Tempe, Arizona 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

355
FXUS65 KPSR 160519
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1019 PM MST Tue Jul 15 2025

.UPDATE...Updated 06Z Aviation Discussion.

&&

.KEY MESSAGES...

- Rain chances will improve over the next couple of days with the
  best chances over eastern Arizona and at least a 20-30 percent
  chance expanding into south-central Arizona Wednesday into
  Thursday.

- A few strong storms will be possible this afternoon and
  evening, likely focused east and southeast of the Phoenix area.

- After near normal temperatures today, expect slightly below
  normal temperatures with plenty of clouds Wednesday and
  Thursday.

&&

.SHORT TERM /Rest of today through Wednesday/...
The latest radar imagery as of mid-afternoon depicts thunderstorm
activity across the vicinity of the Mogollon Rim through southeast
AZ as MLCAPE values range between 500-1000 J/KG across the region.
The latest HREF membership continues to show the greatest
thunderstorm coverage to remain confined mostly across southeast
AZ into the evening hours with the potential for an outflow
boundary to move northwestward and affecting portions of south-
central AZ later this evening, however, at this time not much in
the way of strong wind gusts are expected with the HREF only
showing a 10-30% chance of gusts in excess of 30 mph across the
Phoenix area while slightly higher probabilities exist
southeastward into northwest Pinal County. If the stronger winds
materialize in Pinal County, then some blowing dust will likely
materialize. Otherwise, not much in the way of thunderstorm
activity is expected across south-central Arizona this evening,
most likely due to some convective inhibition remaining in place.
Guidance suggests the complex of storms over southeast Arizona is
likely to induce an MCV which may bring additional showers or a
weak thunderstorm during the overnight and early morning hours
Wednesday as the MCV gradually lifts to the north northwest
through south-central Arizona.

If the MCV scenario comes to fruition, it now looks like it may
be a determent for additional shower and thunderstorm development
across south-central Arizona at least through Wednesday afternoon.
There is also model evidence of some drying already beginning to
take place across southwest Arizona to as far north and east as
the Phoenix area starting Wednesday morning. Because of these
potential negative factors, we have lowered PoPs for south-central
Arizona on Wednesday. Guidance does still suggest a good deal of
shower and weak thunderstorm activity over eastern Arizona on
Wednesday and any weak to modest outflows may be enough to help
trigger some activity into the lower deserts by Wednesday evening.
The potential for any strong storms Wednesday has been reduced
largely in part due to warming aloft and weakening instability.
Some higher terrain areas should still be able to see a few
heavier rain producing cells, but the overall risk for excessive
rainfall will be marginal at best.

&&

.LONG TERM /Thursday through Monday/...
Forecast confidence for later this week continues to be fairly low
as model differences remain. Both the GEFS and EPS show noticeable
drying occurring on Thursday, but the uncertainty lies in how
quickly we dry out. Models are finally mostly agreeing on bringing
the upper level low northward into northern Baja with potential
forced ascent still in place over much of Arizona. If there is
enough moisture left over, we may be able to see 500 J/kg or so of
MUCAPE during the afternoon hours, but that may not occur in a
large area as we are still likely to see considerable cloud cover.
Just like Wednesday, Thursday may mostly involve scattered
showers and weak storms over higher terrain areas with a few
isolated storms possible over the Arizona lower deserts.

The drying is expected to continue Friday into Saturday with
forecast PWATs dropping to between 1.1-1.3" Friday to around 1"
Saturday. Rain chances Friday may partially depend on the
eventual track of the upper level low which is mostly shown
tracking up the CO River Valley or across southern California
early on Friday. The eastern Arizona higher terrain should again
have afternoon chances for showers and thunderstorms Friday, but
we may also have a shot at some isolated convection closer to the
upper low, maybe across southwest Arizona. By Saturday, the upper
low is likely to have lifted far enough to the north or west that
it will become a non-factor on our weather. Enough lingering
moisture may still be present across eastern Arizona this weekend
for some afternoon scattered convection, but the south-central
Arizona lower deserts are likely to remain quiet.

Temperatures are expected to cool off a good deal during the
middle part of the week with below normal temperatures on
Wednesday and Thursday, especially across south-central and
eastern Arizona. As we stated yesterday, highs in the Phoenix area
on Thursday may struggle to reach 100 degrees. As we really begin
to dry out Friday into the weekend, temperatures will begin
creeping upward again with readings back into the normal range by
around Saturday. Temperatures at or just above normal are likely
to persist through early next week as the subtropical ridge is
likely to stay just to our east.

&&

.AVIATION...Updated at 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
A decaying outflow boundary moving through the area will switch
the winds out of the southeast heading into the overnight period.
Light and variable to light easterly winds will be common during
the early morning hours before a definite switch out of the west
occurs by the mid to late morning hours with speeds generally aob
10 kts throughout the day Wednesday with some minor afternoon/evening
gustiness into the mid to upper teens. There is a low chance
(10-20%) of a few light showers moving through the area early
Wednesday morning. SCT to BKN mid to high clouds will be common
through Wednesday.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major aviation weather concerns are expected throughout the TAF
period. Winds will generally be out of the east to southeast at
KIPL and out of the south at KBLH. Wind gusts upwards of 20-25 kts
can be expected at times once again Wednesday afternoon/evening,
with the strongest gusts mainly at KBLH. Clear skies will persist
through tonight with a FEW mid to high-level clouds throughout the
day Wednesday.

&&

.FIRE WEATHER...
Moisture will gradually increase across much of Arizona over the
next couple of days providing increased chances for showers and
thunderstorms focused across higher terrain areas. Temperatures
will drop off from near normal today to below normal Wednesday
and Thursday. Afternoon MinRHs will improve with readings around
20% today and 25% Wednesday and Thursday. Expect south
southwesterly gusts of 20-30 mph at times over the CO River
Valley with more diurnal lighter winds over the eastern districts.
Some drying conditions will begin to usher back into the area
later this week resulting in more limited shower and thunderstorm
chances by Friday. Eventually, high pressure is likely to return
to the region by the weekend with RHs dropping back into the
teens, temperatures returning to near normal, and rain chances
ending for all but the higher terrain.

&&

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

$$

SHORT TERM...Lojero/Kuhlman
LONG TERM...Kuhlman
AVIATION...Lojero
FIRE WEATHER...Kuhlman