Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 290918
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
218 AM MST FRI JUL 29 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. Above normal temperatures will continue today with
cooler temperatures moving in this weekend and continuing into early
next week.
.

&&

.DISCUSSION...Latest water vapor imagery shows mid/upper level high
located near Las Vegas this morning with east to northeast flow
aloft across southeast Arizona. We`re still seeing a bit of debris
cloudiness and even an isolated shower or two near the international
border but those will continue to dissipate early this morning.

After the down day yesterday, the atmosphere has had a chance to hit
the reset button with a potentially active day and evening ahead.
Latest high resolution models are consistent in depicting showers
and thunderstorms developing across the Mogollon Rim early this
afternoon and propagating southwest into the lower elevations. With
that said, we`re only expecting modest moisture east of Tucson with
precipitable water values down near an inch. The richer moisture will
be west of Tucson in the lower deserts, with Tucson on the edge of
this deeper moisture field. Given forecast SBCAPE values of 1500-
2500 J/KG in the deserts, especially west of Tucson, once these
storms propagate westward into the lower deserts, some of the storms
will potentially be severe with strong outflow winds producing areas
of blowing dust given the very deep mixed layer. We have added areas
of blowing dust into the forecast across Pinal County this afternoon
and then extending across the T.O. nation into western Pima County
this evening. Confidence is too low at this point to issue any kind
of advance blowing dust advisories but will defer that possibility
to the day shift.

A fairly active monsoon pattern is expected to continue this weekend
into next week with the mid level ridge axis remaining just north of
our area with generally easterly flow aloft. Moisture is expected to
increase this weekend setting the stage for a potentially prolonged
active period, especially as an inverted trough may aid storm
development Sunday into Monday. Meanwhile, given the deep moisture
across the region, we`ll begin to transition to greater flash
flooding threat as well. A fairly typical monsoon pattern for early
August is then expected for much of next week. Temperatures will
cool off to below normal values by Sunday and continue through much
of next week.

&&

.AVIATION...Valid through 30/12Z.
Sctd debris cloud cover will gradually decrease this am. After
29/17z expect an increase in areal coverage of -SHRA and -TSRA
versus Thu which was a down day. Thunderstorms dvlpg over the higher
terrain will propagate generally W into the valleys. Mostly VFR
conditions thru pd except for psbl MVFR in/around -SHRA and -TSRA.
Winds generally 10 kts or less except brief gusts to 50 mph psbl
with stronger TSRA. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...After a down day on Thursday today is expected to be
much more active with isolated to scattered thunderstorms this
afternoon and evening. Biggest threat from these storms later today
will be very strong outflow winds. The rest of the forecast period
will see a continued threat for isolated to scattered showers and
thunderstorms along with slight cooler daytime temperatures.
Significant winds are not expected except in the vicinity of
thunderstorms.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

GL

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