825
FXUS65 KPSR 050855
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
155 AM MST Wed Feb 5 2025

.SYNOPSIS...
Weakening high pressure across the region over the next several
days will still keep temperatures quite warm into the weekend with
highs between 75 and 80 degrees across the lower deserts each day.
Dry conditions will continue through early next week, albeit with
occasional breeziness and temperatures eventually retreating much
closer to the seasonal normal.

&&

.DISCUSSION...
The unseasonably strong upper level ridge that helped to bring
record high temperatures to the Phoenix area over the past couple
of days has weakened while also getting pushed back farther to the
south. This southward shift is largely due to a large Pacific
trough which has set up just off the Pacific Northwest coast.
Westerly quasi-zonal flow is now positioned over the Desert
Southwest and guidance shows this lasting into the weekend keeping
H5 heights fairly stable between 573-579dm. The lower heights are
ushering in some modestly cooler air into the region and this
will drop high temperatures down to below 80 degrees for the bulk
of the lower deserts starting today. Daily highs mostly in the
upper 70s are forecast to persist into the weekend before finally
seeing another cooling trend. Dry conditions are also expected
through this weekend with any good moisture easily bypassing our
region to the north with only some periods of higher level clouds
expected.

Once the main Pacific weather system finally ejects eastward into
the central U.S. over the weekend, another much weaker trough is
seen developing well to our west before likely tracking through
our region at some point early next week. However, this next
weather system for our region is looking very dry as forecast
PWAT anomalies look to be mainly between 40-70% of normal.
Guidance agrees this will not be a precipitation maker for our
region, but it should drop temperatures back to around or even
slightly below normal by next Tuesday. NBM forecast highs for the
middle of next week continue this cool trend with highs mostly in
the upper 60s to around 70 degrees. Beyond that, slightly more
than half of the ensemble members shows precipitation chances at
some point late next week into the following weekend. However,
this potential weather system is likely to come from the northwest
and so far does not seem to be connected with a good stream of
Pacific moisture.

&&

.AVIATION...Updated at 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No major weather issues will exist through the TAF period as clear
skies will persist with light and diurnal winds aob 7kts. A short
time period of southerly cross runway winds are possible during
the transition tomorrow afternoon, but speeds should be very light
and temporally limited.

Southeast California/Southwest Arizona including KIPL and KBLH:

No major weather issues will exist Throughout the TAF period. W
direction will be dominate at KIPL but KBLH can expect VRB
conditions. Wind speeds at KIPL should decrease overnight with
decoupling, however maintaining a W component aob 10kt after 09Z.

&&

.FIRE WEATHER...
Weak high pressure will remain over the region through the rest
of the week providing a continuation of the above normal
temperatures and dry conditions. MinRHs over the next few days
will mostly range between 20-30% over the western districts to
15-25% over the eastern districts. Winds will remain fairly light,
but expect some afternoon and evening breeziness with gusts up to
around 20 mph mainly across the western districts. Starting this
weekend into early next week, the weather pattern will gradually
shift to allow for temperatures to cool back into the normal
range, but expect continued dry conditions and low humidities.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&

$$

DISCUSSION...Kuhlman
AVIATION...Ryan
FIRE WEATHER...Kuhlman