Severe Thunderstorm Warning 19, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
1237 PM MST Sun Jul 13 2025

.SYNOPSIS...Above normal temperatures will continue through
Monday. Increasing monsoon activity is expected in to begin
today in areas east and south of Tucson. These chances increase
across southeastern Arizona through the work week. As moisture and
storm chances increase, temperatures will drop back down to
seasonable levels Tuesday onwards.

&&

.KEY MESSAGES...

- Scattered thunderstorm activity this afternoon and evening will
  likely create blowing dust through areas of Greenlee, Graham,
  and Cochise counties. Isolated activity may move as far west as
  the Tucson area Sunday evening.

- Increasing chances for monsoon activity is expected this coming
  work week. Adequate moisture for increased flash flood concerns
  may arrive by mid-week.

- High temperatures transition from above normal through Monday to
  near or slightly below normal for the remainder of the week.

&&

.DISCUSSION... Build ups and isolated storms are starting to form
along the ridgelines of the Sky Islands and the White Mountains.
Minor to Moderate HeatRisk today as high temperatures will be
around 100 to 105 degrees this afternoon. Today is still looking
to be an active monsoon day. The 18Z upper air sounding launched
from TUS shows that there is around 1400 J/kg of DCAPE with about
800 J/kg of MU CAPE. SPC mesonalysis indicates that CAPE will
increase this afternoon to values around 1000 J/kg. PWATS observed
by the sounding are 1.22 inches which coincides with satellite
derived PWATs around 1 to 1.25 inches across Pinal county to Santa
Cruz county. PWATs decrease to 0.8 to 1.0 inches in far western
Pima county and northern Graham and Greenlee counties. More
moisture may be advected into the area from convection later this
afternoon into the evening.

Several convective allowing models are showing two convective
systems developing, one in Graham and Greenlee counties and the
other in Cochise and Santa Cruz counties. The Graham and Greenlee
counties system has storms starting noon to 1 PM moving south-
southwest off the Whites. The other system in Cochise and Santa
Cruz counties has storms developing around 1 to 2 PM moving west-
southwest. Both systems have the potential for strong, gusty
outflows, locally heavy rainfall and blowing dust. There is a
Blowing Dust Advisory for these counties (with the exception of
Santa Cruz) until 8 PM. With blowing dust expect visibilities to
be between 1/4 to 3 miles. There is a lower chance (20-30 percent)
for storms to impact the Tucson area however there is still the
potential for blowing dust to move into the area from storms to
the west or south. There is also the potential for a strong storm
to push moisture and lift into the Tucson area that could initiate
storms to develop. If that does happen, storms in the Tucson area
would be later this afternoon into the early evening hours.

The atmospheric pattern we are in throughout this coming week is
driven by the oscillation and ever-evolving magnitude of an upper
level low pressure center near northern Baja and a high pressure
center in southeast New Mexico/ northern Mexico. The low pressure
center goes through a cycle of strengthening off the coast of
Baja, moving eastward into northern Baja/ far southwestern
Arizona, then weakening and moving back west off the coast of
northern Baja. At the same time, high pressure is weakening and
receding southward, strengthens and pushes into southern New
Mexico then weakens again. Because of this gradually evolving
cycle, we continually get the ingredients needed for thunderstorms
to develop this week. The interaction between the low and the
high draw in moisture, instability, and suitable wind alignment.
Mean 700 to 300 mb winds will initially be from the north to
northeast early in the week transitioning to be from the southeast
by the end of the week. Due to the aforementioned atmospheric set
up, thunderstorm impacts to start the week will mainly be strong,
gusty outflow winds and blowing dust and transition to strong
gusty winds and flash flooding by the middle to end of the week.

&&

.AVIATION...Valid through 15/00Z
Scattered thunderstorms expected to develop from 13/19Z-13/22Z
over the White Mountains north of KSAD and along higher terrain
from KOLS through KDUG. Isolated to scattered thunderstorm
activity will move off these mountains and spread across
southeastern Arizona, especially east of KTUS. Isolated
thunderstorms possible in KTUS vicinity between 14/01Z and 14/04Z,
though with less confidence in this outcome at this time. Wind
gusts of 40-50 kts and blowing dust possible with any
thunderstorm, which may bring 1-3 mile visibilities in blowing
dust east and south of KTUS between 13/20Z- 14/04Z. Isolated
strong wind gusts may briefly produce even lower visibilities at
times. Otherwise winds today mainly light and west to northwest,
with the exception of KSAD with 10-15 kt northwesterly winds and
gusts up to 30 kts. Winds tonight become light and terrain driven.
Additional thunderstorm activity likely tomorrow afternoon and
evening. Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...An uptick in monsoon activity is expected to begin
today and persist throughout the week. Temperatures will remain
above normal through tomorrow, then drop back down to near or
slightly below normal by mid week. Winds will remain westerly
from 10-15 mph, with occasional gusts at or above 25 mph.
Afternoon RH values in the low lying areas will be between 10-15%
through Monday, then 20-30% through the remainder of the week.

&&

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Blowing Dust Advisory from 2 PM this afternoon to 8 PM MST this
evening for AZZ507>509.

&&

Malarkey

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