Area Forecast Discussion
Issued by NWS Tucson, AZ
FXUS65 KTWC 210443
Area Forecast Discussion
National Weather Service Tucson AZ
940 PM MST Fri Jan 20 2017
.SYNOPSIS...An approaching storm system will bring widespread
valley rain and significant mountain snows across southern Arizona
into Saturday. The precipitation will taper off Saturday evening with
mostly dry conditions lasting into Monday. Another storm system will
impact the region later Monday through Wednesday with cool
temperatures and a chance of showers.
.DISCUSSION...Areas of showers continue to push east northeast
across SE AZ this evening with the snow level, based on mountain
observation sites, down around 6000 feet as of 9 PM. Its been
interesting this evening watching showers increase in intensity when
moving into the mountains thanks to orographics.
Main event still to our west this evening with cold front pushing
through Imperial and Riverside counties in SE CA as of this writing.
Wind speeds will also be on the increase in advance of the cold
front. The 00s San Diego sounding showed wind speeds up to 65 kts
between 800mb and 700 mb. Some of this wind will be transported down
to the surface with the shower activity as the cold front pushes east
across the area. Wind advisories for most of the area during the
overnight hours into Saturday morning. There is also a High Wind
Warning for western Cochise county. Winter Storm warning for the
mountains above 5000 feet still looks good. The howling winds in the
mountains combined with the falling snow will produce localized
blizzard conditions during the overnight hours. Snow levels down as
low as 4500 feet with passage of cold front.
.AVIATION...Valid through 22/04Z.
Numerous SHRA/mountain SHSN will continue overnight into Saturday
morning with ISOLD TSRA possible mainly between 21/06z and 21/12z.
Expect widespread MVFR conditions and occasional IFR conditions with
mountains mostly obscured through Saturday morning then conditions
improving from the west. Southwest surface wind increasing to 15-35
kts with gusts of 30-50 kts then becoming westerly late tonight.
Surface wind diminishing somewhat after 12Z Saturday but still gusty.
Aviation discussion not updated for TAF amendments.
.FIRE WEATHER...A strong storm system will move across the area
through Saturday morning with widespread valley rains, significant
mountain snows and strong winds. Winds and precipitation will taper
off west to east Saturday with mostly dry conditions Saturday night
into early Monday. Another series of storms will impact the area
Monday night through Wednesday with cool temps and occasional
breezes but they will not expected to be significant precipitation
producers. Dry and warmer conditions late next week into the
Winter Storm Warning until noon MST Saturday for AZZ510-515.
Wind Advisory until 8 am MST Saturday for AZZ501-502-504>506.
High Wind Warning until noon MST Saturday for AZZ507.
Wind Advisory until noon MST Saturday for AZZ503>508.
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