Area Forecast Discussion
Issued by NWS Tucson, AZ

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105
FXUS65 KTWC 220356
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
856 PM MST SAT MAY 21 2016

.SYNOPSIS...Expect breezy to locally windy conditions this weekend
into next week. It will also be cooler this weekend with below
average temperatures persisting through most of the week. No rain in
sight.

&&

.DISCUSSION...Water vapor imagery and 22/00Z upper-air plots show a
ridge axis over the center of the nation, while a large low pressure
system resides over the Pacific Northwest and into the Great Basin.
The pressure gradient between these two systems was tight, which
resulted in our breezy to locally windy conditions earlier today. IR
satellite imagery shows some patches of high cirrus clouds streaming
eastward across southeast Arizona. That said, the inherited sky
condition wording of `mostly clear` stills seems reasonable.

As of 03Z (8 PM MST), temperatures across the region ranged from the
lower 70s to the lower 80s, with the Tucson Intl airport reporting a
temp of 81 degs. Todays high was 89 degs, which was 4 degs below
normal for this date. These current temp readings are on track with
inherited/expected overnight low temps, but will continue to monitor
and will make adjustments if needed.

For details beyond tonight, please refer to the previous discussion
below.

&&

.AVIATION...VALID THRU 23/06Z.
Few to Scattered clouds above 20k ft agl thru 22/12z, then clearing
skies from west to east. Sly/swly surface wind diminishing aft
22/04z, with surface wind generally less than 10 kts between 22/05z
and 22/14z. Increasing surface wind aft 22/14z, with sly/swly
surface wind at 14-22 kts and gusts to between 25-30 kts aft 22/18z.
Aviation discussion not updated for TAF ammendments.

&&

.FIRE WEATHER...Dry conditions will prevail through next Friday.
Daytime minimum relative humidity this weekend will range from 10-15
percent in the lower elevations, and 20-25 percent across the
mountains. Daytime minimum relative humidity Monday through Friday
will mostly range from the upper single digits to mid teens.

Although gusty winds and low daytime relative humidities are
expected through Monday, these values are expected to stay below
critical fire weather thresholds.

An increase in wind speeds mid to late next week will result in the
possibility of exceeding critical fire weather thresholds across
eastern portions of the forecast area in the Tuesday through
Thursday time frame.

&&

.PREV DISCUSSION...The large pattern mean trough position that has
set up over the Pacific Northwest and western to central Great Basin
will keep winds above average and temperatures below average for the
next week or so.  Breezy to locally windy most days, with our
strongest winds probably on Wednesday as a stronger impulse carves
the trough a bit deeper immediately upstream.

The main threats will be borderline critical fire weather concerns
along with possible areas of localized blowing dust, however winds
are not expected to be strong enough for an advisory.  These systems
should not dig deep enough to bring precip this far south.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

DISCUSSION...Mollere
PREVIOUS DISCUSSION...Meyer/Zell

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