394
FXUS65 KPSR 170949
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
249 AM MST Fri Apr 17 2026

.KEY MESSAGES...

- A dry front will sweep the region from the northwest leading to
  locally windy conditions and elevated fire weather concerns,
  primarily for portions of Southeast California later this
  morning.

- A Wind Advisory will be in effect from early this morning until
  the early afternoon for an area stretching from Joshua Tree
  National Park to along the Lower Colorado River Valley.

- Temperatures near to slightly below normal today will warm back
  into an above normal category over the weekend, with widespread
  lower desert highs in the nineties likely by Sunday.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
A core of strongly negative midlevel height anomalies sits over
North-Central Montana extending into Southern Canada early this
morning, with a shortwave trough axis attached to it and swinging
through the Great Basin and into Utah. Clues from surface analysis
and station observations, midlevel wv imagery, and early morning
RAP analysis indicate that a low-level front and associated area
of tight pressure/temperature gradients is moving southward
through Southern NV. Surface winds are picking up at several sites
in the CA/AZ/NV tri-state area, but the main surge of more
widespread windy conditions will not occur until after sunrise for
our western deserts. A Wind Advisory remains in effect through 1
PM MST/PDT this afternoon for an area extending from Joshua Tree
NP toward the Lower Colorado River Valley, where gusts to between
30-45 mph will become common after sunrise. These strong winds
will present difficult travel conditions, especially for high
profile vehicles along portions of I-10 around and west of Blythe,
CA. Some blowing dust channels cannot be ruled out. Other breezy
spots will be the Imperial Valley and portions of wester Yuma and
La Paz Counties. However, gusts for these areas should range
closer to 25-35 mph, though an isolated advisory-level gust would
not be surprising. As local pressure/temperature gradients relax
during the afternoon, so too will the winds.

Ensembles remain in excellent agreement that this initial
shortwave will quickly eject eastward, with upper level ridging
shifting over the Western US in its wake and building over the
West-Central CONUS late this weekend into early next week.
Meanwhile, an upper level low dives southward off the Pacific
Northwest Coast and eventually settles off the NorCal coast.
Temperatures today, thanks in large part to the front passing over
the region, will be near to slightly below normal, with the below
normal readings more common out west. The influence of upper
level ridging will allow temperatures to rebound into an above
normal category over the weekend. This will translate to lower
deserts highs near 90F by Saturday. Forecast highs from the latest
NBM maintain Sunday as the warmest of the next 7 days, with lower
desert highs likely attaining the middle 90s. The influence of
upper level ridging will maintain highs in the 90s into early next
week.

As the initial shortwave ejects eastward over the next couple
days, an attendant area of surface high pressure currently over
the Great Basing will shift over the Rockies, then slide south
southeastward over NM/Western TX by Sunday morning. NAEFS mean
MSLP in this area will in fact exceed the 90th percentile and
locally upwards of the 97th percentile of climatology. This will
set up a strong ESE-WNW regional pressure gradient by Sunday
morning. As a result, another round of breezy to locally windy
conditions are expected to develop for the southeastern portion of
AZ. For our forecast area, the strongest winds will be focused
over higher terrain to the east/southeast of Phoenix. This
southeasterly fetch will moisten the midlevels of the atmosphere
modestly, and even allow dewpoints across South-Central AZ to
reach the 30s F from their much drier values in the teens Saturday
night.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Early next week, the upper level pattern with West-Central CONUS
ridging and a broad upper low off the West Coast will be
maintained, however, shortwaves rotating around the broad upper
low to our northwest will bring sensible weather changes for the
forecast area as we head into the middle of the week. Forecast
uncertainty remain moderate to high, with WPC cluster analysis
revealing discrepancies in timing and the N/S displacement of the
upper low as it eventually makes its way inland. The uncertainty
is still reflected in the probabilistic NBM temperatures, as IQRs
for the forecast highs/lows increase to 5F or greater Wednesday
onward. Overall, temperatures should retreat closer to or even
slightly below seasonal normals during the middle of next week.
Another uncertainty is whether the forcing from the shortwaves
rotating about the broad upper low will combine with meager
moisture (mostly in the mid levels) to produce light shower
activity over portions of AZ. However, the vast majority of global
guidance shows the area remaining dry, with PoPs below 10%.
Regardless, this pattern evolution will almost certainly result in
another widespread breezy to locally windy period during the
middle of the upcoming work week.

&&

.AVIATION...Updated at 0530Z.

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

VFR conditions will persist under gradually clearing high clouds.
Winds will tend to follow their typical diurnal tendencies with a
slightly later easterly shift tonight and again tomorrow night
(08-09Z). Wind speeds will generally be around 10 kt or less,
with some occasional gusts into the upper teens during the
afternoon and early evening hours.

Southeast California/Southwest Arizona including KIPL and KBLH:

VFR conditions will persist under gradually clearing high clouds.
At KIPL, current SW`rly winds will go N`rly early tomorrow
morning. Wind speeds will generally be around 10 kt or less, with
some occasional gusts of 20-25 kt during the late morning hours.
At KBLH, current S/SW winds will go NW overnight and then turn
northerly early tomorrow morning (~13Z). Winds will generally be
around 10 kt or less through early tomorrow morning when winds
will start gusting 20-30 kt, with some occasional gusts of 30-35
kt possible during the mid to late morning hours. Wind gusts will
gradually taper off through tomorrow evening.

&&

.FIRE WEATHER...
Dry and occasionally breezy conditions will prevail through the
next week. A dry cold front is currently moving southward down the
Colorado River Valley, which will produce gusty winds later this
morning, with gusts to 30-45 mph for portions of Southeast CA and
Southwest AZ. Winds will gradually relax heading into the
afternoon as humidity drops into the single digits. Elevated and
locally critical fire weather conditions are expected to
materialize for portions of the western deserts as a result,
particularly along the Lower Colorado River Valley. Winds will be
much lighter, generally below 15 mph, on Saturday. Afternoon
MinRHs below 15% and at times in the single digits will be common
through the next 7 days, with minor day to day variations.
Overnight recoveries will offer little relief this weekend, with
values commonly between 10-30% (on the lower end of that range for
the western deserts).

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Wind Advisory until 1 PM MST this afternoon for AZZ530.

CA...Wind Advisory until 1 PM PDT this afternoon for CAZ560-561-564-
     565-568>570.

&&

$$

SHORT TERM..Whittock
LONG TERM...Whittock
AVIATION...Berislavich
FIRE WEATHER...Whittock

NWS Phoenix (PSR) Office