Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 131014
Area Forecast Discussion
National Weather Service Tucson AZ
313 AM MST Fri Jan 13 2017
.SYNOPSIS...Mild temperatures today with increasing clouds. A
few sprinkles possible later today, then a low pressure system will
bring a good chance of valley rain and mountain snow over the
weekend into early Monday along with cooler temperatures. A few
showers near the mountains early next week, then another storm
system may impact the area later next week.
.DISCUSSION...A low pressure system will continue to drop south
along the southern California coast today before turning east and
tracking through Sonora Mexico on Saturday. Ahead of the storm
system, clouds will continue to increase and thickening over
southeast Arizona today. Enough mid-level moisture was expected to
spread into the area for some light sprinkles this afternoon and
tonight, especially in the mountains. As the system approaches the
Baja Spur tonight, precipitation chances will be on the increase.
The bulk of the precipitation will be Saturday afternoon and night
as the storm system passes through Sonora Mexico. Snow levels will
start out rather high tonight and Saturday, generally above 7,500
feet, then drop to around 5,500 feet by daybreak Sunday. A winter
weather advisory has already been posted for total snow
accumulations of 6 to 12 inches above 6500 feet Saturday into Sunday
morning. Models eject the system northeast into the west Texas
Sunday evening, with some wrap around precipitation possible through
early Monday. Otherwise, improving weather conditions can be
expected through the middle of next week. Thereafter, models track
another system through the central Rockies with the tail end
bringing more precipitation to the area around Thursday and Friday
of next week.
.AVIATION...Valid through 14/12Z.
There is a slight chance of -SHRA west to northwest of KTUS today.
Otherwise, expect SCT-BKN clouds at 8-13k ft AGL and BKN-OVC clouds
above 15k ft AGL thru the forecast period. Surface wind from KTUS
westward generally less than 10 kts. Surface wind east to south of
KTUS (including the KOLS/KDUG terminals) thru 13/15Z less than 12
kts, then between 13/15Z and 14/02Z sly/sely surface wind at 12-18
kts with gusts to 25 kts. Surface wind aft 14/02Z, generally less
than 12 kts. Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...Relatively mild temperatures with increasing
cloudiness through late tonight. A low pressure system will then
move into the region this weekend, resulting in a good chance of
valley rain and mountain snow Saturday and Sunday and a slight
chance of showers lingering on Monday. Dry conditions are expected
to return areawide Tuesday and Wednesday before another storm system
brings more precipitation the second half of next week. Outside of
some elevated southerly 20-foot winds at 10-20 mph today and
Saturday, 20-foot winds are expected to be terrain driven and
generally less than 15 mph.
Winter Weather Advisory from 11 AM Saturday to 11 AM MST Sunday
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