Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 121006
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
305 AM MST Thu Jan 12 2017

.SYNOPSIS...Mild temperatures today under a mix of sun and
clouds. A few sprinkles possible Friday, then a low pressure system
will bring a chance of valley rain and mountain snow over the
weekend into early Monday along with cooler temperatures. Dry
conditions with warmer temperatures Tuesday and Wednesday. Another
storm system may impact the area later next week.

&&

.DISCUSSION...Mostly clear across SE AZ this morning with extensive
cloud cover across western and northern AZ. Will see cirrus level
clouds increase later this morning with the thick cloud cover
upstream starting to move into the western and northern areas later
this afternoon. Highs today will be similar to what on Wednesday.

Our next precipitation system is currently off the Oregon coast this
morning. By later this afternoon the upper low will be near Frisco
and then drop S to off the southern CA/northern Baja coast late
Friday afternoon. By Saturday morning the closed low will be north
of the Baja Spur and then lift E-NE across northern Sonora/far SE AZ
later Saturday night into Sunday morning. A little slower than
previous solutions and we`ve been backing off on the timing of
precipitation.

Moisture values will start to increase on Friday under S/SW flow
aloft where a few sprinkles is possible as the atmosphere moistens
up from top down. Isolated to scattered light showers west and north
of Tucson Friday night will gradually increase in areal coverage on
Saturday with best chances for scattered to numerous showers
occurring Saturday afternoon into early Sunday morning. Snow levels
lowering into the 5500 to 6500 foot area Saturday night into Sunday
morning with the lower end being near the center of the low, which
would mean across the southern sections. Forecast snow amounts above
6500 feet range from 4-11 inches depending on mountain ranges.
Valley QPF values are forecast to range from 0.10" to 0.70".

As the upper low lifts NE into the central plains late Sunday into
Monday, several upper level trofs will move across the area keeping
unsettled conditions Sunday night into Monday with a few lingering
showers far eastern areas on Tuesday.

Highs will be below normal Saturday through Wednesday. Freezing
temperatures return to the eastern areas Tuesday and Wednesday
morning.

Another storm system is possible late next week.

&&

.AVIATION...Valid through 13/12Z.
FEW-SCT clouds AOA 25k ft AGL thru 13/03Z. Aft 13/03Z, FEW-SCT
clouds at 10-14k ft AGL and BKN-OVC clouds around 20k ft AGL.
Surface wind generally less than 12 kts thru the forecast period.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...Dry conditions with mild daytime temperatures
will continue through today. A low pressure system will then move
into the region over the weekend, resulting in a chance of valley
rain and mountain snow. Dry conditions are expected to return Monday
through Wednesday of next week. Outside of some elevated south to
southeast 20-foot winds at 10-20 mph on Friday and Saturday, 20-foot
winds Sunday through Wednesday of next week are expected to be
terrain driven and generally less than 15 mph.

&&

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

&&

$$

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