Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 290357
Area Forecast Discussion
National Weather Service Tucson AZ
857 PM MST THU JUL 28 2016
.SYNOPSIS...A monsoon pattern will remain in place through at least
the middle of next week. Daily rounds of showers and thunderstorms
will be possible. Temperatures will remain warm and near to above
normal readings are likely.
.DISCUSSION...Water vapor imagery and 29/00Z upper-air plots show a
ridge centered over southern Nevada and Utah with east to northeast
flow aloft, generally from around 775MB up to around 275MB. A swath
of dry mid to upper level air can be seen over southern parts of New
Mexico and extreme southeast Arizona, but this area continues to
slip to the south. IR satellite imagery and radar data shows
lingering activity mostly over northern parts of the state from
around the Wickenburg area, northward toward Winslow. Closer to
home, only a couple of very weak cells noted near the international
border from south of Sierra Vista to near Arivaca. These showers
will continue to move to the west, but should dissipate within the
next hour or less.
Much farther to the south, a storm complex resides over central and
southern Sonora, Mexico with cloud tops as of 03Z of minus 80-84
degs C. This complex should continue to move to the west or west
northwest overnight and could push some outflows our direction. That
said, based on the latest satellite and radar trends will trim POPs
downward for most areas through the remainder of this evening, but
then show a slight increase after midnight based on the potential
for outflows to perhaps trigger isolated activity near the border
with Mexico overnight.
As of 03Z (8 PM MST), temperatures ranged from the lower to mid 80s
along the international border, to the mid to upper 90s for areas
farther north. The Tucson International Airport reported a temp of
99 degs after reaching an afternoon high temperature of 105 degs,
which was 7 degs above normal for this date. These current readings
seem to be on track with the expected/inherited overnight low temps,
but will continue to monitor and will make changes if needed.
Please see the previous discussion below for details beyond tonight.
.AVIATION...Valid through 30/06Z.
VFR conditions throughout Friday, except for possible MVFR in/around
showers and thunderstorms. Winds generally 10 kts or less except
brief gusts to 45 mph possible with stronger TSRA. Aviation
discussion not updated for TAF amendments.
.FIRE WEATHER...Generally isolated showers or thunderstorms through
the remainder of this evening and into the overnight hours, mainly
along the border with Mexico. Isolated to scattered showers and
thunderstorms again Friday afternoon and evening. However, we are
unstable enough that any storms that develop have the potential for
very strong outflow winds. Beyond that, increasing moisture Saturday
onward will result in an increase in the amount of convection across
the region along with higher humidity levels with dewpoints peaking
around 70 at times. The increased moisture will also result in lower
afternoon high temperatures. Significant winds are not expected
except in the vicinity of thunderstorms.
.PREV DISCUSSION...The threat of daily showers and thunderstorms is
expected to continue for the next several days. Latest model
predictions point to a more significant threat of storms Friday
through the weekend as the mid-level ridge shifts a bit to the east.
This will allow for a tinge more east to southeast flow and an
increase in low-level moisture. No significant changes to this
pattern are anticipated into mid next week. Temperatures will remain
at or above normal throughout.
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