Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 181641

Area Forecast Discussion
National Weather Service Tucson AZ
940 AM MST WED MAY 18 2016

.SYNOPSIS...A low pressure system over Arizona this morning will
move slowly across the area through early Thursday. This will result
in cooler temperatures and a chance of showers and thunderstorms
mainly north and east of Tucson. Dry and warmer conditions will
return for the latter part of the weak, then another upper level
system will impact the region this weekend into early next week with
another round of windy conditions.


.DISCUSSION...Water vapor imagery this morning showed upper level
low pressure over central Arizona moving slowly to the east.
Regional radars since sunrise showed a few quick showers across
Graham and Cochise counties with bulk of activity occurring up
across northern Arizona. Most recent high resolutions model runs
continue to show that the best areal coverage for showers and
thunderstorms, mainly between 11 am and 4 pm, will be across Graham
and Greenlee counties. Isolated activity across the remainder of the
forecast area. Gusty erratic winds with any of these storms that
could cause some dust issues, especially east of Tucson near the New
Mexico border. Nice cool day for May across the region with highs
running 8 to 10 degrees below normal. Most of the activity this
evening will be done by 10 pm`ish.


Isolated very light showers mainly north and east of KTUS this
morning. Then isolated to scattered showers and thunderstorms this
afternoon with the most widespread coverage north and east of KTUS.
Variable winds mainly less than 12 kts early this morning, then
trending south late this morning to early afternoon and becoming west
at 10 to 15 knots with higher gusts through the afternoon. Gusty and
variable winds are expected near any showers and thunderstorms. Cloud
coverage will generally be scattered to broken at 6-10k ft agl
through this evening with a bit of clearing overnight. Aviation
discussion not updated for TAF ammendments.


.FIRE WEATHER...Expect an increase in areal coverage of showers and
thunderstorms across the region as the day progresses. The best
chance of wetting rains will be north and east of Tucson and
especially in the higher elevations. Gusty and erratic winds are
expected near showers and thunderstorms mainly from early this
afternoon through early this evening. Precipitation chances will
decrease tonight, though enough moisture should remain Thursday
for a chance of showers and thunderstorms mainly across the White
mountains. Dry conditions will then prevail area-wide Friday into
early next week.

A few afternoon gusts on Thursday due to daytime heating, otherwise
fairly light winds. Breezy to locally windy conditions will return
Friday and continue through this weekend into early next week as a
low pressure system deepens northwest of the area. Wind speeds may
approach critical levels for portions of the area as early as
Friday, then continuing through the weekend into early next week.
The best potential for critical fire weather thresholds being met
looks to be Sunday for eastern areas.





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