746
FXUS65 KTWC 242030
AFDTWC
Area Forecast Discussion
National Weather Service Tucson AZ
130 PM MST Tue Jun 24 2025
.SYNOPSIS... Increasing moisture today will bring chances for
showers and thunderstorms this afternoon and evening. Highest
chances will be in Cochise county into Graham and Greenlee
counties with just slight chances as far west as Tucson to
Nogales. Additional shower and thunderstorm chances are possible
each afternoon through this week mainly closer to the New Mexico
border.
&&
.DISCUSSION... Build ups and storms are starting to form Tucson
eastward. A few storms are producing brief rainfall with amounts
around 0.1 to 0.25 inches and frequent lightning. The 18Z sounding
launched at TUS shows there is 1.33 inches of PWATs with DCAPE
around 1500 J/kg. The sounding also shows there is a solid cap,
indicating that any storms that develop will need to break
through this for deeper convection otherwise they will remain
fairly shallow. The greatest chance for storm development will be
in Cochise, and southern Graham and Greenlee counties (20 to 40%)
and decrease northwestward to only a slight chance (15 to 25%) in
eastern Pima county. Pockets of precipitation rates up to 0.25
inch/hour are likely with stronger storms. The concern for flash
flooding is low though there is a chance for some storms to
produce brief heavy rainfall that may lead to slick roads and some
ponding. Gusty outflow winds may also accompany any stronger
storms, there is a chance that if these storms are able to break
the cap outflows may be severe.
A similar pattern aloft remains over the coming days, with some
variance in moisture quality and therefore precipitation chances.
Guidance pushes moisture east on Wednesday with any convective
chances kept to Cochise, Graham, and Greenlee counties. A similar
precipitation outlook returns on Thursday as recent model runs
have trimmed back the western edge of the moisture field away from
Pinal through eastern Pima and Santa Cruz counties. By the end of
the week the upper level pattern will become a more diffuse after
the previous trough lifts away from the region, reducing
confidence in day to day chances as moisture quality will depend
on outflows and previous days activities. Drier conditions are
likely this weekend with the loss of the previous upper level
pattern.
As mid-level heights rise with the exiting of the upper trough,
temperatures will rise to above normal again by the weekend. With
the ridging process the upper high should become oriented over the
southwest CONUS next week, potentially centered over the Four
Corners. While this would be a favored location to usher in good
monsoon moisture, there are still some differences in global model
ensemble members on the orientation of this ridge, which adds some
uncertainty at this time regarding exact timing of moisture
arrival.
&&
.AVIATION...Valid through 26/00Z.
SCT to BKN clouds AOA 6 to 10k ft AGL KTUS eastward will continue
throughout the forecast period. Scattered showers and
thunderstorms developing now KTUS eastward. Activity diminishing
near KTUS- KOLS after 25/00Z, lingering through the evening in
eastern terminals including near KSAD-KDUG. Brief periods of MVFR
visibility and gusts to 40 kts possible under showers and
thunderstorms. Winds today otherwise generally light and
southwesterly up to 12 kts with a few afternoon gusts to 20 kts.
Aviation discussion not updated for TAF amendments
&&
.FIRE WEATHER... Increasing moisture today in eastern zones,
especially across Cochise, Graham, and Greenlee county will keep
minimum relative humidities above 20 percent. Minimum values 10-20
percent west of this area. This moisture will bring chances for
showers and thunderstorms this afternoon and evening, with a
slight chance as far west as Tucson to Nogales. Winds turn
southwest and remain generally light and under 15 mph, though
brief gusty and erratic winds possible with any thunderstorm.
Chances for showers and thunderstorms return daily this week but
mainly for far eastern areas closer to the New Mexico border.
Conditions likely dry this by this weekend as temperatures rise
above normal.
&&
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Malarkey/ Edwards
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NWS Tucson (TWC) Office
Tucson, AZ 
