461
FXUS65 KPSR 130541
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1041 PM MST Sun May 12 2024

.UPDATE...Updated 06z Aviation Discussion.

&&

.SYNOPSIS...
Temperatures will remain above normal for the week ahead with the
lower desert communities nearing or exceeding 100 degrees most
days. Dry conditions will persist with the usual late afternoon
breeziness. An exception will be the higher elevations of northern
and eastern Arizona which will see a few late day showers each
day. These showers could be supportive of some erratic, gusty
winds descending into the lower deserts each evening.

&&

.DISCUSSION...
Midday water vapor imagery showing upper level low circulation now
into SE CO and continuing to move away from the region. Visible
imagery still indicating some residual moisture over the high
country back into central/eastern AZ with some cumulus forming.
Could be a couple showers form in these areas later today, but
isolated in coverage and no impact into the lower elevations.

Otherwise, ensembles in overall good agreement with heights
building slightly over the region into Monday, bringing with it
another day of temperatures a few degrees warmer, with highs
around 100 degrees. HeatRisk will maximize in the moderate
category at best for scattered locations and mainly across SE CA.
The weak ridging will be short lived as another upper low moves in
from off the SW CA coast. This will produce height falls again
across the SW US. Not enough moisture for showers, except for
some higher elevations once again to the north of the forecast
area. A northerly mid level flow around this low would suggest the
potential for some occasional outflow winds dropping south across
the deserts, just something to monitor for potential erratic
winds and elevated fire weather. The lower heights through the
week would suggest keeping temperatures in check somewhat, right
around that century mark. Otherwise, typical May weather this week
with dry conditions and afternoon breeziness.

Cluster analysis out to days 6 and 7 for next weekend, favoring
some type of building heights, could bring the warmest
temperatures of the season so far. However the overall consensus
is that positive height anomalies remain low so not seeing any
higher levels of HeatRisk at the moment.

&&

.AVIATION...Updated at 0540Z.

South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are anticipated through the forecast period
under mostly clear skies. Wind directions will favor their typical
diurnal tendencies through tomorrow evening with periods of very
light and variable winds during direction switches. The west
switch will take hold between 18-20z, and though sustained speeds
will remain aob 10 kts, gusts into the mid to upper teens may pick
up later in the afternoon and last through the early evening
tomorrow. Widely scattered, high-based cu are expected to develop
again tomorrow over the high terrain to the north and east.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected through the TAF period under
passing FEW-SCT high clouds. There is low confidence in the exact
wind directions at BLH, though a southerly component will be
favored through much of the period. West winds will be favored at
IPL through tomorrow morning and late tomorrow afternoon into the
evening. Extended periods of light speeds (aob 6 kts sustained)
and variability will be common at both terminals.

&&

.FIRE WEATHER...
Periodically gusty winds, dry fine fuels, and low humidity levels
will yield a locally elevated fire danger this week. Temperatures
will maintain at above normal levels with seasonably dry weather
persisting across the districts. Minimum afternoon humidity levels
around 10% will be common across lower desert elevations with
values in the teens over higher terrain areas. Overnight recovery
will range widely from poor to fair in a 20-50% range. Afternoon
breeziness with gusts 20-25 mph will be common over most areas
with some enhancement possible in far eastern districts due to
high based showers over mountains.

&&

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

$$

DISCUSSION...Frieders
AVIATION...Whittock
FIRE WEATHER...18/Frieders