038
FXUS65 KPSR 072355
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
455 PM MST Sun Jul 7 2024

.UPDATE...Updated 00z Aviation Discussion.

&&

.SYNOPSIS...
Extreme heat will continue to prevail through the upcoming week
as strong high pressure remains entrenched across the region. High
temperatures across the lower deserts will range between 112-120
degrees. Some moisture will start to move over the region by the
middle to latter half of the week, aiding in increasing
thunderstorm chances across southeast AZ and the Arizona high
terrain.

&&

.DISCUSSION...
Strong surface high pressure is currently situated along the central
CA/NV border with a northerly wind flow prevailing across the
region. This northerly flow is continuing to promote a very dry air
mass with SPC mesoanalysis indicating PWATs ranging between 0.5-0.8"
across the majority of the region. As a result, mostly clear skies
along with near zero storm activity will continue. The surface high
pressure is expected to very slowly drift eastward and be situated
near the NV/AZ/UT border heading into middle to latter of the
week. As a result, the 500 mb height fields will continue to
remain steady state, in the 594-597dm range, through the majority
of the upcoming week. The enhanced 500 mb heights in combination
with the mostly clear skies will continue to result in extreme
heat conditions through most of the upcoming week. High
temperatures across the lower deserts will range between 112-120
degrees, with the highest readings across the western deserts. The
magnitude of these temperatures will result in widespread major
to locally extreme HeatRisk, with Excessive Heat Warnings in
effect through Thursday. Therefore, if performing outdoor
activities, it is crucial to take all the necessary heat
precautions to protect yourself and others from these extreme
temperatures as they can become life-threatening!

As the center of the high pressure moves near the NV/AZ/UT border
by mid-week, the flow pattern will become a bit more favorable to
allow for some moisture intrusion into portions of southeastern
and eastern AZ. This will lead to afternoon and early evening
isolated storm chances starting as early as Tuesday across
portions of southeastern and the higher terrain areas of eastern
AZ. Unfortunately, given the isolated nature of the storms, any
associated outflow boundaries or cloud debris will likely not be
enough to have a significant effect on the overall temperatures,
which is why confidence is high enough for the extreme heat
conditions to continue through the latter half of the week.

Heading into next weekend, the high pressure is expected to migrate
towards the Four Corners Region. As it does so, it will promote
better moisture advection with model ensembles showing PWATs
rising to above 1" across the region. This will lead to increased
storm chances, at least for the Arizona lower deserts, where NBM
PoPs for next weekend range between 20-30%. With the increased
moisture, temperatures will trend down below the excessive heat
threshold.

&&

.AVIATION...Updated at 2355Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation weather concerns will exist through the TAF period
under mostly clear skies. Winds will exhibit diurnal tendencies,
with W/SW gusts to around 20 kt ceasing over the next several
hours and gusts into the mid teens returning tomorrow afternoon.
The typical E`rly switch is expected to take hold around 10-12Z at
KPHX before westerly winds reestablish late tomorrow morning.

Southeast California/Southwest Arizona including KIPL and KBLH:
Winds will follow diurnal trends at both terminals, with perhaps
some periods of variability at IPL this afternoon. Speeds at IPL
should remain generally aob 12 kts. Stronger speeds are
anticipated at BLH, with sustained winds in the mid-teens through
early tonight, with some occasional gusts 20-25 kts. Clear skies
will prevail through Monday afternoon.

&&

.FIRE WEATHER...
Hot and dry conditions continue through most of next week as high
pressure remains overhead. Extreme temperatures continue with daily
high temperatures generally between 110-120 degrees across the lower
deserts and 95-110 degrees across the higher terrain. Daily MinRH
values will range from 5-15% across the lower deserts and 10-20%
across the Arizona higher terrain, with overnight recoveries
generally in the 30-50% range. Winds will be fairly light and tend
to follow their typical diurnal patterns, with some occasional
gusts near 20 mph in the afternoons. This afternoon looks to be
the breeziest this week, with afternoon wind gusts up around 20-30
mph, mainly across the eastern districts. The very hot and dry
conditions will lead to an increased fire danger threat.

&&

.CLIMATE...

Record Highs

           Phoenix      Yuma      El Centro
          ---------    -------   -----------
July 7    118 (2017)  118 (2017)  121 (2017)
July 8    115 (1985)  118 (1958)  117 (1942)
July 9    116 (1958)  119 (1958)  117 (1958)
July 10   115 (1958)  118 (1959)  116 (2021)
July 11   118 (1958)  118 (1958)  117 (1975)

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Thursday for AZZ530>555-
     559.

CA...Excessive Heat Warning until 8 PM PDT Thursday for CAZ560>570.

&&

$$

DISCUSSION...Lojero
AVIATION...Whittock/RW
FIRE WEATHER...Berislavich
CLIMATE...Berislavich/Kuhlman