Severe Thunderstorm Warning 6, NWS Tucson, AZ

Area Forecast Discussion
National Weather Service Tucson AZ
222 PM MST Tue Jun 16 2026

.SYNOPSIS...Increased moisture will result in isolated to
widely scattered afternoon showers and thunderstorms mainly south of
Tucson near the Int'l border, then from Tucson south and eastward
Wednesday. Thereafter, some residual thunderstorm chances along the
Int'l border Thursday then dry conditions Friday through the
weekend. Otherwise, breezy afternoons with temperatures near normal
through the forecast period.

&&

.DISCUSSION...This afternoon, the upper level divergence/deformation
is weaker than yesterday and focused more south and east along
the International Border. However, terrain forced convection is
still on the table with cloud buildups and some showers and
storms having already formed on the highest peaks. The weaker
dynamics will result today overall be more of a low-grade
Monsoon day with only isolated to widely scattered showers and
storms. There is also a small chance (10-15%) that there could a
couple showers or storms out over T.O. Nation as well, but this
is only supported by a couple of the hires models. The main
hazard associated with any storms that do form other than
lightning and brief heavy downpours will be gusty outflow winds
that could loft blowing dust and locally reduce visibility. The
HREF gives a 50-70% chance of maximum wind speeds to exceed 35
mph.

Tomorrow will bring an uptick in thunderstorm activity with the
approach of a weak mid/upper low ejecting out of California. The
upper feature will help to create added upper level diffluence aloft
which may increase overall storm coverage and/or intensity provided
sufficient moisture and instability exist. It looks to me like
the most favorable area for lift will be along a Phoenix/Tucson/Nogales
line. Storms are also possible (10-30%) over the mountains as
the terrain will act as a forcing mechanism. The HREF depicts a
50-70% chance for winds exceeding 35 mph and even a slight
chance (10%) for maximum winds exceeding 58 mph. With drier air
getting imported into the mid/upper levels with the upper low
this might help lead to dry air entrainment and enhance the
outflows of taller storms that can tap into the environment.

Thursday we will see a downward trend in convective activity as
drier air starts to move in associated with dry westerly flow aloft.
Still enough recycled moisture will exist to support isolated to
widely scattered storms right along the Int'l border mainly from
Nogales eastward and also in the White Mountains. By Friday and
beyond, dry conditions are expected to prevail area-wide as the high
remains over Sonora and westerly flow aloft remains over Arizona.
Even with the drying, temperatures will still remain near normal
through the forecast period.

Breezy conditions will continue each afternoon with the strongest
winds in the Upper Gila River Valley near Safford where afternoon
gusts of 30 to 35 mph are expected Wednesday and Thursday. That will
result in elevated to locally near critical fire weather conditions,
especially as we dry out on Thursday afternoon.

&&

.AVIATION...Valid through 18/00Z.
SCT-BKN clouds 8k-12k ft AGL south and east of KTUS thru 17/04Z with
gradual clearing thereafter. Isolated to Scattered TSRA/SHRA between
through 17/03Z mainly near the Int'l border from KOLS eastward. Main
threats will be gusty outflow winds 25-45 kts with these storms.
Otherwise, SFC winds light at 10 kts or less thru 16/16Z.
Thereafter, outside of any storm influences, SFC winds become
WLY/NWLY 8-16 kts, gusting to 25 kts with gusts up to 30 kts for
KSAD. SFC winds diminish to 10 kts or less again aft 17/04Z and will
pick up again after 17/17Z becoming WLY/NWLY. Aviation discussion
not updated for TAF amendments.

&&

.FIRE WEATHER...Winds will remain west/northwest through this
week with speeds of 10-20 mph and gusts 25-30 mph across much of the
area with stronger speeds of 15-25 mph and gusts to 35 mph in lower
elevations of Graham county. Moisture levels will remain slightly
elevated through Thursday, with minimum relative humidity 15-30
percent in lower elevations and 30-40 percent in the mountains. This
will bring bring chances (20-30 percent) for showers and
thunderstorms along the Int'l border from Sasabe eastward this
afternoon, then from Tucson south and eastward, along with the White
Mountains Wednesday. Precipitation chances remain in the White
Mountains Thursday but otherwise retreat to the Int'l border once
again. Dry conditions area-wide Friday and beyond with minimum
relative humidity lowering this weekend to 5 to 15 percent in the
valleys and 10 to 20 percent in the mountains. For Wednesday and
Thursday elevated to near critical fire weather conditions will be
possible in the Gila River Valley as winds increase and RH drops
below 15 percent.

&&

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

&&

DVS

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