470
FXUS65 KPSR 200519
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1019 PM MST Sat Sep 19 2026

.UPDATE...06Z Aviation Discussion.

&&

.KEY MESSAGES...

- Dry, tranquil weather conditions with near to slightly above
normal temperatures will continue through the first half of next
week.

- A low pressure system with returning moisture will yield renewed
rainfall chances to at least the high terrain of northern and
eastern Arizona during the latter half of next week.

&&

.SHORT TERM /Today through Monday/...
Early afternoon WV imagery depicts a seasonally deep midlevel
cyclone over the Great Basin with a southerly extended trough axis
sweeping into eastern Arizona. With the central negative height
anomaly filling and weakening, little in the way of height falls or
cooling will affect the SW Conus, however the resultant flow pattern
will become increasingly westerly as the region preeminently
transitions out of monsoon. Lingering shallow moisture in the form
of 8-10 g/kg mixing ratios and total column PWATs near 0.75" over
the eastern half of the CWA will be further scoured away with
vertical mechanical mixing in the dry westerly flow this afternoon
reaching levels of 5 g/kg and 0.50" respectively. While shallow, low
level moisture will occasionally slosh back into parts of the CWA
over the next 48 hours, the overarching drying environment will
preclude deep convection and rainfall chances into the middle of
next week. Otherwise, H5 heights will remain fairly steady around
588dm with only modest height falls entering the region Monday. As a
result, forecast confidence is excellent that temperatures will
hover within a few degrees of the seasonal normal yielding only
minor HeatRisk.

&&

.LONG TERM /Tuesday through Friday/...
On Tuesday, an upper low will slowly weaken as it moves northeast
into NV/UT before getting swept up into the large scale flow on
Wednesday moving into the northern Plains. At the same time, a weak
ridge over TX and will start to strengthen on resulting in
southwesterly flow over our area. With moisture return and some
upper level forcing from the aforementioned low, rain chances will
return to the higher terrain areas in northern and eastern Arizona.
Weak large scale troughing will remain across the eastern
Pacific/West Coast through the end of next week, battling the ridge
of high pressure over TX. By the end of the week, the ridge will
try to retrograde into NM/AZ. Additionally, ensemble members bring a
surge of moisture into our area from the SE, pushing PWATs back into
a 1.0-1.3" range. As a result, NBM/WPC PoPs for the end of next week
reflect a 30-50% chance of showers and storms across the higher
terrain in southern Gila County, and around 10-20% across the lower
deserts of south-central Arizona.

Temperatures next week will remain largely unchanged in the upper
90s to low 100s across the lower deserts, and in the upper 80s to
mid 90s across the higher terrain. Morning lows will generally be
in the 70s to to low 80s across the lower deserts, and in the 60s
across the higher terrain areas. Morning lows should start to creep
up by the end of next week (more morning lows in the low 80s across
the lower deserts). As a result, widespread minor HeatRisk will
continue through the beginning of next week with moderate HeatRisk
returning to the lower deserts for the latter half of next week as
the morning lows creep up and daily normals decrease.

&&

.AVIATION...Updated at 0520Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation weather concerns will exist through the TAF period
under mostly clear skies overnight, followed by increasing high
clouds on Sunday morning. Winds will follow typical diurnal
patterns with speeds remaining aob 8 kts. A 3-4 hr period of light
southerly cross-runway winds is likely again at KPHX early Sunday
afternoon before shifting out of the southwest around 21Z-22Z.

Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns will exist at the SE California
terminals through Sunday. Increasing high clouds are expected
overnight into early Sunday morning. Winds will follow diurnal
trends remaining generally below 10 kts at both terminals. There
will also be extended periods of calm and vrb conditions,
especially at KIPL Sunday morning.

&&

.FIRE WEATHER...
Overall there are no fire weather concerns through the next week.
Conditions will continue to dry out today with no chances for rain
continuing through Monday. Slight chances for showers and storms
return to the higher terrain areas of southern Gila County beginning
on Tuesday. MinRHs will be around 10-25% today and tomorrow before
increasing to around 15-30% for the first half of next week.
Overnight recoveries will range from fair to good across the region
through the middle of next week. Besides a potential increase in
breeziness early next week with a weather system, winds will mostly
follow typical diurnal patterns with modest afternoon
upslope/upvalley gustiness (15-25 mph).

&&

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

$$

SHORT TERM...18
LONG TERM...Berislavich
AVIATION...Salerno
FIRE WEATHER...Berislavich/Benedict