Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 210929

Area Forecast Discussion
National Weather Service Tucson AZ
230 AM MST FRI OCT 21 2016

.SYNOPSIS...Gusty east to southeast winds will continue through the
morning hours today, diminishing this afternoon. Increasing moisture
will then result in a slight chance of showers and thunderstorms
Saturday afternoon and evening, followed by increasing precipitation
chances Sunday and especially Monday. Dry conditions will return
Tuesday and persist into next Friday.


.DISCUSSION...Gusty east to southeast winds will persist across
portions of southeast Arizona through the mid/late morning hours
before slackening off this afternoon as the surface pressure
gradient weakens. Otherwise, expect clear skies and well above
normal temperatures today with afternoon highs topping out 6-10
degrees above seasonal averages. Not expecting record levels
although a few locales may be with a degree or two of their record
highs this afternoon.

The models indicate the upper high currently situated to our west
will shift eastward into southern Texas by early Saturday and over
the northern Gulf of Mexico on Sunday as a trough pushes into the
Pacific Northwest. As the high shifts eastward, moisture to our
south will work its way northward into the back side of the ridge in
advance of the developing west coast trough. This will lead to a
slight chance of showers and thunderstorms starting Saturday
afternoon and evening, mainly south/southeast of Tucson along the
international border. Although moisture will continue to increase
during the day Sunday, not a lot in the way of forcing or dynamics
to work with, so again the best precipitation chances are expected
to be from Tucson south/southeast.

There will be increasing chances for more widespread precipitation
Sunday night as the trough approaches the state from the west and
especially Monday/Monday night as the trough axis shifts across the
state. By Monday night, expect shower/thunderstorm chances to mainly
be from Tucson eastward. The forecast area will then rapidly dry out
from west to east on Tuesday as high pressure aloft builds in from
the southwest. However, there may be enough lingering moisture for a
slight chance of showers over far northeastern portions of the area,
roughly from Safford northeast into the White Mountains. Tuesday`s
high temperatures will be the `coolest` over the next 7 days, with
valley locations generally in the lower to mid 80s, which is still
2-4 degrees above normal.

High pressure will then strengthen over the desert southwest and
northern Mexico in the latter periods of the forecast, in the
Wednesday through Friday time frame. This will lead to dry and
warmer conditions areawide. Afternoon high temperatures are expected
to top out in the upper 80s to near 90 degrees across the Tucson
metro area over this period.


.AVIATION...Valid through 22/12Z.
Generally SKC with perhaps a FEW clouds above 20k ft AGL filtering
in from the south late in the period. Ely sfc wind around 10-15 kts
this morning with the strongest speeds near KTUS. Speeds will
diminish this afternoon to mainly less than 10 kts and continue
overnight into Saturday morning. Aviation discussion not updated for
TAF amendments.


.FIRE WEATHER...Above normal temperatures will prevail into next
week. Expect dry conditions through Saturday morning, with a slight
chance of showers and thunderstorms developing from Tucson southward
Saturday afternoon into Sunday morning. Shower and thunderstorm
chances will continue Sunday and Sunday night from Tucson south and
east to the NM border before extending area-wide Monday and Monday
night. Dry conditions are expected Tuesday night through Friday of
next week.

20-ft winds will continue to be elevated around 15 mph this morning,
eventually decreasing this afternoon. Normal diurnal wind trends
will return this weekend into the middle of next week.


.CLIMATE...Yesterday marked the 14th consecutive day of at least 90
degrees recorded at Tucson International Airport for October 2016.
This currently ties the tenth longest period of 90 degrees or warmer
on record. The current official forecast suggests that 90 degrees or
warmer should continue through Sunday. If this occurs, there will be
17 consecutive days this month of at least 90 degrees recorded at
Tucson International Airport. This 17 consecutive day period would
be the sixth longest on record.





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