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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS65 KPSR 222340
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
440 PM MST Mon Apr 22 2024

.UPDATE...
-- Changed Discussion --
00Z Aviation Discussion.
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&&

.SYNOPSIS...
Hot weather continuing today, but a cooling trend through the end
of the week will result in more pleasant weather as temperatures
dip back near normal going into this weekend. Breezy to localized
windy conditions will spread across the region over the next
several days. No rain chances through this week, but non-zero
chances develop this weekend.

&&

.DISCUSSION...
Another 100 degree day in central Phoenix has already occurred,
but today will be the hottest day in the foreseeable future.
Current satellite depicts mostly clear skies, with only thin
cirrus passing overhead and fair weather cumulus developing in
some spots of the higher terrain of southcentral Arizona. Clear
skies will persist through at least tomorrow, ahead of some higher
clouds passing over the region tomorrow night.

The larger scale pattern consisting of ridging over the Desert
Southwest, causing the temperatures to soar near record levels the
last couple of days. The positive height anomalies will begin to
weaken over the next day or two, as longwave troughing across the
eastern Pacific deepens well offshore of California. This trough
will then move inland, leading to more breezy to localized windy
conditions and cooling temperatures beginning as early as
tomorrow. Temperatures are expected to remain above normal through
at least Wednesday, before below normal temperatures settle into
the region going into the weekend.

This trough will bring enhance mid-level winds to the region as
early as tomorrow, with the western districts the first to
experience breezy to localized windy conditions. At this point,
Wednesday looks to be the peak across the central to western
portions of Imperial County, with borderline advisory level
sundowner winds (40+ mph gusts) at least in the higher terrain of
southwestern Imperial County, with lower gusts for the lower
deserts. Enhanced winds will then spread eastward to southcentral
Arizona on Thursday as the initial trough moves east of the
region.

Ensembles are in good agreement of a secondary trough diving
southward upstream of the initial trough across western CONUS late
week, with this trough influencing temperatures and potential rain
chances over the weekend. By that point, spread amongst the
ensembles are a bit more noticeable, as there seems to be
discrepancies on how anomalous this trough will become.
Regardless, temperatures will continue to remain below normal
through at least Saturday, but if a stronger solution verifies,
then the cooler temperatures could persist longer. Additionally,
the deeper the system, the more available moisture would be
available to potentially spark shower activity across southcentral
Arizona. However, this scenario is a very low probability, as
latest NBM PoP`s for Saturday remains below 20% (10%) for the
higher terrain (lower deserts) at this point.

&&

.AVIATION...
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Updated at 2340Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are anticipated through the forecast period.
Winds have been slow to shift fully out of the W at KPHX, and this
will likely not occur for a couple more hrs. Until then winds
will likely remain S-SW (170-220 deg). Winds will shift back out
of the E-SE by 07Z-09Z at all metro terminals. Tuesday will be
similar as winds slowly veer through the afternoon. There will
likely be another prolonged period of southerly crosswinds until
winds ultimately shift out of the SW after 21Z.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns will exist through Tuesday under
mostly clear skies. Winds will generally be southerly at KBLH and
southwesterly at KIPL overnight. Some gustiness will be possible
at both terminals late Tuesday morning as S-SW flow increases.
-- End Changed Discussion --

&&

.FIRE WEATHER...
Dry conditions with above normal temperatures will persist early
this week with winds steadily becoming more breezy ahead of an
approaching weather system set to move through midweek. Afternoon
humidity levels will continue to fall to around 10% following poor
to fair overnight recovery of 20-40%. Cooler weather arriving during
the latter half of the week will allow an improvement to RH with
afternoon values only falling into a 15-25% range. As this weather
disturbance moves through the region later in the week, very breezy
conditions will also occasionally impact districts with afternoon
gusts commonly reaching 20-30 mph. Given this combination of winds
and humidity levels, a periodic elevated fire danger should be
planned for during the second half of the week.

&&

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

$$

DISCUSSION...Young
AVIATION...Salerno
FIRE WEATHER...Young/Kuhlman