113
FXUS65 KPSR 040506
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
1005 PM MST Thu Jul 3 2025

.KEY MESSAGES...

- After limited chances for isolated showers and thunderstorms
through this evening, the entire 4th of July weekend should remain
dry.

- Near to slightly below normal temperatures are forecast through
Saturday with above normal temperatures returning by Sunday.

- Daily highs for the lower deserts are expected to warm to around
or just over 110 degrees starting Sunday resulting in widespread
Moderate HeatRisk.

&&

.SHORT TERM/FRIDAY AND SATURDAY/...
Once the trough lifts to the northeast of the area beginning
tomorrow, heights aloft will begin to rebuild allowing for a gradual
warming trend into the weekend. By Saturday, daytime highs are
expected to be back into the normal range in Arizona to a couple
degrees above normal across southeast California. Dry air will also
continue to push into the area this weekend, with PWATs decrease to
around 0.7-1.1" across the area. With this decrease in moisture we
will also see decreasing shower/storm chances. With around a 15% or
less chance for showers/storms over the higher terrain east of
Phoenix, with most/any activity this weekend mainly confined to
southeast AZ.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Considerable forecast uncertainty is seen by next week, mainly
involving any monsoon moisture. There seems to be a disconnect
between the GEFS and the EPS with the GEFS showing a modest moisture
return starting early next week, whereas the EPS shows continued dry
conditions. At this point, there is no clear evidence supporting
either model`s solution, so we will likely have to wait at least a
couple more days to have a better sense on what`s going to happen.

Both models do show the sub-tropical ridge building back over the
region this weekend and then lasting through much if not all of next
week. H5 heights are expected to rise to around 592-594dm this
weekend allowing for a fairly quick warm up with highs likely
topping out around 110 degrees by Sunday. Models also agree the
ridge will continue to strengthen through the first part of next
week with H5 heights likely reaching 595-597dm, or into the 90th
percentile of climatology. One of the main issues is exactly where
the high center will be with the GEFS suggesting it will be more
over northern Arizona, where the EPS favors more over central and
southern Arizona. If the GEFS is correct on its position, then we
are likely to see some sort of moisture return early next week and
likely a return of at least higher terrain storm chances. If the EPS
is correct, then we are likely to stay dry with nearly no storm
chances and even hotter temperatures. For now, the NBM seems to be
favoring more of the GEFS solution, likely due to the Canadian
agreeing with the GEFS position. However, we are doubtful of the
NBM`s PoPs as even if the high center is to our north, it will
likely be too strong to allow for much if any convection into the
lower deserts. We have lowered NBM PoPs by around 10-15% during the
first half of next week, but even that may not be enough.

The other forecast concern is if the EPS is correct and we stay dry,
we are likely to see another heat episode with areas Major HeatRisk.
The latest NBM forecast highs mostly keeps readings between 109-113
degrees, but this is assuming higher levels of moisture and at least
some daily convection. It would not be surprising to see forecast
temperatures for next week to creep several degrees higher once
models resolve the position of the high.

&&

.AVIATION...Updated at 0505Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
No significant weather issues will exist through Friday evening
under mostly clear skies. Some uncertainty and variability in winds
will occur through early overnight due to residual outflows sweeping
around the PHX airspace. In general, a south component should back
to easterly shortly after midnight, then switch back to westerly
late Friday morning. A FEW cloud decks over mountains will be common
Friday afternoon, however any thunderstorms will remain well into SE
Arizona and New Mexico.


Southeast California/Southwest Arizona including KIPL and KBLH:
No weather issues will exist through Friday evening under clear
skies. Trends in wind directions and speeds will be similar to the
past 24 hours generally varying between SE and SW with some enhanced
gusts 20-25kt possible at times.

&&

.FIRE WEATHER...
Lingering moisture today may bring a few isolated thunderstorms
across south-central and eastern Arizona, but CWR will be below
10%. Below normal temperatures and the moisture will help to keep
MinRHs between 20-30% for the eastern districts to 15-20% for the
western districts. Outflow boundaries are possible from any storm
activity with a 30-50% chance of wind gusts of 35 mph in the
Phoenix Metro this evening. The drying trend will continue
tomorrow with MinRHs of 20-25% across the SW and south- central AZ
and 10-15% across SE CA. Winds return to a more typical diurnal
trend today with any afternoon breeziness generally less than 20
mph. Highest wind gusts will be along the lower CO river valley
with afternoon breeziness of 20-25 mph today and tomorrow. High
pressure is then expected to rebuild across the region this
weekend into next week with temperatures warming to above normal
by Sunday. Limited moisture should also return early next week
providing at least daily chances for isolated showers and
thunderstorms for the eastern Arizona higher terrain.

&&

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

&&

$$

SHORT TERM...Berislavich/Kuhlman
LONG TERM...Kuhlman
AVIATION...18
FIRE WEATHER...Berislavich/Kuhlman