731
FXUS65 KPSR 150025
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
525 PM MST Fri Mar 14 2025

.UPDATE...
Updated Aviation section.

&&

.SYNOPSIS...
A weather system will quickly move through the region tonight,
bringing chances for showers and mountain snow. Over the weekend,
expect dry conditions and warming temperatures as high pressure
builds over the Desert Southwest. Afternoon high temperatures will
approach seasonal normals by Sunday and may exceed eighty degrees
across the lower deserts Monday. Another weather system will
progress through the region early next week, increasing winds and
cooling temperatures back below normal for a day or two.

&&

.DISCUSSION...
With the Western US under longwave troughing today, one more quick-
moving, sheared shortwave is evident in mid-level wv imagery
diving southeastward over CA at this hour. This shortwave will
make its way into Central AZ this evening. Large-scale ascent
associated with the rapidly approaching shortwave and attendant
jet streak, along with some modest advection of higher theta-e air
at 850 mb, will provide the right ingredients to trigger some
elevated convective showers over the South-Central AZ lower
deserts late this evening into the early morning hours Saturday.
With these, some moderate rainfall rates and occasional lightning
are possible. QPF amounts will be light for most areas as lower
desert amounts look to be generally around 0.10" or less. Higher
amounts will reside over orographically favored areas north and
east of Phoenix. Given the cold airmass in place, snow levels will
be around 4,000-5,000 feet and thus expect to see snow occur at
these elevations this evening into early Saturday. A Winter
Weather Advisory remains in effect for the Mazatzal Mountains,
Pinal/Superstition Mountains, and Southeast Gila County high
terrain above 5,000 feet where the best snowfall accumulations are
expected to occur (4 to 7 inches).

Thanks to the influence of longwave troughing over the forecast
area, temperatures today will be well below seasonal normals. NAEFS
mean 850 mb temperature reflect the colder air mass in place over
the region, with values below the 1st percentile of climatology for
the time of year. Temperatures this afternoon in the Phoenix area
are near their forecast highs already, generally in the middle to
upper 50s. Further west, places like Yuma and El Centro have reached
the middle 60s this afternoon.

Ensemble guidance remain in good agreement that the overall
progressive pattern will continue, with ridging temporarily building
into the region later this weekend into early next week with H5
heights peaking around 580 dm. As a result, temperatures will warm
up to near normal readings by Sunday before climbing slightly
above normal Monday into the upper 70s to low 80s. WPC Clusters
are in good agreement that a shortwave trough will pass through
the Southwest CONUS Tuesday, though there remains some uncertainty
in the amplitude of the trough. Despite the uncertainty, ensemble
members are in good agreement in mostly dry conditions persisting
locally with an uptick in winds along with cooler temperatures
being the primary sensible weather impacts. Following the passage
of this trough, global ensembles suggest flat ridging building
into the region and will lead to a warming trend for the latter
half of next week with temperatures climbing slightly above normal
by the end of next week.

&&

.AVIATION...Updated at 0025Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:

A strong weather disturbance from the northwest will lead to
increasing low clouds and the development of scattered light
showers this evening. The main window of time for the showers is
04Z-09Z. In the process, ceilings will fluctuate between
FL060-FL090 and decline to FL040-FL060 after 04Z. With the
showers, there will be shorter lived ceilings of FL030-FL050 and
visibilities of 5SM-7SM. Expect an improving trend after 09Z with
little to no ceilings after 13Z or so. As for surface winds,
southwest directions will be favored through 02Z (occasional gusts
to 20kts) before directions become more variable (favoring
S/SEly). A Wly component is anticipated to become more prevalent
after 09Z with Wly/NWly breeziness (gusts 20-25kts) after 20Z.


Southeast California/Southwest Arizona including KIPL and KBLH:

A strong weather disturbance from the northwest will maintain
windy Wly conditions at KIPL (gusts 25-35kts) through much of the
evening (less so at KBLH). Winds weaken by late evening before
NWly directions develop between 16Z-18Z (gusts to 25kts at KBLH).
As for sky cover, SCT-BKN layers at FL060-FL090 can be expected
until about 05Z or so before thinning out.

&&

.FIRE WEATHER...
Another weather system will push through the region later today
into early Saturday, bringing additional chances for showers and
higher elevation snow. The best chances for showers are expected
this evening into the overnight hours with the chance for wetting
rain greatest across south-central Arizona. Winds will be much
lighter today with some afternoon wind gusts upwards of 20-30 mph
primarily across the western districts. Drier conditions will
prevail for the weekend with Min RHs dropping to around 20-30%
across south-central Arizona and 15-25% across southwest Arizona
and southeast California by Sunday. Another weather system will
pass through the region next Tuesday with gusty winds and cooler
temperatures expected to be the primary sensible weather impacts.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Winter Weather Advisory until 5 AM MST Saturday for AZZ557-558-
     563.

CA...Wind Advisory until 5 AM PDT Saturday for CAZ562.

&&

$$

DISCUSSION...Whittock/Smith
AVIATION...AJ
FIRE WEATHER...Smith