982
FXUS65 KPSR 030942
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
242 AM MST Thu Jul 3 2025

.KEY MESSAGES...

- After limited chances for isolated showers and thunderstorms
  through this afternoon, 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/TODAY THROUGH SATURDAY/...
After an eventful afternoon and evening with scattered
thunderstorms and decent areal coverage of rainfall across
Arizona, conditions are quickly drying out. The Pacific low center
is now situated just west of Las Vegas with southwesterly flow
pushing much drier air aloft through all of southwest and portions
of south-central Arizona. Any lingering rain activity has now
pushed to the east and northeast of the Phoenix area and even this
activity is likely to push out of our area before sunrise. It
would not be impossible to see a few isolated showers redevelop
through sunrise, focused closer the low center in La Paz Co., but
any activity should be weak and provide for little additional
rainfall.

As the Pacific low continues to weaken, becoming an open wave by
mid to late morning, it will eventually push through northern
Arizona this afternoon. The drier air aloft will continue to push
eastward through the entire area today with any lingering low
level moisture situated below 6000 feet. The widespread convection
yesterday has effectively overturned the atmosphere leaving
little instability left in most areas. The lingering low level
moisture may be enough to spark off a few isolated showers and
maybe a weak thunderstorm across south-central and eastern Arizona
this afternoon, but given the worked over atmosphere and drier
air moving into the area we are not expecting much from this
activity. The cooler overnight temperatures, in the 70s across
south-central Arizona, should also keep daytime highs today up to
five degrees below normal. Once the trough lifts to the northeast
of the area beginning Friday, 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.

&&

.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 0515Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
Uncertainty regarding winds overnight, then the potential for isold
SHRA/TSRA Thursday afternoon will be the primary weather issues this
TAF period. As very light -RA and 10K ft cigs clear the terminals
late this evening, winds will briefly become highly variable before
settling on a E/SE component though confidence in timing and exact
directions is only moderate. Confidence is higher that the wind
shift back to W/SW will occur by late Thursday afternoon under SCT
midlevel cloud decks. While a few isold SHRA/TSRA could pop around
the airspace late afternoon, probabilities are far too low to
include in TAFs with west winds likely persisting well into Thursday
night.

Southeast California/Southwest Arizona including KIPL and KBLH:
No major weather concerns will exist through Thursday night under
mostly clear skies. Wind directions will generally vary between SE
during the morning/early afternoon and SW during the evening/early
overnight period. A few gusts around 20kt will be common, especially
at KBLH.

&&

.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. The drying trend will pick up by Friday with
MinRHs dipping into the teens for all of the lower deserts to
20-25% over the higher terrain. Winds will return to the more
typical diurnal trend today with any afternoon breeziness
generally less than 20 mph. 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/LONG TERM...Kuhlman
AVIATION...18
FIRE WEATHER...Kuhlman