Area Forecast Discussion
Issued by NWS Tucson, AZ

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000
FXUS65 KTWC 181139
AFDTWC

Area Forecast Discussion
National Weather Service Tucson AZ
439 AM MST Mon Feb 18 2019

.SYNOPSIS...Increasing moisture for mostly valley rain and mountain
snow today into Tuesday. This cold system should produce some snow
to valley floors east of Tucson later tonight into early Tuesday,
and snow potentially within portions of the Tucson metro area as
well. Dry conditions on Wednesday as unseasonably cool temperatures
prevail. The next system late in the week will produce more rain
and potentially significant mountain snow accumulations.

&&

.DISCUSSION...Regional radars this morning showed scattered
showers across south-central Arizona with snow across northern
Arizona. Closer to home it was mostly dry but a few of the
mountain cameras were showing snow. Water vapor imagery showed an
upper level low east of Las Vegas with associated cold front over
western Arizona. Showers this morning will be increasing west and
northwest of Tucson and gradually spread east through the
afternoon hours. Snow levels hovering between 3500 and 5000 feet
across the area into this afternoon then fall to between 2500 and
3500 feet tonight into Tuesday morning. Snow amounts above 7000
feet 6-12 inches, between 5000 and 7000 feet 3 to 6 inches. The
valleys south and east of Tucson will see up to two inches with
portions of Tucson metro seeing some light accumulation. Various
winter weather advisories are currently out east and south of
Tucson. Quite chilly across most of the area today with highs
ranging from the upper 40s to the mid 50s, warmest across
southeast Cochise county.

Tuesday, precipitation ending from Tucson west with lingering
rain/snow showers east of Tucson. Highs once again quite cool.

Tuesday night, clear skies will lead to a rather cold night across
southeast Arizona. Made some slight adjustments to previous
forecasts by going a few degrees colder. Still may not be cold
enough in the eastern valleys where lows in the upper teens are
possible. For the lower deserts from Tucson west, lows will range
from 25 to 32 degrees. Thus have hoisted Hard Freeze Watches for
south-central Pinal, central and eastern Pima counties and a
Freeze Watch for western Pima county starting late Tuesday night
through Wednesday morning. A few locals with be close to record
lows for February 20th.

Dry and cool Wednesday as the area braces for a strong winter
storm. This winter storm will impact the area Thursday into Friday
and bring a significant amount of snow to the mountains where up
to two feet are possible. There is an outside chance some high
elevations spot could see up to three feet. Confidence rather low
with this idea. Lower elevations east and south of Tucson once
again will have a shot of snow Friday night into Saturday morning.
Well below normal high temperatures continue Thursday into
Saturday. Warmer and dry on Sunday.

&&

.AVIATION...Valid through 19/12Z.
BKN clouds 5k-8k ft AGL with SHRA/mtn SHSN mainly NW of KTUS will
gradually move east across the area today. Surface winds mainly
less than 10 kts thru 15z then SW-W 12-20 kts with lcl gusts of
25-30 kts, especially at KDUG. Aviation discussion not updated
for TAF amendments.

&&

.FIRE WEATHER...The cool and wet pattern continues with a series of
weather systems this week. The first system brings rain and low
elevation snow Sunday night into Tuesday morning, with a second more
vigorous system Thursday into Saturday morning. 20-foot winds become
breezy at times, especially Thursday afternoon as southwesterly
winds reach 15-25 mph.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...
 Winter Weather Advisory until 3 AM MST Tuesday for AZZ510.

 Winter Weather Advisory until 8 PM MST this evening for AZZ511-
  513-514.

 Winter Weather Advisory from 1 AM to 8 AM MST Tuesday for
  AZZ507>509.

 Winter Weather Advisory from 8 PM this evening to 3 AM MST
  Tuesday for AZZ503.

 Hard Freeze Watch from Tuesday evening through Wednesday morning
  for AZZ502-504-505.

 Freeze Watch from Tuesday evening through Wednesday morning for
  AZZ501.

&&

$$

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