Maricopa, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

494
FXUS65 KPSR 130521
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1021 PM MST Tue Nov 12 2024

.UPDATE...Updated 06Z Aviation Discussion.

&&

.SYNOPSIS...
Near to above normal temperatures will persist through
Thursday before a much more noticeable cooling trend to well-below
normal levels materializes Friday through the upcoming weekend as a
low pressure system moves across the western United States. Along
with the cooling trend, some precipitation chances will exist late
this weekend, mainly across the eastern half of Arizona.

&&

.DISCUSSION...
Latest objective analysis as of early this afternoon depicts an
upper trough situated near the Utah/Colorado border with the
region situated on the southern periphery of this system. This
trough will not cause any weather impacts other than cool
afternoon high temperatures several degrees from what they were the
last couple days as readings are expected to only top out in the
mid 70s across the lower deserts. Some breezy conditions will also
be seen, especially across portions of southeast CA into the
Lower Colorado River Valley, through this afternoon as peak wind
gusts approach 25-30 mph at times. The upper trough will quickly
eject eastward through the Central Plains early Wednesday with a
weak upper ridge settling over the Desert Southwest through
Thursday. As a result, temperatures are expected to warm back up
again to near to above normal levels with lower desert highs back
up in the upper 70s Wednesday with areas in south-central AZ
topping out in the low 80s Thursday.

A significant pattern change is expected to materialize late this
week through the weekend as a potent large scale trough moves
through the western CONUS. Starting on Friday, the trough will
move onshore over northern CA with the upper-level height fields
expected to decrease. As a result, temperatures will begin a
cooling trend as highs only top out in the low to mid 70s across
the lower deserts. The lowering height fields will also support an
increase in the regional pressure gradient, especially across the
western deserts, over southeast CA, where enhanced westerly winds
will likely materialize. Heading into the weekend, the ensembles
show a piece energy detaching from the larger scale trough and
cutting off southward towards the northern Baja Peninsula.
However, discrepancies in terms of how deep and how fast the
trough ejects eastward continues amongst the ensembles. This
overall evolution will be critical to determining the overall
precipitation chances across portions of the forecast area heading
into late this weekend. A weaker and faster eastward trough
movement scenario will limit precipitation mainly across far
eastern AZ towards New Mexico. A stronger and slower trough
scenario would advect more moisture and provide greater forcing
for ascent across the region and thus precipitation would be more
expansive and affect much of central and eastern AZ. At this time,
given the discrepancies noted amongst the ensemble membership,
NBM PoPs for late this weekend remain modest with chances between
15-20% across the lower deserts of south-central AZ to 30-50%
across the AZ high terrain. Despite the precipitation uncertainty,
the aspect of the forecast that is more certain is a continuing
cooling of temperatures throughout the weekend as highs will
struggle to reach 70 degrees across much of the lower deserts.

After the cutoff low ejects eastward, a second trough will move
in from the northwest heading into early next week. This second
trough will help reinforce the below normal temperatures with
readings likely to stay stuck in the mid to upper 60s for highs
across the lower deserts. By mid to late next week, there are
strong signals from the ensembles of a strong blocking pattern
materializing across the higher latitudes and thus the overall
trough progression eastward is likely to be slowed down at some
point. However, how fast and how far east this trough moves before
the blocking pattern sets up is highly uncertain with some
ensemble members showing the trough ejecting far enough east that
ridging builds over the Desert Southwest whereas other members
show the trough hanging back. As a result of this uncertainty in
the overall pattern evolution mid to late next week, the overall
temperature forecast is highly uncertain and this is reflected in
the latest NBM inter-quartile distribution which shows about a
7-10 degree spread between the 25th and 75th percentile.

&&

.AVIATION...Updated at 0520Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Wind speeds will generally be aob 7 kt through the period. Winds
are currently in the process of becoming easterly and will be
easterly through tomorrow morning. A later westerly switch is
anticipated tomorrow afternoon, where winds will be aob 5 kt and
may become more variable at times rather than a definitive
westerly/northwesterly tomorrow afternoon and evening. FEW cirrus
clouds will be common through the overnight before clearing out
tomorrow afternoon.

Southeast California/Southwest Arizona including KIPL and KBLH:
Wind speeds will generally be aob 7 kt through the TAF period. At
KIPL, current westerly winds will become light and variable by
late tomorrow morning. At KBLH, current northwesterly winds will
become northeasterly late tomorrow morning and then back
northwesterly tomorrow evening. FEW cirrus clouds will be common
through the overnight hours before clearing out tomorrow morning.

&&

.FIRE WEATHER...
Temperatures fluctuating a few degrees above and below normal
through Thursday will precede a marked cooling trend going into and
through the weekend. Winds will follow typical diurnal
upslope/nocturnal drainage tendencies, with only some modest morning
ridge top gustiness during the middle of the week. MinRHs will fall
mostly in a 10-15% range through the week, with readings closer to
20-25% over higher terrain of eastern districts. Overnight recovery
will be better in the eastern districts, mostly between 40-60% with
poor to fair overnight recovery (around 20-40%) in lower elevations
and western districts through most of the week. Cooler temperatures
and increasing moisture levels will result in higher RH levels late
week and into the weekend. Overall, dry weather will persist this
week, but precipitation chances will increase late this weekend,
albeit 25-35% chances confined to the eastern districts mainly in
Gila County as early as Sunday.

&&

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

$$

DISCUSSION...Lojero
AVIATION...Berislavich
FIRE WEATHER...Young