718
FXUS65 KTWC 162030
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
130 PM MST Sun Aug 16 2026

.SYNOPSIS...

Hot conditions return this week with temperatures becoming 5 to
7 degrees above normal across southeastern Arizona. An Extreme
Heat Warning is in effect Monday through Friday for portions of
the area. Monday should see scattered thunderstorms develop over
the region, with additional chances returning during the second
half of the upcoming week.

&&

.DISCUSSION...

An upper ridge remains centered over Texas today, while a tight
easterly wave sits within this ridge, gradually drifting west
over far west Texas and northern Mexico this afternoon. Mean
flow aloft is mainly southwesterly today, which has contributed
to a relative reduction in moisture across southeastern Arizona.
Early afternoon surface dew points range from the upper 40s to
mid 50s with precipitable water values at about normal for this
time of year. While the wave to the east remains well away from
the area today and with no other real triggering mechanisms,
monsoon activity will remain limited today to mainly high
terrain areas, especially closer to the New Mexico border. Given
the lack of coverage, the 12Z HREF shows little in the way of
a signal for monsoon hazards, but a quick 40-45 mph wind gust
and heavy downpour can`t be ruled out with any storm today.

Upper level support for increased thunderstorm activity becomes
a more favorable on Monday as the easterly wave approaches and
an upper high drifts out of Sonora west over Baja. No real
change in the moisture profile is expected, but this is enough
to produce 15-30 percent chances Monday afternoon and evening
mainly from eastern Pima/Pinal eastward through the New Mexico
border and south through Santa Cruz/Cochise. Mean wind will have
turned to come out of the northeast, with thunderstorms forming
over the White Mountains and other high terrain areas likely to
move south/southwest with a gusty wind and potentially a blowing
dust threat. The 12Z HREF highlights the potential for 35-45 kt
winds off the White Mountains into Greenlee-Graham-Pinal
counties with more isolated chances further south.

The upper ridge originally centered to the east will gradually
build into the Great Basin through the week, with positive
height anomalies increasing over Arizona. This will bring
unseasonably warm temperatures with highs 5-7 degrees above
normal. An Extreme Heat Warning remains in effect Monday through
Friday for portions of southeastern Arizona. This northward push
of the ridge will also allow for a more favorable monsoon
pattern by the second half of the week.

&&

.AVIATION...Valid through 18/00Z.

FEW-SCT ceilings 9k-13k feet into the early evening, then areas
of high level cirrus tonight. Isolated -SHRA/-TSRA mainly over the
higher terrain near the Arizona and New Mexico state line
between 16/22Z and 17/02Z. Gusty and erratic winds possible near
TSRA with gusts to 35-40 kts. Surface winds west to northwest
7-12 kts with occasional gusts to 20 kts, then light and terrain
driven after 17/02Z. Scattered -TSRA forecast tomorrow after
17/19Z. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...

A warming trend with modestly drier conditions will allow for
minimum relative humidities to fall to 15-25 percent in lower
elevation areas this week with 25-35 percent in higher terrain.
Scattered thunderstorms possible Monday afternoon-evening, then
chances return with a more active pattern during the second half
of the week. Temperatures will be around 5-7 degrees above
normal with an Extreme Heat Warning in effect for portions of
southeastern Arizona Monday-Friday. Outside of thunderstorms, winds
will be terrain driven around 10 mph with occasional afternoon
gusts to 20 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning from 10 AM Monday to 8 PM MST Friday for
AZZ501-502-504>506-509.

&&

$$

DISCUSSION...Edwards
AVIATION...Edwards
FIRE WEATHER...Edwards

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