Why, Arizona Weather Forecast Discussion

465
FXUS65 KTWC 130916
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
216 AM MST Sat Sep 13 2025
.SYNOPSIS...Scattered afternoon and evening thunderstorms will
again be possible today south and east of Tucson. An isolated
risk of strong winds, large hail, heavy rain, and blowing dust
will accompany these thunderstorms. Dry air moves in Sunday
leading to no thunderstorms. Temperatures transition from below
normal this weekend to above normal next week with a modest return
of thunderstorm chances Tuesday and the end of the work week.
&&
.DISCUSSION...Current radar shows isolated showers and
thunderstorms east of Tucson. This overnight activity is the
result of a trough moving into northern Arizona providing enough
synoptic scale lift for some weak convection. This activity will
continue through the early morning. Expect another round of strong
to severe storms this afternoon and evening. The same
environmental ingredients as yesterday are in place with plenty
of moisture and instability as well as 0-6km wind shear of 20-35
kts. The only difference is dry air will intrude a little further
east than yesterday which will keep most thunderstorms activity
east of Tucson. Best chances will be in Cochise County and
southern Graham/Greenlee Counties. Eastern Santa Cruz County could
see some activity as well. Storms will again be capable of
rotation, which will lead to longer lived updrafts with the main
hazards being hail and strong to severe wind gusts. Heavy rainfall
will also be possible but fast moving storms will lessen the flash
flood threat.
Sunday the trough will be east of Arizona and will take the
moisture with it leading to dry conditions. Temperatures will also
begin to rebound. Highs today will be a few degrees below normal,
warm to around normal Sunday, then above normal Monday into the
middle of next week. High pressure builds over northern Mexico
next week which allows moisture to slowly move in from the south.
Monday will see low PoPs (generally 15 percent) along the
international border increasing Tuesday south and east of Tucson
to 20-40 percent. Later in the week models are hinting at a better
push of moisture especially west of Tucson.
&&
.AVIATION...Valid through 14/12Z.
Isolated thunderstorms possible through the morning mainly over
Cochise and Graham Counties. By late morning into the afternoon
scattered strong thunderstorms will be possible east of Tucson
with KSAD and KDUG seeing the best chances to be impacted by a
thunderstorm. The ingredients will be in place for wind gusts to
50 kts and large hail. Heavy rainfall and mountain obscurations
will also be possible. Storms will begin to dissipate after 14/03Z
as dry air begins to move in. Otherwise, sfc wind SLY/SWLY at
8-12 kts with gusts to 20 kts this afternoon and evening. SFC wind
less than 10 kts and variable in direction at other times.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Minimum RH values will be in the 20-35 percent
range today, lowering into the 15-30 percent range Sunday and
Monday, then back into the 20-35 percent range. Scattered showers
and thunderstorms are expected mainly for Cochise County and east
Santa Cruz County today. Thunderstorms today will have a risk of
very strong gusty winds, hail, and heavy rainfall. Dry area-wide
Sunday, then a slight chance of thunderstorms south and east of
Tucson return again next week. Outside of thunderstorm outflows,
expect 20-foot winds to be 15 mph or less, with some
afternoon/early evening gusts to around 25 mph.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Hardin
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NWS TWC Office Area Forecast Discussion