798
FXUS65 KPSR 222314
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
414 PM MST Sat Feb 22 2025

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Above normal temperatures will prevail through the next 7 days. A
warming trend will carry us into next week, with afternoon high
temperatures reaching the lower 80s by Sunday and upper 80s to
near 90 degrees during the middle of next week. Aside from periods
of higher level clouds over the next week, dry conditions will
continue.

&&

.DISCUSSION...
A dry shortwave is shown in the latest RAP 500 mb analysis exiting
AZ to the east early this afternoon. Meanwhile, mid-level wv imagery
reveals a N-S elongated, innocuous disturbance dragging some cirrus
over the state from the WNW today. These shortwave disturbance have
done little to suppress the broad area of positive H5 height
anomalies aloft, and so we can expect continued above normal
temperatures across the forecast area today. Afternoon highs will
fall mostly in the middle-to-upper 70s across the lower deserts of
South-Central AZ, with some of the typically warmer locales out west
(e.g., Yuma, El Centro, and Blythe) nearing 80F. For Sunday into
early next week, global guidance shows the axis of an upper level
ridge shifting over the Southwest US, leading to warming
temperatures aloft. In fact, NAEFS mean 700 mb temperatures exceed
the 90th and at times 98th percentile of CFSR climatology over
the forecast area during the 24-48 hour timeframe. This will
translate to a rather quick warming trend at the surface across
the forecast area, with lower desert highs reaching the lower 80s
Sunday and middle 80s by Monday.

During the first half of the upcoming workweek, the upper level flow
will be characterized by a zonally extended North Pacific Jet
streak, strong negative height anomalies to the north of it, and
upper level ridging downstream over the Western CONUS. The north
Pacific jet will send several shortwaves downstream and over the top
of the ridge, acting to dampen the ridge somewhat as they pass well
to the north of our region. One shortwave ensembles show passing
well to the north on Tuesday has trended further south in the latest
ensemble runs, and so NBM highs on Tuesday have come down a couple
degrees. Temperatures are still likely to be warmer on Tuesday than
Monday, with highs in the middle-to-upper 80s over South-Central AZ,
and nearing 90F over the typically warmer areas of the western
deserts. The Wednesday-Thursday timeframe still looks to be the
warmest for the forecast area, with widespread lower desert highs in
the upper 80s to near 90F, approximately 15 degrees above normal
for the time of year.

By the end of the workweek and into next weekend, a pattern change
is expected, as the North Pacific Jet begins to retract and shift
equatorward. Upper level closed lows will begin to undercut the
ridge, bringing a more disturbed pattern to the Desert Southwest. An
initial closed low will be mostly dry, passing overhead possibly
Friday or Saturday, with timing differences apparent between WPC
Clusters. The main impacts from this initial systems will be locally
breezy conditions and the potential for elevated fire weather
conditions for the high terrain of South-Central AZ. Temperatures
should begin to trend down as well, though latest NBM shows them
remaining above normal through at least Saturday.

&&

.AVIATION...Updated at 2311Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

No weather concerns will exist through tomorrow morning under
clear skies. Trends in wind speeds and directions will be nearly
identical to the past 24 hours with the typical easterly shift in
the Phoenix metro late tonight, while N/NW directions will
prevail the majority of the period in SE California. There will
also be periods of calm and light variable winds at all terminals.

&&

.FIRE WEATHER...
High pressure will gradually overtake the region again this
weekend leading to warming conditions and continued low
humidities. Daily MinRHs of 10-15% will persist into early next
week with fair to poor overnight recoveries to around 25-30%.
Expect high temperatures to climb well into the 80s across the
lower deserts by Monday before peaking at around 90 degrees
during the middle part of next week.

&&

.CLIMATE...

Record high temperatures next week:

Date         Phoenix           Yuma         El Centro
----         -------           ----         ---------
Feb 24      91 in 1904      93 in 1986      92 in 1986
Feb 25      92 in 1921      95 in 1986      94 in 1986
Feb 26      91 in 1986      96 in 1986      95 in 1986
Feb 27      92 in 1986      95 in 1986      96 in 1986
Feb 28      89 in 1986      97 in 1986      92 in 1986

&&

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

$$

DISCUSSION...Whittock
AVIATION...Ryan
FIRE WEATHER...Kuhlman CLIMATE...18