186
FXUS65 KTWC 250921
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
221 AM MST Sat Jul 25 2026

.SYNOPSIS...High temperatures will be 8 to 12 degrees above
normal again today, with an Extreme Heat Warning in effect
through 8 PM. Storm coverage and chances will increase today
with a threat for severe winds and locally heavy rainfall.
Sunday into next week expect daily afternoon and evening
thunderstorms as the monsoon pattern holds steady.

&&

.DISCUSSION...Storms have dissipated over southeast Arizona, but
well to the south a strong MCS is moving through Hermosillo in
Sonora. Skies are mostly clear with temperatures in Tucson still
in the low to even mid 90s for some locations. High temperatures
today will be similar to yesterday running 8-12 degrees above
normal with the Tucson airport making another run at 110
degrees. Current NBM probabilities are around 20 percent to hit
110 at KTUS. The Extreme Heat Warning continues today through 8
PM.

Aloft the center of the high will shift slightly north with
storm coverage and chances increasing compared to yesterday.
Plenty of moisture will be in place with PWAT values 1.2"-1.6"
and surface dewpoints around 60 degrees. MLCAPE values will be
around 500-1000 J/kg and mid-level flow will be slightly
elevated around 15-20 knots especially along the international
border. Model soundings also show inverted V profiles and this
along with all of the other parameters will lead to a severe
wind threat this afternoon and evening. SPC has a marginal risk
for severe weather today for most of southeast Arizona. Hi-res
guidance shows storms initiating over the higher terrain of
Graham and Greenlee Counties and along the international border
early to mid-afternoon. Storms then propagate along outflows
into the lower deserts late afternoon into the evening. Tucson
will likely see its first storms around 4-6 pm. Blowing dust
will also likely be an issue along I-10 in Cochise County during
the afternoon and in Pinal County late in the afternoon into
the evening. Storms will also be capable of heavy rainfall
leading to isolated areas of flash flooding. The best chances
for heavy rainfall look to be south of Tucson with the wind
threat more widespread.

Sunday expect another round of scattered thunderstorms following
a similar evolution to today. However mid-level winds are a bit
weaker, generally 5-10 kts, so the severe wind threat is
diminished some. Storm motion will likely be a bit slower
leading to a greater flash flooding threat, especially south of
Tucson. The HREF has a small area over Santa Cruz county of 40
km neighborhood probabilities of 10 percent for 3 inches of
rain in 3 hours.

Going into the work week the ridge stays in a favorable place
for daily afternoon and evening thunderstorms. Coverage of
storms may decrease some after Wednesday as the ridge moves
slightly southward and increases in strength, but still expect
some activity due to plentiful moisture and intense daytime
heating. High temperatures will drop back to around normal by
Monday then back to 3-8 degrees above normal Wednesday into the
end of the work week.

&&

.AVIATION...Valid through 26/12Z.
SKC this morning becoming SCT-BKN 8k-12k ft AGL this afternoon
and evening. TSRA will develop over the higher terrain and along
the international border early this afternoon then move into the
lower deserts. KOLS and KDUG could see TSRA by 25/22Z and KTUS
by 26/00Z. Any thunderstorm may produce strong and erratic wind
gusts, with a chance of a severe wind gust. Otherwise surface
winds variable and less than 8 kts this morning becoming
northwest 5-10 kts this afternoon and early evening. Aviation
discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Strong high pressure aloft will keep high
temperatures 8 to 12 degrees above normal today. Expect
scattered thunderstorms today from central Pima County eastward.
Thunderstorms should form over the Sky Islands and White
Mountains in the first half of the afternoon, spreading into
desert locations westward through central Pima county in the
late afternoon and early evening, moving into western Pima in
the late evening. Any thunderstorm will bring a threat of
severe, erratic wind gusts as well as brief heavy rainfall and
an isolated threat of flash flooding. Daily thunderstorm
chances continue into much of next week with heavy rainfall and
strong winds the main threats. Minimum relative humidity values
will increase from 15-20 percent in desert location and 30-40
percent in the mountains today to above 20-40 percent Sunday
through mid-week next week. Winds this weekend will mainly be
light and under 12 mph outside of thunderstorms.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
Extreme Heat Warning until 8 PM MST this evening for
AZZ501>509.

&&

$$

Hardin

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