099
FXUS65 KPSR 272312
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
410 PM MST Thu Mar 27 2025

.UPDATE...
Updated Aviation

&&

.SYNOPSIS...
After today`s mostly sunny skies and high temperatures around 90
degrees, a zonal flow pattern with lower pressure will develop. This
will allow temperatures to fall back closer to normal for Friday and
likely lasting through at least early next week. Daytime breezy
conditions are also expected starting today and lasting into at
least early next week as dry conditions persist.

&&

.DISCUSSION...
The large scale pattern across the Desert Southwest is entering into
a quasi-zonal pattern with persistent westerly flow. This pattern
looks like it will persist through early next week, based on latest
global modeling. Beyond early next week, global models support the
pattern becoming more amplified, but with high uncertainty/large
model spread across the full global ensemble suite. During the quasi-
zonal pattern there will at least be several low-amplitude shortwave
troughs that will role through quickly through this weekend, with
the first shortwave expected tomorrow. This will help lower 500mb
heights and allow temperatures to drop back down a bit closer to
normal for this time of year, with lower desert highs back into the
middle 80s instead of the 90s of the last several days.

This quasi-zonal pattern will also lead to some breezier conditions
each day across the region, most notably across parts of southern CA
and northern and eastern AZ. The shortwave trough moving through
tomorrow will lead to some stronger winds across Southeast CA, with
downsloping wind gusts up to 25-35 mph this evening and tomorrow
afternoon and evening. A Wind Advisory has been issued for the far
southwest corner of Imperial County where HREF probability of wind
gusts >40 mph is up to 100% for much of the period from this evening
through tomorrow night. Elsewhere across the lower deserts,
afternoon peak wind gusts tomorrow through at least early next week
will be more around 20-30 mph.

The pattern through early next week will not be favorable for any
precipitation chances, largely due to a lack of forcing with the
weak passing shortwaves and limited moisture. At most there will be
some thick high clouds and high level virga at times.

Ensemble guidance starts to diverge considerably by the middle of
next week with the EPS favoring a shortwave trough tracking just
past our region to the north, while the GEFS mostly digs this trough
just off the West Coast. Additional model divergence is seen
thereafter, but at least both model ensemble suites try to indicate
a more substantial trough moving into or near our region by the
following weekend. These model differences do introduce a larger
spread in forecast temperatures starting next Wednesday with the
upper end of highs around 90 degrees to the lower end in the 70s. We
may even see some precip potential around next Friday or Saturday,
but given the trajectory of the potential weather system from the
west or northwest and the time of year, we shouldn`t expect any
widespread precipitation.

&&

.AVIATION...Updated at 2310Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major weather issues will exist through Friday evening as thin
high cloud decks thicken and lower into midlevel cigs through the
period. Confidence is good that occasional westerly gusts near 20kt
will subside near sunset, then switch to an easterly component
around/shortly after midnight. While some uncertainty exists
regarding exact timing of wind shifts, an earlier than usual switch
back to westerly should occur by late morning. Some stronger gusts
Friday afternoon are possible, however thicker cigs may preclude
this outcome.


Southeast California/Southwest Arizona including KIPL and KBLH:
Periods of gusty W/SW winds will be the primary weather issue
through Friday evening as thick midlevel cigs pass through the
region. Confidence is good that gusts 25-30kt will be common at KIPL
this evening before relaxing somewhat overnight and Friday morning.
Gusts should be more reserved in time and magnitude at KBLH with
some uncertainty in wind directions Friday morning. Some resumption
of gustiness should return to the area Friday afternoon.

&&

.FIRE WEATHER...
Increased winds and continued low humidities will likely create a
somewhat elevated fire weather risk concern through at least the
weekend. Late morning to early evening breeziness with gusts upwards
of 25 to 30 mph at times will combine with afternoon MinRHs around
15-20% to increase the fire threat beginning today. Strongest winds
will be across Southeast CA and the higher terrain of southern Gila
County. The above normal temperatures will continue today, but then
ease back closer to normal starting tomorrow. The weather pattern
should continue to support daily breezy and dry conditions during
the first half of next week before some improvement in moisture
levels looks likely later next week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 5 PM this afternoon to 5 AM PDT Saturday for
     CAZ562.

&&

$$

DISCUSSION...Benedict/Kuhlman
AVIATION...18
FIRE WEATHER...Kuhlman/Benedict