294
FXUS65 KPSR 071140
AFDPSR

Area Forecast Discussion
National Weather Service Phoenix AZ
440 AM MST Fri Jun 7 2024

.UPDATE...Updated Aviation Discussion.

&&

.SYNOPSIS...
Strong high pressure over the Desert Southwest will lead
to another day of hot temperatures with highs nearing 110 degrees
across most of the lower desert communities. As a weak weather
disturbance moves across the region over weekend, a slight
cooldown in temperatures can be expected. Another uptick in
temperatures is expected heading into next week as high pressure
once again builds over the region.

&&

.DISCUSSION...
Latest water vapor satellite imagery as well as streamline analysis
depicts a strong ridge of high pressure centered over New Mexico
along with a weak upper-level low centered just off the Baja
Peninsula. The ridge of high pressure will continue to influence our
weather pattern today, keeping the hot temperatures in place with
highs across most of the lower desert communities ranging between
107-111 degrees, which will continue to result in areas of major
HeatRisk. As a result, an Excessive Heat Warning remains in place
across the lower deserts through this evening. Southerly flow
currently in place will continue to advect some moisture into region
along with an increase in mid to upper-level clouds. The moisture
will be enough to spark a few mainly dry thunderstorms this
afternoon, well north and east of Phoenix towards the White
Mountains and the Mogollon Rim with just a 10% chance of activity
across eastern Gila County.

Heading into this weekend, the aforementioned upper-level low will
migrate northward into the region. As it does so, an increase in
upper-level cloud cover as well as cooler temperatures are expected.
Highs on Saturday will range between 105-110 degrees, cooling even
further on Sunday to 103-107 degrees on Sunday across the lower
deserts. Even though the HeatRisk will drop into the moderate
category, if planning outdoor activities make sure to continue to
take all the necessary heat precautions such as drinking plenty
of water, wear light-loose fit clothing, and taking frequent
breaks in shade.

The weather pattern heading into next week will feature a repeat to
the weather pattern from the past few days as the model guidance is
in good agreement in depicting another cutoff upper-level low
pressure system developing off the northern Baja/southern CA coast
with the ridge of high pressure strengthening once again over the
southwest CONUS. However, the ensembles still continue to show
uncertainties in terms of the overall position/strength of the
cutoff low, which will dictate the overall positioning of the
ridge downstream. Therefore, even though another uptick in
temperatures is expected, how hot it will get still remains
uncertain given the aforementioned uncertainties to the overall
evolution of the cutoff low. However, if a stronger ridge does
indeed develop over the area, another round of excessive heat with
highs of 110+ degrees, especially across the lower deserts of
south- central AZ, will become more likely heading into the middle
of next week.

&&

.AVIATION...Updated at 1140Z.

South-Central Arizona including KPHX, KIWA, KSDL, KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:

Winds will continue to follow typical diurnal tendencies at all
terminals, with speeds generally aob 10 kt outside of occasional
gusts to around 15-20 kt this afternoon and evening. Gusts to
around 25 kts will be possible at KIPL later this afternoon
through the evening. SCT-BKN high clouds will continue throughout
the TAF period.

&&

.FIRE WEATHER...
Hot and seasonably dry conditions will continue to support a high
fire danger across the area during the next several days.
Isolated thunderstorms developing over the White Mountains,
Mogollon Rim, and in the far eastern districts later today could
lead to an increased risk of lightning-related fire starts,
however, the chances of dry thunder across the far eastern
districts remains below 10 percent. Another day of excessive heat
is forecast across most of the lower deserts with highs near 110
degrees before a gradual cooldown over the weekend. Winds during
the next several days will continue to favor diurnal tendencies
with sustained speeds remaining below 15 mph along with occasional
afternoon breeziness upwards of 20-25 mph. MinRHs through next
week will hover at around 10% with poor to fair overnight
recoveries of around 20-40%.

&&

.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST this evening for
     AZZ530>556-559>562.

CA...Excessive Heat Warning until 8 PM PDT this evening for CAZ561-
     563-566-567-569-570.

&&

$$

DISCUSSION...Lojero
AVIATION...Smith
FIRE WEATHER...Lojero