Area Forecast Discussion
Issued by NWS Tucson, AZ

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

000
FXUS65 KTWC 171550
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
850 AM MST Sun Sep 17 2017

.SYNOPSIS...Isolated afternoon and evening thunderstorms mainly east
to south of Tucson this week. Expect near normal high temperatures
through midweek followed by a cooling trend with breezy to windy
conditions, especially Thursday into next Saturday.

&&

.DISCUSSION...Satellite imagery revealed mostly clear skies across
the CWA this morning. Surface temperatures were comfortable,
generally in the 70`s for most valley locations. A bit of drying has
occurred, with dewpoints 1 to 7 degrees cooler than 24 hours ago.
This was also reflected on this morning`s 12Z RAOB, with PWAT down
below 1 inch.

Southwesterly flow will be the rule again today. Lingering moisture
will allow for some mountain buildups this afternoon, but any
rainfall will likely be confined to terrain east of the Tucson area.
The synoptic pattern will vary little this week, so expect much of
the same over the next several days. Near normal temperatures will
continue today through Wednesday with a slight cool down expected
next weekend. No updates needed this morning. Please see the
additional sections for more details.

&&

.AVIATION...Valid thru 18/18Z.
Generally SKC west of KTUS, with FEW-SCT clouds at 8k-12k ft AGL
east of KTUS. Slight chance of -TSRA/-SHRA east of KTUS this
afternoon and evening. SFC wind less than 10 kts increasing out of
the S/SW at 10-14 kts this afternoon. Less wind will occur overnight
into Monday morning. Aviation discussion not updated for TAF
amendments.

&&

.FIRE WEATHER...Expect isolated afternoon and evening showers and
thunderstorms mainly east to south of Tucson during the upcoming
week. 20-foot winds will generally be terrain driven at less than 15
mph into Tuesday morning, with breezy to windy conditions expected
Tuesday afternoon through Friday as an upper trough deepens over the
western United States. The strongest winds will occur on Thursday
and Friday. Temperatures will also fall below seasonal normals
Thursday and Friday.

&&

.PREV DISCUSSION...A mean trough of low pressure will remain over
the western states through the forecast period. This will maintain a
cooler flow regime with near seasonable daytime temperatures slated
through next weekend. Latest models depicted a few systems embedded
in the mean trough passing through the northern tier states this
week. The most notable one deepens across the western United States
by late next week. This system will bring even cooler temperatures
and strong winds starting around Thursday into next weekend. Despite
the drier westerly flow pattern in place, models keep enough
moisture around to support a slight chance of thunderstorms mainly
southeast and east of Tucson. Otherwise, dry conditions can be
anticipated.

&&

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

&&

$$

Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.