253
FXUS65 KTWC 300948
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
248 AM MST Sun Aug 30 2026

.SYNOPSIS...Expect scattered thunderstorms through Monday with
storms capable of strong to severe wind gusts and heavy
rainfall. After Monday storm chances begin to decrease. High
temperatures will be around normal through much of the coming
week.

&&

.DISCUSSION...Current radar shows scattered showers east of
Tucson with a few embedded weak thunderstorms. To the south in
Sonora there is a large decaying MCS. CAMs show this MCS sending
an outflow into southern Arizona later this morning, but will
likely not lead to any storm formation, just send some
reinforcing surface moisture. Aloft high pressure is centered
near Oklahoma and Arkansas and a trough is sitting over the west
coast. The upper air pattern will more or less remain in this
state with the ridge well to the east and a trough just to the
west.

Ample moisture will again be in place today with scattered
thunderstorms forming later this afternoon through the evening
hours. Could be a little delayed depending on how long the
current shower activity lasts. Coverage looks to be similar to
Saturday with the main threat being heavy rainfall and flash
flooding. There were areas west of Tucson, over the eastern
portion of Tohono O`Odham Nation, that received 2-3 inches of
rain Saturday according to radar estimates. The 30/00Z HREF
shows this same area, from central Pima County to western Graham
and Cochise Counties, under threat of similar rainfall amounts.
A Flash Flood Watch is in effect for these areas through early
Monday morning. Areas that received rainfall yesterday will be
at greater risk of flash flooding today. There will also be a
threat of strong to severe wind gusts, but the greater threat
will still be heavy rainfall. Convection could continue through
Sunday night as a couple shortwaves move through Arizona ahead
of the main trough.

Nocturnal convection could delay or decrease storm coverage and
intensity Monday. But CAMs still show scattered showers and
thunderstorms over most of southeast Arizona with the main
threat heavy rainfall. The HREF again paints areas just west of
Tucson and south with the best chances for rainfall totals
1"-2".

After Monday PWATs decrease by about 0.25" leading to an
expected downturn in monsoon activity. Southeast Arizona stays
in a transitional type of pattern with southwesterly mid-level
winds. Tuesday and Wednesday expect isolated coverage of storms
mainly south and east of Tucson. Later in the week models show a
possible tropical system moving parallel to the west coast of
Baja a few hundred miles offshore. This could send tropical
moisture our way as early as Thursday leading to an uptick in
thunderstorm activity. Still a little ways out with lots of
uncertainty in the track of the tropical system. But ensembles
are showing a 40-70 percent chance for PWATs to be above 1.5"
from Tucson westward Friday into next weekend.

High temperatures will cool to around normal today, 2-6 degrees
below normal Monday and Tuesday, then back to around normal the
rest of the work week.

&&

.AVIATION... Valid through 31/12Z.
SCT -SHRA/-TSRA south and east of Tucson through 30/14Z with BKN
cigs 8k-12k ft AGL. Scattered TSRA returns after 30/20Z and
continues through the overnight hours. Clouds will be SCT-BKN
8k-12k ft AGL. Outflow SFC winds near TSRA 35-45 kts otherwise
SFC winds less than 10 kts and terrain driven. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Expect scattered afternoon and evening showers
and thunderstorms through Monday (30 to 70 percent daily
thunderstorm chances). There is also a chance storms continue
overnight Sunday. Storms will be capable of strong to severe
wind gusts and heavy rainfall. After Monday storm chances and
coverage decrease with activity mainly from Tucson south and
eastward. Temperatures will be around normal today through the
coming work week. Minimum relative humidity values mainly 20 to
45 percent in the valleys and 30 to 60 percent in the mountains
over the next week. Winds will generally remain less than 15
mph and terrain driven through the week.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Flood Watch through late tonight for AZZ502>507-513>515.

&&

$$

Hardin

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