Severe Thunderstorm Warning 16, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
1015 AM MST Thu Jul 3 2025

.SYNOPSIS...Monsoon moisture remains across southeast Arizona today,
however thunderstorm coverage will be less compared to Wednesday.
The storms that do occur will be capable of producing locally
heavy rain. A drying trend is expected for Independence Day and
this weekend with storm coverage more isolated and focused on
locales south of Tucson. Temperatures will remain below normal
through Friday before warming back up to above normal levels by
Sunday and continuing through much of next week.

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.DISCUSSION...The one thing to know about the nature of Monsoon
season, in general...the day after an active thunderstorm day
is usually followed by a down day as the atmosphere has a
difficult time recovering. That doesn't mean that storms will not
occur, because they will. It is just that despite having ample
moisture in place like we do today, it is difficult to realize
enough CAPE for deeper/strong convection. This is where we find
ourselves today.

The latest GOES PWAT imagery indicates PWAT values around and 1
inch to the east and southeast of Tucson, around 1.20 inches in
Tucson, and an area aoa 1.50 inches across Maricopa and western
Pinal counties. This matches up with the 03/12Z KPSR sounding that
reported a PWAT of 1.52 inches. This moisture is reflected in the
lower levels, as surface dewpoints in the lower 60s make for a
muggy feeling across the entire forecast area.

The upper pattern today is defined by an upper trough across Nevada,
with high pressure over Texas/northeast Mexico. The upper trough
will continue to lift NE today, with the southern periphery of the
500 mb trough axis swinging through our neck of the woods this
afternoon. Normally this would be a bigger player in providing
a lifting mechanism, especially given the ample moisture in
place, but again, the atmosphere is trying to recover from
yesterday. I would still expect to see scattered thunderstorms
develop early this afternoon, especially along an axis from Three
Points to Sierra Vista, which will align itself with the best
deformation aloft from the trough passage. The main threat from
today will be locally heavy rainfall with the thunderstorms, and
to a much lesser extent gusty and erratic thunderstorm outflows.

We can expect a downturn in thunderstorm activity for Independence
Day and into the weekend as high pressure builds into the area from
the south, extending across Southeast Arizona and Sonora Mexico.
The unfortunate side effect from this is that we will begin to
warm up to above normal readings Sunday into early next week. The
high then is progged to shift north toward the Four Corners by the
middle of next week. Although this should be a more favorable
location for thunderstorm activity, the 300 mb high stacking on
top of will somewhat limit deep convection. With direr air setting
up across the eastern CWA, and a surge of moisture moving up the
Gulf early next week, the main threat from thunderstorms will be
strong and gusty outflow winds east of Tucson, with the potential
for heavy rainfall from Tucson west.

&&

.AVIATION...Valid through 04/18Z. SCT 7-12k ft becoming SCT-BKN
7-12k ft AGL from KTUS eastward thru 04/05Z before diminishing
thru end of valid period. Scattered SHRA/TSRA is expected 03/20Z-
04/04Z with CIGS BKN 5-8k ft AGL and gusty outflow winds up to 35
kts. Surface winds generally WLY 8-13 kts today, becoming SLY less
than 10 kts overnight. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Slightly below normal temperatures through
Friday, then warming back this weekend into next week. Expect
scattered showers and thunderstorms this afternoon into evening with
locally heavy rainfall. A decrease in thunderstorm activity is
expected Friday through the weekend as the area transitions into a
low grade monsoon pattern. An eventual uptick in monsoon activity is
expected next week but will be dependent on how quick the high
pressure aloft shifts north. Winds generally light and under 15 mph
with the exception of gusty and erratic winds up to 35-45 mph near
any thunderstorms.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

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