667
FXUS65 KPSR 292320
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
420 PM MST Fri May 29 2026

.UPDATE...00Z Aviation Discussion

&&

.KEY MESSAGES...

- Breezy conditions and locally elevated fire danger will exist
  today, with the strongest gusts focused over the eastern Arizona
  high terrain.

- Lighter, more seasonable wind speeds with only modest afternoon
  breezes will return this weekend and likely persist through
  much of next week.

- Temperatures as much as 10 to 15 degrees below normal today will
  quickly warm over the weekend, reaching a slightly above normal
  category early next week.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...
Early afternoon water vapor satellite imagery and 500 mb RAP
analysis depict an upper level low, one which has been cut off and
meandering over CA/NV for much of the week, opening up to the
northern stream and finally ejecting northeastward towards the Four
Corners. Relatively strong midlevel flow with NAEFS mean 700 mb wind
speeds upwards of 30-35 kts (above the 90th percentile of
climatology) remains over AZ, tracking ahead/around the base of the
upper low. By late afternoon, this narrow band of higher momentum
air will have shifted almost entirely east of the forecast area.
Mixing heights remaining below the 700 mb level, as shown in GFS
bufr soundings for Phoenix, will preclude chances for this higher
momentum air to mix down to the surface, even during peak heating.
However, gusts up to these speeds (30-35 kts) may be realized over
the Northeastern AZ higher terrain. For our forecast area, the
strongest gusts (around 30 mph) will be relegated to the higher
terrain of Southern Gila County, resulting in locally elevated fire
danger.

The main story through the weekend will be warming temperatures and
a return to more seasonable, lighter winds Saturday onward. A period
of quasi-zonal flow establishing over the weekend, with H5 heights
rebounding to the 50th-60th percentile of climatology for late
May/early June (582-584 dam), is favored by ensemble membership.
Narrow spread in latest probabilistic NBM guidance suggests
excellent confidence in temperatures heating back up to near the
daily normals by Sunday. Forecast highs for the lower deserts this
afternoon mostly in the middle 80s represents values as much as 10
to 15 degrees below daily normals. By Saturday, lower desert highs
are likely to reach the lower 90s, followed by further warming into
the upper 90s to near 100F Sunday.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Upper level ridging will begin to settle over the Desert SW starting
Monday. Latest model guidance has shifted the axis of this ridge
more eastward, now centered over the eastern half of Texas, where
previous runs had the axis centered more over central to western
Texas. Regardless of the ridge axis position, H5 heights over
Arizona will increase to 585-588 dam causing temperatures to warm to
103F-108F starting as early as Monday and lasting through the week.
These temperatures will easily push our HeatRisk into a moderate
category, but relatively mild overnight lows in the upper 60s to mid
70s will help to limit the chance of reaching near the major
category. Otherwise, dry conditions with mostly clear skies through
early next week.

&&

.AVIATION...Updated at 2320Z.

South Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation concerns are expected during the TAF period. Winds
will follow light and diurnal trends with the typical E`rly shift
taking place slightly later than usual. Marginal breeziness will
linger through about sundown with light winds aob 10 kt being
common through the remainder of the forecast. Mostly clear skies
will be present through Saturday evening.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather issues will exist through Saturday morning under
clear skies. W`rly winds will persist at KIPL with some occasional
gusts this evening between 20-25 kt. At KBLH, outside of VRB
conditions overnight, a SW`rly direction will be common, with
perhaps a brief window of WNW/NW`rly flow. Clear skies will
prevail through Saturday evening.

&&

.FIRE WEATHER...
Locally elevated fire weather conditions will exist over the
eastern districts this afternoon into the early evening due to
elevated wind speeds, with gusts peaking between 25-35 mph over
the higher terrain. This weekend into early next week, lighter
winds following mostly diurnal upslope/upvalley and nocturnal
drainage patterns will prevail, with typical afternoon breeziness
for late May/early June. Below normal temperatures today will
quickly warm to near normal Sunday and slightly above normal early
next week. Afternoon minRHs will decrease from 15-25% today to a
10-20% range areawide Saturday, then further decrease to an 8-15%
range Sunday. Afternoon minRHs will commonly bottom out in the
single digits areawide early next week. Overnight will similarly
deteriorate over the weekend, with values between 35-60% tonight
decreasing into a 25-45% range Saturday night. Poor overnight
recoveries will be common early next week.

&&

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

$$

SHORT TERM...Whittock
LONG TERM...Ryan
AVIATION...RW
FIRE WEATHER...Whittock