Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 242240
Area Forecast Discussion
National Weather Service Tucson AZ
340 PM MST SUN JUL 24 2016
.SYNOPSIS...Adequate moisture will provide scattered mainly
afternoon and evening thunderstorms into next weekend. Daytime
temperatures will generally trend a few degrees above normal.
.DISCUSSION...Isolated to scattered showers and thunderstorms were
occurring mainly across the White Mountains, the Chiricahua
Mountains, and near the International border adjacent southeastern
Santa Cruz County and southwestern Cochise County at this time.
Otherwise, mostly clear skies prevailed across southeast Arizona.
Various mesoscale models suggest that the White Mountains as well as
locales south-to-southeast of Tucson will be favored for showers/
tstms this evening. Ample moisture in combination with MUCAPES
ranging from 1000-2000 J/kg will continue into this evening.
However, storm motions will be quite slow given the surface-3 km
mean wind flow. Have noted the rapidly cooling cloud tops southeast
of this forecast area across far eastern Sonora/western Chihuahua
Mexico. These showers and thunderstorms are developing ahead of an
approaching inverted trough, and the GFS moves this system nwwd into
northeastern Sonora around daybreak Monday.
Have maintained scattered showers and thunderstorms this evening
from Tucson ewd/swd, and isolated showers/tstms across western
sections. A slight chance of showers/tstms exists area-wide late
tonight into Monday morning. The 24/12Z GFS/ECMWF/CMC were similar
with depicting a quasi-stationary upper high centered over southern
Utah/northern Arizona Tuesday into next weekend. These solutions
depict some drying of significance Thur-Fri across northern/central
Arizona. However, there appears to be only very minor daily changes
in moisture content across southeast Arizona. Thus, the scenario of
scattered afternoon/evening showers/tstms, and a slight chance of
late night/early morning showers/tstms will suffice Tuesday through
High temps during this forecast period will trend close to seasonal
normals, or a few degs above normal depending upon location.
.AVIATION...VALID THRU 26/00Z.
Few-sct clouds at 8-12k ft msl with isolated to scattered SHRA/TSRA
mainly across the White Mtns NE of KSAD, and S-SE of KTUS. Brief
wind gusts to around 40 kts and MVFR conditions are possible with
the stronger TSRA. Otherwise, sfc wind generally NWLY at 8-12 kts
with slightly stronger speeds and gusts to around 25 kts through the
Gila Valley near KSAD into this evening. Mainly light and terrain
driven winds will occur overnight, becoming WLY/NWLY at around 10
kts late Monday morning. Isolated to scattered SHRA/TSRA will occur
again Monday afternoon. Aviation discussion not updated for TAF
.FIRE WEATHER...Scattered mainly afternoon and evening showers and
thunderstorms will occur into next weekend. Outside of gusty
thunderstorm outflow winds, 20-foot winds will generally be terrain
driven and less than 15 mph. The exception will be the Gila River
Valley, where northwesterly winds around 20 mph with higher gusts
are possible during the afternoon hours through midweek.
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