436
FXUS65 KPSR 290507
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1007 PM MST Tue May 28 2024

.UPDATE...Updated 06Z Aviation Discussion.

&&

.SYNOPSIS...
Dry and mostly tranquil conditions will be the norm over the next
several days as highs across the lower deserts reach into the triple
digits. A weak disturbance will pass north of the region Wednesday
into Thursday but will result almost no noticeable change in day-
to-day conditions outside of a slight increase in regional winds.
This hot and quiet pattern will persist into this weekend and
likely into next week.

&&

.DISCUSSION...
Atmospheric analysis reveals ridging entrenched across much of the
western CONUS, promoting dry and tranquil conditions across the
Desert Southwest, which will continue for today. Temperatures this
afternoon will be a few degrees warmer compared to where they were
yesterday due to heights aloft continuing to increase day-by-day.
Lower desert high temperatures will range generally between
100-105 degrees, helping to increase the coverage of Moderate
HeatRisk for parts of the region, especially for areas around the
Phoenix metro, Colorado River Valley, and Imperial Valley. If you
plan to be outside for a prolonged period during the hours of peak
heating, be sure to take frequent breaks and hydrate often.

A weak, transient trough will pass over the western CONUS Wednesday,
with the greatest energy focused over the Pacific Northwest and
northern Rockies. Outside of a slight increase in the regional
pressure gradient leading to some nuisance breeziness during the
afternoon, and perhaps a degree or two drop in temperatures compares
to Tuesday, little to no sensible weather changes will occur with
this system. Afternoon highs on Wednesday will range from the
upper 90s to around 103 degrees across the lower deserts. With the
aforementioned system moving over the the Plains by Thursday,
heights aloft will rebound slightly, allowing for a small rebound
in temperatures as highs that afternoon will range between 100-105
degrees once again. Friday looks to be much of the same, albeit a
degree or two warmer, with daytime highs between 102-106 degrees.

Some global ensembles are now hinting at another weak trough
traversing the western CONUS by this weekend, but keep the
greatest associated height falls/coldest air well off to our
north, this time focused over southern Canada, yielding almost no
changes for regional conditions. Model clusters, even with the
passage of a trough, agree that heights aloft over our forecast
area will remain climatological normals, which help keep the
streak of triple-digit heat going into the weekend. Clusters also
agree that an amplified ridge will develop by next week,
suggesting that a continuation of dry, tranquil, and hot
conditions is in store for next week, with some areas potentially
seeing their first 110 readings since last September. The NBM 75th
percentile has Phoenix reaching that point by next Wednesday, but
it is still too early to say with confidence that temperatures
will reach that high.

&&

.AVIATION...Updated at 0505Z.

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

Winds will follow their typical diurnal patterns with some
extended periods of light and variable winds. Wind speeds will
generally be aob 10 kt through the TAF period, however, some
periodic gusts into the teens will be possible once again tomorrow
afternoon. FEW- SCT high clouds will clear out tomorrow
afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:

At KIPL winds will mainly be out of the west through the TAF
period whereas at KBLH winds will be out of the south to
southwest. Winds at KIPL will gust into the low 20s through the
overnight hours, with speeds returning to aob 10 kt through the
mid- to- late morning and afternoon hours. Then, around 00Z
tomorrow night winds will once again gust into the mid 20s for the
evening and into the overnight hours. At KBLH, wind speeds will be
aob 10 kt through the TAF period. FEW high clouds will clear out
through the overnight hours.

&&

.FIRE WEATHER...
Hot and dry conditions will persist through this weekend with highs
topping out around 5 degrees above normal each afternoon. MinRH
values will remain at or below 10% across the central and western
deserts and overnight recoveries will continue to range from poor
to fair at around 25-40%. Winds are generally expected to remain
below 15 mph, but an uptick in breeziness could result in pockets
of elevated fire weather concerns by the middle of this week
(peaking on Wednesday).

&&

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

$$

DISCUSSION...RW
AVIATION...Berislavich
FIRE WEATHER...Salerno