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000
FXUS65 KPSR 130528
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1028 PM MST Fri Apr 12 2024

.UPDATE...Updated 06Z Aviation Discussion.

&&

.SYNOPSIS...
Dry and warm temperatures will continue through tomorrow, ahead of
a cool down back to below normal through early next week. The only
other weather highlight is that with this cool down, stronger
winds will develop during this period due to pressure falls across
the region. Warming temperatures back to above normal is expected
by the middle of next week.

&&

.DISCUSSION...
Another warm afternoon continues today, with breezy conditions
spreading across the lower deserts. Central Phoenix is already in
the lower 90s, with all of the lower deserts expected to range in
the low to mid-90s for highs today. Temperatures will begin to
cool over the next couple of day ahead of the next troughing
feature that will scoot across the region going into early next
week.

With the approach of this system, breezy to windy conditions will
be an afternoon occurrence across the region through at least this
weekend. Southerly to southwesterly flow will begin to ramp up
tomorrow across the western portions of the region as the
troughing feature moves onshore of central California. Wind
Advisories are now in effect for portions of Imperial County due
to winds anticipated to gust in the 40-50 mph range tomorrow
afternoon and evening due to the sundowner effect. Similar
conditions are anticipated for Sunday as well out west, with
strong 40-50 knot winds aloft persisting across the region.
Stronger winds are also expected to then spread into southcentral
Arizona, with gusts in the 25-35 mph range for Sunday across the
lower deserts. For Monday, residual breeziness may persist across
southcentral Arizona, mainly confined to the higher terrain areas,
as the upper low exits the region. Rain chances across the region
remain very low, with maximum NBM PoP`s around 5% Sunday into
Monday, which isn`t overly surprising given the limited moisture
advection into the region for this event (PWAT`s in the
0.30-0.40" range).

Heading into the middle of next week, mid-level heights will
rebound, resulting in a warming trend. However, there remains some
uncertainty in regards to the magnitude of warming due to
ensembles showing discrepancies in a trough traversing across the
Intermountain West Tuesday into Thursday. Greater than 50% of the
clusters for Wednesday would suggest a dampening of the ridge
across Western CONUS, which could result in lesser warming trend.
Clusters then continue to show some version of a trough, although
to much more minor extent around 30% of the members, potentially
persisting across the Intermountain West through the end of the
week. Thus, the NBM interquartile spread increases from Wednesday
onward. We`ll have to keep an eye on how things trend over the
next several days, as the other extreme, where some clusters
depict strong positive height anomalies building across the
Desert Southwest, currently gives a small chance (10-20%) of
hitting triple digits for highs late next week according to the
latest NBM.

&&

.AVIATION...Updated at 0530Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Wind directions are expected to establish out of the E-SE over the
next few hours, with speeds mainly aob 8 kt overnight. Beginning
tomorrow morning, confidence is good that there will be a similar
evolution in the wind directions to what we saw today, veering out
of the SE-SSE mid-late morning, followed by a southerly cross
runway component midday, and eventually establishing out of the
SSW-SW tomorrow afternoon. Speeds will be lower, with gusts
peaking in the mid-to-upper teens to around 20 kt in the
afternoon. SKC skies will prevail through the period.

Southeast California/Southwest Arizona including KIPL and KBLH:
The primary aviation weather concern through the TAF period will
be gusty west winds, particularly at IPL tomorrow evening. Wind
directions will favor S-SW through much of the period at BLH and W
at IPL except during the day tomorrow, where a relatively light
(aob 7 kt sustained) SE prevailing wind is expected. West winds
will pick up between 21-23Z at IPL, with gusts peaking upwards of
35 kts during the evening. Accompanying the stronger gusts,
temporary reductions in visibility from lofted dust will be
possible. Mostly clear skies will prevail through the period.

&&

.FIRE WEATHER...
Dry conditions and near to above normal temperatures are expected
through Saturday, with highs in the low to mid 90s today and mid to
upper 80s Saturday. Temperatures then cool and moisture levels nudge
up slightly Sunday and Monday with the passage of a weather system
just to the north. This weather system, on approach to the region
and as it passes through, will lead to daily breezy to locally windy
conditions each afternoon and evening through at least Monday. Wind
gusts up to 20-30 mph are anticipated across nearly all districts
each day, with locally higher gusts up to 35-40+ mph in parts of
southwest AZ, southeast CA, and southern Gila County. Wind
Advisories are in effect for portions of central to western
Imperial County tomorrow as a result of winds anticipated to gust
in excess of 40 mph for the late afternoon and into the evening
hours. These increased winds may lead to periods of elevated fire
weather conditions, as minimum RHs bottom out at or below 15%
across the region today and Saturday and around 15-25% Sunday and
Monday. Overnight recoveries will be good through this weekend,
with max RHs upwards of 45-75%. Winds lower, temperatures warm
back up, and minimum RHs lower back to 15% or lower by the middle
of next week.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...Wind Advisory from 3 PM to 11 PM PDT Saturday for CAZ562-563-566-
     567.

&&

$$

DISCUSSION...Young
AVIATION...Whittock
FIRE WEATHER...Young/Benedict