Area Forecast Discussion
Issued by NWS Tucson, AZ

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FXUS65 KTWC 151558

Area Forecast Discussion
National Weather Service Tucson AZ
850 AM MST Sun Jan 15 2017

.SYNOPSIS...Expect periods of valley rain and mountain snow through
the day, followed by decreasing precipitation chances Monday. Dry
conditions with a warming trend will prevail Tuesday and Wednesday,
then valley rain and mountain snow will return especially Thursday
night into Saturday.


.DISCUSSION...The upper low responsible for the damp weather is
currently just SE of the NM bootheel and moving quickly to the east
where it will help to produce severe thunderstorms across Texas.
Closer to home a large area of showers continues over eastern Pima,
western Cochise and Santa Cruz counties where we still have lower
level convergence and waning upper level divergence.  As the forcing
continues to shift east these showers will diminish however with a
little solar heating we should see scattered showers redevelop this
afternoon mainly from the Tucson area eastward.  As a result of all
the clouds and wet weather high temperatures today will be rather
cool and peaking 10-15 degrees cooler than average.

With the group of organized showers over the higher terrain will
leave the Winter Weather Advisory in affect through 11 am.  Looking
around at the mountain top cameras it appears that about 3 inches of
snow has fallen on average across the peaks thus far with a bit
more to go. Currently, snow flakes are falling as low as around 6,500
feet and likely sticking above 7,000 feet.

With lack of dynamics and setting sun would expect the remaining
showers to quickly diminish this evening. However can`t totally
rule out a shower or two during the night as the region will remain
under a large scale upper level trough and there is plenty of
moisture around.  same can be said of Monday with the extra added
bonus of some sunshine to stir things up a bit in the afternoon.
Convective allowing models indicating a decent chance of convection
developing over higher terrain and drifting to the SE Monday

The upper trough over the area lingers into Tuesday which may result
in a stray shower over the mountains and then moves east out of the
area Wednesday for a completely dry and warmer day.

Then Thursday onward we will have a series of trough move across the
region each bringing a threat of precipitation a least through the
first half of next weekend. Winter is still with us.


.AVIATION...Valid through 16/12Z.
Periods of -SHRA and mountain -SHSN will occur thru this afternoon,
with the best coverage from KTUS vicinity east to the New Mexico
border. This precip will result in occasional MVFR conditions and
perhaps brief IFR conditions and higher terrain will be obscured.
Surface wind thru this evening will mainly be sely to swly at 5-15
kts with gusts to 22 kts. The exception will be in the upper Gila
River valley near KSAD, where surface wind will be nwly at 11-16 kts
with some gusts to near 28 kts. Aviation discussion not updated for
TAF amendments.


.FIRE WEATHER...There will be a good chance of valley rain and
mountain snow through this afternoon, then precipitation chances
will decrease from west to east tonight into Monday. Expect dry
conditions Tuesday and Wednesday, then valley rain and mountain snow
will return especially Thursday night into next Saturday. Outside of
some gusty northwest winds in the upper Gila River valley this
afternoon and evening, 20-foot winds will be terrain driven and
generally less than 15 mph into the middle of the upcoming week.


  Winter Weather Advisory until 11 AM MST today for AZZ510>514.



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