Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 282109
Area Forecast Discussion
National Weather Service Tucson AZ
209 PM MST THU JUL 28 2016
.SYNOPSIS...A monsoon season pattern will remain in place through
at least mid next week. Daily rounds of showers and thunderstorms
will be possible. Temperatures will remain warm and near to above
normal readings are likely.
.Discussion...High pressure remains in control this afternoon and
is now centered over southern Nevada. Satellite and sounding
information indicates broad northeast to east flow in the mid and
upper level portions of the atmosphere. Additionally, daytime
heating is rapidly increasing convective potential energy across
the area from the Mogollon Rim southward to the International
Border. Thus far convection has been on the weak side, however,
the combination of heating, ambient moisture, and terrain will
lead to isolated to scattered storm development as the afternoon
and early evening approach. Absent from this afternoon`s weather
scenario is much in the way of mid/upper level dynamic forcing.
This will likely make storm coverage more sparse than what
occurred yesterday. As storms do develop there exists a
significant threat of downburst winds in any of the stronger
cells. Storm chances will peak between 2pm and 8pm.
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.
.AVIATION...Valid through 30/00Z.
VFR conditions throughout today, except for possible MVFR in/around
showers and thunderstorms thru 29/03z this evening and again Friday
afternoon and evening. Winds generally 10 kts or less xcp brief
gusts to 45 mph psbl with stronger TSRA. Aviation discussion not
updated for TAF amendments.
.FIRE WEATHER...Generally isolated to scattered thunderstorms through
this evening and again Friday afternoon and evening, basically not
as active as yesterday. However, like yesterday 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.
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