764
FXUS65 KPSR 281052
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
352 AM MST Tue May 28 2024

.SYNOPSIS...
Hot and dry weather will continue for the foreseeable future with
lower desert highs reaching 100-105 degrees each afternoon. A
weak disturbance will pass north of the region mid-week, but will
result in almost no sensible change in conditions outside of a
slight increase in winds. Above normal temperatures will carry
into this weekend with dry conditions prevailing.

&&

.DISCUSSION...
We will begin today with an upper level ridge becoming more
amplified over the Intermountain West. This ridge will continue to
bring dry and tranquil conditions to AZ and southeast CA. 500 mb
hghts are expected to rise slightly this afternoon to around 584-586
mb, resulting in highs peaking a couple degrees warmer than
yesterday. Expect highs across the lower deserts to reach the upper
90s to around 105 degrees or around 5 degrees above average.
HeatRisk levels will increase to moderate in some areas including
the Phoenix Metro area, Colorado River Valley, and Imperial Valley
this afternoon, so make sure to take proper heat precautions if
working outdoors. Besides localized gusty winds in the Imperial
Valley this evening, another tranquil night is anticipated across
the region with lows settling into the mid 60s to lower 70s.

On Wednesday, a trough of low pressure will move into the Pac NW and
displace the upper ridge ewd into the Central Plains. Despite a
slight decline in hghts aloft, there will be little to no
discernible difference in temperatures across our region with
widespread 100 degree highs still expected. A tightening pressure
gradient between the troughing feature to our north and high
pressure in N Mexico will result in slightly breezier conditions
Wednesday afternoon with gusts reaching 15-20 mph across the lower
deserts and 20-25 mph in the AZ high terrain. Higher gusts up to 35
mph will also be possible in far western Imperial County. Once the
trough axis passes through the region, high pressure will again
build across the Desert Southwest through the rest of this week.
Temperatures will rise a degree or two each day, peaking on Friday
which looks to be the hottest day of the forecast period with highs
approaching 105-106 in the Phoenix Metro. Therefore, we can expect a
greater coverage in Moderate HeatRisk by Friday afternoon.

Heading into this weekend, 500 mb cluster analysis continues to
indicating positive hght anomalies overspreading the region despite
overall broad troughing across the western CONUS. Temperatures will
therefore remain around 5 degrees above average Saturday and Sunday
with highs mainly ranging from 100-105 degrees across the lower
deserts. Clusters analysis and global ensembles are still showing
the potential for a further amplification of ridging aloft by the
middle of next week, which may result in the first 110 degree
highs in some desert communities. The 75th percentile of the NBM
has temperatures in Phoenix reaching close to that mark by next
Wednesday, and this will certainly be something to keep an eye on
in the coming days.

&&

.AVIATION...Updated at 2350Z.

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

No major aviation weather concerns are expected through the TAF
period under mostly clear skies. Winds will continue to exhibit
diurnal tendencies with speeds generally aob 10 kts, although some
periodic gusts in the mid to upper teens will be common Tuesday
afternoon once again. There will likely be extended periods of
light and variable directions as well.

Southeast California/Southwest Arizona including KIPL and KBLH:

No major aviation weather concerns are expected through the TAF
period under mostly clear skies. At KIPL, winds will mostly be out
of the west, with a period of southerly winds Tuesday afternoon.
At KBLH, winds will mostly be out of the south to southwest. Winds
will generally be light below 10 kts through Tuesday morning with
periods of variability, with gusts picking up to near 20 kts at
KBLH during the afternoon and at KIPL during the early evening
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...Salerno
AVIATION...Lojero
FIRE WEATHER...Salerno