Severe Thunderstorm Warning 52, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
1242 PM MST Sun Jul 19 2026

.SYNOPSIS...
Rain showers and a few thunderstorms from Tucson west into the
lower desert this afternoon, with more widespread shower and
storm activity south and east of Tucson. An uptick in activity
is likely into the first half of the week. Daytime temperatures
remain below average by several degrees into midweek.

&&

.DISCUSSION...
Showers and thunderstorms continue to develop over the higher
terrain of SEAZ, the Mogollon Rim, and higher elevations in NM.
This activity will push into the lower deserts/valley locales
by late afternoon and into the evening. The main threats will be
heavy rainfall and gusty winds. While organized and more
widespread severe weather is not expected, we cannot rule out an
isolated 50kt gust. However, most wind gusts should remain
below 40kts. As for flash flooding, the threat remains where
storms are slow to move or any cell mergers. In addition, any
area that has received heavy rainfall over the past several days
will be quite susceptible.

As for the Tucson Metro, confidence remains low for any
activity today. Convection off the rim and to the east will try
and push W/SW, but will run into increasingly stable conditions,
especially as the sun goes down. We still cannot rule it out,
but the best chance will be for the Catalina Foothills, Tanque
Verde over to the far east side and south of the metro. Same
threat of heavy rainfall and gusty winds with any activity in
the metro.

As we move into early week, better forcing moves in from the
E/SE. A weak upper level low moves across AZ, which should help
increase storm coverage for areas south and east on Monday.
There should be westward expansion into the Tucson metro and
central Pima Co by Tuesday, but confidence is only moderate on
how far west activity gets. The main threats with the early week
activity will be heavy rain, localized flash flooding, and
gusty winds. There is a Marginal to Slight Risk for Excessive
rainfall for much of SEAZ Mon/Tue, but confidence is too low at
this time for a Flash Flood Watch. It will be more dependent on
how the activity evolves today and better resolve in the higher
res CAMs as we move into Mon/Tue.

By mid week, the mid and upper level pattern shifts with a more
E/SE flow. Flow will also increase with the potential for a weak
easterly wave to move across AZ. This will keep daily isolated
to scattered showers and storms through the rest of the work
week. As flow increases, stronger storms with an increasing
threat for strong gusty winds are possible.

Temperatures remain several degrees below average through mid
week, before warming to near/a few degrees above average.

&&

.AVIATION /19Z SUNDAY THROUGH 19Z MONDAY/...
Majority of the region went from BKN/OVC this morning to
FEW/SCT AOA 6-8k ft agl this aftn. Iso/sct showers/storms
developing over the higher terrain and will move into the lower
deserts by later afternoon. KOLS/KDUG has the greatest chance
for showers/storms with brief MVFR in storms. Otherwise, VFR
with winds less than 12kts with the exception of gusts to
35-40kts in storms. KTUS on the fringe of activity today, but
could still see VCTS/VCHS.

VCTS/VCHS and the occasional shower could linger into the
evening and overnight, but VFR will prevail. More shower and
storm activity tomorrow.

&&

.FIRE WEATHER...
Daily chances for thunderstorms will continue each afternoon
and evening through the next 7 days with day to day variability.
An increase in thunderstorm activity is expected east of Tucson
today, then expand in coverage the first half of the week.
Minimum relative humidity 25-30 percent in the lower desert
locations and above 40 percent in the mountains this week. Winds
this week will remain mainly light and under 15 mph, though
strong and erratic winds will be possible with any thunderstorm.

&&

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

&&

SYNOPSIS...
DISCUSSION...Michael
AVIATION...Michael
FIRE WEATHER...Michael

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