804
FXUS65 KPSR 082343
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
443 PM MST Sat Jun 8 2024

.UPDATE...
00z Aviation Discussion.

&&

.SYNOPSIS...
Slightly cooler, although above normal, temperatures are forecast
through the weekend into Monday. Expect temperatures to heat up
by the middle of next week due in large part to high pressure
building into the region. Dry conditions will prevail through the
forecast period.

&&

.DISCUSSION...
For the short term, weak circulation associated with a very weak
upper-level low located over the Sonoran Desert region of the northwest
corner of Mexico continues to gradually move northward into AZ
helping to slightly lower 500 mb heights dropping temps a couple
of degrees. Expect low temperatures this evening to dip to the low
80s for the Phoenix Metro and low to mid 70s for the surrounding
region. Expect low temps to fall to the upper 60s in higher
mountain elevations. Along with the cooler temperatures, the weak
upper-level low will also help enhance somewhat the early evening
breeziness across the area, with the potential for some gusts
exceeding 30 mph at times across portions of western Imperial
County. Upper level clouds will continue to build into the eastern
portions of the CWA this evening, slightly clearing overnight,
building back in tomorrow during the day. Winds will continue to
generally favor diurnal tendencies with occasional afternoon gusts
of 20-25 mph expected across most of the region tomorrow.

Heading into next week, model guidance continues to remain in
pretty good agreement in the overall synoptic pattern as another
upper-level low is set to cutoff off the coast of southern
CA/northern Baja by Monday with a ridge strengthening across the
southwestern CONUS. There still continues to be some discrepancies
examining the ensemble cluster analysis in the overall
positioning/strength of the cutoff low, which will dictate the
positioning of the ridge downstream. Latest trend indicates a
pretty robust ridge building across NM/AZ by midweek with 500 mb
height fields rising above 590dm across most of the region with
values as high as 594-597dm across the eastern half of AZ through
NM. Therefore, an uptick in temperatures can be expected heading
into the Tuesday-Thursday timeframe with another round of
excessive heat conditions possible, especially across the south-
central AZ lower deserts, as highs will likely once again reach
110+ degrees and potentially necessitating the issuance of new
excessive heat products.

Ensemble and cluster analysis shows a cutoff low eventually
making its way through the region by the end of next week,
bringing slightly cooler temperatures. Heading into next weekend,
a more potent large-scale trough will approach the Pacific
Northwest and traverse the western CONUS. However, there is a
large degree of spread amongst the ensembles and large
uncertainty in cluster analysis on the overall depth and position
of the trough, which will dictate whether or not the Desert
Southwest will see any impacts in the form increased winds,
further cooling, and potential precipitation.

&&

.AVIATION...Updated at 2340Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT;
No aviation weather concerns are anticipated through the TAF
period. Wind directions will continue to follow diurnal patterns
with westerly flow expected through sunset before easterly winds
become reestablished around 07Z at KIWA and 09Z at KPHX. Speeds
should remain aob 10 kts through tonight. Hi-resolution guidance
continues to show the potential for some weak virga showers
passing over South-Central AZ this evening, but no impacts to the
terminals are expected. High clouds will increase in coverage this
evening, becoming BKN at 20-25 kft.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns will exist through the TAF period.
Winds will favor southerly to southwesterly at KBLH through
tonight with gusts upwards of 20 to 25 kt possible early this
evening. Wind directions will favor westerly at KIPL with gusts
increasing to around 25 kt and occasionally up to 30 kt this
evening, before diminishing overnight and returning to southeast
by early tomorrow morning. Skies will remain mostly clear over
southeast CA, with the exception of a few passing high clouds.

&&

.FIRE WEATHER...
Hot and seasonably dry conditions will continue to support a high
fire danger across the area into late next week. Slightly cooler
temperatures, although still remaining above normal, can be
expected through Sunday before heating up once again heading into
the middle of next week. Winds will continue to generally favor
diurnal tendencies with occasional afternoon breeziness of 20-25
mph expected across most of the region. MinRHs ranging between
5-15% with poor to fair overnight recoveries of between 20-45%
will be common.

&&

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

$$

DISCUSSION...95/Lojero
AVIATION...Salerno
FIRE WEATHER...95/Lojero