806
FXUS65 KTWC 032256
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
356 PM MST Thu Jul 3 2025

.SYNOPSIS...Ample Monsoon moisture remains across Southeast
Arizona today resulting in scattered showers and thunderstorm
across Southeast Arizona, especially from the Tucson Metro Area
to the Southeast in to Cochise county. The primary threat from
storms into this evening will be heavy rainfall producing
localized flash flooding. 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.

&&

.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. Things were starting off that way until
the mid-afternoon, then strong to severe storms developed near
the Tucson Metro Area producing flash flooding to the west, south
and northern portions of Tucson.

There was plenty of atmospheric moisture across Southeast Arizona
today. The latest GOES PWAT imagery indicates PWAT values around
1 inch east and southeast of Tucson and an area around 1.45 inches
to the northwest. This matches up with the 03/18Z KTWC sounding
that reported a PWAT of 1.40 inches. The sounding also indicated
plenty of CAPE for deep convection (MU CAPE 1129 k/kg), but the
problem initially was that there was strong shear between the
middle and upper portions of the storms that caused the storm
updrafts to tilt toward the northeast. It wasn`t until we saw
enough surface heating the the valleys this afternoon to get
sustained and deep updrafts. The upper pattern is defined by an
upper trough across Nevada, with high pressure over
Texas/northeast Mexico. The upper trough continues to lift NE
today, with the southern periphery of the 500 mb trough axis
swinging through our neck of the woods. This trough passage was
able to provide a lifting mechanism, eroding the warm layer seen
on the sounding around 500 mb. The coverage of the storms this
afternoon will continue to be scattered in nature, but they will
be capable of producing heavy rainfall rates resulting in flash
flooding. I would still expect additional scattered thunderstorms
develop this afternoon into the early evening, especially along an
axis from Tucson to Douglas (which will align itself with the
best deformation aloft from the trough passage).

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 05/00Z. SCT-BKN 7-12k ft AGL from KTUS
eastward thru 04/05Z, becoming SCT 12-15k ft AGL overnight. SCT-
BKN 7-12k ft AGL will redevelop aft 04/19Z. Scattered SHRA/TSRA
are expected through 04/04Z with CIGS BKN 5-8k ft AGL and gusty
outflow winds up to 40 kts. Surface winds generally WLY 8-13 kts,
becoming SLY less than 10 kts overnight. Aviation discussion not
updated for TAF amendments.

&&

.FIRE WEATHER...Slightly below normal temperatures Friday, then
warming back this weekend into next week. Expect scattered showers
and thunderstorms this afternoon into this evening with locally
heavy rainfall/flash flooding the primary threat. 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.

&&

$$

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson