Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 231546

Area Forecast Discussion
National Weather Service Tucson AZ
846 AM MST TUE AUG 23 2016

.SYNOPSIS...A drying trend will continue to limit thunderstorms to
mainly east of Tucson through Thursday. Isolated to scattered
afternoon and evening thunderstorms should return by next weekend.
High temperatures will generally be within a few degrees of normal
into next weekend.


.DISCUSSION...A nice system is pushing through northern Arizona
today. Unfortunately it is wrapping significantly drier air into
most of Southeast Arizona as it does so, as per current Water
Vapor and CIRA layered precipitable water totals. Most of our
moisture loss has been between 700-500mb with contributions from
that layer dropping from .5 to .2 inches in the past 24 hours.
As our lower level moisture recycles into cu fields today we will
also have plenty of room for surface dew points to mix much lower
this afternoon.

The bottom line is that we will struggle with available moisture
for much of the week before deeper moisture returns Friday and
Saturday. Please see the previous discussion below for additional


VFR through the period with decreasing moisture. Scattered Cumulus
fields during the afternoon with isolated thunderstorms possible
in mountains east and northeast of KTUS. Surface wind generally
less than 12 kts, except in the upper Gila River valley in the
vicinity of KSAD where surface wind will be nwly at 12-17 kts
between 23/20z and 24/02z. Aviation discussion not updated for TAF


.FIRE WEATHER...Isolated thunderstorms will occur mainly near
mountains east of Tucson through Thursday. Isolated to scattered
coverage is then expected Friday through Sunday from Tucson eastward
as monsoonal moisture increases from the south. 20-foot winds
into the upcoming weekend will be terrain driven and less than 15
mph in most locations. Expect the potential for strong and gusty
winds near thunderstorms...and a little stronger afternoon and
early evening winds in the upper Gila River valley, with northwest
winds around 20 mph through Thursday.


.PREV DISCUSSION...Last nights upper air plots showed an upper
level trof extending from e-central UT SW across srn NV into srn
CA. Scattered thunderstorms were occurring across NW AZ down to
near the Phoenix area. Across SE AZ, it was clear to partly cloudy
under SW flow aloft. The above mentioned upper level trof will
continue to push across northern AZ today with bulk of
thunderstorm activity occurring across the northern half of AZ.
With PW values below 1" across the area, it will be a down day
thunderstorm wise with a few developing over the higher terrain
east of Tucson. Highs today will be similar to what occurred on
Monday. The flow aloft tonight becomes NW with the passage of the
upper level trof.

A trailing upper level trof will move across the area on Wednesday.
Enough moisture will be around, especially E-NE of Tucson, for a
chance of afternoon and early evening storms.

Thunderstorms on Thursday relegated to the higher terrain near the
AZ/NM border and along the international border. Sonora should be
more active Thursday night as an inverted trof will be passing by
south of this area.

Some of this moisture will be advected north on Friday for the
potential for an areal increase in scattered afternoon/evening
showers and thunderstorms.

Scattered showers and thunderstorms to start the upcoming weekend
then drier air pushes in from the west on Sunday limiting storms to
areas east of Tucson.

Highs for the most part this week into the weekend will be near late
August normals. Triple digit highs return to the low deserts early
next week as high pressure aloft expands over the desert






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