Phoenix, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

695
FXUS65 KPSR 180506
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1006 PM MST Fri Jan 17 2025

.UPDATE...Updated 06z aviation discussion.

&&

.SYNOPSIS...
An overall quiet and benign weather pattern is expected to set up
across the region this weekend and into early next week. Dry
northwesterly flow is expected to prevail over the forecast area,
keeping temperature near to slightly below normal levels and skies
mostly clear. Morning lows will still be on the cool side with some
of the lowest desert elevations reaching the freezing mark each
morning. Dry conditions will continue for the next several days.

&&

.DISCUSSION...
Latest wv and visible satellite imagery reveals a departing upper
low which is now located over the Southern Plains. Subsidence on
the back side of this system has resulted in clear skies and dry
conditions across the Desert Southwest. We did see a few weak
showers last night, however most of this rainfall did not reach
the ground as the sub cloud layer was too dry. However there were
isolated locations in the higher terrain NE of Phoenix that
measured a few hundredths of an inch. Sky Harbor is now at 147
days with no measurable precipitation which ties for 2nd longest
dry period on record. Most of AZ is in dire need of precipitation
and unfortunately chances are nil through at least next week.

The upper air pattern heading into this weekend will feature a
deepening trough across the central and eastern CONUS which will
unleash extremely cold temperatures for most locations east of the
Rockies. Our forecast area will remain on the back side of this
trough, and while heights aloft will not be particularly low over
the forecast area, the deeper cold airmass east of the Rockies will
still seep into portions of the Desert Southwest. Therefore our
temperatures are expected to remain near or slightly below
seasonal norms for the next several days. Highs should top out in
the low to mid 60s across the lower deserts this weekend with lows
mainly in the upper 30s to lower 40s. Some of the outlying desert
locations such as N Pinal County and the river valleys in W AZ
could see lows reach the freezing mark both Sat and Sun morning.

On Monday, a strengthening polar jet on the western periphery of
the large scale trough will carve out a weak mid-lvl shortwave
over the Intermountain West. The passage of this disturbance will
send a cold front through our region Monday evening which will
result in increasing winds mainly across the Lower Colorado River
Valley. Post frontal gusts in the 25-35 mph range can be expected
with locally higher gusts up to 40 mph possible. The post frontal
airmass is also projected to be quite dry with dewpoints falling
into the single digits Tuesday morning which will result in a
fairly widespread freeze across the lower deserts. Tuesday is
forecast to be the coolest day of the week with highs in the upper
50s to lower 60s.

GEFS and EPS clusters indicate height anomalies will begin to
increase by the middle of next week as ridging over the eastern
Pacific moves inland. This will result in a brief warm up with
temperatures rebounding to normal levels from Wednesday through
Friday. There are some signs in the GEFS and EPS clusters that a
stronger and deeper trough will develop over the Intermountain
West by next weekend which could result in more active weather
across our region, however there is a lot of spread in the
ensembles regarding how the pattern will evolve at this time.

&&

.AVIATION...Updated at 0510Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Winds will tend to follow their typical diurnal tendencies. Wind
speeds will generally be aob 6-7 kt with some periods of light
and variable winds. Clear skies are expected through the TAF
period.

Southeast California/Southwest Arizona including KIPL and KBLH:
Wind speeds will generally be aob 8kt through the TAF period.
Winds at KIPL will favor a westerly component. Current southerly
winds at KBLH will eventually shift to the north by late Saturday
morning with an extended period of variable winds in between.
Clear skies are expected through the TAF period.

&&

.FIRE WEATHER...
A weak weather system exiting the region will result in temperatures
falling closer to the seasonal normal through the middle of next
week. With expansive dry air in place and essentially no chance of
wetting rainfall, minimum afternoon humidity levels will hover
around 15-25% through this weekend, then closer to a 10-20% range
next week. This will follow fair to good overnight recovery of 30-
60%. While some gusty north winds will be possible across western
districts early next week, light winds will be more common over the
remainder of the region.

&&

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

$$

DISCUSSION...Salerno
AVIATION...Estupinan/Berislavich
FIRE WEATHER...18