NV/UT over the next 48 hours. The pronounced strong
cyclonic flow edging into the SW Conus will ensure moisture
continues to be scoured away from the area with forecast soundings
showing boundary layer mixing ratios falling to around 7-8 g/kg, and
total column PWATs under 0.75". Closer to the trough axis in
California, a Pacific front will surge onshore today, however
shallow moisture should mostly be trapped on the windward side of
the coastal range, and only a few elevated showers might survive
inland.

Midlevel height falls and enhanced winds in the H8-H7 layer will
continue to support locally strong, gusty winds near SE California
terrain features today, though with the vorticity center beginning
to lift away from the region, winds should slowly relax through
Wednesday. Otherwise, H5 heights falling into a 570-574dm range and
cold advection aloft over the next 48 hours will allow temperatures
to cool to 8F-12F below normal by Wednesday.

&&

.LONG TERM /Thursday through Monday/...
The core of negative height anomalies will have lifted into the
northern Rockies/plains and weakened substantially during the latter
half of the week, albeit with positively tilted troughing lingering
into the SW Conus. Persistent westerly flow will ensure further
moisture erosion throughout the week while H5 heights hovering below
578dm will keep temperatures sequestered 4F-8F below normal, though
larger than expected ensemble numerical spread only yields moderate
confidence with temperature potentially warming faster than
forecast. Nevertheless by the weekend, there is good model agreement
that some form of shortwave ridging will build into the SW Conus
with H5 heights possibly exceeding 588dm and temperature rebounding
into a near normal range. The majority of ensemble output shows the
next Pacific trough early next week remaining north of the forecast
area before potentially amplifying downstream over the plains (a
very La Nina-like pattern). However, enough membership (including
the operational GFS) shows vorticity and strong jet energy digging
close enough to the CWA to possibly incur strong, gusty winds and
reemergence of below normal temperatures. Regardless, there is
little to no model evidence of any better moisture source returning,
and the prevailing dry weather should continue.

&&

.AVIATION...Updated at 1105Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds and the potential for brief cloud decks below 6K ft AGL will
be the main weather issues through Wednesday. Winds have been widely
variable (SE to SW) this morning, but should settle towards a S/SE
direction by mid/late morning. Gusts near 20kt may be common into
the afternoon as directions only slow attempt to veer to SW, and a
prolonged period of a cross runway component (160v210) appears
likely into mid afternoon. Confidence is moderate that cloud decks 5-
7K ft may materialize this morning, though actual cigs may be
limited to upslope areas northeast of terminals. Scattered cloud
decks will have the tendency to rise through the afternoon before
dissipating around sunset. Confidence in the timing of the nocturnal
wind shift tonight back to easterly is rather low.


Southeast California/Southwest Arizona including KIPL and KBLH:
Occasionally gusty winds will be the main weather issue through
Wednesday morning under mostly clear skies. Winds will continue to
favor a westerly component at KIPL and S/SW at KBLH. Gusts 20-30kt
should reemerge this afternoon before relaxing after sunset this
evening.

&&

.FIRE WEATHER...
Drier air across western districts will completely sweep through the
entire region today and Wednesday bringing the start to a prolonged
period of more tranquil weather. While minimum humidity levels will
only fall into a 30-50% range the next couple days, values will
retreat closer to a 20-35% range during the latter half of the week.
Overnight recovery will largely be good to excellent above 50%.
Locally gusty winds 20-30 mph will be common today, particularly
across western districts, however winds will be far weaker the
remainder of the week with limited gustiness.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory until 11 AM PDT this morning for CAZ562.

&&

$$

SHORT TERM...18
LONG TERM...18
AVIATION...18
FIRE WEATHER...18