El Cerrito, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

373
FXUS65 KPSR 011158
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
458 AM MST Sun Jun 1 2025

.UPDATE...Updated Aviation Discussion...

&&

.DISCUSSION...

Key Messages:
- Showers and isolated thunderstorms will spread across the region
  today, with some lingering higher terrain shower activity into
  Monday.

- A few strong thunderstorms with gusty winds, small hail, and
  localized heavy rainfall are possible on Sunday, anticipated to
  be strongest in southeastern California, which could preclude a
  minor flash flood threat as well as localized blowing dust
  impacts.

- Temperatures will drop below normal with highs in the nineties
  for several days starting today, though temperatures will warm
  each day after that resulting in a return to above normal
  temperatures by the end of the workweek.

The long awaited and unusual weather pattern for this time of year
is finally upon us, as early morning radar depicts scattered to
numerous showers spreading across mainly south-central and
southwestern Arizona. Some embedded thunder has also been observed
with these showers, as they rotate northwestwards over the next
couple of hours around the low circulation situated offshore of
the Baja Peninsula. While hi-res guidance did not do a good job
depicting this early morning convection, its anticipated that the
vort lobe that is aiding in this shower activity will lift
northwards, resulting in a lull in shower coverage in a few hours
until later this morning.

As the low circulation meanders eastward this morning, this will
result in the main event creeping into southwestern Arizona and
then spreading into south-central Arizona, with the Phoenix metro
seeing the bulk of shower/storm activity during the afternoon and
evening hours. The thunderstorm threat is much more muted, as
very little daytime instability is being depicted by the HREF (100
J/kg or less) across south-central Arizona. Thus, don`t expect
much more than some embedded thunder throughout the day, with some
improving thermodynamic profiles post-front this evening, but then
showery activity will be much more scattered by then. On the other
hand, more robust thunderstorm activity will be possible further
west, particularly across southeastern California this afternoon
and early evening. Due to being closer to the low center (cooler
temperatures aloft/steeper lapse rates), better instability will
be available (500-1000 J/kg) with maybe enough clearing after this
initial wave of showers/clouds early this morning to spark some
thermally induced thunderstorms during the afternoon hours. Should
this be the case, a few strong storms will be possible with gusty
outflow winds (30-50% chance of 35+ mph gusts), patchy blowing
dust, small hail, and heavy downpours that could preclude to a
minor flash flood threat all potential threats from these storms.

Overall, the vast majority of the region should see some level of
shower activity, with accumulating rains anywhere from 0.10" to
upwards of 0.50" in upslope enhanced locations. In areas that have
multiple rounds of showers/storms or a strong storm (such as
southeastern California), localized areas receiving 1.00"+
accumulations is not out of the question, but still generally less
than a 25% chance of that occurring in any one spot across the
region. Otherwise, hi-res guidance depicts the main frontal band
progressing northeastward concentrated across southern Arizona and
extending into south-central Arizona, thus the more widespread
higher accumulations for the AOR are anticipated to be more
centered across south-central Arizona.

As the low continues to progress eastward, post-frontal showery
activity will continue to linger into the overnight hours tonight
across the lower deserts, but become primarily confined to higher
terrain areas east of Phoenix during the daytime hours on Monday.
Otherwise, cooler temperatures several degrees below normal
persisting through early this week. A secondary shortwave will
dive southward across the West Coast early in the week and
eventually progress eastward across the Desert Southwest. This
feature will unfortunately not bring much in terms of moisture to
increase rain chances again Tuesday into Wednesday, as the main
moisture is in the lower levels and will remain offshore as this
trough progresses eastward. Thus, this trough will, at most, spark
some higher terrain showers and temper the warming the trend set
to take place late this week. Subtropical ridging will take hold
across northern Mexico starting mid to late week, resulting in
warming conditions to above normal as early as Thursday.
Temperatures will continue to warm as the ridge remains anchored
across northern Mexico, with considerably above normal
temperatures by late this upcoming weekend. Ensemble guidance is
in good agreement of the general pattern setup mid- week onward,
with the main differences being the strength of the sub-tropical
high. Regardless, the IQR of NBM temperatures remain around five
degrees through the extended period, thus will have to keep a
watch on whether the higher end scenario could creep into extreme
heat concerns for early June.

&&

.AVIATION...Updated at 1155Z.

South Central Arizona including KPHX, KIWA, KSDL, KDVT:
Lowering cigs, periods of showers, and gusty winds will be the
main weather concerns today into tonight. Light showers early this
morning with southeasterly winds should move out of the metro by
around 13-14Z. Winds should quickly return to a west component by
late morning and become gusty by the afternoon as another round of
more robust showers and maybe a few embedded thunderstorms
progresses through the Phoenix Metro. This VCSH/SHRA will persist
for around 6 hrs before slowly shifting NE of the region by mid
to late evening. There is still low confidence (<30%) in cigs
falling below 6 kft at KPHX, however could be a brief reduction to
MVFR cigs and/or vsby if showers become heavy enough.

Southeast California/Southwest Arizona including KIPL and KBLH:
Lowering cigs, periods of SHRA/TSRA through this afternoon, and
gusty and erratic winds will all be the main weather concerns.
Scattered light showers will become a bit heavier and more
persistent after sunrise before becoming fairly isolated in the
afternoon. Winds will predominately be out of the south for much
of the period with KIPL more out of the southeast and KBLH more
often out of the southwest. Gusts increasing to around 20-25 kts
later this morning are likely, particularly at KBLH. After the
morning shower activity, another round of SHRA with the potential
for isold TSRA will become the main concern heading into the
evening hours, particularly at KIPL.

&&

.FIRE WEATHER...
An unseasonably wet weather system will track through the area
today bringing widespread wetting rain chances of 50-80% and
chances for thunderstorms (15-30% chance). Afternoon minRHs will
rise to 20-40% areawide today, with similar values anticipated
Monday. The elevated humidities Sunday-Monday will begin to lower
starting Tuesday, but MinRHs should mostly stay above 15% through
the middle of the workweek. A drier weather system is likely to
move through the region on Tuesday possibly bringing some isolated
showers and a few thunderstorms focused over higher terrain
areas. Hotter and seasonably dry conditions are likely to return
later this week, with minRH`s dipping below 10% late week.

&&

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

$$

DISCUSSION...Young
AVIATION...Kuhlman
FIRE WEATHER...Young/Whittock