852
FXUS65 KTWC 012206
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
306 PM MST Tue Jul 1 2025

.SYNOPSIS...Monsoon moisture has arrived in Southeast Arizona. The
main focus area this afternoon and evening for thunderstorm activity
will be across eastern Pima, Santa Cruz, southeast Pinal and the
Tohono O`odham Nation where strong outflow winds and blowing dust
expected with thunderstorm activity. More widespread thunderstorm
activity to include a heavy rain and localized flash flood threat
along with gusty winds Wednesday. A drying trend is expected for
the July 4th holiday and this weekend with storm coverage more
isolated and focused from Tucson southward. Temperatures will drop
to near normal levels by Wednesday, then below normal to end the
week before warming back up to near to slightly above normal this
weekend and early next week.

&&

.DISCUSSION...The suspended dust from the strong and gusty
thunderstorm outflows yesterday continue to slowly settle out of
the air this afternoon...but a significant haze resides across all
of Southeast Arizona. Unfortunately, conditions are ripe for
another round of isolated to scattered thunderstorms to produce
outflow wind gusts to 40-50 mph this afternoon/evening...resulting
in additional blowing dust across central Pima (Tohono O`odham
Nation), eastern Pima (Tucson Metro Area) and southeast Pinal
counties. There is a Blowing Dust Advisory in effect until 8 pm
MST.

The upper pattern this afternoon is defined by a 500 mb high centered
over northern Arizona and an established upper trough across the
California coastline. The latest GOES Total Precipitable Water
imagery indicated values between 0.95 and 1.10 inches across all
of Southeast Arizona, with 1.50 inches nudging northward into
central Sonora Mexico.

Thunderstorms development today will initially occur across south
central Arizona (S to SSW of Tucson) and the east central
mountains of Arizona. The are to the south coincides with the
best area of deep-layer moisture flux convergence seen on the SPC
Mesoscale Analysis. Although this is where the deeper lower-to-mid
level moisture is moving into the area, the lower-levels still
remain fairly dry which will enhance downdrafts. Expect strong
thunderstorm outflow winds to 40-50 mph to produce blowing dust
again this afternoon. The development that occurs in the White
Mountains will move WSW toward Pinal county as the afternoon
progresses. The outflows from these storms and the aforementioned
storms in south-central Arizona will focus the area of blowing
dust across the central portions of our CWA.

That deeper moisture south of central Sonora Mexico will continue
to nudge its way into our neck of the woods Wednesday shifting
the threat from thunderstorms with strong thunderstorm outflows
to more of a heavy rainfall threat. The upper trough over
California begins to shift east Wednesday...and as it does, it
provides an nice enhancement to the lift due to the diffluence
aloft. The 01/12Z HREF indicated the heaviest rainfall will occur
along a line from Sells to Nogales tomorrow afternoon, with a 70%
chance of 3-hr rainfall in excess of an inch, and even a 10%
chance of rainfall in excess of 3 inches across portions of Santa
Cruz county. Given the combination of the deeper atmospheric
moisture in place, and the upper lift provided by the approaching
upper trough, we have decided to issue a Flash Flood Watch
Wednesday between 11 am MST and 11 pm MST. We extended the area of
the Flash Flood Watch to include eastern Pima county (Tucson
Metro Area) and western Cochise county (Sierra Vista). It has been
a long time since we have seen a solid rainfall across the
forecast area. We are hoping the FFA will assist us in messaging
the importance of staying safe when encountering running water of
unknown depth in normally dry washes, roadway dips and other low-
lying areas...especially in urban areas.

We will see a drying trend for the Fourth of July holiday, with
only isolated showers and thunderstorms expected. Deeper moisture
returns early next week, and a more favorable flow pattern will
increase chances of thunderstorms as we move toward the middle of
next week.

&&

.AVIATION...Valid through 03/00Z. SCT-BKN 7-12k ft AGL thru
02/06Z, becoming SCT-BKN 12-15k ft AGL overnight, then SCT-BKN
5-10k ft AGL aft 02/18Z. Sfc winds ELY/SELY at 5-15 kts with
gusts 20-25 kts. Expect scattered -SHRA/-TSRA thru 02/03Z with
KTUS/KOLS most likely terminals to be impacted (~40-50% chance).
Scattered to numerous -SHRA/-TSRA will occur after 02/18Z
Wednesday with CIGS BKN 5-8k ft AGL. Storms that develop this
afternoon and evening will produce gusty outflow winds greater
than 35 kts with reduced visibility due to localized BLDU.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Hot this afternoon cooling to around climatological
normal through Saturday as deeper atmospheric moisture moves into
Southeast Arizona, then warming back up Sunday into early next
week. Min RH`s 15 to 30 percent today with scattered showers and
thunderstorms for most of southeast Arizona. Even higher moisture
levels move in for Wednesday and Thursday with potential that some
of the thunderstorms will produce locally heavy rainfall. Some
drying will tend to lower thunderstorm chances to around 20 to 30
percent Friday into the weekend with the highest chances along the
Int`l border. Gusty east to southeast winds today with gusty and
erratic winds to 40-50 mph near any thunderstorms. Otherwise
winds generally light and under 15 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...

Blowing Dust Advisory until 8 PM MST this evening for AZZ502>506-
515.

Flood Watch from Wednesday morning through Wednesday evening for
AZZ502>504-507-513>515.

&&

$$

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