Area Forecast Discussion
Issued by NWS Tucson, AZ

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 29 30
FXUS65 KTWC 120915

Area Forecast Discussion
National Weather Service Tucson AZ
215 AM MST Tue Dec 12 2017

.SYNOPSIS...Considerable cloudiness will continue across southeast
Arizona into this evening due to an area of low pressure centered
over the Gulf of California. This low will remain to our south
through Wednesday with variable amounts of clouds and potentially
even a few sprinkles near the Mexico border. The low will also
result in breezy east to southeast winds today. From Thursday into
early next week, expect mostly clear skies, dry conditions and less
wind as high pressure aloft builds back overhead. Above average
temperatures will continue the next seven days.


.DISCUSSION...A Rex block pattern continues across the western
United States, with high pressure aloft centered over the Great
Basin and a closed low over the northern Gulf of California. Both of
these features slowly retrograde west-southwest into Saturday, when
the high will be over eastern Pacific Ocean and the upper low west
of Cabo. A stronger system then dives southeast out of Canada and
into the front range of Colorado by late in the upcoming weekend,
with high pressure aloft again nosing eastward into the southwestern
United States from the eastern Pacific.

Variable amounts of mid/high clouds are expected into Wednesday as
southeast Arizona remains in close proximity to the upper low. There
may even be a sprinkle or two, although more than likely just some
"virga-ish" looking clouds. Main impact of this feature will be to
continue the elevated easterly flow across the area today. Breezy
east-southeast winds are expected this morning and afternoon at 15
to 22 mph and some gusts to around 30 mph, before diminishing this
evening. As the upper low slowly tracks southwest on Wednesday, the
forecast area should see greatly reduced wind speeds and more
typical diurnal patterns.

Otherwise, expect above average temperatures the next 7 days with
afternoon highs topping out at 7-10 degrees above normal. Clear
skies will return late Wednesday and continue into early next week,
with just the possibility of some high clouds over the upcoming
weekend. No sign of winter yet.


.AVIATION...Valid thru 13/12Z.
SCT-BKN clouds above 15k ft AGL through the period. SFC winds this
morning will remain ELY/SELY at less than 12 kts before increasing
to 15-20 kts after 12/16Z. Winds will then diminish to less than 12
kts this evening. Aviation discussion not updated for TAF amendments.


.FIRE WEATHER...Dry air will remain in place over the region through
the forecast period. Sustained 20-foot winds will be east-southeast
and at 15-22 mph and some gusts to around 30 mph this morning and
afternoon before diminishing this evening. A few locations may
briefly approach critical fire weather thresholds today, but
conditions are not expected to be widespread, nor long-lived.
Otherwise, for the rest of the forecast period, expect 20-foot winds
to be less than 15 mph and follow typical diurnal trends across the





Aviation/Fire Weather...Pegram

Visit us on Facebook...Twitter...YouTube...and at is the U.S. government's official web portal to all federal, state and local government web resources and services.