Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 302153
Area Forecast Discussion
National Weather Service Tucson AZ
253 PM MST FRI SEP 30 2016
.SYNOPSIS...A drying trend from the west will greatly reduce the
chance of storms over the weekend. A trough will bring cooler air
and breezy conditions along with a few showers late Monday or
Tuesday. High pressure will then bring dry conditions and a rapid
warming trend the second half of next week.
.DISCUSSION...Not quite as much coverage as yesterday, but not by
much. Despite anvils spreading ahead of the storm tracks and a
little less moisture to work with, the impulse tracking west
across Arizona today has helped to keep us active. The best CAPE
and shear is now east of Tucson with strongest storms the
remainder of the afternoon expected for that area. Subsidence
behind the impulse will coincide nicely with sundown, so don`t
expect much to hang on this evening.
Over the weekend the high center to our southeast will
reconsolidate well south of our area as a strong trough digs into
the region from the eastern Pacific. Limited moisture and a more
stable atmosphere will limit convection over the weekend with
temperatures a few degrees above average.
The strong low associated with the trough will push through the
central Great Basin Monday, with a slower trailing frontal
boundary dragging through Arizona late Monday into early Tuesday
(reaching our corner of the state last sometime during the day
Tuesday). A few showers associated with this but nothing
significant this far south. Our main impacts will be the breezy
conditions Monday into Tuesday morning, as well as about 10 to 15
degrees of cooling that will drop daytime highs to around 6-8
degrees below average Tuesday.
Much cooler nights for the middle of next week, then the Mexican
ridge noses in for a strong warming trend the second half of next
.AVIATION...Valid through 02/00Z. Areas of TSRA through the
afternoon with clearing from the west after 01/02Z. VFR through
the period with brief MVFR possible near storms. Normal diurnal
wind trends generally less than 12kts. Aviation discussion not
updated for TAF amendments.
.FIRE WEATHER...Scattered showers and thunderstorms this
afternoon, then a slow drying trend over the weekend. 20-ft winds
will generally be less than 15 mph through Sunday, along with
normal diurnal wind trends. 20-ft winds will then increase on
Monday and Tuesday of next week, as a system moves across the
Great Basin and brings cooler and drier air.
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