Oracle, Arizona Weather Forecast Discussion

360
FXUS65 KTWC 101613
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
913 AM MST Wed Sep 10 2025
.SYNOPSIS...Isolated daily shower and thunderstorm chances remain
through Friday, generally from Tucson eastward. Expect some breezes
through Friday. Slightly above normal temperatures today then
seasonable temperatures thereafter.
&&
.UPDATE...
New high-resolution guidance this morning continues to point to
the development of scattered thunderstorms this afternoon, mainly
focused on Cochise through Graham and Greenlee counties. A mid-
level moisture gradient sits to the west, in the Tucson-Nogales
vicinity, putting eastern Pinal/Pima and Santa Cruz counties on
the western edge of thunderstorm chances today. There remains some
variation from model to model whether or not Tucson or Nogales
sees activity, therefore forecast chances with this update remain
in the 15-20 percent range. 20-30 percent chances sit further
east. As previously discussed, an isolated strong wind gust threat
remains (as well as blowing dust), while the modest atmospheric
moisture content present should keep the flash flooding threat
very low. With increasing upper level support from the trough to
the west, isolated thunderstorms lingering into the late night
tonight can`t be ruled out.
&&
.PREV DISCUSSION... /issued 231 AM MST Wed Sep 10 2025/ Clear
skies across southeast Arizona as the area is between a ridge of
high pressure from west Texas/Chihuahua and an upper low over
northern California and associated longwave trough extending south
from there. The south to southwesterly flow aloft will increase
mid level moisture as southeast Arizona is perfectly situated on
the periphery of these weather systems to transport increased
moisture northward from Sonora. With that said, PWATs will be
around 1 inch, which combined with some lift due from the
approaching trough will be enough to support more convection than
the past couple of days. HREF/CAMs are in good agreement focusing
on isolated thunderstorms (15-30 percent chances) for
Cochise/Graham/Greenlee Counties today with Tucson on the western
edge and this seems reasonable. Main concern today is gusty
outflow winds with DCAPE values up around 2000 J/KG. We can`t rule
out a severe thunderstorm or two with any storms that have more
sustained updrafts and the HREF does indicate a 10 percent chance
of 40-km neighborhood probabilities of greater than 50 kts across
Graham County. Outside of any thunderstorms, given the increased
pressure gradient from the approaching trough, winds will be on
the breezy side with gusts up to around 25-35 mph. High
temperatures today will be about 5 degrees above normal.
Not much change for Thursday and even Friday as the trough slowly
nudges eastward into the Great Basin. This will continue to result
in breezy afternoon winds with isolated showers and thunderstorms,
generally from the Tucson area eastward. Temperatures during this
time will nudge down to seasonable levels.
This weekend the trough will eject east allowing for some drying
which should shunt thunderstorm chances back into Sonora/Chihuahua.
However, any drying will be short lived as the moisture never gets
too far away and a return to more southerly flow will allow a return
of some moisture and thunderstorm chances early to mid next week.
The monsoon isn`t quite done with us yet but this is clearly a
transition pattern.
&&
.AVIATION...Valid through 11/12Z. Scattered 10k-13k feet ceilings
with isolated -SHRA/-TSRA this afternoon and early evening, mainly
east of KTUS-KOLS. With any thunderstorm expect variable and gusty
winds up to 40 knots. Surface winds light and terrain driven thru
10/15Z, then becoming southwesterly and increasing to 12-18 knots
with gusts to 30 knots between 10/18Z and 11/03Z. Surface winds then
diminish and become light and terrain driven through the end of the
valid period. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Minimum relative humidities mainly 15-30 percent
through the week, though a bit higher Thursday and Friday. Isolated
showers and thunderstorms mainly east of Tucson through Friday.
Gusty and erratic winds are expected with thunderstorms.
Otherwise, outside of thunderstorms, expect breezy southwesterly
winds each afternoon through Friday with sustained winds of 12-18
mph and gusts of 25-35 mph. High temperatures slightly above normal
today then seasonable thereafter.
&&
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Edwards
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NWS TWC Office Area Forecast Discussion