FXUS65 KTWC 172139

Area Forecast Discussion
National Weather Service Tucson AZ
239 PM MST Sat Nov 17 2018

.SYNOPSIS...Dry conditions with seasonably mild daytime temperatures
this weekend and during most of the upcoming week. A passing weak
weather system on Thanksgiving Day may produce a few showers
mainly across the White Mountains.


.DISCUSSION...A zonal westerly flow over SE Arizona for the time
being. This will continue to bring mild conditions today along
with patches of cirrus clouds at times through the weekend and
early in the new week. Fairly dry below that with precipitable
water values below 1/3 of an inch and surface dew points in the
teens and 20s. Daytime highs and overnight lows within a few
degrees of climatology and normal diurnal wind trends.

A pattern change will bring a split in the flow over the next 72
hours with a weakness in the flow undercutting the base of the
ridge Tuesday. Not much moisture to work with but it should
enhance some cloud cover Tuesday and bring a few degrees of
cooling Wednesday.

A broader trough pushing through the region will bring a few rain
and snow showers near the mountains Thursday. This will also set
the table for the kicker system to dig further south next weekend
with a better chance of showers for the area. Also accompanied by
gusty winds and below average temperatures by next Saturday.


.AVIATION...Valid through 19/00Z.
Scattered to broken clouds above 20k ft AGL, and surface wind
variable in direction mainly less than 12 kts. Aviation
discussion not updated for TAF amendments.


.FIRE WEATHER...Expect continued dry conditions across much of the
area this weekend and during the upcoming. However, a few showers
may occur on Thanksgiving Day mainly across the White Mountains. 20-
foot winds will be terrain driven and mostly less than 10 mph. The
exception is Monday into Tuesday when east to southeast gusts near
20 mph may occur at times.






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